Kieran C. Molloy

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Organization: University of Bath , England

Department: Department of Chemistry

Title: (PhD)

TOPICS

Inorganic Chemistry

Chemicals
References

New Multi-Ferrocenyl- and Multi-Ferricenyl- Materials via Coordination-Driven Self-Assembly and via Charge-Driven Electro-Crystallization

Co-reporter:Hakikulla H. Shah ; Rayya A. Al-Balushi ; Mohammed K. Al-Suti ; Muhammad S. Khan ; Christopher H. Woodall ; Anna L. Sudlow ; Paul R. Raithby ; Gabriele Kociok-Köhn ; Kieran C. Molloy ;Frank Marken

Inorganic Chemistry 2013 Volume 52(Issue 20) pp:12012-12022

Publication Date(Web):October 9, 2013

DOI:10.1021/ic401803p

Three new tetra-ferrocenylethynylpyridinyl copper complexes, L4(CuI)4 (3), L4(CuBr)2 (4), and L4(CuCl)2 (5) have been prepared from the reaction of ferrocenylethynylpyridine (L)(2) with copper halides CuX (with X = I–, Br–, Cl–).The ligand 2 and the complexes 3–5 have been fully characterized by spectroscopic methods. The structures of 2–4 have been confirmed by single-crystal X-ray crystallography. 2 forms a dimer in the crystalline-state through C–H··N hydrogen bonds. 4 and 5 are dimers and 3 a tetramer, in all cases linked through Cu–X··Cu bridging interactions. Cyclic voltammetry in dichloroethane showed chemically reversible multiferrocenyl oxidation signals with evidence for product electro-crystallization. The oxidation products were isolated by electrodeposition onto a Pt disc electrode and investigated by scanning electron microscopy which confirmed the spontaneous formation of crystalline oxidation products with distinctive morphologies. Energy dispersive X-ray elemental analysis shows the presence of hexafluorophosphate (counterion) with the P:Fe ratio of 1:1, 0.5:1, and 1:1 for the electrocrystallized products 3, 4, and 5, respectively, suggesting the formulas [3]4+(PF6–)4, [4]2+(PF6–)2, and [5]4+(PF6–)4 for the electro-crystallized products.

Synthesis of heterobimetallic tungsten acetylacetonate/alkoxide complexes and their application as molecular precursors to metal tungstates

Co-reporter:Hamid Choujaa, Andrew L. Johnson, Gabriele Kociok-Köhn, Kieran C. Molloy

Polyhedron 2013 Volume 59() pp:85-90

Publication Date(Web):1 August 2013

DOI:10.1016/j.poly.2013.04.031

A series of M2W2(O)2(acac)2(OMe)10 [M = Co (1), Ni (2), Mg (3), Zn (4)] have been synthesised and structurally characterised by X-ray crystallography. All the compounds share common structural features which are identical to the analogous molybdenum species, with four edge-sharing octahedra situated in the same plane, and incorporating two μ3-bridging and four μ2-bridging methoxide groups. The divalent metal M and tungsten have both octahedral coordination environments with six oxygen atoms. The structure of Na[Zn(acac)3] (6), a by-product of a failed synthesis of 4, is also reported, and is a linear polymer in which [Zn(acac)3]− anions use all six oxygen atoms to link sodium cations either side of the anion.Thermal decomposition of representative samples (1, 3) shows them to be single-source precursors for metal tungstates MWO4. When the decomposition is carried out under an autogenerated pressure (RAPET) at 700 °C 1 forms CoWO4 nanoparticles, along with WOx-filled carbon nanotubes and amorphous carbon, while 3 forms MgWO4 nanoparticles and rods, though the latter lack a carbon shell and are much shorter in length.The structures of M2W2(O)2(acac)2(OMe)10 [M = Co (1), Ni (2), Mg (3), Zn (4)] have been determined and 1, 3 have been shown to act as single-source precursors for MWO4 materials.

