Co-reporter:Vanessa A. Béland, Matthew A. S. Ross, Matthew J. Coady, Ryan Guterman, and Paul J. Ragogna
Chemistry of Materials October 24, 2017 Volume 29(Issue 20) pp:8884-8884
Publication Date(Web):September 26, 2017
DOI:10.1021/acs.chemmater.7b03674
In an attempt to address the growing demand for well-defined metallized regions for electronic applications, we developed a new method of forming patterned ceramics. Using UV-curing to synthesize a phosphonium-containing semi-interpenetrating polymer network (S-IPN) followed by ion exchange on the surface with a bis(phosphino)borate molybdenum tetracarbonyl complex (2Mo) results in 71% ion exchange of 2Mo to phosphonium sites by attenuated total reflectance infrared (ATR-IR) spectroscopy. The functionalized films were pyrolyzed at temperatures ranging between 800 and 1000 °C to create Mo-containing ceramics. The polymer network can be patterned using electron beam lithography prior to the metal functionalization step. The patterns had good shape retention after metal functionalization and pyrolysis. The polymer networks were characterized using ATR-IR spectroscopy, thermogravimetric analysis, and differential scanning calorimetry, and the swellability and gel content were determined. The resulting ceramics were characterized using optical and scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and powder X-ray diffraction.
Co-reporter:Cameron M. E. Graham, Juuso Valjus, Taylor E. Pritchard, Paul D. Boyle, Heikki M. Tuononen, and Paul J. Ragogna
Inorganic Chemistry November 6, 2017 Volume 56(Issue 21) pp:13500-13500
Publication Date(Web):October 13, 2017
DOI:10.1021/acs.inorgchem.7b02217
The reactivity of 4-membered (RPCh)2 rings (Ch = S, Se) that contain phosphorus in the +3 oxidation state is reported. These compounds undergo ring expansion to (RPCh)3 with the addition of a Lewis base. The 6-membered rings were found to be more stable than the 4-membered precursors, and the mechanism of their formation was investigated experimentally and by density functional theory calculations. The computational work identified two plausible mechanisms involving a phosphinidene chalcogenide intermediate, either as a free species or stabilized by a suitable base. Both the 4- and 6-membered rings were found to react with coinage metals, giving the same products: (RPCh)3 rings bound to the metal center from the phosphorus atom in tripodal fashion.
Co-reporter:Tyler J. Cuthbert, Josh J. Jadischke, John R. de Bruyn, Paul J. Ragogna, and Elizabeth R. Gillies
Macromolecules July 25, 2017 Volume 50(Issue 14) pp:5253-5253
Publication Date(Web):July 5, 2017
DOI:10.1021/acs.macromol.7b00955
Self-healing, ionically cross-linked networks were prepared from poly(acrylic acid) (PAA) and poly(triethyl(4-vinylbenzyl)phosphonium chloride) (P-Et-P), and their properties were studied. Three different ratios of PAA/P-Et-P were incorporated into the networks by varying the addition orders of the components. Swelling of the networks increased with increasing NaCl concentration when they were immersed in aqueous solution. All networks retained their structural integrity in 0.1 M NaCl. Studies of the rheological and tensile properties of the networks swelled in 0.1 M NaCl showed that PAA>P-Et-P exhibited high elongation and viscoelastic properties suitable for self-healing with a relaxation time of ∼30 s, whereas the other networks exhibited predominantly elastic behavior. The moduli were similar to those of soft tissues. Self-healing of PAA>P-Et-P in 0.1 M NaCl was demonstrated through repair of a 0.5 mm diameter puncture in the material whereas healing was incomplete for the other networks and also for PAA>P-Et-P in the absence of NaCl. Healing after completely severing a tensile testing sample showed significant recovery of the modulus, strength, and elongation. The properties of these materials and their ability to self-heal in low and physiologically relevant salt concentrations make them promising candidates for a variety of applications, particularly in the biomedical area.
Co-reporter:Cameron M. E. Graham, Charles L. B. Macdonald, Philip P. Power, Zachary D. Brown, and Paul J. Ragogna
Inorganic Chemistry August 7, 2017 Volume 56(Issue 15) pp:9111-9111
Publication Date(Web):July 24, 2017
DOI:10.1021/acs.inorgchem.7b01138
The manipulation of white phosphorus (P4) has been a long-standing challenge for chemists. While the holy grail remains at finding a method to catalytically activate and functionalize P4 to yield new organophosphorus compounds, fundamental research lies in developing procedures to control the reactivity of elemental phosphorus. In this work, Lewis acidic transition metal moieties M(CO)5 (M = Cr, Mo, W) and AuCl react with P4 derivatized with a low valent germanium compound. For both M(CO)5 and AuCl, bis-functionalized products can be formed; however the monosubstituted derivatives are found to be more stable, and the decomposition can be monitored by 31P{1H} NMR spectroscopy. The selective reactivity of white phosphorus, once a P–P bond has been activated, is a key step in yielding new organophosphorus compounds.
Co-reporter:Ryan Guterman;Tristan D. Harrison;Elizabeth R. Gillies;Paul J. Ragogna
Polymer Chemistry (2010-Present) 2017 vol. 8(Issue 22) pp:3425-3430
Publication Date(Web):2017/06/06
DOI:10.1039/C7PY00438A
Diphenylgermane was polymerized with a multifunctional olefin to create a polymer network possessing pendant Ge–H functional groups within the material. Unlike silanes, which do not efficiently undergo radical mediated hydrosilylation reactions, we observed that hydrogermylation with triphenylgermane and diphenylgermane was possible, which could be extended to a polymerization reaction. Using a small-molecule model system, we demonstrated that Ge–H bonds add to olefins in a 1 : 1 fashion according to a step-growth, radical mediated process, similar to thiol–ene and phosphane–ene systems. This was accomplished using a small amount of initiator under mild conditions, demonstrating the efficiency of this process. The unreacted Ge–H functionality within the polymer network provided a latent handle to perform onwards chemistry, including bond activation, thiolation, and solid-supported germane–ene chemistry. The resulting materials were characterized using EDX, IR, and Raman spectroscopy.
