Co-reporter:Sébastien Rochat;Katarzyna Polak-Kraśna;Mi Tian;Leighton T. Holyfield;Timothy J. Mays;Christopher R. Bowen
Journal of Materials Chemistry A 2017 vol. 5(Issue 35) pp:18752-18761
Publication Date(Web):2017/09/12
DOI:10.1039/C7TA05232D
We report on a series of composites based on a polymer of intrinsic microporosity matrix (PIM-1) containing a high surface area porous aromatic framework filler (PAF-1). The hydrogen uptake and mechanical properties of the composites are presented along with an assessment of their potential for integration into high-pressure hydrogen storage tanks, either to increase storage capacity or to reduce operating pressure for the same uptake. The composites are more stable and processable than systems such as finely divided physisorbent materials, and they can be made into self-standing films. In addition to retaining the processability of PIM-1, they also possess enhanced surface areas and pore volumes approximately proportional to the amount of incorporated PAF-1. Hydrogen uptake measurements combined with theoretical modelling show that the composites can store up to 6.7 wt% H2 at 77.4 K. Tensile testing and dynamic mechanical thermal analyses indicate decreasing stress and strain to failure with increasing proportion of PAF-1, although the processability and elasticity of the compounds are maintained until the weight percentage of filler reaches 30%. These lightweight composites show promise as effective hydrogen storage materials, especially for applications where pressures up to 7.5 MPa are required. We also provide guidelines for the design of polymer-based porous composites for gas storage or separation.
Co-reporter:K. Polak-Kraśna, C. Fuhrhop, S. Rochat, A.D. Burrows, ... T.J. Mays
International Journal of Hydrogen Energy 2017 Volume 42, Issue 37(Volume 42, Issue 37) pp:
Publication Date(Web):14 September 2017
DOI:10.1016/j.ijhydene.2017.04.081
•PIM-1 film was mechanically tested for hydrogen storage tank liner application.•Young's modulus was measured using AFM nanoindentation technique.•Results are consistent with values obtained with tensile testing and DMTA.•Elastic properties are decreasing with indentation depth.Polymers of intrinsic microporosity (PIMs) have promising gas adsorption properties for potential applications such as incorporation into high-pressure hydrogen storage tanks in an effort to increase the storage capacity or decrease the operating pressure. Such applications require detailed mechanical characterisation and determination of the structure-properties relationships to enable optimisation of the interface between the polymer and the tank. In this study, we show that Atomic Force Microscopy (AFM) nanoindentation can be used to determine the elastic modulus of cast PIM-1 films and that this property is depth-dependent. Average values of elastic modulus obtained experimentally were 1.87 GPa and are compared with elastic tensile modulus and storage tensile modulus obtained in previous studies. In addition, Scanning Electron Microscopy (SEM) and AFM imaging was performed to investigate the surface structure of the cast PIM-1 film, which has been shown to be highly granular.
Co-reporter:Andrew D. Burrows;Siobhan Chan;William J. Gee;Mary F. Mahon;Christopher Richardson;Viorica M. Sebestyen;Domenyk Turski;Mark R. Warren
CrystEngComm (1999-Present) 2017 vol. 19(Issue 37) pp:5549-5557
Publication Date(Web):2017/09/28
DOI:10.1039/C7CE01447C
Combining Zn(NO3)2·6H2O with a series of dicarboxylic acids in the presence of the N,N′-ditopic ligand di(4-pyridyl)-1H-pyrazole (Hdpp) results in a series of mixed-linker metal–organic frameworks (MOFs) that have been crystallographically characterised. The reaction with 1,4-benzenedicarboxylic acid (H2bdc) gives [Zn2(bdc)2(Hdpp)2]·2DMF 1, which shows Zn2(μ-carboxylate)2(carboxylate)2 secondary building units (SBUs) linked by bdc ligands into sheets, and these are pillared by the Hdpp linkers into a doubly-interpenetrated three-dimensional network. The reaction with 1,4-naphthalene dicarboxylic acid (H2ndc-1,4) gives two products: [Zn2(1,4-ndc)2(Hdpp)]·4DMF 2a forms a three-dimensional network in which sheets, formed from Zn2(carboxylate)4 ‘paddle-wheel’ SBUs being linked by 1,4-ndc, are connected together by Hdpp pillars, whereas [Zn(1,4-ndc)(Hdpp)]·DMF 2b forms a fourfold interpenetrated structure based on diamondoid networks with single zinc centres as nodes. The reaction with 1,3-benzenedicarboxylic acid (H2mbdc) produces [Zn(mbdc)(Hdpp)]·DMF 3, which forms a two-dimensional network with (4,4) topology in which ZnO2N2 nodes are interlinked by mbdc and Hdpp linkers. The reaction with 5-methyl-1,3-benzenedicarboxylic acid (H2mbdc-Me) also forms a two-dimensional network structure, [Zn2(mbdc-Me)2(Hdpp)2]·DMF 4, albeit wherein dicarboxylates bridge between zinc-dicarboxylate tapes, themselves formed by interlinking of Zn2(μ-carboxylate)2(carboxylate)2 SBUs similar to those in 1. Finally, the reaction with 2,6-naphthalene dicarboxylic acid (H2ndc-2,6) yields two crystalline species, both having the formula [Zn2(2,6-ndc)2(Hdpp)]·DMF 5a/5b and possessing infinite zinc-carboxylate chain motifs interlinked by both naphthalene rings and Hdpp linkers into a three-dimensional framework. In compounds 1, 2b, 3 and 4, the pyrazole NH groups are involved in hydrogen bonding that serves to link either interpenetrated networks or neighbouring sheets together. However, in 2a and 5a/5b the NH groups project into the pores of the framework enabling interactions with guest molecules.
Co-reporter:Andrew D. Burrows;Siobhan Chan;William J. Gee;Mary F. Mahon;Christopher Richardson;Viorica M. Sebestyen;Domenyk Turski;Mark R. Warren
CrystEngComm (1999-Present) 2017 vol. 19(Issue 37) pp:5549-5557
Publication Date(Web):2017/09/28
DOI:10.1039/C7CE01447C
Combining Zn(NO3)2·6H2O with a series of dicarboxylic acids in the presence of the N,N′-ditopic ligand di(4-pyridyl)-1H-pyrazole (Hdpp) results in a series of mixed-linker metal–organic frameworks (MOFs) that have been crystallographically characterised. The reaction with 1,4-benzenedicarboxylic acid (H2bdc) gives [Zn2(bdc)2(Hdpp)2]·2DMF 1, which shows Zn2(μ-carboxylate)2(carboxylate)2 secondary building units (SBUs) linked by bdc ligands into sheets, and these are pillared by the Hdpp linkers into a doubly-interpenetrated three-dimensional network. The reaction with 1,4-naphthalene dicarboxylic acid (H2ndc-1,4) gives two products: [Zn2(1,4-ndc)2(Hdpp)]·4DMF 2a forms a three-dimensional network in which sheets, formed from Zn2(carboxylate)4 ‘paddle-wheel’ SBUs being linked by 1,4-ndc, are connected together by Hdpp pillars, whereas [Zn(1,4-ndc)(Hdpp)]·DMF 2b forms a fourfold interpenetrated structure based on diamondoid networks with single zinc centres as nodes. The reaction with 1,3-benzenedicarboxylic acid (H2mbdc) produces [Zn(mbdc)(Hdpp)]·DMF 3, which forms a two-dimensional network with (4,4) topology in which ZnO2N2 nodes are interlinked by mbdc and Hdpp linkers. The reaction with 5-methyl-1,3-benzenedicarboxylic acid (H2mbdc-Me) also forms a two-dimensional network structure, [Zn2(mbdc-Me)2(Hdpp)2]·DMF 4, albeit wherein dicarboxylates bridge between zinc-dicarboxylate tapes, themselves formed by interlinking of Zn2(μ-carboxylate)2(carboxylate)2 SBUs similar to those in 1. Finally, the reaction with 2,6-naphthalene dicarboxylic acid (H2ndc-2,6) yields two crystalline species, both having the formula [Zn2(2,6-ndc)2(Hdpp)]·DMF 5a/5b and possessing infinite zinc-carboxylate chain motifs interlinked by both naphthalene rings and Hdpp linkers into a three-dimensional framework. In compounds 1, 2b, 3 and 4, the pyrazole NH groups are involved in hydrogen bonding that serves to link either interpenetrated networks or neighbouring sheets together. However, in 2a and 5a/5b the NH groups project into the pores of the framework enabling interactions with guest molecules.
Co-reporter:William J. Gee, Laura K. Cadman, Harina Amer Hamzah, Mary F. Mahon, Paul R. Raithby, and Andrew D. Burrows
Inorganic Chemistry 2016 Volume 55(Issue 21) pp:10839
Publication Date(Web):October 17, 2016
DOI:10.1021/acs.inorgchem.6b01917
Postsynthetic modification (PSM) of amino-functionalized metal–organic frameworks (MOFs) to those bearing pendant β-amidoketone arms using diketene is herein reported. Three unique MOF families demonstrate the scope of this transformation, which both is atom-economical and yields high conversions. In each case, the crystallinity was retained, and instances of exceptional solid-state ordering were observed in the PSM products, which has allowed detailed crystallographic characterization in multiple instances.
Co-reporter:Luke L. Keenan, Harina Amer Hamzah, Mary F. Mahon, Mark R. Warren and Andrew D. Burrows
CrystEngComm 2016 vol. 18(Issue 30) pp:5710-5717
Publication Date(Web):28 Jun 2016
DOI:10.1039/C6CE01270A
[Zn4O(bdc-NH2)3], IRMOF-3 (bdc-NH2 = 2-amino-1,4-benzenedicarboxylate), and [Cr3O(H2O)2F(bdc-NH2)3], MIL-101(Cr)-NH2, undergo tandem post-synthetic modification reactions with aldehydes and NaCNBH3 to form secondary amine-functionalised metal–organic frameworks (MOFs). The degree of conversion ranges from 17–74% for IRMOF-3 (2a–i) and from 35–51% for MIL-101(Cr)-NH2 (4a–d), and alkene, sulfide, ferrocenyl and pyridyl substituents can be successfully introduced into the zinc MOFs. For both the zinc and chromium MOFs, an increase in the steric bulk of the aldehyde leads to a reduction in the degree of conversion. Low conversion with bulky aldehydes can be exploited to generate products containing two different secondary amine substituents, such as [Zn4O(bdc-NH2)1.93(bdc-NHCH2CH2CH2SMe)0.47(bdc-NHEt)0.59] 2k in which sequential tandem modifications have taken place. N2 adsorption experiments reveal that the post-synthetically modified MOFs display lower than anticipated BET surface areas together with hysteresis. This is consistent with some degradation of crystallinity occuring on treatment with NaCNBH3, as verified by control experiments, which leads to the formation of mesopores. Reactions of H2bdc-NH2 with aldehydes and NaCNBH3 afforded a series of secondary amine functionalised dicarboxylic acids H2L1–8 after acid work up. These acids were reacted with Zn(NO3)2·6H2O to form the secondary amine-functionalised MOFs 5a–h through direct synthesis. 1H NMR analysis of 5a–g showed the presence of some bdc-NH2 linkers in addition to the secondary amine-containing linkers, and indeed the presence of H2bdc-NH2 was required for the reaction with H2bdc-NHCH2Fc (Fc = ferrocenyl) to form a crystalline MOF. In the case of the zinc MOFs, N2 adsorption experiments generally showed greater BET surface areas for the products of the direct synthesis reactions than for those from post-synthetic modifications suggesting that, in this case, the former is the best approach to these functionalised MOFs. In contrast, post-synthetic modification is the optimal approach to form crystalline derivatives of MIL-101(Cr)-NH2 as direct synthesis gave amorphous products.
Co-reporter:Laura K. Cadman, Jessica K. Bristow, Naomi E. Stubbs, Davide Tiana, Mary F. Mahon, Aron Walsh and Andrew D. Burrows
Dalton Transactions 2016 vol. 45(Issue 10) pp:4316-4326
Publication Date(Web):14 Dec 2015
DOI:10.1039/C5DT04045K
A new approach is reported for tailoring the pore geometry in five series of multivariate metal–organic frameworks (MOFs) based on the structure [Zn2(bdc)2(dabco)] (bdc = 1,4-benzenedicarboxylate, dabco = 1,8-diazabicyclooctane), DMOF-1. A doping procedure has been adopted to form series of MOFs containing varying linker ratios. The series under investigation are [Zn2(bdc)2–x(bdc-Br)x(dabco)]·nDMF 1 (bdc-Br = 2-bromo-1,4-benzenedicarboxylate), [Zn2(bdc)2–x(bdc-I)x(dabco)]·nDMF 2 (bdc-I = 2-iodo-1,4-benzenedicarboxylate), [Zn2(bdc)2–x(bdc-NO2)x(dabco)]·nDMF 3 (bdc-NO2 = 2-nitro-1,4-benzenedicarboxylate), [Zn2(bdc)2–x(bdc-NH2)x(dabco)]·nDMF 4 (bdc-NH2 = 2-amino-1,4-benzenedicarboxylate) and [Zn2(bdc-Br)2–x(bdc-I)x(dabco)]·nDMF 5. Series 1–3 demonstrate a functionality-dependent pore geometry transition from the square, open pores of DMOF-1 to rhomboidal, narrow pores with increasing proportion of the 2-substituted bdc linker, with the rhomboidal-pore MOFs also showing a temperature-dependent phase change. In contrast, all members of series 4 and 5 have uniform pore geometries. In series 4 this is a square pore topology, whilst series 5 exhibits the rhomboidal pore form. Computational analyses reveal that the pore size and shape in systems 1 and 2 is altered through non-covalent interactions between the organic linkers within the framework, and that this can be controlled by the ligand functionality and ratio. This approach affords the potential to tailor pore geometry and shape within MOFs through judicious choice of ligand ratios.