The synthesis of W–O–M (M=Al, Ti, Ni, Zn) μ–oxo clusters by hydrolysis of tungsten aminoalkoxides and their structural characterisation

Co-reporter:Hamid Choujaa, Andrew L. Johnson, Gabriele Kociok-Köhn, Kieran C. Molloy

Polyhedron 2013 63() pp: 199-206

Publication Date(Web):

DOI:10.1016/j.poly.2013.06.047

The synthesis of W–O–W μ-oxo clusters by hydrolysis of tungsten aminoalkoxides and their structural characterisation

Co-reporter:Hamid Choujaa, Andrew L. Johnson, Gabriele Kociok-Köhn and Kieran C. Molloy

Dalton Transactions 2012 vol. 41(Issue 37) pp:11393-11401

Publication Date(Web):16 Jul 2012

DOI:10.1039/C2DT30966A

The tungsten aminoalkoxides W(O)(OPri)3L [L = dmae, OCH2CH2NMe2 (1); bdmap, OCH(CH2NMe2)2 (2); tdmap, OC(CH2NMe2)3 (3)] have been synthesised. Controlled hydrolysis of 1–3 has allowed isolation of W4O4(μ-O)6(dmae)4 (4), W4O4(μ-O)4(OPri)4(bdmap)4 (5), W6O6(μ-O)9(tdmap)6 (6), W4O4(μ-O)6(tdmap)4 (7), W4O4(μ-O)6(tdmap)4·4H2O (7a), all of which have been characterised by X-ray crystallography. 4, 7, 7a each embody a W4O6 core with adamantane structure, 5 incorporates a folded W4O4 square and 6 has a trigonal prismatic W6O9 at its heart. 7 decomposes in air at to give orthorhombic WO3, while 1–3 decomposed under an autogenerated pressure (Reaction under Autogenic Pressure at Elevated Temperatures, RAPET) to form mixtures of carbon-coated WOx needles and carbon spherules.

New Organocadmium Hydrazine Adducts and Hydrazide Complexes

Co-reporter:Andrew L Johnson;Nathan Hollingsworth;Andrew Kingsley;Gabriele Kociok-Köhn

European Journal of Inorganic Chemistry 2012 Volume 2012( Issue 2) pp:246-250

Publication Date(Web):

DOI:10.1002/ejic.201100885

Abstract

The synthesis of (Me₂CdL)_n [L = H₂NN(H)tBu, n = 2 (1); L = H₂NN(CH₂CH₂)₂NMe, n = ∞ (2)] and the conversion of 2 to MeCdN(H)N(CH₂CH₂)₂NMe (4) are reported. In the solid state, 1 is a dimer in which each H₂NN(H)tBu bridges two metal centres to generate discrete, isolated Cd₂N₄ rings, whereas 2 is a 1D polymer in which Me₂Cd units are bridged by H₂N and MeN moieties; the chains in 2 are further reinforced by NH···N hydrogen bonds. Hydrazide 4 is tetrameric and isostructural with the known aminomorpholine analogue; it forms a Cd₄N₈ cage structure that embodies both five-membered Cd₂N₃ and six-membered Cd₂N₄ rings. In addition to X-ray crystallography, 1, 2 and 4 have been characterised by ¹H, ¹³C, and ¹¹³Cd NMR spectroscopy.

The synthesis of a novel heterobimetallic amidotungsten–antimony complex

Co-reporter:Hamid Choujaa, Andrew L. Johnson, Gabriele Kociok-Köhn, Kieran C. Molloy

Polyhedron 2010 29(6) pp: 1607-1611

Publication Date(Web):

DOI:10.1016/j.poly.2010.01.033

Structural Study of the Reaction of Methylzinc Amino Alcoholates with Oxygen

Co-reporter:Nathan Hollingsworth, Andrew L Johnson, Andrew Kingsley, Gabriele Kociok-Köhn and Kieran C Molloy