Co-reporter:T. J. Cuthbert;E. Evoy;J. P. J. Bow;R. Guterman;J. M. Stubbs;E. R. Gillies;P. J. Ragogna;J. M. Blacquiere
Catalysis Science & Technology (2011-Present) 2017 vol. 7(Issue 13) pp:2685-2688
Publication Date(Web):2017/07/03
DOI:10.1039/C7CY00391A
A soft polymer network prepared through a phosphane–ene reaction successfully sequestered Rh and Ru from hydrogenation and ring closing metathesis reactions, respectively. Scavenging effectively quenches catalytic activity and ultimately removes >98% of the metal.
Co-reporter:Cameron M. E. Graham;Taylor E. Pritchard;Paul D. Boyle;Juuso Valjus; Heikki M. Tuononen; Paul J. Ragogna
Angewandte Chemie 2017 Volume 129(Issue 22) pp:6332-6336
Publication Date(Web):2017/05/22
DOI:10.1002/ange.201611196
AbstractFour-membered rings with a P2Ch2 core (Ch=S, Se) and phosphorus in the +3 oxidation state have been synthesized. The utility of these rings as a source of monomeric phosphinidene chalcogenides was probed by the addition of an N-heterocyclic carbene, resulting in a base-stabilized phosphinidene sulfide. Similarly, persistence of the phosphinidene selenide in solution was shown through cycloaddition chemistry with 2,3-dimethylbutadiene at elevated temperatures. The observed reactivity was explained by detailed computational work that established the conditions upon which the P2Ch2 rings can liberate phosphinidene chalcogenides.
Co-reporter:M. Azizpoor Fard, A. Rabiee Kenaree, P. D. Boyle, P. J. Ragogna, J. B. Gilroy and J. F. Corrigan
Dalton Transactions 2016 vol. 45(Issue 7) pp:2868-2880
Publication Date(Web):21 Jan 2016
DOI:10.1039/C5DT03962B
Ferrocene-based phosphines constitute an important auxiliary ligand in inorganic chemistry. Utilizing the (ferrocenylethyl)phosphines (FcCH2CH2)3−nHnP (Fc = ferrocenyl; n = 2, 1; n = 1, 2; n = 0, 3) the synthesis of a series of coordination complexes [(FcCH2CH2)3−nHnPCuCl]4 (n = 2, 1-CuCl; n = 0, 3-CuCl), [(FcCH2CH2)2HPCuCl] (2-CuCl), {[(FcCH2CH2)H2P]2AgCl}2 (1-AgCl), [(FcCH2CH2)2HPAgCl] (2-AgCl), [(FcCH2CH2)3PAgCl]4 (3-AgCl), [(FcCH2CH2)3PM(OAc)]4 (M = Cu, 3-CuOAc M = Ag, 3-AgOAc), [(FcCH2CH2)3−nHnPAuCl] (n = 1, 2-AuCl; n = 0, 3-AuCl), via the reaction between the free phosphine and MX (M = Cu, Ag and Au; X = Cl, OAc), is described. The reaction between the respective phosphine with a suspension of metal–chloride or -acetate in a 1:1 ratio in THF at ambient temperature affords coordinated phosphine-coinage metal complexes. Varying structural motifs are observed in the solid state, as determined via single crystal X-ray analysis of 1-CuCl, 3-CuCl, 1-AgCl, 3-AgCl, 3-CuOAc, 3-AgOAc, 2-AuCl and 3-AuCl. Complexes 1-CuCl and 3-CuCl are tetrameric Cu(I) cubane-like structures with a Cu4Cl4 core, whereas silver complexes with primary and tertiary phosphine reveal two different structural types. The structure of 1-AgCl, unlike the rest, displays the coordination of two phosphines to each silver atom and shows a quadrangle defined by two Ag and two Cl atoms. In contrast, 3-AgCl is distorted from a cubane structure via elongation of one of the Cl⋯Ag distances. 3-CuOAc and 3-AgOAc are isostructural with step-like cores, while complexes 2-AuCl and 3-AuCl reveal a linear geometry of a phosphine gold(I) chloride devoid of any aurophilic interactions. All of the complexes were characterized in solution by multinuclear 1H, 13C{1H} and 31P NMR spectroscopic techniques; the redox chemistry of the series of complexes was examined using cyclic voltammetry. This class of complexes has been found to exhibit one reversible Fe(II)/Fe(III) oxidation couple, suggesting the absence of electronic communication between the ferrocenyl units on individual phosphine ligands as well as between different phosphines on the polymetallic cores.
Co-reporter:Ryan Guterman, Amir Rabiee Kenaree, Joe B. Gilroy, Elizabeth R. Gillies, and Paul J. Ragogna
Chemistry of Materials 2015 Volume 27(Issue 4) pp:1412
Publication Date(Web):January 26, 2015
DOI:10.1021/cm504784e
Air-stable primary phosphines were photopolymerized using phosphane–ene chemistry, the phosphorus analogue of the thiol–ene reaction, to fabricate a completely new class of polymer networks. It was demonstrated that the tunable thermal and physical properties accessible using thiol–ene chemistry could also be achieved using an analogous phosphane–ene reaction. At the same time, the presence of the 31P nucleus that is easily observed using NMR spectroscopy allowed the chemical structures of the networks to be directly probed using solid state NMR spectroscopy. Following its incorporation into the network, phosphorus offers the distinct difference and advantage of being able to undergo a diverse array of further derivatization to afford functional materials. For example, the networks were demonstrated to serve as effective oxygen scavengers and to bind transition metals (e.g., Pd). By using the air stable ferrocenyl phosphine (FcCH2CH2)PH2, redox-active networks were produced and these materials could be pyrolyzed to yield magnetic ceramics. Overall, this demonstrates the promise of phosphane–ene chemistry as an alternative to thiol–ene systems for providing functional materials for a diverse range of applications.