Co-reporter:Jane V. Knichal;Dr. Helena J. Shepherd; Chick C. Wilson; Paul R. Raithby;Dr. William J. Gee; Andrew D. Burrows
Angewandte Chemie International Edition 2016 Volume 55( Issue 20) pp:5943-5946
Publication Date(Web):
DOI:10.1002/anie.201601525
Abstract
A vapor-induced cyclization has been observed in the host environment of a crystalline molecular flask (CMF), within which 1,8-bis(2-phenylethynyl)naphthalene (bpen), a diarenynyl system primed for cyclization, was exposed to iodine vapor to yield the corresponding indeno[2,1-α]phenalene species. The cyclization process, unique in its vapor-induced, solvent-free nature, was followed spectroscopically, and found to occur concurrently with the displacement of lattice solvent for molecular iodine in CMF⋅0.75 bpen⋅2.25 CHCl3⋅H2O. The cyclization occurred under mild conditions and without the need to suspend the crystals in solvent. The ability of CMFs to host purely gas-induced reactions is further highlighted by the subsequent sequential oxidation reaction of cyclized 7-iodo-12-phenylindeno[2,1-α]phenalene (ipp) with molecular oxygen derived from air, yielding 12-hydroxy-7-iodo-2-phenylindeno[2,1-α]phenalen-1(12H)-one (hipp).
Co-reporter:Jane V. Knichal;Dr. Helena J. Shepherd; Chick C. Wilson; Paul R. Raithby;Dr. William J. Gee; Andrew D. Burrows
Angewandte Chemie International Edition 2016 Volume 55( Issue 20) pp:
Publication Date(Web):
DOI:10.1002/anie.201603084
Co-reporter:Jane V. Knichal;Dr. Helena J. Shepherd; Chick C. Wilson; Paul R. Raithby;Dr. William J. Gee; Andrew D. Burrows
Angewandte Chemie 2016 Volume 128( Issue 20) pp:6047-6050
Publication Date(Web):
DOI:10.1002/ange.201601525
Abstract
A vapor-induced cyclization has been observed in the host environment of a crystalline molecular flask (CMF), within which 1,8-bis(2-phenylethynyl)naphthalene (bpen), a diarenynyl system primed for cyclization, was exposed to iodine vapor to yield the corresponding indeno[2,1-α]phenalene species. The cyclization process, unique in its vapor-induced, solvent-free nature, was followed spectroscopically, and found to occur concurrently with the displacement of lattice solvent for molecular iodine in CMF⋅0.75 bpen⋅2.25 CHCl3⋅H2O. The cyclization occurred under mild conditions and without the need to suspend the crystals in solvent. The ability of CMFs to host purely gas-induced reactions is further highlighted by the subsequent sequential oxidation reaction of cyclized 7-iodo-12-phenylindeno[2,1-α]phenalene (ipp) with molecular oxygen derived from air, yielding 12-hydroxy-7-iodo-2-phenylindeno[2,1-α]phenalen-1(12H)-one (hipp).
Co-reporter:Jane V. Knichal;Dr. Helena J. Shepherd; Chick C. Wilson; Paul R. Raithby;Dr. William J. Gee; Andrew D. Burrows
Angewandte Chemie 2016 Volume 128( Issue 20) pp:
Publication Date(Web):
DOI:10.1002/ange.201603084
Co-reporter:Dominic J. Wales, Julien Grand, Valeska P. Ting, Richard D. Burke, Karen J. Edler, Chris R. Bowen, Svetlana Mintova and Andrew D. Burrows
Chemical Society Reviews 2015 vol. 44(Issue 13) pp:4290-4321
Publication Date(Web):18 May 2015
DOI:10.1039/C5CS00040H
Improvements in the efficiency of combustion within a vehicle can lead to reductions in the emission of harmful pollutants and increased fuel efficiency. Gas sensors have a role to play in this process, since they can provide real time feedback to vehicular fuel and emissions management systems as well as reducing the discrepancy between emissions observed in factory tests and ‘real world’ scenarios. In this review we survey the current state-of-the-art in using porous materials for sensing the gases relevant to automotive emissions. Two broad classes of porous material – zeolites and metal–organic frameworks (MOFs) – are introduced, and their potential for gas sensing is discussed. The adsorptive, spectroscopic and electronic techniques for sensing gases using porous materials are summarised. Examples of the use of zeolites and MOFs in the sensing of water vapour, oxygen, NOx, carbon monoxide and carbon dioxide, hydrocarbons and volatile organic compounds, ammonia, hydrogen sulfide, sulfur dioxide and hydrogen are then detailed. Both types of porous material (zeolites and MOFs) reveal great promise for the fabrication of sensors for exhaust gases and vapours due to high selectivity and sensitivity. The size and shape selectivity of the zeolite and MOF materials are controlled by variation of pore dimensions, chemical composition (hydrophilicity/hydrophobicity), crystal size and orientation, thus enabling detection and differentiation between different gases and vapours.
Co-reporter:Jane V. Knichal, William J. Gee, Andrew D. Burrows, Paul R. Raithby, and Chick C. Wilson
Crystal Growth & Design 2015 Volume 15(Issue 1) pp:465-474
Publication Date(Web):December 2, 2014
DOI:10.1021/cg501535b
The influence of weak hydrogen bonds on the crystal packing of a series of heavy and transition metal coordination polymers synthesized using the ligand 5-ethynyl-1,3-benzenedicarboxylic acid (H2ebdc) has been evaluated. Five coordination polymers were prepared and crystallographically characterized. These comprise two 1D chains, [Pb(ebdc)(DMSO)2] (1) and [Pb(ebdc)(DMF)] (2), two 2D nets, [Cu3(ebdc)(H2O)1.5(MeOH)0.5]·6H2O (3) and [Pb2(ebdc)2(DMF)4]·H2O (4), and a single 3D framework, [HNEt3][Zn3(μ3-OH)(μ2-H2O)(ebdc)3(MeOH)0.67(H2O)0.33]·MeOH·1.33H2O (5). The crystal structure of the free acid ligand form, H2ebdc·H2O, is also reported. Within the lead(II) coordination structures, ethynyl-derived C–H···O interactions are consistently found to provide the dominant influence over the crystal packing, as determined by solid-state structural analysis in combination with vibrational spectroscopy. The influence of weak hydrogen-bonding effects on the crystal packing of the transition metal coordination polymers that contain lattice water and methanol molecules was found to be far less prominent, which is interpreted in terms of the greater prevalence of strong hydrogen-bond donors and acceptors forming O–H···O interactions within these crystalline lattices.
Co-reporter:Macguire R. Bryant, Andrew D. Burrows, Christopher M. Fitchett, Chris S. Hawes, Sally O. Hunter, Luke L. Keenan, David J. Kelly, Paul E. Kruger, Mary F. Mahon and Christopher Richardson
Dalton Transactions 2015 vol. 44(Issue 19) pp:9269-9280
Publication Date(Web):17 Apr 2015
DOI:10.1039/C5DT00011D
The synthesis, structural and thermal characterisation of a number of coordination complexes featuring the N,O-heteroditopic ligand 4-(3,5-dimethyl-1H-pyrazol-4-yl)benzoate, HL are reported. The reaction of H2L with cobalt(II) and nickel(II) nitrates at room temperature in basic DMF/H2O solution gave discrete mononuclear coordination complexes with the general formula {[M(HL)2(H2O)4]·2DMF} (M = Co (1), Ni (2)), whereas the reaction with zinc(II) nitrate gave [Zn(HL)2]∞, 3, a coordination polymer with distorted diamondoid topology and fourfold interpenetration. Coordination about the tetrahedral Zn(II) nodes in 3 are furnished by two pyrazolyl nitrogen atoms and two carboxylate oxygen atoms to give a mixed N2O2 donor set. Isotopological coordination polymers of zinc(II), {[Zn(HL)2]·2CH3OH·H2O}∞, 4, and cobalt(II), [Co(HL)2]∞, 5, are formed when the reactions are carried out under solvothermal conditions in methanol (80 °C) and water (180 °C), respectively. The reaction of H2L with cadmium(II) nitrate at room temperature in methanol gives {[Cd(HL)2(MeOH)2]·1.8MeOH}∞6, a 2-D (4,4)-connected coordination polymer, whereas with copper(II) the formation of green crystals that transform into purple crystals is observed. The metastable green phase [Cu3(HL)4(μ2-SO4)(H2O)3]∞, 7, crystallises with conserved binding domains of the heteroditopic ligand and contains two different metal nodes: a dicopper carboxylate paddle wheel motif, and, a dicopper unit bridged by sulfate ions and coordinated by ligand pyrazolyl nitrogen atoms. The resultant purple phase {[Cu(HL)2]·4CH3OH·H2O}∞, 8, however, has single copper ion nodes coordinated by mixed N2O2 donor sets with trans-square planar geometry and is threefold interpenetrated. The desolvation of 8 was followed by powder X-ray diffraction and single crystal X-ray diffraction which show desolvation induces the transition to a more closely packed structure while the coordination geometry about the copper ions and the network topology is retained. Powder X-ray diffraction and microanalysis were used to characterise the bulk purity of the coordination materials 1–6 and 8. The thermal characteristics of 1–2, 4–6 and 8 were studied by TG-DTA. This led to the curious observation of small exothermic events in networks 4, 6, and 8 that appear to be linked to their decomposition. In addition, the solid state structures of H2L and that of its protonated salt, H2L·HNO3, were also determined and revealed that H2L forms a 2-D hydrogen bonded polymer incorporating helical chains formed through N–H⋯O and O–H⋯N interactions, and that [H3L]NO3 forms a 1-D hydrogen-bonded polymer.
Co-reporter:Andrew D. Burrows, Monika Jurcic, Mary F. Mahon, Sandrine Pierrat, Gavin W. Roffe, Henry J. Windle and John Spencer
Dalton Transactions 2015 vol. 44(Issue 31) pp:13814-13817
Publication Date(Web):14 Jul 2015
DOI:10.1039/C5DT02458G
A series of bismuth–dicarboxylate–deferiprone coordination networks have been prepared and structurally characterised. The new compounds have been demonstrated to release the iron overload drug deferiprone on treatment with PBS and have also been shown to have antibacterial activity against H. pylori.
Co-reporter:Emmanuel N. Nfor, Andrew D. Burrows, Luke L. Keenan
Inorganic Chemistry Communications 2014 Volume 46() pp:180-183
Publication Date(Web):August 2014
DOI:10.1016/j.inoche.2014.05.014
•A new flumequine-containing zinc coordination polymer is reported.•Flumequine coordinates in a bridging bidentate mode to give zinc dimers.•The dimers are interlinked by dicarboxylates to form a coordination polymer.•The new compound displays strong photoluminescence.The compound [Zn2(flmq)2(bdc)(H2O)2], 1, based on flumequine (Hflmq) and 1,4-benzenedicarboxylate (bdc), has been synthesised and shown by single crystal X-ray analysis to contain one-dimensional chains linked into sheets by hydrogen bonding. Photoluminescent measurements on the complex in the solid state show that it displays strong photoluminescence at 467 nm.[Zn2(flmq)2(bdc)(H2O)2], based on flumequine (Hflmq) and 1,4-benzenedicarboxylate (bdc), has been synthesised and shown to contain one-dimensional chains linked into sheets by hydrogen bonding. The compound displays strong photoluminescence at 467 nm.
Co-reporter:Dongmei Jiang, Andrew D. Burrows, Yuli Xiong and Karen J. Edler
Journal of Materials Chemistry A 2013 vol. 1(Issue 18) pp:5497-5500
Publication Date(Web):05 Apr 2013
DOI:10.1039/C3TA10766C
A facile polyethylenimine (PEI)-assisted dip-coating method allows crack-free films of MIL-101(Cr) and MIL-101(Cr)-NH2 to be prepared on alumina supports. The presence of PEI enhances the selectivity of the films for CO2 with respect to N2. The film surfaces can be made hydrophobic by further dip-coating with an aliphatic monocarboxylic acid.