Organometallics 2010 Volume 29(Issue 15) pp:3318-3326

Publication Date(Web):July 2, 2010

DOI:10.1021/om100449t

Reaction of ZnMe2 with 1,3-bis(dimethylamino)propan-2-ol (Hbdmap) in 2:1 ratio forms both [MeZn(bdmap)·ZnMe2]2 (2) and [MeZn(bdmap)]3·ZnMe2 (3) depending on the concentration of the reaction. In the former, ZnMe2 is coordinated to a free N-donor of the bdmap ligand and rather more loosely to the oxygen of the alkoxide. In 3, the ZnMe2 is coordinated to two free N-donors of the bdmap ligand. 2 reacts with O2 at low temperatures with controlled insertion into one of the Zn−C bonds of the coordinated ZnMe2 group to form the peroxide [MeZn(bdmap)]2MeZnOOMe (4). 4 decomposes slowly, and the hydroxide [MeZn(bdmap)]2MeZnOH (5) was isolated; in addition to 5, two other decomposition products have been unambiguously identified, namely, (MeZn)5(bdmap)3O (6) and (MeZn)4(bdmap)4ZnO (7). The formation of these species can be linked to reactions of the hydroxide (5), or its associated radical [MeZn(bdmap)]2MeZn(O•)], with species such as ZnMe2 or MeZn(bdmap), present is solution as a result of operating Schlenk equilibria. The structure of [MeZn(bdmap)]4 (1) is also reported.

Synthesis and structural chemistry of metallo-xanthate anions (M = Zn, Sn, Bi)

Co-reporter:A. ur Rehman, S. Ali, G. Kociok-Köhn, K.C. Molloy

Journal of Molecular Structure 2009 Volume 937(1–3) pp:56-60

Publication Date(Web):26 November 2009

DOI:10.1016/j.molstruc.2009.08.012

The structures of the metallo-xanthate anions [Zn(S2COR)3]− (R = Et (1), Pri (2)), [Sn(S2COR)3]− (R = Et (3), Pri (4)), and [Bi(S2COPri)4]− (5) have been determined as their [Me4N]+ salts. The two zinc species differ in having either all S,S bonded ligands (1) or both S,S and S,O-ligation (2). The tin compounds are either monomeric (4) or weakly associated into dimers (3), while 5 adopts a monomeric dodecahedral structure.

Organocadmium Hydrazide and Hydrazine Complexes

Co-reporter:Andrew L. Johnson, Nathan Hollingsworth, Andrew Kingsley, Gabriele Kociok-Köhn and Kieran C. Molloy

Organometallics 2009 Volume 28(Issue 8) pp:2650-2653

Publication Date(Web):March 26, 2009

DOI:10.1021/om900121z

The first structurally authenticated organocadmium hydrazine and hydrazide complexes are reported. Reaction of CdMe2 with H2NN(CH2)4O in a 1:1 ratio forms the adduct [(Me2Cd)3(H2NN(CH2)4O)2]∞ (1) below room temperature. Heating the same solution to 90 oC liberates methane and generates [MeCdN(H)N(CH2)4O]4 (2). The structure of 1 consists of dimers, [Me2Cd·H2NN(CH2)4O]2, which form six-membered Cd2N4 rings, linked into 1-D chains by CdMe2 moieties coordinated to the oxygen of the morpholine ring. 2 is a tetramer embodying a Cd4N8 cage analogous to related organozinc hydrazides, but unlike the latter, each metal center has the same coordination environment. Hydrolysis of 2 gives [MeCdN(H)N(CH2)4O]3[MeCdOH] (3), which is isostructural with its known zinc analogue. In addition to X-ray crystallography, 1 and 2 have been characterized by 1H, 13C, and 113Cd NMR.