Co-reporter:Mahboubeh Hadadpour, Jessica Gwyther, Ian Manners, and Paul J. Ragogna
Chemistry of Materials 2015 Volume 27(Issue 9) pp:3430
Publication Date(Web):April 16, 2015
DOI:10.1021/acs.chemmater.5b00752
Sequential reversible addition–fragmentation transfer (RAFT) polymerization of a mixed sandwich cobaltocene monomer (η5-cyclopentadienyl-cobalt-η4-cyclobutadiene (CpCoCb)) and a phosphonium salt functionalized styrene monomer resulted in the first example of a unique multifunctional block copolymer consisting of a metallopolymer block and a polyelectrolyte block. The polyelectrolyte block was decorated with a gold anion (AuCl4–) via salt metathesis, resulting in a heterobimetallic block copolymer with distinct gold and cobalt sections. Solution self-assembly behavior of this unique metallopolymer-b-polyelectrolyte copolymer before and after salt metathesis was studied. Heterobimetallic micelles with a gold containing core and a cobalt-containing corona were obtained, and then the core was reduced to form gold nanoparticles (AuNPs). Studies on the solid-state self-assembly of this unique block copolymer showed that it phase separated into hexagonally packed cylinders. Salt metathesis of the phase-separated block copolymers was utilized as the first example of a nonstandard selective staining method to exclusively stain the polyelectrolyte domains with the AuCl4– anion. Staining the metallopolymer domain by RuO4 provided the complementary pattern. Pyrolysis of the self-assembled block copolymers resulted in magnetic cobalt-phosphate nanoparticles with 17% char yield.
Co-reporter:Ryan Guterman, Elizabeth R. Gillies and Paul J. Ragogna
Dalton Transactions 2015 vol. 44(Issue 35) pp:15664-15670
Publication Date(Web):30 Jul 2015
DOI:10.1039/C5DT02364E
Air-sensitive and air-stable primary phosphines (RPH2) were compared for their ability to undergo photoinitiated phosphane–ene chemistry with 1-hexene. Despite their increased air-stability, the primary phosphines displayed equal to or greater reactivity when compared to air-sensitive alkyl or aryl analogues. The phosphane–ene reaction was also performed in the presence of 1-octanethiol to determine whether thiol–ene and phosphane–ene chemistries could proceed simultaneously. It was determined that the phosphane–ene process takes precedence over thiol–ene as P–H bond conversion was independent of thiol concentration. Tertiary phosphine (R3P) and some secondary phosphine (R2PH) products were found to react with thiols under experimental conditions to create phosphine–sulfides (P–S), but this chemistry only proceeded at low P–H bond concentrations. These results suggests that hydrogen transfer reactions take precedence over P–S formation and demonstrate the unique relationship between phosphane–ene and thiol–ene chemistry.
Co-reporter:Ryan Guterman, Elizabeth R. Gillies, and Paul J. Ragogna
Langmuir 2015 Volume 31(Issue 18) pp:5181-5189
Publication Date(Web):April 20, 2015
DOI:10.1021/acs.langmuir.5b00235
A phosphonium salt possessing three methacrylate groups has been incorporated into a photopolymeric system to generate highly cross-linked polyelectrolyte networks. Emergent chemical and physical properties in the polymers were observed and attributed to the tandem increase in cross-link density and ion-content upon incorporation of the self-cross-linking cation. Anion-exchange with bis(trifluoromethylsulfonyl)imide or dodecylbenzenesulfonate resulted in significant differences in wettability and ion-exchange behavior. The passivating effects of dodecylbenzenesulfonate were utilized to selectively pattern fluorescein dye into the polymer network, highlighting a new patterning procedure using ionic-bond forming reactions.
Co-reporter:Mahboubeh Hadadpour ;Paul J. Ragogna
Journal of Polymer Science Part A: Polymer Chemistry 2015 Volume 53( Issue 23) pp:2747-2754
Publication Date(Web):
DOI:10.1002/pola.27745
ABSTRACT
Reversible addition fragmentation transfer (RAFT) agent functionalized polydimethylsiloxane (PDMS-RAFT) was used as a macro-RAFT agent to polymerize a mixed sandwich cobaltocene containing monomer featuring η5-cyclopentadienyl-cobalt-η4-cyclobutadiene. High molecular weight block copolymers (BCP) consisting of a metallic block and a PDMS block with excellent control over molecular weight and polydispersity were prepared. Solid-state self-assembly of this BCP resulted in hexagonal domains of metallopolymer phase-separated from PDMS. In solution, spherical micelles with a metallic core, stabilized by a PDMS corona were prepared. Pyrolysis of the BCP resulted in magnetic nanoparticles with 30% char yield. The BCP was used as an ink material for microcontact printing (μCP) to transfer long-ranged patterns. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2747–2754
Co-reporter:Amir Rabiee Kenaree, Bradley M. Berven, Paul J. Ragogna and Joe B. Gilroy
Chemical Communications 2014 vol. 50(Issue 73) pp:10714-10717
Publication Date(Web):01 Aug 2014
DOI:10.1039/C4CC05296J
The synthesis and characterization of a novel class of highly-metallized, redox-active polyelectrolytes that employ phosphorus as a scaffold for the installation of transition metals is described. Pyrolysis of thin films of the title polyelectrolytes resulted in the production of magnetite crystallites and ill-defined carbon-, phosphorus- and oxygen-rich phases in char yields of nearly 50%.