Co-reporter:Ayi A. Ayi, Andrew D. Burrows, Mary F. Mahon and Viorica M. Sebestyen
CrystEngComm 2013 vol. 15(Issue 45) pp:9301-9303
Publication Date(Web):24 Apr 2013
DOI:10.1039/C3CE40484F
A new molybdenum diphosphonate network structure has been prepared and structurally characterised. It shows reversible dehydration, which occurs with a structural change. The dehydrated material is able to adsorb methanol but not ethanol.
Co-reporter:Dongmei Jiang, Luke L. Keenan, Andrew D. Burrows and Karen J. Edler
Chemical Communications 2012 vol. 48(Issue 99) pp:12053-12055
Publication Date(Web):18 Oct 2012
DOI:10.1039/C2CC36344E
The functionalised metal–organic framework MIL-101(Cr)-NH2, containing 2-aminobenzene-1,4-dicarboxylate as the linker, has been synthesised. A new tandem post-synthetic modification strategy involving diazotisation as the first step has been developed and used to introduce halo- and azo dye-functional groups into the pores.
Co-reporter:Sean P. Bew, Andrew D. Burrows, Tina Düren, Mary F. Mahon, Peyman Z. Moghadam, Viorica M. Sebestyen and Sean Thurston
Chemical Communications 2012 vol. 48(Issue 40) pp:4824-4826
Publication Date(Web):22 Mar 2012
DOI:10.1039/C2CC30988B
An upper rim-functionalised calix[4]arene dicarboxylic acid (H2caldc) has been used to prepare four metal–organic frameworks, three of which have been structurally characterised and shown to form two- or three-dimensional network structures. Simulations suggest that such networks are likely to display interesting selectivity to guest molecules.
Co-reporter:Dongmei Jiang, Andrew D. Burrows, Robben Jaber and Karen J. Edler
Chemical Communications 2012 vol. 48(Issue 41) pp:4965-4967
Publication Date(Web):17 Apr 2012
DOI:10.1039/C2CC31079A
A facile in situ nanoparticle seeding method is reported to prepare MIL-101(Cr) films on alumina supports. The in situ seeding of MIL-101(Cr) nanoparticles was promoted by use of dimethylacetamide (DMA). The generality of this approach is further demonstrated for Cu3(btc)2 films by using a (poly)acrylate promoter.
Co-reporter:Andrew D. Burrows, Mary F. Mahon, Viorica M. Sebestyen, Yanhua Lan, and Annie K. Powell
Inorganic Chemistry 2012 Volume 51(Issue 20) pp:10983-10989
Publication Date(Web):September 17, 2012
DOI:10.1021/ic301478x
The reaction between CuSO4·5H2O and [NMe2H2]Cl in N,N′-dimethylformamide (DMF) at 95 °C yielded green crystals of (NMe2H2)4[Cu6O2(SO4)6(DMF)4] 1. The discrete [Cu6(μ4-O)2(μ3-SO4)4(μ2-SO4)2(DMF)4]4– anions present in 1 contain two edge-sharing Cu4(μ4-O) tetrahedra, with the copper(II) centers bridged by sulfato ligands. These anions are linked into a two-dimensional network through hydrogen bonds involving the dimethylammonium cations. When the reaction was carried out in the absence of [NMe2H2]Cl, yellow-green crystals of (NMe2H2)4[Cu6O2(SO4)6(DMF)2] 2 were obtained. The anions in 2 contain similar Cu6O2(SO4)6 aggregates to those in 1, though these differ in terms of the copper(II) coordination geometries. In addition, the anions in 2 are linked into chains through bridging sulfato ligands. The Cu6O2(SO4)6 aggregates observed in 1 and 2 are related to those present in the rare copper sulfate mineral fedotovite, K2Cu3O(SO4)3, and in common with this mineral both 1 and 2 decompose in the presence of moisture. The reaction between CuSO4·5H2O and [NMe2H2]Cl in DMF at room temperature gave (NMe2H2)[Cu2(OH)(SO4)2(H2O)2] 3, the structure of which contains triangular Cu3(OH)(SO4) units that share vertices to form tapes. Magnetic measurements revealed that 1 and 3 are both spin-canting metamagnetic systems. Field-induced responses were observed below 5 K, with the critical field indicating metamagnetic behavior from antiferromagnetic to ferromagnetic equal to 110 Oe for both compounds.
Co-reporter:Jonathan E. Halls, Alberto Hernán-Gómez, Andrew D. Burrows and Frank Marken
Dalton Transactions 2012 vol. 41(Issue 5) pp:1475-1480
Publication Date(Web):26 Jul 2011
DOI:10.1039/C1DT10734H
Metal–organic framework (MOF) materials based on zinc(II) and aluminium(III) dicarboxylate frameworks with covalently attached ferrocene functional redox groups were synthesised by post-synthetic modification and investigated by voltammetry in aqueous and non-aqueous media. In the voltammetry experiments, ferrocene oxidation occurs in all cases, but chemically reversible and stable ferrocene oxidation without decay of the voltammetric response requires a “mild” dichloroethane solvent environment. The voltammetric response in this case is identified as “surface-confined” with fast surface-hopping of electrons and without affecting the bulk of MOF microcrystals. In aqueous media a more complex pH-dependent multi-stage redox process is observed associated with chemically irreversible bulk oxidation and disintegration of the MOF framework. A characteristic 30 mV per pH unit dependence of redox potentials is observed attributed to a “framework effect”: the hydroxide-driven MOF framework dissolution.
Co-reporter:Andrew D. Burrows and Luke L. Keenan
CrystEngComm 2012 vol. 14(Issue 12) pp:4112-4114
Publication Date(Web):09 Mar 2012
DOI:10.1039/C2CE25131K
The amine-functionalised metal–organic framework (MOF) [Zn4O(bdc-NH2)3] (IRMOF-3, bdc-NH2 = 2-amino-1,4-benzenedicarboxylate) has been post-synthetically modified in a tandem condensation-reduction process into secondary amine-containing MOFs. The degree of modification is enhanced by introduction of methanol, which helps to remove boron-containing side-products from the pores.
Co-reporter:Andrew D. Burrows, Mary F. Mahon, Catherine L. Renouf, Christopher Richardson, Anna J. Warren and John E. Warren
Dalton Transactions 2012 vol. 41(Issue 14) pp:4153-4163
Publication Date(Web):26 Jan 2012
DOI:10.1039/C2DT12115H
The iron(III) and aluminium(III) complexes of 1,3-di(4-pyridyl)propane-1,3-dionato (dppd) and 1,3-di(3-pyridyl)propane-1,3-dionato (dmppd), [Fe(dppd)3] 1, [Fe(dmppd)3] 2, [Al(dppd)3] 3 and [Al(dmppd)3] 4 have been prepared. These complexes adopt molecular structures in which the metal centres contain distorted octahedral geometries. In contrast, the copper(II) and zinc(II) complexes [Cu(dppd)2] 5 and [Zn(dmppd)2] 6 both form polymeric structures in which coordination of the pyridyl groups into the axial positions of neighbouring metal centres links discrete square-planar complexes into two-dimensional networks. The europium complex [Eu(dmppd)2(H2O)4]Cl·2EtOH·0.5H2O 7 forms a structure containing discrete cations that are linked into sheets through hydrogen bonds, whereas the lanthanum complex [La(dmppd)3(H2O)]·2H2O 8 adopts a one-dimensional network structure, connected into sheets by hydrogen bonds. The iron complexes 1 and 2 act as metalloligands in reactions with silver(I) salts, with the nature of the product depending on the counter-ions present. Thus, the reaction between 1 and AgBF4 gave [AgFe(dppd)3]BF4·DMSO 9, in which the silver centres link the metalloligands into discrete nanotubes, whereas reactions with AgPF6 and AgSbF6 gave [AgFe(dppd)3]PF6·3.28DMSO 10 and [AgFe(dppd)3]SbF6·1.25DMSO 11, in which the metalloligands are linked into sheets. In all three cases, only four of the six pyridyl groups present on the metalloligands are coordinated. The reaction between 2 and AgNO3 gave [Ag2Fe(dmppd)3(ONO2)]NO3·MeCN·CH2Cl212. Compound 12 adopts a layer structure in which all pyridyl groups are coordinated to silver centres and, in addition, a nitrate ion bridges between two silver centres. A similar structure is adopted by [Ag2Fe(dmppd)3(O2CCF3)]CF3CO2·2MeCN·0.25CH2Cl213, with a bridging trifluoroacetate ion playing the same role as the nitrate ion in 12.
Co-reporter:Andrew D. Burrows, Laura C. Fisher, Christopher Richardson and Sean P. Rigby
Chemical Communications 2011 vol. 47(Issue 12) pp:3380-3382
Publication Date(Web):15 Feb 2011
DOI:10.1039/C1CC10143A
Zinc(II) nitrate reacts with different ratios of 1,4-benzenedicarboxylic acid (H2bdc) and 2-halo-1,4-benzenedicarboxylic acid (H2bdc-X, X = Br or I) to give [Zn4O(bdc)3−x(bdc-X)x], in which preferential incorporation of bdc is observed. The selective incorporation is related to crystal growth rates, and the proportion of incorporated bdc-X rises with increasing reaction time.
Co-reporter:Andrew D. Burrows
CrystEngComm 2011 vol. 13(Issue 11) pp:3623-3642
Publication Date(Web):
DOI:10.1039/C0CE00568A
Co-reporter:Dongmei Jiang, Andrew D. Burrows and Karen J. Edler
CrystEngComm 2011 vol. 13(Issue 23) pp:6916-6919
Publication Date(Web):19 Oct 2011
DOI:10.1039/C1CE06274C
Nanoparticles of MIL-101(Cr) have been fabricated using a hydrothermal method for the first time. The particle size can be controlled from 19 (4) nm to 84 (12) nm, by using a monocarboxylic acid as a mediator. These nano MIL-101(Cr) materials exhibit higher selectivities for CO2 over N2 than bulk MIL-101(Cr).
Co-reporter:Andrew D. Burrows, Christopher G. Frost, Mathivathani Kandiah, Luke L. Keenan, Mary F. Mahon, Teresa L. Savarese, John E. Warren
Inorganica Chimica Acta 2011 Volume 366(Issue 1) pp:303-309
Publication Date(Web):30 January 2011
DOI:10.1016/j.ica.2010.11.025
Co-reporter:Ayi A. Ayi;Mary F. Mahon
Journal of Chemical Crystallography 2011 Volume 41( Issue 8) pp:1165-1168
Publication Date(Web):2011 August
DOI:10.1007/s10870-011-0064-0
Crystals of sodium trihydrogen-1,4-benzenediphosphonate, Na[H3bdp], were prepared from the addition of aqueous sodium hydroxide to an acidified solution of 1,4-benzenediphosphonic acid (H4bdp). These were shown by X-ray crystallography to crystallize in the space group P\( \bar{1} \), with cell parameters a = 5.7500(3) Å, b = 7.9180(5) Å, c = 10.4420(6) Å, α = 80.398(3)°, β = 76.844(4)° and γ = 81.389(4)°. The crystal structure revealed that the title compound forms a coordination network in which sodium-phosphonate sheets are pillared by the benzene rings into a three-dimensional structure.
Co-reporter:Andrew D. Burrows, Christopher G. Frost, Mary F. Mahon, Paul R. Raithby, Catherine L. Renouf, Christopher Richardson and Anna J. Stevenson
Chemical Communications 2010 vol. 46(Issue 28) pp:5067-5069
Publication Date(Web):08 Jun 2010
DOI:10.1039/C0CC00646G
The Group 13 metal complexes [M(L2)3], where M is Al or Ga and L2 is 1,3-di(4-pyridyl)-1,3-propanedionato, are hexatopic metalloligands that have been used to prepare mixed-metal–organic frameworks containing interpenetrated primitive cubic networks. In contrast, the europium complex [Eu(HL2)3(H2L2)]Cl4·EtOH forms a hydrogen-bonded network following partial protonation of the pyridyl groups.
Co-reporter:Andrew D. Burrows, Christopher G. Frost, Mary F. Mahon, Paul R. Raithby, Christopher Richardson and Anna J. Stevenson
Chemical Communications 2010 vol. 46(Issue 28) pp:5064-5066
Publication Date(Web):08 Jun 2010
DOI:10.1039/C0CC00826E
The reaction of silver(I) perchlorate with the semi-rigid ligand 1,4-bis((3,5-dimethylisoxazol-4-yl)methyl)benzene (bisox) in methanol gives a triply-interpenetrated sheet structure, but a structure containing both interpenetrated sheets and Ag2(bisox)3 cages is formed on recrystallisation from acetonitrile–diethyl ether. Rearrangement of the cages into sheets occurs on heating under vacuum, a process which involves a solid state change in conformation of the bisox ligands.
Co-reporter:Andrew D. Burrows, Christopher G. Frost, Mary F. Mahon and Christopher Richardson
Chemical Communications 2009 (Issue 28) pp:4218-4220
Publication Date(Web):08 Jun 2009
DOI:10.1039/B906170C
A series of sulfur-tagged zinc MOFs containing functionalised 4,4′-biphenyldicarboxylate ligands has been prepared: oxidative post-synthetic modification with dimethyldioxirane has converted the sulfide tags into sulfones, leaving the MOF networks intact.