Organozinc Aminoalcoholates: Synthesis, Structure, and Materials Chemistry

Co-reporter:Andrew L. Johnson, Nathan Hollingsworth, Gabriele Kociok-Köhn and Kieran C. Molloy

Inorganic Chemistry 2008 Volume 47(Issue 24) pp:12040-12048

Publication Date(Web):November 13, 2008

DOI:10.1021/ic801591d

A series of novel organozinc aminoalcoholates have been synthesized by the reaction of the amino alcohols HOCHx(CH2NMe2)3−x (x = 2, Hdmae; 1, Hbdmap; 0, Htdmap) with R2Zn (R = Me, Et). The 1:1 reaction with Hdmae leads to the tetramers [RZn(dmae)]4 [R = Me (1), Et (2)], while with Htdmap, dimeric [RZn(tdmap)]2 [R = Me (7), Et (8)] are produced. Reaction with Hbdmap only yields [MeZn(bdmap)]n (3), an oil which mass spectral data suggests contains a mixture of Zn2 - Zn7 species, when a 2-fold excess of ligand is used. Crystals of dimeric [Zn(bdmap)2·Hbdmap]2 (4) deposit from this oil on prolonged standing. Reaction of Et2Zn with Hbdmap (1:1) affords [EtZn(bdmap)]n (5), also an oil made up of Zn3 and Zn4 clusters on the basis of mass spectral evidence. Crystals of EtZn3(bdmap)5 (6) are formed within the oil that is 5 on standing. [MeZn(tdmap)]2 (7) has been used as a single-source precursor for hexagonal ZnO films under low pressure chemical vapor deposition (LPCVD) conditions and a substrate temperature of 500 °C.

Atmospheric pressure chemical vapour deposition of WO3 thin films from a volatile fluorinated tungsten oxo-alkoxide precursor, W(O)(OCH2CF3)4

Co-reporter:K. C. Molloy;P. A. Williams

Applied Organometallic Chemistry 2008 Volume 22( Issue 10) pp:560-564

Publication Date(Web):

DOI:10.1002/aoc.1439

Abstract

The monomeric tungsten oxo-fluoroalkoxide W(O)(CH₂CF₃)₄ (1) was synthesized from W(O)Cl₄ and CF₃CH₂OH in the presence of ammonia. It was used in atmospheric pressure chemical vapour deposition experiments to deposit non-stoichiometric WO_2.9 when used as a single-source precursor or stoichiometric WO₃ when O₂ was used as co-reagent. Copyright © 2008 John Wiley & Sons, Ltd.

Aerosol-Assisted CVD of Antimony Sulfide from Antimony Dithiocarbamates

Co-reporter:J. Rodriguez-Castro;M. F. Mahon;K. C. Molloy

Chemical Vapor Deposition 2006 Volume 12(Issue 10) pp:

Publication Date(Web):16 OCT 2006

DOI:10.1002/cvde.200506369

Asymmetric antimony dithiocarbamates, Sb[S₂CN(Me)R]₃ (R = Bu, Hex, Bz), can be thermally decomposed under a dynamic vacuum to yield high-purity Sb₂S₃ rods. These precursors do not, however, have sufficient volatility for low-pressure (LP) CVD, but are soluble in organic solvents and can be exploited in aerosol-assisted (AA) CVD. Sb₂S₃ can be deposited using the latter procedure, but the film purity is dependent on substrate temperature. As temperature increases the films become more susceptible to oxidation, and the deposition of oxides and mixed oxide/sulfides becomes more prevalent.

Aerosol-Assisted CVD of Antimony Sulfide from Antimony Dithiocarbamates

Co-reporter:J. Rodriguez-Castro;M. F. Mahon;K. C. Molloy

Chemical Vapor Deposition 2006 Volume 12(Issue 12) pp:

Publication Date(Web):19 DEC 2006

DOI:10.1002/cvde.200690026

Tin(II) aminoalkoxides and heterobimetallic derivatives: the structures of Sn6(O)4(dmae)4, Sn6(O)4(OEt)4 and [Sn(dmae)2Cd(acac)2]2

Co-reporter:Nathan Hollingsworth;Graeme A. Horley;Muhammed Mazhar;Mary F. Mahon;Peter W. Haycock;Christopher P. Myers;Gary W. Critchlow

Applied Organometallic Chemistry 2006 Volume 20(Issue 10) pp:

Publication Date(Web):25 JUL 2006

DOI:10.1002/aoc.1118

Tin(II) methoxide reacts with N,N′-dimethylaminoethanol (dmaeH) to yield Sn(dmae)₂ (1) along with small amounts of the hydrolysis product Sn₆(O)₄(dmae)₄ (2). The geometrically more regular iso-structural cage Sn₆(O)₄(OEt)₄ (3) was obtained as the only tractable product isolated from reaction of 2 and Sb(OEt)₃, while 1 reacted with CdX₂ (X = acac, I) to afford Sn(dmae)₂Cd(acac)₂ (4) and Sn(dmae)₂CdI₂ (5). The X-ray structures of 2, 3 and 4 are reported. Decomposition of 4 under aerosol-assisted chemical vapour deposition conditions leads to amorphous tin oxide films with no detectable cadmium (i.e. ca < 2% cadmium), rather than a stoichiometric Sn:Cd oxide. Copyright © 2006 John Wiley & Sons, Ltd.

Atmospheric pressure chemical vapour deposition of fluorine-doped tin(IV) oxide from fluoroalkyltin precursors

Co-reporter:Joanne E. Stanley;Anthony C. Swain;David W. H. Rankin;Heather E. Robertson;Blair F. Johnston

Applied Organometallic Chemistry 2005 Volume 19(Issue 5) pp:

Publication Date(Web):4 MAR 2005

DOI:10.1002/aoc.721

Perfluoroalkytin compounds R_(4−n)Sn(R_f)_n (R = Me, Et, Bu, R_f = C₄F₉, n = 1; R = Bu, R_f = C₄F₉, n = 2, 3; R = Bu, R_f = C₆F₁₃, n = 1) have been synthesized, characterized by ¹H, ¹³C, ¹⁹F and ¹¹⁹Sn NMR, and evaluated as precursors for the atmospheric pressure chemical vapour deposition of fluorine-doped SnO₂ thin films. All precursors were sufficiently volatile in the range 84–136 °C and glass substrate temperatures of ca 550 °C to yield high-quality films with ca 0.79–2.02% fluorine incorporation, save for Bu₃SnC₆F₁₃, which incorporated <0.05% fluorine. Films were characterized by X-ray diffraction, scanning electron microscopy, thickness, haze, emissivity, and sheet resistance. The fastest growth rates and highest quality films were obtained from Et₃SnC₄F₉. An electron diffraction study of Me₃SnC₄F₉ revealed four conformations, of which only the two of lowest abundance showed close F Sn contacts that could plausibly be associated with halogen transfer to tin, and in each case it was fluorine attached to either the γ- or δ-carbon atoms of the R_f chain. Copyright © 2005 John Wiley & Sons, Ltd.

Atmospheric pressure deposition of fluorine-doped SnO2 thin films from organotin fluorocarboxylate precursors

Co-reporter:Mary F. Mahon;Joanne E. Stanley;David W. H. Rankin;Heather E. Robertson;Blair F. Johnston

Applied Organometallic Chemistry 2005 Volume 19(Issue 5) pp:

Publication Date(Web):4 MAR 2005

DOI:10.1002/aoc.722

Nine organotin fluorocarboxylates R_nSnO₂CR_f (n = 3, R = Bu, R_f = CF₃, C₂F₅, C₃F₇, C₇F₁₅; R = Et, R_f = CF₃, C₂F₅; R = Me, R_f = C₂F₅; n = 2, R = Me, R_f = CF₃) have been synthesized; key examples have been used to deposit fluorine-doped SnO₂ thin films by atmospheric pressure chemical vapour deposition. Et₃SnO₂CC₂F₅, in particular, gives high-quality films with fast deposition rates despite adopting a polymeric, carboxylate-bridged structure in the solid state, as determined by X-ray crystallography. Gas-phase electron diffraction on the model compound Me₃SnO₂CC₂F₅ shows that accessible conformations do not allow contact between tin and fluorine, and that direct transfer is therefore unlikely to be part of the mechanism for fluorine incorporation in SnO₂ films. The structure of Me₂Sn(O₂CCF₃)₂(H₂O) has also been determined and adopts a trans-Me₂SnO₃ coordination sphere about tin in which each carboxylate group is monodentate. Copyright © 2005 John Wiley & Sons, Ltd.