Co-reporter:Jonathan W. Dube, Zachary D. Brown, Christine A. Caputo, Philip P. Power and Paul J. Ragogna
Chemical Communications 2014 vol. 50(Issue 16) pp:1944-1946
Publication Date(Web):09 Dec 2013
DOI:10.1039/C3CC48933G
The reaction of phosphine gas with a low coordinate diaryl germylene or diarylstannylene results in both oxidative addition and arene elimination at the group 14 atom. The products were characterised by 31P NMR spectroscopy and X-ray crystallography, and represent the first P–H bond activation by a heavy group 14 element compound.
Co-reporter:Brian J. Malbrecht, Jonathan W. Dube, Mathew J. Willans, and Paul J. Ragogna
Inorganic Chemistry 2014 Volume 53(Issue 18) pp:9644-9656
Publication Date(Web):September 3, 2014
DOI:10.1021/ic501139w
The differing structures and reactivities of “GaI” samples prepared with different reaction times have been investigated in detail. Analysis by FT-Raman spectroscopy, powder X-ray diffraction, 71Ga solid-state NMR spectroscopy, and 127I nuclear quadrupole resonance (NQR) provides concrete evidence for the structure of each “GaI” sample prepared. These techniques are widely accessible and can be implemented quickly and easily to identify the nature of the “GaI” in hand. The “GaI” prepared from exhaustive reaction times (100 min) is shown to possess Ga2I3 and an overall formula of [Ga0]2[Ga+]2[Ga2I62–], while the “GaI” prepared with the shortest reaction time (40 min) contains GaI2 and has the overall formula [Ga0]2[Ga+][GaI4–]. Intermediate “GaI” samples were consistently shown to be fractionally composed of each of these two preceding formulations and no other distinguishable phases. These “GaI” phases were then shown to give unique products upon reactions with the anionic bis(phosphino)borate ligand class. The reaction of the early-phase “GaI” gives rise to a unique phosphine Ga(II) dimeric coordination compound (3), which was isolated reproducibly in 48% yield and convincingly characterized. A base-stabilized GaI→GaI3 fragment (4) was also isolated using the late-phase “GaI” and characterized by multinuclear NMR spectroscopy and X-ray crystallography. These compounds can be considered unique examples of low-oxidation-state P→Ga coordination compounds and possess relatively long Ga–P bond lengths in the solid-state structures. The anionic borate backbone therefore results in interesting architectures about gallium that have not been observed with neutral phosphines.
Co-reporter:Mahboubeh Hadadpour, Yuqing Liu, Preeti Chadha, and Paul J. Ragogna
Macromolecules 2014 Volume 47(Issue 18) pp:6207-6217
Publication Date(Web):September 8, 2014
DOI:10.1021/ma501323q
Reversible addition–fragmentation transfer (RAFT) polymerization of a η5-cyclopentadienylcobalt-η4-cyclobutadiene (CpCoCb) containing monomer under a wide variety of experimental conditions (e.g., different solvents, temperatures, RAFT agents, concentrations, and [RAFT agent]/[initiator]) was examined. In all cases the results revealed that although the monomer was being consumed over the course of the reaction, there was no significant increase in the molecular weight of the resulting polymer. It was determined that as the polymer chain grows (DP ≈ 10), a tight coil morphology was adopted, which hinders the approach of an additional, sterically demanding CpCoCb-containing monomer. This resulted in premature termination/chain transfer reactions rather than an increase in the polymer chain length. To address this problem, methyl acrylate (MA) with its lower steric demand was copolymerized with the bulky CpCoCb-containing monomer to act as a spacer. This provided the necessary steric relief and an opportunity for the metallopolymer to grow. This copolymerization resulted in dramatic improvements in the polydispersity and molecular weight of the end material. In subsequent experiments, the random copolymer was used as a macro-RAFT agent to prepare diblock copolymers, with good control over the molecular weight, allowing for an examination of the self-assembly behavior of the block copolymer in the solid state.
Co-reporter:Jonathan W. Dube;Cameron M. E. Graham; Charles L. B. Macdonald;Dr. Zachary D. Brown; Philip P. Power; Paul J. Ragogna
Chemistry - A European Journal 2014 Volume 20( Issue 22) pp:6739-6744
Publication Date(Web):
DOI:10.1002/chem.201402031
Abstract
Two unique systems based on low-coordinate main group elements that activate P4 are shown to quantitatively release the phosphorus cage upon short exposure to UV light. This reactivity marks the first reversible reactivity of P4, and the germanium system can be cycled 5 times without appreciable loss in activity. Theoretical calculations reveal that the LUMO is antibonding with respect to the main group element–phosphorus bonds and bonding with respect to reforming the P4 tetrahedron, providing a rationale for this unprecedented activity, and suggesting that the process is tunable based on the substituents.
Co-reporter:Eleanor Magdzinski, Pierangelo Gobbo, Mark S. Workentin, and Paul J. Ragogna
Inorganic Chemistry 2013 Volume 52(Issue 19) pp:11311-11319
Publication Date(Web):September 19, 2013
DOI:10.1021/ic401598e
The synthesis of a diiminopyridine (DIMPY) ligand containing pendant mixed sandwich cobaltocene functionalities on the imine nitrogens was prepared and characterized (18). Its reactivity with 2 equiv of GeCl2·dioxane and SnCl2 in THF yields the respective Lewis base mediated autoionization products (18Ge and 18Sn). Analogous low-valent complexes utilizing an N,N′- differocenyl diiminopyridine support were also prepared (15Ge and 15Sn). All compounds were characterized by spectroscopic and X-ray crystallographic methods. Electrochemical studies were conducted for both 15Sn and the precursor of 18.