Co-reporter:Andrew D. Burrows, Ross W. Harrington, Andrew S. Kirk, Mary F. Mahon, Frank Marken, John E. Warren and Michael K. Whittlesey
Inorganic Chemistry 2009 Volume 48(Issue 20) pp:9924-9935
Publication Date(Web):September 11, 2009
DOI:10.1021/ic900874f
The reaction between PPh(CH2OH)2, iron(II) sulfate, ammonium sulfate, and formaldehyde in aqueous solution gives the iron(II) complex [Fe(κ2-O2SO2)L2] (1), where L is the bidentate phosphine ligand 3,7-diphenyl-1,5-diaza-3,7-diphosphabicyclo[3.3.1]nonane. During the course of the reaction, the ligand L self-assembles on the metal center. The reaction between PPh(CH2OH)2, iron(II) chloride, ammonium chloride, and formaldehyde under similar conditions gives cis-[FeCl2L2] (cis-2). The complex cis-2 is converted into trans-2 in Et2O, whereas in water it is converted into cis-[Fe(OH2)2L2]2+, though both of these interconversions are reversible. The chloro ligands in cis-2 are readily displaced by reaction with thiocyanate, azide, and carbonate to give cis- and trans-[Fe(NCS)2L2] (cis- and trans-3), cis- and trans-[Fe(N3)2L2] (cis- and trans-4), and [Fe(κ2-O2CO)L2] (5), respectively. The complex cis-2 reacts with CO in water to give trans-[FeCl(CO)L2]Cl (trans-6), whereas trans-2 reacts with CO in diethyl ether to give cis-[FeCl(CO)L2]Cl (cis-6), though cis-6 isomerizes in water to form trans-6. The reaction of cis-2 with sodium borohydride gives the hydride chloride complex trans-[FeCl(H)L2] (7). Electrochemical studies have been undertaken on complexes 1, cis-2, and 7. These reveal reversible oxidations for cis-2 and 7, with the latter giving rise to an unusual 17-electron iron(III) hydride chloride complex. Crystal structures have been obtained for 1, trans-2, trans-3, 5, and 7.
Co-reporter:Andrew D. Burrows, Kevin Cassar, Tina Düren, Richard M. W. Friend, Mary F. Mahon, Sean P. Rigby and Teresa L. Savarese
Dalton Transactions 2008 (Issue 18) pp:2465-2474
Publication Date(Web):19 Mar 2008
DOI:10.1039/B718947H
The products isolated from the reaction between Cd(NO3)2·4H2O and 1,4-benzenedicarboxylic acid (H2bdc) in DMF are very dependent on the conditions. At 115 °C, the reaction gives [Cd(bdc)(DMF)]∞1, which has a three-dimensional network structure, whereas at 95 °C, 1 is formed alongside [Cd3(bdc)3(DMF)4]∞2, which has a two-dimensional network structure. When the reaction is carried out under pressure, it yields [Cd3(bdc)3(DMF)4]∞3, which is a supramolecular isomer of 2. The structure of 3 differs from that of 2 regarding the way the Cd3(O2CR)6 units are interlinked to form layers. When the reaction was carried out in DMF that had undergone partial hydrolysis, the only isolated product was {(NMe2H2)2[Cd(bdc)2]·2DMF}∞4. Compound 4 has a three-dimensional triply-interpenetrated diamondoid structure, with dimethylammonium cations and DMF molecules included within the pores. The reaction between Cd(NO3)2·4H2O and H2bdc in DEF gave [Cd(bdc)(DEF)]∞5, regardless of the solvent quality. Compound 5 has a three-dimensional network structure. The reaction of Cd(NO3)2·4H2O and 1,3-benzenedicarboxylic acid (H2mbdc) in DMF gave [Cd(mbdc)(DMF)]∞6 which has a bilayer structure. The thermal properties of the new materials have been investigated, and the coordinated DEF molecules from 5 can be removed on heating to 400 °C without any change in the powder X-ray diffraction pattern. The H2 sorption isotherm for the desolvated material shows marked hysteresis between adsorption and desorption, and less adsorption than predicted by simulations. Kinetic data indicate that the hysteresis is not due to mass transfer limitations, and the most likely explanation for this behaviour lies in partial collapse of the framework to an amorphous phase under the conditions of activation.
Co-reporter:Andrew D. Burrows, Christopher G. Frost, Mary F. Mahon, Melanie Winsper, Christopher Richardson, J. Paul Attfield and Jennifer A. Rodgers
Dalton Transactions 2008 (Issue 47) pp:6788-6795
Publication Date(Web):22 Oct 2008
DOI:10.1039/B807063F
Two new copper metal-organic frameworks containing 5-nitro-1,3-benzenedicarboxylate (5-nbdc) have been prepared from the reaction between Cu(NO3)2·3H2O and H2(5-nbdc) in DMF at different temperatures. Single crystal X-ray structures of {[Cu2(5-nbdc)2(DMF)2]·2DMF}∞ (1) and {[Cu2(5-nbdc)2(DMF)2]·3⅓DMF}∞ (2) revealed similar sheet structures, containing triangular and hexagonal pores, but differences in the stacking of the sheets. Magnetic measurements on 1 and 2 are consistent with antiferromagnetic dimers containing a small quantity of paramagnetic impurity. The desolvated forms of 1 and 2 were applied as Lewis acid catalysts in the acetylation of methyl 4-hydroxybenzoate. When the reaction between Cu(NO3)2·3H2O and H2(5-nbdc) was carried out in a mixture of DMF and water, the reaction gave metallomacrocycles of formula [Cu6(5-nbdc)6(H2O)12(DMF)6] (3). These assemble through hydrogen-bonding interactions to form a gross structure in which the macrocycle pores align into channels. The reaction between Cu(NO3)2·3H2O and 5-methylsulfanylmethyl-1,3-benzenedicarboxylic acid, H2(5-msbdc), in DMF-water gave {[Cu2(5-msbdc)2(OH2)2]·3DMF}∞ (4), which contains similar sheets to those in 1 and 2, whereas the reaction with 5-amino-1,3-benzenedicarboxylic acid, H2(5-abdc), gave {[Cu2(5-abdc)2(DMF)2]}∞ (5), which has a previously reported network based on sheets containing rhombohedral pores. The reaction between Cu(NO3)2·3H2O and 2-methoxy-1,3-benzenedicarboxylic acid, H2(2-mbdc), in DMF gave [Cu2(2-mbdc)2(DMF)2] (6). The presence of the substituent in the 2-position removes the co-planarity of the carboxylate groups, and the sheet structure adopted by 6 contains rhomboidal pores.
Co-reporter:AndrewD. Burrows Dr.;ChristopherG. Frost Dr.;MaryF. Mahon Dr. ;Christopher Richardson Dr.
Angewandte Chemie International Edition 2008 Volume 47( Issue 44) pp:8482-8486
Publication Date(Web):
DOI:10.1002/anie.200802908
Co-reporter:AndrewD. Burrows Dr.;ChristopherG. Frost Dr.;MaryF. Mahon Dr. ;Christopher Richardson Dr.
Angewandte Chemie 2008 Volume 120( Issue 44) pp:8610-8614
Publication Date(Web):
DOI:10.1002/ange.200802908
Co-reporter:Andrew D. Burrows, Kevin Cassar, Mary F. Mahon and John E. Warren
Dalton Transactions 2007 (Issue 24) pp:2499-2509
Publication Date(Web):23 Apr 2007
DOI:10.1039/B702074K
The complexes [Cu(L1)2] 1, [Fe(L1)3] 3 and [Al(L1)3] 4 [L1 = CH3C(O)C(CN)C(O)CH3] have been prepared for use as metallo-ligands in mixed-metal coordination networks. Surprisingly, the nature of the copper precursor is important in the synthesis of 1, with the reaction between Cu(NO3)2·3H2O, HL1 and NEt3 giving [Cu6(µ3-OMe)4(µ-OMe)2(L1)6] 2 instead of the anticipated 1, which was obtained with CuCl2·2H2O under the same conditions. Compound 1 reacts with AgNO3 to form [Cu(L1)2·AgNO3]∞5, the structure of which contains one-dimensional chains in which Ag+ ions bridge between molecules of 1. These chains are cross-linked into ladders by bridging nitrates. The product obtained from the reaction of 3 and AgNO3 is crucially dependent on the solvent used. The reaction in methanol–acetone gives [Fe(L1)3·AgNO3]∞6, {[Fe2(µ-OMe)2(L1)4·2AgNO3]·CH3C(O)CH3}∞7 and [Fe2(µ-OMe)2(L1)4·AgNO3]∞8. Compounds 6 and 8 both have one-dimensional chain structures, whereas 7 has a two-dimensional layer structure. The reaction in methanol gives 6 and 8 as the major products and, in addition, small quantities of {[AgFe2(µ-OMe)2(L1)4]OH·0.4H2O]∞9. Compound 9 has a three-dimensional structure based on doubly interpenetrated PtS nets. Compounds 7–9 contain Fe2(µ-OMe)2(L1)4 dimers, but the coordination properties of the dimers differ, with all the cyanides coordinated in 7 and 9 but one uncoordinated in 8. The orientation of the cyanide groups depends on the relative chirality of the iron centres. A transmetallation reaction occurs between 4 and AgNO3 to give [Ag(L1)]∞10, which has a two-dimensional layer structure. Compounds 2, 3 and 5–10 have been characterised by X-ray crystallography.
Co-reporter:Andrew D. Burrows, Deborah Dodds, Andrew S. Kirk, John P. Lowe, Mary F. Mahon, John E. Warren and Michael K. Whittlesey
Dalton Transactions 2007 (Issue 5) pp:570-580
Publication Date(Web):22 Dec 2006
DOI:10.1039/B614726G
Facile substitution reactions of the two water ligands in the hydrophilic tetradentate phosphine complex cis-[Fe{(HOCH2)P{CH2N(CH2P(CH2OH)2)CH2}2P(CH2OH)}(H2O)2](SO4) (abbreviated to [Fe(L1)(H2O)2](SO4), 1) take place upon addition of Cl−, NCS−, N3−, CO32− and CO to give [Fe(L1)X2] (2, X = Cl; 4, X = NCS; 5, XN3), [Fe(L1)(κ2-O2CO)], 6 and [Fe(L1)(CO)2](SO4), 7. The unsymmetrical mono-substituted intermediates [Fe(L1)(H2O)(CO)](SO4) and [Fe(L1)(CO)(κ1-OSO3)] (8/9) have been identified spectroscopically en-route to 7. Treatment of 1 with acetic anhydride affords the acylated derivative [Fe{(AcOCH2)P{CH2N(CH2P(CH2OAc)2)CH2}2P(CH2OAc)}(κ2-O2SO2)] (abbreviated to [Fe(L2)(κ2-O2SO2)], 10), which has increased solubility over 1 in both organic solvents and water. Treatment of 1 with glycine does not lead to functionalisation of L1, but substitution of the aqua ligands occurs to form [Fe(L1)(NH2CH2CO2-κ2N,O)](HSO4), 11. Compound 10 reacts with chloride to form [Fe(L2)Cl2] 12, and 12 reacts with CO in the presence of NaBPh4 to form [Fe(L2)Cl(CO)](BPh4) 13b. Both of the chlorides in 12 are substituted on reaction with NCS− and N3− to form [Fe(L2)(NCS)2] 14 and [Fe(L2)(N3)2] 15, respectively. Complexes 2·H2O, 4·2H2O, 5·0.812H2O, 6·1.7H2O, 7·H2O, 10·1.3CH3C(O)CH3, 12 and 15·0.5H2O have all been crystallographically characterised.
Co-reporter:Ritu Bala, Raj Pal Sharma, Upendra Sharma, Andrew D. Burrows, Kevin Cassar
Journal of Molecular Structure 2007 Volume 832(1–3) pp:156-163
Publication Date(Web):30 April 2007
DOI:10.1016/j.molstruc.2006.08.028
The compounds [Co(NH3)6]Br2(BF4) 1 and [Co(NH3)6]Cl2(HC2O4)·H2O 2 have been prepared and structurally characterised. The two crystallographically independent cations in 1 are involved in different hydrogen bonding patterns, with one forming predominantly NH⋯F interactions with the tetrafluoroborates and the other forming NH⋯Br hydrogen bonds. The supramolecular structure of 2 shows unusual hydrogen oxalate–water chains in addition to NH⋯O and NH⋯Cl interactions. An analysis of crystal structures containing [Co(NH3)6]3+ and mixed anions reveals that multiple hydrogen bonds between cations and anions can lead to both face- and edge-capping of the [Co(NH3)6]3+ octahedron.