Atmospheric Pressure CVD of Antimony Oxides

Co-reporter:P. W. Haycock;G. A. Horley;K. C. Molloy;C. P. Myers;S. A. Rushworth;L. M. Smith

Chemical Vapor Deposition 2001 Volume 7(Issue 5) pp:

Publication Date(Web):30 AUG 2001

DOI:10.1002/1521-3862(200109)7:5<191::AID-CVDE191>3.0.CO;2-U

Organocadmium Aminoalcoholates: Synthesis, Structure, and Materials Chemistry

Co-reporter:Andrew L. Johnson ; Nathan Hollingsworth ; Gabriele Kociok-Köhn

Inorganic Chemistry () pp:

Publication Date(Web):

DOI:10.1021/ic800897t

The novel methylcadmium aminoalkoxides MeCd(dmae) (Hdmae = dimethylaminoethanol), MeCd(bdmap) [Hbdmap = 1,3-bis-(dimethylamino)-propan-2-ol], and MeCd(tdmap) [tdmap = 1,3-bis(dimethylamino)-2-(dimethylaminomethyl)-propan-2-ol] have been synthesized and structurally characterized. MeCd(dmae) (1) forms a tetrameric heterocubane with a Cd4O4 core, while MeCd(bdmap) (2) is trimeric and MeCd(tdmap) (3) is a dimer. Only in the case of MeCd(dmae) are all the ligand donors fully utilized. In solution, MeCd(tdmap) undergoes a Schlenk equilibrium, with Me2Cd and Cd(tdmap)2 evident at 218 K. The structure and solution-state chemistry of Cd(tdmap)2 (5) have been independently studied and, in the solid-state, found to exist as a dimer whose coordination number at cadmium (CN = 6) is greater than in the organocadmium complexes (CN = 4, 5). MeCd(tdmap) has been used as a single-source precursor for CdO films by LPCVD with a glass substrate temperature of only 140 °C. Evidence is also presented for the formation of a heterometallic precursor, [(MeZn)(MeCd)(tdmap)2] (6), which has been used to deposit films of CdO mixed with ZnO by LPCVD at 140 °C. The structure of Me4Cd4(tdmap)2Cl2 (4), obtained serendipitously, is also included. Crystal data: 1, C20H52Cd4N4O4, FW 862.26, triclinic, P1̅, a = 11.47560(10), b = 13.55400(10), c = 21.5966(2) Å, α = 99.7869(4), β = 90.7476(4), γ = 98.7823(4)°, V = 3268.82(5) Å3, Z = 4; 2, C27H67Cd3N6O3, FW 861.07, triclinic, P1̅, a = 11.4148(2), b =13.1886(2), c = 14.3139(3) A, α = 102.1962(10), β = 108.3064(10), γ = 100.8446(10)°, V = 1923.09(6) Å3, Z = 4; 3, C22H54Cd2N6O2, FW 659.51, monoclinic, P21/n, a = 10.2912(1), b = 13.46930(1), c = 11.79130(1) Å, β = 112.8051(1)°, V = 1506.59(2) Å3, Z = 2; 4, C24H60Cd4Cl2N6O2, FW 985.28, monoclinic, P21/c, a = 10.89780(10), b = 20.3529(2), c = 16.5317(2) Å, β = 94.8550(10)°, V = 3653.61(7) Å3, Z = 4; 5, C40H96Cd2N12O4, FW 1034.09, orthorhombic, P21cn, a = 12.33290(10), b = 14.25060(10), c = 29.9003(2) Å, V = 5255.01(7) Å3, Z = 4.

The synthesis of W–O–W μ-oxo clusters by hydrolysis of tungsten aminoalkoxides and their structural characterisation

Co-reporter:Hamid Choujaa, Andrew L. Johnson, Gabriele Kociok-Köhn and Kieran C. Molloy

Dalton Transactions 2012 - vol. 41(Issue 37) pp:NaN11401-11401

Publication Date(Web):2012/07/16

DOI:10.1039/C2DT30966A