Co-reporter:Jonathan W. Dube, Charles L. B. Macdonald, Bobby D. Ellis, and Paul J. Ragogna
Inorganic Chemistry 2013 Volume 52(Issue 19) pp:11438-11449
Publication Date(Web):September 18, 2013
DOI:10.1021/ic401766j
A collection of zwitterionic phosphanide metal carbonyl coordination complexes has been synthesized and fully characterized, representing the first isolated series of metal complexes for the triphosphenium family of compounds. The dicoordinate phosphorus atom of the zwitterion is formally in the +1 oxidation state and can coordinate to one metal, 2M (M = Cr, Mo, W) and 2Fe, or two metals, a Co2(CO)6 fragment 4, depending on the starting reagents. All complexes have been isolated in greater than 80% yield, and structures were confirmed crystallographically. Metrical parameters are consistent with 1 being a weak donor and results in long metal–phosphorus bonds being observed in all cases. Unique bimetallic structures, 3M (M = Cr, Mo, W), consisting of a M(CO)5 fragment on phosphorus and a piano-stool M(CO)3 fragment on a boron phenyl group have been identified in the 31P{1H} NMR spectra and confirmed using X-ray diffraction studies. Use of the borate backbone in 1, which renders the molecule zwitterionic, proves to be a determining factor in whether these metal complexes will form; the halide salt of a cationic triphosphenium ion, 6[Br], shows no evidence for formation of the analogous metal complexes by 31P{1H} NMR spectroscopy, and tetraphenylborate salts, 6[BPh4] and 7[BPh4], produce complexes that are unstable.
Co-reporter:Jacquelyn T. Price ; Paul J. Ragogna
Chemistry - A European Journal 2013 Volume 19( Issue 26) pp:8473-8477
Publication Date(Web):
DOI:10.1002/chem.201301086
Abstract
Within the past decade photochromic materials, specifically dithienylethenes (DTEs), have received increased interest because of their ability to function as potential photoswitchable molecular devices and optical memory storage systems. Current research in this area has focused on incorporating organic architectures to functionalize the DTE framework and alter the resulting photophysical properties; however, their syntheses are often not trivial. In this context, we have designed a simple and versatile diimine (2) containing adjacent 2,5-dimethyl(thienyl) rings in the backbone. This redox active diimine (2) acts as a precursor to a novel photochromic ligand and has been used to coordinate to both boron and phosphorus elements, along with the synthesis of a phosphorane-side-chain functionalized polymer without further functionalization to the parent DTE framework. A study of the resulting photochromic properties of these compounds revealed that 1) the UV-visible absorption spectra of the closed-ring isomer were dependent of the element present in the N,N′-chelating pocket and 2) incorporating the dithienylethene into a side-functionalized phosphorane polymer greatly increased the closed-/open-ring reversibility and decreased the formation of by-products.
Co-reporter:Sarah A. Weicker, Jonathan W. Dube, and Paul J. Ragogna
Organometallics 2013 Volume 32(Issue 22) pp:6681-6689
Publication Date(Web):May 17, 2013
DOI:10.1021/om400186m
Novel cationic E–Cl (E = Ge, Sn) fragments stabilized by a bis(phosphino)borate ligand (2E) were synthesized by a 1:1 stoichiometric addition of ECl2 and [Tl][(Ph2PCH2)2BPh2]. The metrical parameters are consistent with dative bonds between the phosphorus atoms and the electron-deficient group 14 element, which is in contrast to the traditionally used aryl- and nitrogen-based ligands, which are always covalently bound. The reaction of a second equivalent of bis(phosphino)borate results in the unexpected insertion of the main group center into the aliphatic B–C bond of the ligand backbone to form 3E, in addition to phosphine-borane dimer (Ph2PCH2BPh2)2 (4). The pendant phosphine on 3E was shown to possess donor ability in the coordination of BH3 (5E).
Co-reporter:Ryan Guterman, Mahdi Hesari, Paul J. Ragogna, and Mark S. Workentin
Langmuir 2013 Volume 29(Issue 21) pp:6460-6466
Publication Date(Web):March 8, 2013
DOI:10.1021/la400516v
UV curing (photopolymerization) is ubiquitous in many facets of industry ranging from the application of paints, pigments, and barrier coatings all the way to fiber optic cable production. To date no reports have focused on polymerizable phosphonium salts under UV irradiation, and despite this dearth of examples, they potentially offer numerous substantial advantages to traditional UV formulation components. We have generated a highly novel coating based on UV-curable trialkylacryloylphosphonium salts that allow for the fast (seconds) and straightforward preparation of ion-exchange surfaces amenable to a roll-to-roll process. We have quantified the surface charges and exploited their accessibility by employing these surfaces in an anion exchange experiment by which [Au25L18]− (L = SCH2CH2Ph) nanocrystals can be assembled into the solid state. This unprecedented application of such surfaces offers a paradigm shift in the emerging chemistry of Au25 research where the nanocrystals remain single and intact and where the integrity of the cluster and its solution photophysical properties are resilient in the solid state. The specific loading of [Au25L18]− on the substrates has been determined and the completely reversible loading and unloading of intact nanocrystals to and from the surface has been established. In the solid state, the assembly has an incredible mechanical resiliency, where the surface remains undamaged even when subjected to repeated Scotch tests.
Co-reporter:Jonathan W. Dube ; Paul J. Ragogna
Chemistry - A European Journal 2013 Volume 19( Issue 35) pp:11768-11775
Publication Date(Web):
DOI:10.1002/chem.201301003
Abstract
The bis(phosphino)borate ligand class is used as an anionic anchor to stabilize reactive, low coordinate arsenic centers. The neutral, zwitterionic AsI species, 2, is formed very cleanly, and isolated in good yields using cyclohexene as a halogen scavenger. The uniqueness of this heterocyclic AsI compound is on display with the coordination to Group 6 metal centers, (2 M(CO)5; M=Cr, Mo, W). The arsenicmetal bond lengths are longer than the related AsPh3 complexes suggesting that compound 2 is a weak sigma donor. The metal complexes reveal a trigonal pyramidal arsenic atom, which provides the first experimental evidence for the presence of two “lone pairs” of electrons on the AsI center. When more flexible and more electron-donating isopropyl substituents were used, an intermediate (compound 5) in the formation of low coordinate pnictogen compounds was crystallographically characterized. This structure, formally a base-stabilized dichloroarsenium cation, provides an alternative mechanistic proposal to the one described in the literature.