Co-reporter:Raj Pal Sharma, Rajni Sharma, Ritu Bala, Andrew D. Burrows, Mary F. Mahon, Kevin Cassar
Journal of Molecular Structure 2006 Volume 794(1–3) pp:173-180
Publication Date(Web):7 August 2006
DOI:10.1016/j.molstruc.2006.02.002
Green coloured single crystals of [trans-Co(en)2Cl2]IO4I and dark red coloured single crystals of [trans-Co(en)2(N3)2]N3II were obtained by slowly mixing stoichiometric quantities of the separately dissolved trans-dichlorobis(ethylenediamine)cobalt(III) chloride with sodium metaperiodate or sodium azide in aqueous medium. Elemental analyses, spectroscopic studies (IR, UV/visible, 1H and 13C NMR) and solubility measurements were performed to characterize the complex salts. The compound I crystallizes in the monoclinic space group P21/c with a=6.3970(2), b=16.6790(4), c=12.3730(3) Å, β=99.148(1)°, V=1303.35(6) Å3, Z=4 and II crystallizes in the orthorhombic space group Pbca with a=10.1790(1), b=13.5350(1), c=17.2410(2) Å, V=2375.34(4) Å3, Z =8. Supramolecular hydrogen bonding networks between ionic groups [NHen+⋯Xanion−] by second sphere coordination besides electrostatic forces of attraction have been observed. Compound II represents the first reported structure of a salt containing the cation, [trans-Co(en)2(N3)2]+.
Co-reporter:Rodolphe F.R. Jazzar, Maurizio Varrone, Andrew D. Burrows, Stuart A. Macgregor, Mary F. Mahon, Michael K. Whittlesey
Inorganica Chimica Acta 2006 Volume 359(Issue 3) pp:815-820
Publication Date(Web):1 February 2006
DOI:10.1016/j.ica.2005.05.021
Two isomers of the N,O-coordinated acetylpyrrolyl complex [Ru(PPh3)2(CO)(NC4H3C(O)CH3)H] {cis-N,H (1) and trans-N,H (2)} have been prepared as models for catalytic intermediates in the Murai reaction. Complex 2 isomerises to 1 upon heating via a dissociative pathway (ΔH‡ = 195 ± 41 kJ mol−1; ΔS‡ = 232 ± 62 J mol−1 K−1); the mechanism of this process has been modeled using density functional calculations. Complex 2 displays moderate catalytic activity for the Murai coupling of 2′-methylacetophenone with trimethylvinylsilane, but 1 proved to be catalytically inactive under the same conditions.Thermolysis of the N-keto pyrrolyl phosphine PPh2(NC4H3C(O)CH3-2) with [Ru(PPh3)3(CO)H2] affords the acetyl pyrrolyl complex cis-N,H-[Ru(PPh3)2(CO)(NC4H3C(O)CH3)H] (1), which is also the product of heating the stereoisomer, trans-N,H-[Ru(PPh3)2(CO)(NC4H3C(O)CH3)H] (2). The activity of these complexes for ketone–alkene coupling (Murai reaction) is described.
Co-reporter:Nichola J. Burke, Andrew D. Burrows, Mary F. Mahon, John E. Warren
Inorganica Chimica Acta 2006 Volume 359(Issue 11) pp:3497-3506
Publication Date(Web):1 August 2006
DOI:10.1016/j.ica.2006.01.008
Interactions between guanidinium cations and the sulfonate groups on the phosphine [PPh2C6H4-m-SO3]− have been exploited to incorporate iridium(I) centres into hydrogen-bonded networks. The crystal structure of [C(NH2)3]2{trans-[IrCl(CO)(PPh2C6H4-m-SO3)2]} (4) contains hexagonal guanidinium sulfonate (GS) sheets in which both of the sulfonate groups from each complex anion form hydrogen bonds within the same sheet. The crystal structures of [C(NH2)2(NHMe)][PPh2C6H4-m-SO3] (5) and [C(NH2)2(NHEt)][PPh2C6H4-m-SO3] (6) reveal that the GS sheets can tolerate the loss of one hydrogen bond donor, though twisting occurs to accommodate the alkyl group. However, the crystal structure of [C(NH2)2(NMe2)][PPh2C6H4-m-SO3] (7) shows that ribbon structures are formed instead of sheets when two hydrogen bond donors are lost. The compound [C(NH2)2(NHMe)]2{trans-[IrCl(CO)(PPh2C6H4-m-SO3)2]} · 3/8H2O (8) contains hydrogen-bonded cylinders as opposed to sheets. This is a likely consequence of a mismatch between the intramolecular S⋯S distance present in the anion, and the closer S⋯S distance present in a twisted GS sheet such as that in 5. The crystal structures of [C(NH2)2(NHEt)][P(O)Ph2C6H4-m-SO3] (9) and [C(NH2)2(NMe2)][P(O)Ph2C6H4-m-SO3] · H2O (10) show that the phosphine oxide group successfully competes with the sulfonate as a hydrogen bond acceptor. The crystal structure of 9 contains hydrogen-bonded ribbons that are interlinked through the anions which act as pillars to form a layer structure. In contrast, the crystal structure of 10 contains hydrogen-bonded sheets that involve cations, sulfonate groups, phosphine oxides and the included water molecule. These sheets are linked into a three-dimensional network through the anion pillars.The crystal structures of seven compounds containing guanidinium or substituted guanidinium cations and derivatives of the sulfonated phosphine PPh2C6H4-m-SO3- are reported. The effects on the supramolecular structure of inclusion of the trans-[IrCl(CO)(PPh2C6H4-m-SO3)2]2− anion is investigated, along with those of substitution on the cation and incorporation of a phosphine oxide group which is a competing hydrogen bond acceptor.
Co-reporter:Andrew D. Burrows, Kevin Cassar, Richard M. W. Friend, Mary F. Mahon, Sean P. Rigby and John E. Warren
CrystEngComm 2005 vol. 7(Issue 89) pp:548-550
Publication Date(Web):12 Aug 2005
DOI:10.1039/B509460G
Hydrolysis of the DMF or DEF solvent influences the nature of the product observed in the reaction between zinc(II) nitrate and 1,4-benzenedicarboxylic acid, with dialkylammonium cations able to template the formation of anionic networks.
Co-reporter:Nichola J. Burke, Andrew D. Burrows, Mary F. Mahon and Simon J. Teat
CrystEngComm 2004 vol. 6(Issue 71) pp:429-436
Publication Date(Web):17 Sep 2004
DOI:10.1039/B406614F
The reaction of [C(NH2)3]Cl with methyl orange, Na[O3SC6H4NNC6H4NMe2], leads to formation of [C(NH2)3][O3SC6H4NNC6H4NMe2] 1 in which the sulfonate dye has been incorporated into a guanidinium sulfonate hydrogen-bonded bilayer sheet structure. Similar reactions with substituted guanidinium cations give [C(NH2)2(NHMe)][O3SC6H4NNC6H4NMe2]·MeOH 2·MeOH, [C(NH2)2(NHEt)][O3SC6H4NNC6H4NMe2] 3 and [C(NH2)2(NMe2)][O3SC6H4NNC6H4NMe2] 4. Although substitution disrupts formation of the GS sheets, the gross structures of 2–4 all have pseudo-bilayer structures, with similar gross features to 1. Compound 1 reacts with HCl in solution to generate the zwitterionic compound O3SC6H4NHNC6H4NMe25, but solid samples of 1 react reversibly with HCl gas to give the HCl adduct 1a. This interconversion has been studied by powder X-ray diffraction, IR spectroscopy and diffuse reflectance visible spectroscopy.
Co-reporter:Andrew D. Burrows, Mary F. Mahon and Maurizio Varrone
Dalton Transactions 2004 (Issue 20) pp:3321-3330
Publication Date(Web):03 Sep 2004
DOI:10.1039/B408841G
The series of N-carbazolyl phosphines PPh3−n(NC12H8)n
(n
= 1, L1111111; n
= 2, L2222222; n
= 3, L3333333) has been synthesised using BuLi to generate the N-carbazolyl lithium salt, followed by reaction with the appropriate chlorophosphine. The reactions between [Rh(μ-Cl)(CO)2]2 and four equivalents of L1111111 or L2222222 gave [RhCl(CO)(L1111111)2]
1 and [RhCl(CO)(L2222222)2]
2, though attempts to synthesise the analogous complex using L3333333 resulted in the formation of [Rh(μ-Cl)(CO)(L3333333)]23 instead. The inability of L3333333 to cleave the chloride bridges can be related to its considerable steric requirements. The electronic properties of L1–31–31–31–31–31–31–3 were assessed by comparison of the ν(CO) values of the [Rh(acac)(CO)(L1–31–31–31–31–31–31–3)] complexes 4–6. The increase in number of N-carbazolyl substituents at the phosphorus atom results in a decrease of the σ-donor and increase in the π-acceptor character in the order L1111111 < L2222222 < L3333333. In the reactions of L1–31–31–31–31–31–31–3 with [PdCl2(cod)] only L1111111 was able to displace cod from the metal centre and form [PdCl2(L1111111)2]
7. The use of [PdCl2(NCMe)2] instead of [PdCl2(cod)] resulted in the formation of the complexes [PdCl2(L1111111)2]
7 from L1111111, the cyclometallated complex [Pd(μ-Cl){P(NC12H8)2(NC12H7)-κ2P,C}]28 from L3333333, and a mixture of [PdCl2(L2222222)2]
9 and [Pd(μ-Cl){PPh(NC12H8)(NC12H7)-κ2P,C}]210 from L2222222. The reaction of L3333333 with [Pd(OAc)2] produced the cyclometallated complex [Pd(μ-O2CCH3){P(NC12H8)2(NC12H7)-κ2P,C}]211. The reaction of L3333333 with [Pd2(dba)3]·CHCl3 produced the 14-electron complex [Pd(L3333333)2]
12. The X-ray crystal structures of six complexes are reported, all of which show the presence of C–H⋯Pd hydrogen bonding.
Co-reporter:Andrew D. Burrows;Adele S. Donovan;Ross W. Harrington;Mary F. Mahon
European Journal of Inorganic Chemistry 2004 Volume 2004(Issue 23) pp:
Publication Date(Web):14 OCT 2004
DOI:10.1002/ejic.200400502
The reaction between [Zn(tu)4]Cl2 and the appropriate sodium dicarboxylate has been shown to give the coordination polymers [Zn(tu)2(μ-succinate)]n (7), [Zn(tu)2(μ-itaconate)]n (8), [Zn(tu)2(μ-ethylmalonate)]n (9), [Zn(tu)2(μ-1,3-phenylenediacetate)]n (10) and {[Zn(tu)2(μ-mesaconate)]·2H2O}n (11), all of which have been crystallographically characterised. The crystal structures of 7−9 demonstrate that these compounds form helical structures in which the dicarboxylates adopt conformations with the relative positions of the carboxylate groups similar to those in constrained anions such as phthalate. The role of the chloride counterion in the starting material has been explored by investigating the reactions of [Zn(tu)4](NO3)2 with a range of dicarboxylates. Although in the majority of cases the counterion was shown to have no effect, in the case of fumarate, a hydrated coordination polymer {[Zn(tu)2(μ-fumarate)]·2H2O}n (12) was observed in addition to the anhydrous product [Zn(tu)2(μ-fumarate)]n (1), which was formed as the sole product from [Zn(tu)4]Cl2. Thermogravimetric analyses are reported for compounds 1−12. The compounds {[Zn(tu)2(μ-isophthalate)]·H2O}n3 and 12 lose their included water before 140 °C, whereas the compounds {[Zn(tu)2(μ-maleate)]·H2O}n6 and 11 only lose their water molecules at higher temperatures with the onset of decomposition. This difference in behaviour can be related to the structural role of the water molecules. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Co-reporter:Nichola J. Burke, Andrew D. Burrows, Adele S. Donovan, Ross W. Harrington, Mary F. Mahon and Caroline E. Price
Dalton Transactions 2003 (Issue 20) pp:3840-3849
Publication Date(Web):17 Sep 2003
DOI:10.1039/B307420J
The reactions of the zinc thiourea complexes [Zn{SC(NHR)(NHR′)}4]Cl2
(L =
L1, R = H, R′
= Me; L =
L2, R = Me, R′
= Me) with a range of dicarboxylates have been investigated. From these reactions eleven products –
[Zn(L1)2(μ-terephthalate)]n, [Zn(L1)2(μ-fumarate)]n, {[Zn(L1)2(μ-isophthalate)]·H2O}n, [Zn(L1)2(μ-1,3-phenylenediacetate)]n, [Zn(L1)2(μ-phthalate)]2·4H2O, {[Zn(L2)2(μ-terephthlate)]·0.5H2O}n, [Zn(L2)2(μ-fumarate)]n, [Zn(L2)2(μ-isophthalate)]2·2H2O, [Zn(L2)2(μ-phthalate)]n, [Zn(L2)2(μ-maleate)]2·2H2O and [Zn(L2)2(μ-citraconate)]2·2H2O – have been crystallographically characterised. The structural characterisation of these compounds demonstrates that by increasing the number of methyl substituents on the thiourea ligand, the likelihood of forming a dimer as opposed to a coordination polymer also increases. Moreover, dimer formation is only favoured for non-linear dicarboxylates – those in which the angle between the carboxylate groups is less than 180°.