Co-reporter:Bradley M. Berven;Richard O. Oviasuyi;Robert J. Klassen;Mike Idacavage;Elizabeth R. Gillies;Paul J. Ragogna
Journal of Polymer Science Part A: Polymer Chemistry 2013 Volume 51( Issue 3) pp:499-508
Publication Date(Web):
DOI:10.1002/pola.26388
Abstract
The first anion with four polymerizable groups has been synthesized and used to produce durable, crosslinked polyelectrolyte (PE) coatings in a single step. Sodium tetrakis(4-vinylphenyl)borate (NaBSty4) was produced by the reaction of BCl3 and the Grignard of 4-bromostyrene. The full series of borates NaBPhxSty4−x, x = 1−3, were also synthesized analogously by reaction of the styryl-Grignard and PhBCl2, Ph2BCl, or Ph3B. Anion exchange of the borates with tributyl 4-vinylbenzylphosphonium chloride gave a family of organic salts developed for applications in photopolymerized coatings. The percent UV cure of the polymer films was determined by infrared spectroscopy and this relative level of curing was corroborated by differential scanning calorimetry analysis. The degree of crosslinking imparted to the polymer films by the different monomers has resulted in varied mechanical properties, which were probed by diamond tip scratch tests and nanoindentation. These clearly demonstrated that as the number of polymerizable groups increased, the film hardness increased correspondingly. The final hardness of the films exceeds those of other related systems and identifies styryl borates as viable crosslinking additives in UV curable technologies, especially in the production of durable PE films. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Co-reporter:Ryan Guterman;Bradley M. Berven;T. Chris Corkery;Heng-Yong Nie;Mike Idacavage;Elizabeth R. Gillies;Paul J. Ragogna
Journal of Polymer Science Part A: Polymer Chemistry 2013 Volume 51( Issue 13) pp:2782-2792
Publication Date(Web):
DOI:10.1002/pola.26692
ABSTRACT
An array of highly fluorinated polymerizable phosphonium salts (HFPPS) were synthesized from PH3 and utilized in UV-curable formulations. Inclusion of these salts at very low loading (0.1–1 wt %) into hexanediol diacrylate (HDDA) resulted in hydrophobic surfaces. The water repellency was achieved with short C4F9 fluorocarbon appendages in the monomer as opposed to the bioaccumulative C8F17 appended polymers. The physical properties of these new monomers were also characterized. The molecular architecture of the monomers had a pronounced effect on both their physical properties along with the degree of hydrophobicity imparted in the polymer. Salts utilizing the bis(trifluoromethylsulfonyl)imide anion displayed excellent compatibility with HDDA, while the chloride salts were insoluble. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) confirmed the presence of the HFPPS at the surface of the polymer coating. For the first time this demonstrates how these salts may be used to functionalize the surface of a UV-cured film with ionic species. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2782–2792
Co-reporter:Allison L. Brazeau ; Mikko M. Hänninen ; Heikki M. Tuononen ; Nathan D. Jones ;Paul J. Ragogna
Journal of the American Chemical Society 2012 Volume 134(Issue 11) pp:5398-5414
Publication Date(Web):February 21, 2012
DOI:10.1021/ja300587z
The reported chemistry and reactivity of guanidinate supported group 15 elements in the +3 oxidation state, particularly phosphorus, is limited when compared to their ubiquity in supporting metallic elements across the periodic table. We have synthesized a series of chlorophosphines utilizing homo- and heteroleptic (dianionic)guanidinates and have completed a comprehensive study of their reactivity. Most notable is the reluctancy of these four-membered rings to form the corresponding N-heterocyclic phosphenium cations, the tendency to chemically and thermally eliminate carbodiimide, and the scarcely observed ring expansion by insertion of a chloro(imino)phosphine into a P–N bond of the P–N–C–N framework. Computational analysis has provided corroborating evidence for the unwillingness of the halide abstraction reaction by demonstrating the exceptional electron acceptor properties of the target phosphenium cations and the underscoring strength of the P–X bond.
Co-reporter:Caleb D. Martin ;Paul J. Ragogna
Inorganic Chemistry 2012 Volume 51(Issue 5) pp:2947-2953
Publication Date(Web):February 16, 2012
DOI:10.1021/ic202213x
The reactions of the chalcogen halides (Ch = S, Se, Te) with a series of diiminopyridine (DIMPY) ligands were explored. It was determined through these studies that varying both the substitution on the α-carbon and the chalcogen halide reagent afforded different products. If methyl groups were present on the α-carbon, reactivity was observed through the eneamine tautomer to yield N,N′,C-bound neutral chalcogen complexes. In the cases where H and C6H5 groups were in the same position, N,N′,N″-chelated chalcogen cations or dications were produced. Many of the reactions resulted in complex mixtures postulated to occur by the release of halogen decomposing the product or, for reactions with the CH3 substituted ligand, uncontrollable reactivity with the eneamine tautomer. This is the first report of reactions of sulfur and selenium halides with the ubiquitous diiminopyridine ligands and only the second example for a tellurium halide.
Co-reporter:Jacquelyn T. Price, Nathan D. Jones, and Paul J. Ragogna
Inorganic Chemistry 2012 Volume 51(Issue 12) pp:6776-6783
Publication Date(Web):June 6, 2012
DOI:10.1021/ic300494g
A new N-heterocyclic carbene (NHC) containing a fused bithiophene backbone has been synthesized along with its silver(I) and BPh3 complexes. The donor strength of this unique NHC has been determined from the IR stretching frequencies of the isolated NHC-Rh(CO)2Cl complex. The photophysical properties of all of the novel compounds have been investigated and are presented.