Co-reporter:Andrew D. Burrows, Mary F. Mahon and Maurizio Varrone
Dalton Transactions 2003 (Issue 24) pp:4718-4730
Publication Date(Web):23 Oct 2003
DOI:10.1039/B309882F
The 7-aza-N-indolyl phosphine ligands PR2(N2C7H5)
(L1, R = Ph; L2, R = NC4H4) were prepared in a two-step process involving treatment of 7-azaindole with BuLi, followed by reaction of the lithium salt with PClR2. L1 and L2 react with [MCl2(cod)]
(M = Pd, Pt) to give [PdCl2(L-κ2P,N)]
(1a, L =
L1; 1b, L =
L2) or [PtCl2(L-κ2P,N)]
(2a, L =
L1; 2b, L =
L2) and with [Rh(μ-Cl)(cod)]2 in the presence of CO to give [RhCl(CO)(L-κ2P,N)]
(3a, L =
L1; 3b, L =
L2). Crystal structures for 1a,b and 3a,b are reported, and structural and spectroscopic evidence confirm that L2 is a poorer σ-donor/better π-acceptor than L1. The complexes [PdClMe(L-κ2P,N)]
(4a, L =
L1; 4b, L =
L2), prepared from [PdClMe(cod)], react with AgOTf to yield [PdMe(OTf)(L-κ2P,N)]
(5a, L =
L1; 5b, L =
L2). Complexes 5a,b are active catalysts for the co-polymerisation of CO and ethene, with activities similar to previously reported catalysts containing P,N-donor ligands. From the stepwise insertion reactions of CO and ethene with 5a,b, the acyl complexes [Pd{C(O)Me}(OTf)(L-κ2P,N)]
(7a, L =
L1; 7b, L =
L2) and alkyl complexes [Pd{CH2CH2C(O)Me-κ2C,O}(L-κ2P,N)]OTf (8a, L =
L1; 8b, L =
L2) have been isolated and crystallographically characterised, and the acyl complexes [Pd{C(O)CH2CH2C(O)Me-κ2C,O}(L-κ2P,N)]OTf (9a, L =
L1; 9b, L =
L2) have been spectroscopically characterised. Reactions of 7a and 9a with MeOH gave methyl acetate and methyl 4-ketopentanoate respectively, with formation of palladium metal and conversion of the remaining palladium to [Pd(L1-κ2P,N)2](OTf)210 which has been crystallographically characterised.
Co-reporter:Andrew D. Burrows;Ross W. Harrington;Mary F. Mahon;Simon J. Teat
European Journal of Inorganic Chemistry 2003 Volume 2003(Issue 7) pp:
Publication Date(Web):24 MAR 2003
DOI:10.1002/ejic.200390186
Using the sulfonated phosphane [PPh2(C6H4-m-SO3)]−, L−, we have demonstrated that metal centres can readily be incorporated into guanidinium sulfonate (GS) hydrogen-bonded networks, and that the increase in steric bulk on going from [C(NH2)3][L] (1) to [C(NH2)3][AuCl(L)] (2) leads to a flattening of the GS sheets. The crystal structures of [C(NH2)3][LS] 3 and [C(NH2)3][LSe] 4 (LS− = [SPPh2(C6H4-m-SO3)]−, LSe− = [SePPh2(C6H4-m-SO3)]−) reveal disorder in both the sulfonate groups and the guanidinium cations, which is a consequence of pseudo-sixfold phenyl embraces between the anions. These interactions, identical to those observed in Ph3PS and Ph3PSe, position the sulfonate groups too close together for regular quasihexagonal hydrogen bonding motifs to be formed. The regular GS hydrogen bonding patterns can also be disrupted by using an anion containing two sulfonate groups such as that in [C(NH2)3]2{cis-[PdCl2(L)2]} (5). In this case the incorporation of two sulfonate groups from each anion into the same hydrogen-bonded sheet also serves to constrain the distance between the sulfur atoms to a value incommensurate with that enabling a guanidinium cation to hydrogen bond to both groups. In this case irregular GS sheets are formed involving fewer N−H···O hydrogen bonds than in 1 and 2. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Co-reporter:Andrew D. Burrows;Ross W. Harrington;Mary F. Mahon;Simon J. Teat
European Journal of Inorganic Chemistry 2003 Volume 2003(Issue 4) pp:
Publication Date(Web):5 FEB 2003
DOI:10.1002/ejic.200390106
The reaction of [Zn(tmtsc)2](NO3)2 [tmtsc = 1,1,4-trimethylthiosemicarbazide, MeNHC(S)NHNMe2] with a range of sodium dicarboxylates has been shown to lie on the borderline between commonly used crystal engineering strategies. The products exhibit a wide range of structural diversity with the main driving force being the relative orientation of the carboxylate groups. Thus, fumarate leads to the hydrogen-bonded aggregate [Zn(tmtsc)2(OH2)][fumarate] (2) in which cations and anions are linked by hydrogen bond donor-donor acceptor-acceptor (DD:AA) interactions, whereas isophthalate and (+)-camphorate lead to coordination polymers [Zn(tmtsc)(μ-isophthalate)] (3a) and [Zn(tmtsc)(μ-camphorate)] (4) with the metal centres linked by bridging dicarboxylate ligands. In the case of isophthalate, a hydrated product [Zn(tmtsc)(μ-isophthalate)]·H2O (3b) was also characterised, although microanalysis and powder X-ray diffraction revealed this to be a minor product. Incorporation of water was shown to lead to a change in carboxylate coordination mode from η1 in 3a to η2 in 3b. Use of terephthalate leads to the compound [{Zn(tmtsc)(OH2)}2(μ-terephthalate)][terephthalate]·2H2O (5), in which half of the terephthalates bridge metal centres, to form dimers, and the remainder link the dimeric cations through DD:AA hydrogen bond interactions. Homophthalate leads to discrete dimers [Zn(tmtsc)(μ-homophthalate)]2 (6), whereas acetylenedicarboxylate yields the unexpected compound [Zn(tmtsc)2(OH2)][O2CCH=CC(O)N(Me)C(=NNMe2)S]2·H2O (7) in which the dicarboxylate has reacted with tmtsc to give a 2-hydrazono-4-oxo-1,3-thiazolidineacetate, which is subsequently trapped in the solid state by DD:AA hydrogen bonding interactions with [Zn(tmtsc)2(OH2)]2+. All products were characterised by single crystal X-ray crystallography, and the representational nature of these crystal structures to the bulk materials was confirmed by microanalysis and powder diffraction. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Co-reporter:Andrew D. Burrows, Ross W. Harrington, Mary F. Mahon and Simon J. Teat
CrystEngComm 2002 vol. 4(Issue 89) pp:539-544
Publication Date(Web):08 Oct 2002
DOI:10.1039/B208284E
Deprotonation of a coordinated thiosemicarbazide by a dicarboxylate species competes with the previously reported formation of cation⋯anion tapes via charge-augmented hydrogen bonding between the thiosemicarbazide ligands and the carboxylates. This has resulted in the formation of five bis(thiosemicarbazidato)nickel complexes, [Ni(tscato)2] (1), [Ni(Metscato)2] (2), [Ni(Me2tscato)2] (3), [Ni(Me3tscato)2] (4) and [Ni(EtMe2tscato)2] (5), all of which have been structurally characterised [tscato = H2NC(S)NNH2, Metscato = HMeNC(S)NNH2, Me2tscato = H2NC(S)NNMe2, Me3tscato = HMeNC(S)NNMe2, EtMe2tscato = HEtNC(S)NNMe2]. [Ni(tscato)2] has been structurally characterised before, though the crystal structure analysis of 1 reveals it to be a polymorph of the previously reported complex. The effect of removing hydrogen bond donors through the substitution of NH hydrogen atoms by alkyl groups on the supramolecular structure of the products is assessed.
Co-reporter:Christopher D. Andrews, Andrew D. Burrows, Jason M. Lynam, Mary F. Mahon and Mark T. Palmer
New Journal of Chemistry 2001 vol. 25(Issue 6) pp:824-826
Publication Date(Web):15 May 2001
DOI:10.1039/B102193L
The
synthesis and X-ray crystal structure of the new keto-functionalised N-pyrrolyl phosphine ligand PPh2NC4H3{C(O)CH3}-2 L is reported. The ligand coordinates to molybdenum(II) as either a uni- or a bi-dentate ligand, and the reversibility
of the ketone coordination is demonstrated by the interconversion of the complexes [MoCl(CO)2(L-κ1P)(η5-C5H5)] 1 and [Mo(L-κ2P,O)(CO)2(η5-C5H5)][BF4]
2 on abstraction or addition of chloride.
The X-ray
crystal structure of 1 is also reported.
Co-reporter:Andrew D. Burrows, Mary F. Mahon and Mark T. Palmer
Dalton Transactions 2000 (Issue 10) pp:1669-1677
Publication Date(Web):02 May 2000
DOI:10.1039/B001436M
Ether-functionalised aminophosphines Ph2PNHR [R = CH2CH2OCH3L1, CH2CH(OCH3)2L2, CH2CH2CH2OCH3L3 or C6H4OCH3-2 L4] were prepared from the reaction of Ph2PCl and the amine RNH2 in the presence of triethylamine. Reaction of L1–4 with [MCl2(cod)] (M = Pd or Pt) or [PtBr2(cod)] gave the complexes [MCl2L2] (1, M = Pd, L = L1; 2, M = Pd, L = L2; 3, M = Pd, L = L3; 4, M = Pd, L = L4; 5, M = Pt, L = L1; 6, M = Pt, L = L2; 7, M = Pt, L = L4) and [PtBr2(L1)2] 8. X-Ray crystallographic analyses of complexes 1 and 2 indicated the presence of bifurcated hydrogen bonds between the NH protons and both the chloride ligands and the ether oxygen atoms. Reaction of 1, 5 and 7 with two equivalents of AgBF4 led to formation of trans-[Pd(L1)2][BF4]29 and cis-[PtL2][BF4]2 (L = L1; 10 or L411) containing bidentate P,O-co-ordinated ligands whereas reaction of 1 with one equivalent of AgBF4 gave exclusively [{Pd(μ-Cl)(L1)2}2][BF4]212, containing only unidentate aminophosphine ligands. Reaction of 5 and 8 with NaNO2 led to formation of cis-[PtX(NO2)(L1)2] (X = Cl 13 or Br 14). Shielding of one of the NH protons with respect to 5 and 8 suggested loss of N–H⋯X hydrogen bonding and this was confirmed by an X-ray crystallographic analysis of 14. Reaction of L1–4 with [{M(dmba)(μ-Cl)}2] (M = Pd or Pt; Hdmba = N,N-dimethylbenzylamine) gave [M(dmba)ClL] (16, M = Pd, L = L1; 17, M = Pd, L = L2; 18, M = Pd, L = L3; 19, M = Pd, L = L4; 20, M = Pt, L = L1; 21, M = Pt, L = L2; 22, M = Pt, L = L4). The crystal structure of 16 reveals a similar bifurcated hydrogen bond to those observed in 1 and 2, whereas the structure of 18 shows the N–H⋯Cl interaction to be present but the N–H⋯O interaction absent. Reaction of 16, 20 and 22 with AgBF4 gave the bidentate P,O-co-ordinated complexes [M(dmba)L]BF4 (23, M = Pd, L = L1; 24, M = Pt, L = L1; 25, M = Pt, L = L4). Displacement of the co-ordinated ether oxygen was achieved by reaction of 24 and 25 with CO and of 25 with xylyl isocyanide and acetonitrile. Attempts to recrystallise 24 led instead to isolation of the dinuclear species [{Pt(dmba)(μ-PPh2O)}2] 30 which was characterised by X-ray crystallography.
Co-reporter:Andrew D. Burrows, Mary F. Mahon and Mark T. Palmer
Dalton Transactions 2000 (Issue 20) pp:3615-3619
Publication Date(Web):02 Oct 2000
DOI:10.1039/B005899H
Amine functionalised aminophosphines Ph2PN(R)CH2CH2NMe2 (R = H L1 or Me L2) were prepared from the reaction of PPh2Cl with NHRCH2CH2NMe2 in the presence of the base n-butyllithium (L1) or triethylamine (L2). Reaction of two equivalents of L1,2 with [PtCl2(cod)] gave the complexes cis-[PtCl2L2] (L = L11 or L22), which were shown to be fluxional with one of the amine groups reversibly co-ordinating to displace a chloride. Removal of a chloride in 1 by metathesis gave cis-[PtCl(L1-P)(L1-P,N)]PF63 which was not fluxional on the NMR timescale. Reaction of one equivalent of L2 with [PtCl2(cod)] gave the complex cis-[PtCl2(L2-P,N)] 4 in which L2 is acting as a bidentate ligand. The reaction of L2 with [{Pt(dmba)(μ-Cl)}2] (Hdmba = N,N-dimethylbenzylamine) gave [Pt(dmba)Cl(L2)] 5, which exists as a mixture of the two geometric isomers. Reaction of 5 with TlPF6 gave [Pt(dmba)(L2-P,N)]-PF66 as a single isomer in which the phosphorus atom is co-ordinated trans to the N,N-dimethylbenzylamine nitrogen atom. Complex 2 reacts with CoCl2·6H2O and ZnCl2 to give cis-[(L2-P,N)ClPt(μ-L2)MCl3] (M = Co 7 or Zn 8). The zwitterionic structure of 7 was confirmed by a single-crystal X-ray analysis, which showed no metal–metal interaction between the platinum and cobalt centres.