Co-reporter:Eleanor Magdzinski ; Pierangelo Gobbo ; Caleb D. Martin ; Mark S. Workentin ;Paul J. Ragogna
Inorganic Chemistry 2012 Volume 51(Issue 15) pp:8425-8432
Publication Date(Web):July 9, 2012
DOI:10.1021/ic300974u
A new reversible, redox active diiminopyridine ligand (1Fc) containing pendant ferrocene functionalities was isolated and fully characterized. The reaction of 1Fc with chalcogen pseudohalides of sulfur, selenium, and tellurium yielded the respective N,N′,N″-chelated chalcogen dications. Phosphorus chemistry proceeded in a related manner but, in this case, by the direct addition of 1Fc with PI3 to yield the N,N′,N″-chelated P(I) cation. These species represent the first synthesized main group complexes involving a redox active diiminopyridine ligand containing pendant ferrocenes. Electrochemical studies of the free ligand shows a reversible two-electron process. The chelated phosphorus cation, however, displayed three events, the first being a quasi-reversible two-electron process, involving the oxidation at the P(I) center, resulting in a P(III) cation. The subsequent reversible one- and two-electron processes arise from the ligand framework and pendant ferrocenes, respectively.
Co-reporter:Jonathan W. Dube, Mikko M. Hänninen, Jason L. Dutton, Heikki M. Tuononen, and Paul J. Ragogna
Inorganic Chemistry 2012 Volume 51(Issue 16) pp:8897-8903
Publication Date(Web):July 27, 2012
DOI:10.1021/ic300892p
The synthesis and structural characterization of dicationic selenium and tellurium analogues of the carbodiphosphorane and triphosphenium families of compounds are reported. These complexes, [Ch(dppe)][OTf]2 [Ch = Se, Te; dppe = 1,2-bis(diphenylphosphino)ethane; OTf = trifluoromethanesulfonate], are formed using [Ch]2+ reagents via a ligand-exchange protocol and represent extremely rare examples of homoleptic pnictogen → chalcogen coordination complexes. The corresponding arsenic compounds were also prepared, [Ch(dpAse)][OTf]2 [Ch = Se, Te; dpAse = 1,2-bis(diphenylarsino)ethane], exhibiting the first instance of an arsenic → chalcogen dative bond. The electronic structures of these unique compounds were determined and compared to previously reported chalcogen dications.
Co-reporter:Allison L. Brazeau, Nathan D. Jones and Paul J. Ragogna
Dalton Transactions 2012 vol. 41(Issue 26) pp:7890-7896
Publication Date(Web):02 Mar 2012
DOI:10.1039/C2DT30171G
Cobaltocene has been used as a one-electron reductant in a facile route to generate pnictogen(I) (P, As) synthons. These subsequently undergo a formal 4 + 2 cycloaddition with a pyridyl tethered 1,2-bis(imino)acenaphthene “clamshell” ligand to yield N-heterocyclic chlorophosphines and -arsines, which are precursors to the corresponding N-heterocyclic pnictenium cations. In the absence of a reductant the “clamshell” ligand can be used in forming hypervalent donor–acceptor complexes with heavy main group elements (Sn, Sb and Bi).
Co-reporter:Jonathan W. Dube; Charles L. B. Macdonald; Paul J. Ragogna
Angewandte Chemie International Edition 2012 Volume 51( Issue 52) pp:13026-13030
Publication Date(Web):
DOI:10.1002/anie.201205744
Co-reporter:Jonathan W. Dube; Charles L. B. Macdonald; Paul J. Ragogna
Angewandte Chemie 2012 Volume 124( Issue 52) pp:13203-13207
Publication Date(Web):
DOI:10.1002/ange.201205744
Co-reporter:Sara Ghiassian, Hossein Ismaili, Brett D. W. Lubbock, Jonathan W. Dube, Paul J. Ragogna, and Mark S. Workentin
Langmuir 2012 Volume 28(Issue 33) pp:12326-12333
Publication Date(Web):July 27, 2012
DOI:10.1021/la301975u
3-Aryl-3-(trifluormethyl)diazirine functionalized highly fluorinated phosphonium salts (HFPS) were synthesized, characterized, and utilized as photoinduced carbene precursors for covalent attachment of the HFPS onto cotton/paper to impart hydrophobicity to these surfaces. Irradiation of cotton and paper, as proof of concept substrates, treated with the diazirine-HFPS leads to robust hydrophobic cotton and paper surfaces with antiwetting properties, whereas the corresponding control samples absorb water readily. The contact angles of water were determined to be 139° and 137° for cotton and paper, respectively. In contrast, water placed on the untreated or the control samples (those treated with the diazirine-HFPS but not irradiated) is simply absorbed into the surface. Additionaly, the chemically grafted hydrophobic coating showed high durability toward wash cycles and sonication in organic solvents. Because of the mode of activation to covalently tether the hydrophobic coating, it is amenable to photopatterning, which was demonstrated macroscopically.
Co-reporter:Jason L. Dutton, Paul J. Ragogna
Coordination Chemistry Reviews 2011 Volume 255(11–12) pp:1414-1425
Publication Date(Web):June 2011
DOI:10.1016/j.ccr.2011.01.028
Co-reporter:Allison L. Brazeau, Anton S. Nikouline and Paul J. Ragogna
Chemical Communications 2011 vol. 47(Issue 16) pp:4817-4819
Publication Date(Web):21 Mar 2011
DOI:10.1039/C1CC10949A
A bulky guanidinate ligand has been utilized in supporting a dichloroarsine, which is an excellent precursor to an arsenium cation and a 2,2′-bipyridine base stabilised arsetidinium dication.
Co-reporter:Preeti Chadha and Paul J. Ragogna
Chemical Communications 2011 vol. 47(Issue 18) pp:5301-5303
Publication Date(Web):31 Mar 2011
DOI:10.1039/C1CC11076D
The synthesis of novel Co(I) polymers featuring CpCo(C4R4) units are reported. The cyclopentadienyl ring on the CpCo(C4R4) unit has been functionalized with acrylate or methacrylate groups. Acrylate derivatives of these compounds were found to polymerize giving rise to the first example of polymers containing neutral, 18 e cobaltoarenocenes in the side chain.