Co-reporter:Andrew D. Burrows, Christopher G. Frost, Mary F. Mahon and Christopher Richardson
Chemical Communications 2009(Issue 28) pp:NaN4220-4220
Publication Date(Web):2009/06/08
DOI:10.1039/B906170C
A series of sulfur-tagged zinc MOFs containing functionalised 4,4′-biphenyldicarboxylate ligands has been prepared: oxidative post-synthetic modification with dimethyldioxirane has converted the sulfide tags into sulfones, leaving the MOF networks intact.
Co-reporter:Dongmei Jiang, Andrew D. Burrows, Yuli Xiong and Karen J. Edler
Journal of Materials Chemistry A 2013 - vol. 1(Issue 18) pp:NaN5500-5500
Publication Date(Web):2013/04/05
DOI:10.1039/C3TA10766C
A facile polyethylenimine (PEI)-assisted dip-coating method allows crack-free films of MIL-101(Cr) and MIL-101(Cr)-NH2 to be prepared on alumina supports. The presence of PEI enhances the selectivity of the films for CO2 with respect to N2. The film surfaces can be made hydrophobic by further dip-coating with an aliphatic monocarboxylic acid.
Co-reporter:Andrew D. Burrows, Laura C. Fisher, Christopher Richardson and Sean P. Rigby
Chemical Communications 2011 - vol. 47(Issue 12) pp:NaN3382-3382
Publication Date(Web):2011/02/15
DOI:10.1039/C1CC10143A
Zinc(II) nitrate reacts with different ratios of 1,4-benzenedicarboxylic acid (H2bdc) and 2-halo-1,4-benzenedicarboxylic acid (H2bdc-X, X = Br or I) to give [Zn4O(bdc)3−x(bdc-X)x], in which preferential incorporation of bdc is observed. The selective incorporation is related to crystal growth rates, and the proportion of incorporated bdc-X rises with increasing reaction time.
Co-reporter:Andrew D. Burrows, Christopher G. Frost, Mary F. Mahon, Paul R. Raithby, Christopher Richardson and Anna J. Stevenson
Chemical Communications 2010 - vol. 46(Issue 28) pp:NaN5066-5066
Publication Date(Web):2010/06/08
DOI:10.1039/C0CC00826E
The reaction of silver(I) perchlorate with the semi-rigid ligand 1,4-bis((3,5-dimethylisoxazol-4-yl)methyl)benzene (bisox) in methanol gives a triply-interpenetrated sheet structure, but a structure containing both interpenetrated sheets and Ag2(bisox)3 cages is formed on recrystallisation from acetonitrile–diethyl ether. Rearrangement of the cages into sheets occurs on heating under vacuum, a process which involves a solid state change in conformation of the bisox ligands.
Co-reporter:Dongmei Jiang, Luke L. Keenan, Andrew D. Burrows and Karen J. Edler
Chemical Communications 2012 - vol. 48(Issue 99) pp:NaN12055-12055
Publication Date(Web):2012/10/18
DOI:10.1039/C2CC36344E
The functionalised metal–organic framework MIL-101(Cr)-NH2, containing 2-aminobenzene-1,4-dicarboxylate as the linker, has been synthesised. A new tandem post-synthetic modification strategy involving diazotisation as the first step has been developed and used to introduce halo- and azo dye-functional groups into the pores.
Co-reporter:Andrew D. Burrows, Kevin Cassar, Mary F. Mahon and John E. Warren
Dalton Transactions 2007(Issue 24) pp:NaN2509-2509
Publication Date(Web):2007/04/23
DOI:10.1039/B702074K
The complexes [Cu(L1)2] 1, [Fe(L1)3] 3 and [Al(L1)3] 4 [L1 = CH3C(O)C(CN)C(O)CH3] have been prepared for use as metallo-ligands in mixed-metal coordination networks. Surprisingly, the nature of the copper precursor is important in the synthesis of 1, with the reaction between Cu(NO3)2·3H2O, HL1 and NEt3 giving [Cu6(µ3-OMe)4(µ-OMe)2(L1)6] 2 instead of the anticipated 1, which was obtained with CuCl2·2H2O under the same conditions. Compound 1 reacts with AgNO3 to form [Cu(L1)2·AgNO3]∞5, the structure of which contains one-dimensional chains in which Ag+ ions bridge between molecules of 1. These chains are cross-linked into ladders by bridging nitrates. The product obtained from the reaction of 3 and AgNO3 is crucially dependent on the solvent used. The reaction in methanol–acetone gives [Fe(L1)3·AgNO3]∞6, {[Fe2(µ-OMe)2(L1)4·2AgNO3]·CH3C(O)CH3}∞7 and [Fe2(µ-OMe)2(L1)4·AgNO3]∞8. Compounds 6 and 8 both have one-dimensional chain structures, whereas 7 has a two-dimensional layer structure. The reaction in methanol gives 6 and 8 as the major products and, in addition, small quantities of {[AgFe2(µ-OMe)2(L1)4]OH·0.4H2O]∞9. Compound 9 has a three-dimensional structure based on doubly interpenetrated PtS nets. Compounds 7–9 contain Fe2(µ-OMe)2(L1)4 dimers, but the coordination properties of the dimers differ, with all the cyanides coordinated in 7 and 9 but one uncoordinated in 8. The orientation of the cyanide groups depends on the relative chirality of the iron centres. A transmetallation reaction occurs between 4 and AgNO3 to give [Ag(L1)]∞10, which has a two-dimensional layer structure. Compounds 2, 3 and 5–10 have been characterised by X-ray crystallography.
Co-reporter:Andrew D. Burrows, Christopher G. Frost, Mary F. Mahon, Melanie Winsper, Christopher Richardson, J. Paul Attfield and Jennifer A. Rodgers
Dalton Transactions 2008(Issue 47) pp:NaN6795-6795
Publication Date(Web):2008/10/22
DOI:10.1039/B807063F
Two new copper metal-organic frameworks containing 5-nitro-1,3-benzenedicarboxylate (5-nbdc) have been prepared from the reaction between Cu(NO3)2·3H2O and H2(5-nbdc) in DMF at different temperatures. Single crystal X-ray structures of {[Cu2(5-nbdc)2(DMF)2]·2DMF}∞ (1) and {[Cu2(5-nbdc)2(DMF)2]·3⅓DMF}∞ (2) revealed similar sheet structures, containing triangular and hexagonal pores, but differences in the stacking of the sheets. Magnetic measurements on 1 and 2 are consistent with antiferromagnetic dimers containing a small quantity of paramagnetic impurity. The desolvated forms of 1 and 2 were applied as Lewis acid catalysts in the acetylation of methyl 4-hydroxybenzoate. When the reaction between Cu(NO3)2·3H2O and H2(5-nbdc) was carried out in a mixture of DMF and water, the reaction gave metallomacrocycles of formula [Cu6(5-nbdc)6(H2O)12(DMF)6] (3). These assemble through hydrogen-bonding interactions to form a gross structure in which the macrocycle pores align into channels. The reaction between Cu(NO3)2·3H2O and 5-methylsulfanylmethyl-1,3-benzenedicarboxylic acid, H2(5-msbdc), in DMF-water gave {[Cu2(5-msbdc)2(OH2)2]·3DMF}∞ (4), which contains similar sheets to those in 1 and 2, whereas the reaction with 5-amino-1,3-benzenedicarboxylic acid, H2(5-abdc), gave {[Cu2(5-abdc)2(DMF)2]}∞ (5), which has a previously reported network based on sheets containing rhombohedral pores. The reaction between Cu(NO3)2·3H2O and 2-methoxy-1,3-benzenedicarboxylic acid, H2(2-mbdc), in DMF gave [Cu2(2-mbdc)2(DMF)2] (6). The presence of the substituent in the 2-position removes the co-planarity of the carboxylate groups, and the sheet structure adopted by 6 contains rhomboidal pores.
Co-reporter:Andrew D. Burrows, Deborah Dodds, Andrew S. Kirk, John P. Lowe, Mary F. Mahon, John E. Warren and Michael K. Whittlesey
Dalton Transactions 2007(Issue 5) pp:NaN580-580
Publication Date(Web):2006/12/22
DOI:10.1039/B614726G
Facile substitution reactions of the two water ligands in the hydrophilic tetradentate phosphine complex cis-[Fe{(HOCH2)P{CH2N(CH2P(CH2OH)2)CH2}2P(CH2OH)}(H2O)2](SO4) (abbreviated to [Fe(L1)(H2O)2](SO4), 1) take place upon addition of Cl−, NCS−, N3−, CO32− and CO to give [Fe(L1)X2] (2, X = Cl; 4, X = NCS; 5, XN3), [Fe(L1)(κ2-O2CO)], 6 and [Fe(L1)(CO)2](SO4), 7. The unsymmetrical mono-substituted intermediates [Fe(L1)(H2O)(CO)](SO4) and [Fe(L1)(CO)(κ1-OSO3)] (8/9) have been identified spectroscopically en-route to 7. Treatment of 1 with acetic anhydride affords the acylated derivative [Fe{(AcOCH2)P{CH2N(CH2P(CH2OAc)2)CH2}2P(CH2OAc)}(κ2-O2SO2)] (abbreviated to [Fe(L2)(κ2-O2SO2)], 10), which has increased solubility over 1 in both organic solvents and water. Treatment of 1 with glycine does not lead to functionalisation of L1, but substitution of the aqua ligands occurs to form [Fe(L1)(NH2CH2CO2-κ2N,O)](HSO4), 11. Compound 10 reacts with chloride to form [Fe(L2)Cl2] 12, and 12 reacts with CO in the presence of NaBPh4 to form [Fe(L2)Cl(CO)](BPh4) 13b. Both of the chlorides in 12 are substituted on reaction with NCS− and N3− to form [Fe(L2)(NCS)2] 14 and [Fe(L2)(N3)2] 15, respectively. Complexes 2·H2O, 4·2H2O, 5·0.812H2O, 6·1.7H2O, 7·H2O, 10·1.3CH3C(O)CH3, 12 and 15·0.5H2O have all been crystallographically characterised.
Co-reporter:Andrew D. Burrows, Kevin Cassar, Tina Düren, Richard M. W. Friend, Mary F. Mahon, Sean P. Rigby and Teresa L. Savarese
Dalton Transactions 2008(Issue 18) pp:NaN2474-2474
Publication Date(Web):2008/03/19
DOI:10.1039/B718947H
The products isolated from the reaction between Cd(NO3)2·4H2O and 1,4-benzenedicarboxylic acid (H2bdc) in DMF are very dependent on the conditions. At 115 °C, the reaction gives [Cd(bdc)(DMF)]∞1, which has a three-dimensional network structure, whereas at 95 °C, 1 is formed alongside [Cd3(bdc)3(DMF)4]∞2, which has a two-dimensional network structure. When the reaction is carried out under pressure, it yields [Cd3(bdc)3(DMF)4]∞3, which is a supramolecular isomer of 2. The structure of 3 differs from that of 2 regarding the way the Cd3(O2CR)6 units are interlinked to form layers. When the reaction was carried out in DMF that had undergone partial hydrolysis, the only isolated product was {(NMe2H2)2[Cd(bdc)2]·2DMF}∞4. Compound 4 has a three-dimensional triply-interpenetrated diamondoid structure, with dimethylammonium cations and DMF molecules included within the pores. The reaction between Cd(NO3)2·4H2O and H2bdc in DEF gave [Cd(bdc)(DEF)]∞5, regardless of the solvent quality. Compound 5 has a three-dimensional network structure. The reaction of Cd(NO3)2·4H2O and 1,3-benzenedicarboxylic acid (H2mbdc) in DMF gave [Cd(mbdc)(DMF)]∞6 which has a bilayer structure. The thermal properties of the new materials have been investigated, and the coordinated DEF molecules from 5 can be removed on heating to 400 °C without any change in the powder X-ray diffraction pattern. The H2 sorption isotherm for the desolvated material shows marked hysteresis between adsorption and desorption, and less adsorption than predicted by simulations. Kinetic data indicate that the hysteresis is not due to mass transfer limitations, and the most likely explanation for this behaviour lies in partial collapse of the framework to an amorphous phase under the conditions of activation.
Co-reporter:Sean P. Bew, Andrew D. Burrows, Tina Düren, Mary F. Mahon, Peyman Z. Moghadam, Viorica M. Sebestyen and Sean Thurston
Chemical Communications 2012 - vol. 48(Issue 40) pp:NaN4826-4826
Publication Date(Web):2012/03/22
DOI:10.1039/C2CC30988B
An upper rim-functionalised calix[4]arene dicarboxylic acid (H2caldc) has been used to prepare four metal–organic frameworks, three of which have been structurally characterised and shown to form two- or three-dimensional network structures. Simulations suggest that such networks are likely to display interesting selectivity to guest molecules.
Co-reporter:Andrew D. Burrows, Monika Jurcic, Mary F. Mahon, Sandrine Pierrat, Gavin W. Roffe, Henry J. Windle and John Spencer
Dalton Transactions 2015 - vol. 44(Issue 31) pp:NaN13817-13817
Publication Date(Web):2015/07/14
DOI:10.1039/C5DT02458G
A series of bismuth–dicarboxylate–deferiprone coordination networks have been prepared and structurally characterised. The new compounds have been demonstrated to release the iron overload drug deferiprone on treatment with PBS and have also been shown to have antibacterial activity against H. pylori.
Co-reporter:Andrew D. Burrows, Mary F. Mahon, Catherine L. Renouf, Christopher Richardson, Anna J. Warren and John E. Warren
Dalton Transactions 2012 - vol. 41(Issue 14) pp:NaN4163-4163
Publication Date(Web):2012/01/26
DOI:10.1039/C2DT12115H
The iron(III) and aluminium(III) complexes of 1,3-di(4-pyridyl)propane-1,3-dionato (dppd) and 1,3-di(3-pyridyl)propane-1,3-dionato (dmppd), [Fe(dppd)3] 1, [Fe(dmppd)3] 2, [Al(dppd)3] 3 and [Al(dmppd)3] 4 have been prepared. These complexes adopt molecular structures in which the metal centres contain distorted octahedral geometries. In contrast, the copper(II) and zinc(II) complexes [Cu(dppd)2] 5 and [Zn(dmppd)2] 6 both form polymeric structures in which coordination of the pyridyl groups into the axial positions of neighbouring metal centres links discrete square-planar complexes into two-dimensional networks. The europium complex [Eu(dmppd)2(H2O)4]Cl·2EtOH·0.5H2O 7 forms a structure containing discrete cations that are linked into sheets through hydrogen bonds, whereas the lanthanum complex [La(dmppd)3(H2O)]·2H2O 8 adopts a one-dimensional network structure, connected into sheets by hydrogen bonds. The iron complexes 1 and 2 act as metalloligands in reactions with silver(I) salts, with the nature of the product depending on the counter-ions present. Thus, the reaction between 1 and AgBF4 gave [AgFe(dppd)3]BF4·DMSO 9, in which the silver centres link the metalloligands into discrete nanotubes, whereas reactions with AgPF6 and AgSbF6 gave [AgFe(dppd)3]PF6·3.28DMSO 10 and [AgFe(dppd)3]SbF6·1.25DMSO 11, in which the metalloligands are linked into sheets. In all three cases, only four of the six pyridyl groups present on the metalloligands are coordinated. The reaction between 2 and AgNO3 gave [Ag2Fe(dmppd)3(ONO2)]NO3·MeCN·CH2Cl212. Compound 12 adopts a layer structure in which all pyridyl groups are coordinated to silver centres and, in addition, a nitrate ion bridges between two silver centres. A similar structure is adopted by [Ag2Fe(dmppd)3(O2CCF3)]CF3CO2·2MeCN·0.25CH2Cl213, with a bridging trifluoroacetate ion playing the same role as the nitrate ion in 12.
Co-reporter:Andrew D. Burrows, Christopher G. Frost, Mary F. Mahon, Paul R. Raithby, Catherine L. Renouf, Christopher Richardson and Anna J. Stevenson
Chemical Communications 2010 - vol. 46(Issue 28) pp:NaN5069-5069
Publication Date(Web):2010/06/08
DOI:10.1039/C0CC00646G
The Group 13 metal complexes [M(L2)3], where M is Al or Ga and L2 is 1,3-di(4-pyridyl)-1,3-propanedionato, are hexatopic metalloligands that have been used to prepare mixed-metal–organic frameworks containing interpenetrated primitive cubic networks. In contrast, the europium complex [Eu(HL2)3(H2L2)]Cl4·EtOH forms a hydrogen-bonded network following partial protonation of the pyridyl groups.
Co-reporter:Dominic J. Wales, Julien Grand, Valeska P. Ting, Richard D. Burke, Karen J. Edler, Chris R. Bowen, Svetlana Mintova and Andrew D. Burrows
Chemical Society Reviews 2015 - vol. 44(Issue 13) pp:NaN4321-4321
Publication Date(Web):2015/05/18
DOI:10.1039/C5CS00040H
Improvements in the efficiency of combustion within a vehicle can lead to reductions in the emission of harmful pollutants and increased fuel efficiency. Gas sensors have a role to play in this process, since they can provide real time feedback to vehicular fuel and emissions management systems as well as reducing the discrepancy between emissions observed in factory tests and ‘real world’ scenarios. In this review we survey the current state-of-the-art in using porous materials for sensing the gases relevant to automotive emissions. Two broad classes of porous material – zeolites and metal–organic frameworks (MOFs) – are introduced, and their potential for gas sensing is discussed. The adsorptive, spectroscopic and electronic techniques for sensing gases using porous materials are summarised. Examples of the use of zeolites and MOFs in the sensing of water vapour, oxygen, NOx, carbon monoxide and carbon dioxide, hydrocarbons and volatile organic compounds, ammonia, hydrogen sulfide, sulfur dioxide and hydrogen are then detailed. Both types of porous material (zeolites and MOFs) reveal great promise for the fabrication of sensors for exhaust gases and vapours due to high selectivity and sensitivity. The size and shape selectivity of the zeolite and MOF materials are controlled by variation of pore dimensions, chemical composition (hydrophilicity/hydrophobicity), crystal size and orientation, thus enabling detection and differentiation between different gases and vapours.
Co-reporter:Macguire R. Bryant, Andrew D. Burrows, Christopher M. Fitchett, Chris S. Hawes, Sally O. Hunter, Luke L. Keenan, David J. Kelly, Paul E. Kruger, Mary F. Mahon and Christopher Richardson
Dalton Transactions 2015 - vol. 44(Issue 19) pp:NaN9280-9280
Publication Date(Web):2015/04/17
DOI:10.1039/C5DT00011D
The synthesis, structural and thermal characterisation of a number of coordination complexes featuring the N,O-heteroditopic ligand 4-(3,5-dimethyl-1H-pyrazol-4-yl)benzoate, HL are reported. The reaction of H2L with cobalt(II) and nickel(II) nitrates at room temperature in basic DMF/H2O solution gave discrete mononuclear coordination complexes with the general formula {[M(HL)2(H2O)4]·2DMF} (M = Co (1), Ni (2)), whereas the reaction with zinc(II) nitrate gave [Zn(HL)2]∞, 3, a coordination polymer with distorted diamondoid topology and fourfold interpenetration. Coordination about the tetrahedral Zn(II) nodes in 3 are furnished by two pyrazolyl nitrogen atoms and two carboxylate oxygen atoms to give a mixed N2O2 donor set. Isotopological coordination polymers of zinc(II), {[Zn(HL)2]·2CH3OH·H2O}∞, 4, and cobalt(II), [Co(HL)2]∞, 5, are formed when the reactions are carried out under solvothermal conditions in methanol (80 °C) and water (180 °C), respectively. The reaction of H2L with cadmium(II) nitrate at room temperature in methanol gives {[Cd(HL)2(MeOH)2]·1.8MeOH}∞6, a 2-D (4,4)-connected coordination polymer, whereas with copper(II) the formation of green crystals that transform into purple crystals is observed. The metastable green phase [Cu3(HL)4(μ2-SO4)(H2O)3]∞, 7, crystallises with conserved binding domains of the heteroditopic ligand and contains two different metal nodes: a dicopper carboxylate paddle wheel motif, and, a dicopper unit bridged by sulfate ions and coordinated by ligand pyrazolyl nitrogen atoms. The resultant purple phase {[Cu(HL)2]·4CH3OH·H2O}∞, 8, however, has single copper ion nodes coordinated by mixed N2O2 donor sets with trans-square planar geometry and is threefold interpenetrated. The desolvation of 8 was followed by powder X-ray diffraction and single crystal X-ray diffraction which show desolvation induces the transition to a more closely packed structure while the coordination geometry about the copper ions and the network topology is retained. Powder X-ray diffraction and microanalysis were used to characterise the bulk purity of the coordination materials 1–6 and 8. The thermal characteristics of 1–2, 4–6 and 8 were studied by TG-DTA. This led to the curious observation of small exothermic events in networks 4, 6, and 8 that appear to be linked to their decomposition. In addition, the solid state structures of H2L and that of its protonated salt, H2L·HNO3, were also determined and revealed that H2L forms a 2-D hydrogen bonded polymer incorporating helical chains formed through N–H⋯O and O–H⋯N interactions, and that [H3L]NO3 forms a 1-D hydrogen-bonded polymer.
Co-reporter:Dongmei Jiang, Andrew D. Burrows, Robben Jaber and Karen J. Edler
Chemical Communications 2012 - vol. 48(Issue 41) pp:NaN4967-4967
Publication Date(Web):2012/04/17
DOI:10.1039/C2CC31079A
A facile in situ nanoparticle seeding method is reported to prepare MIL-101(Cr) films on alumina supports. The in situ seeding of MIL-101(Cr) nanoparticles was promoted by use of dimethylacetamide (DMA). The generality of this approach is further demonstrated for Cu3(btc)2 films by using a (poly)acrylate promoter.
Co-reporter:Laura K. Cadman, Jessica K. Bristow, Naomi E. Stubbs, Davide Tiana, Mary F. Mahon, Aron Walsh and Andrew D. Burrows
Dalton Transactions 2016 - vol. 45(Issue 10) pp:NaN4326-4326
Publication Date(Web):2015/12/14
DOI:10.1039/C5DT04045K
A new approach is reported for tailoring the pore geometry in five series of multivariate metal–organic frameworks (MOFs) based on the structure [Zn2(bdc)2(dabco)] (bdc = 1,4-benzenedicarboxylate, dabco = 1,8-diazabicyclooctane), DMOF-1. A doping procedure has been adopted to form series of MOFs containing varying linker ratios. The series under investigation are [Zn2(bdc)2–x(bdc-Br)x(dabco)]·nDMF 1 (bdc-Br = 2-bromo-1,4-benzenedicarboxylate), [Zn2(bdc)2–x(bdc-I)x(dabco)]·nDMF 2 (bdc-I = 2-iodo-1,4-benzenedicarboxylate), [Zn2(bdc)2–x(bdc-NO2)x(dabco)]·nDMF 3 (bdc-NO2 = 2-nitro-1,4-benzenedicarboxylate), [Zn2(bdc)2–x(bdc-NH2)x(dabco)]·nDMF 4 (bdc-NH2 = 2-amino-1,4-benzenedicarboxylate) and [Zn2(bdc-Br)2–x(bdc-I)x(dabco)]·nDMF 5. Series 1–3 demonstrate a functionality-dependent pore geometry transition from the square, open pores of DMOF-1 to rhomboidal, narrow pores with increasing proportion of the 2-substituted bdc linker, with the rhomboidal-pore MOFs also showing a temperature-dependent phase change. In contrast, all members of series 4 and 5 have uniform pore geometries. In series 4 this is a square pore topology, whilst series 5 exhibits the rhomboidal pore form. Computational analyses reveal that the pore size and shape in systems 1 and 2 is altered through non-covalent interactions between the organic linkers within the framework, and that this can be controlled by the ligand functionality and ratio. This approach affords the potential to tailor pore geometry and shape within MOFs through judicious choice of ligand ratios.
Co-reporter:Jonathan E. Halls, Alberto Hernán-Gómez, Andrew D. Burrows and Frank Marken
Dalton Transactions 2012 - vol. 41(Issue 5) pp:NaN1480-1480
Publication Date(Web):2011/07/26
DOI:10.1039/C1DT10734H
Metal–organic framework (MOF) materials based on zinc(II) and aluminium(III) dicarboxylate frameworks with covalently attached ferrocene functional redox groups were synthesised by post-synthetic modification and investigated by voltammetry in aqueous and non-aqueous media. In the voltammetry experiments, ferrocene oxidation occurs in all cases, but chemically reversible and stable ferrocene oxidation without decay of the voltammetric response requires a “mild” dichloroethane solvent environment. The voltammetric response in this case is identified as “surface-confined” with fast surface-hopping of electrons and without affecting the bulk of MOF microcrystals. In aqueous media a more complex pH-dependent multi-stage redox process is observed associated with chemically irreversible bulk oxidation and disintegration of the MOF framework. A characteristic 30 mV per pH unit dependence of redox potentials is observed attributed to a “framework effect”: the hydroxide-driven MOF framework dissolution.
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