Co-reporter:Jacquelyn T. Price, Melanie Lui, Nathan D. Jones, and Paul J. Ragogna
Inorganic Chemistry 2011 Volume 50(Issue 24) pp:12810-12817
Publication Date(Web):November 17, 2011
DOI:10.1021/ic201983n
Thiophene based polymers and oligomers have attracted considerable attention because they can be functionalized to alter the gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), which enables the design of tunable light emitting materials. One area, which has been less explored, is the incorporation of low coordinate, low oxidation state main group elements into these systems. We have currently developed a novel π-conjugated ligand containing two contiguous thiophene rings in which we have demonstrated its ability to support both pnictogen cations and their metal complexes.
Co-reporter:Caleb D. Martin and Paul J. Ragogna
Dalton Transactions 2011 vol. 40(Issue 44) pp:11976-11980
Publication Date(Web):10 Oct 2011
DOI:10.1039/C1DT11111F
The direct reactions of PI3 with –H or –C6H5 substituted diiminopyridine ligands yield the N,N′,N′′-chelated P(I) cations. The analogous chemistry with the ubiquitous –CH3 substituted derivative produces a complex mixture of products underscoring the importance of the substitution on the α-carbon atom. The I3− counteranion of the compounds could be easily exchanged with the more robust B12Cl122− dianion. Reactions of PCl3 and PBr3 with –CH3 and –C6H5 substituted ligands led to indiscernible mixtures or no reaction. However, heating PBr3 with the –H derivative in the presence of a halide trap produced the corresponding phosphorus(I) cation as the bromide salt. These species represent the first phosphorus diiminopyridine complexes reported.
Co-reporter:Jason L. Dutton, Taylor L. Battista, Michael J. Sgro and Paul J. Ragogna
Chemical Communications 2010 vol. 46(Issue 7) pp:1041-1043
Publication Date(Web):23 Dec 2009
DOI:10.1039/B917841D
Alkyl and aryl substituted diazabutadiene ligands are shown to support a highly electrophilic “Se2+” synthon, which can be utilized in ligand exchange reactions to generate Se centred dicationic coordination complexes.
Co-reporter:Caleb D. Martin ;Paul J. Ragogna
Inorganic Chemistry 2010 Volume 49(Issue 9) pp:4324-4330
Publication Date(Web):April 9, 2010
DOI:10.1021/ic100320u
A series of reactions of α-diimine ligands with a 2:1 mixture of SCl2 and trimethylsilyltrifluormethanesulfonate(TMS-OTf), which behaves as an S(OTf)2 synthon, were performed. The reactivity was shown to differ based on the substitution at the nitrogen atoms of the ligand as aromatic groups yielded dicationic sulfur nitrogen heterocycles whereas alkyl groups resulted in the loss of one of the organic substituents at nitrogen giving monocationic 1,2,5-thiadiazolium rings. The substitution on the backbone carbon being a hydrogen atom, phenyl group (diazabutadiene; DAB) or acenaphthene (bisiminoacenaphthene, BIAN) proved not to be influential on the outcome of the reaction as both systems resulted in N,N′-chelated dications. These are rare examples of sulfur structural mimics of the N-heterocyclic silylene, and the BIAN species represent the first complexes of sulfur with this ubiquitous ligand.
Co-reporter:Caleb D. Martin and Paul J. Ragogna
Inorganic Chemistry 2010 Volume 49(Issue 17) pp:8164-8172
Publication Date(Web):August 12, 2010
DOI:10.1021/ic1012582
The stoichiometric 1:2:2 reaction of SCl2, trimethylsilyl trifluoromethanesulfonate, and pyridine produced sulfur(II) dications featuring two pyridine donors. The complexes were reacted with unsaturated organic substrates, which displayed addition with carbon−carbon and carbon−nitrogen double bonds. The substitution on the para position of the ligand was varied by using electron donating, electron withdrawing, and neutral groups. The electronics at this position were determined to have a substantial effect on the outcome of the reaction. The presence of an electron donating group increased the Lewis basicity sufficiently to completely stop the reaction, whereas an electron withdrawing group decreased the reaction time. These observations are unique to the chemistry of sulfur(II) dications and main group polycations as a whole.
Co-reporter:Allison L. Brazeau, Christine A. Caputo, Caleb D. Martin, Nathan D. Jones and Paul J. Ragogna
Dalton Transactions 2010 vol. 39(Issue 45) pp:11069-11073
Publication Date(Web):21 Oct 2010
DOI:10.1039/C0DT01029D
A bis(imino)acenaphthene (BIAN) ligand containing a pendant Lewis base has been used as a new framework to support a N-heterocyclic phosphenium cation (NHP). Reactivity studies demonstrate the ability of the ligand to act as a Lewis base, while the phosphorus centre provides a Lewis acidic site, giving new opportunities in NHP chemistry.
Co-reporter:J.J. Tindale, K.L. Mouland, P.J. Ragogna
Journal of Molecular Liquids 2010 Volume 152(1–3) pp:14-18
Publication Date(Web):15 March 2010
DOI:10.1016/j.molliq.2009.05.005
The synthesis and characterization of thiol terminated fluorinated phosphonium ionic liquids and their application as superhydrophobic coatings are reported. The thiol functionality enables a covalent link to rough silver substrates installing a durable, non-wetting, ionic film. Variables such as the fluorine loading and the mode of interaction of the salt at the surface of the substrate were adapted and their corresponding effects on the wettability were examined. It was found that a thiolated phosphonium ionic liquid could tolerate a lower fluorine loading and maintain flexibility in the type of anion while still imposing superhydrophobic behaviour.
Co-reporter:JocelynJ. Tindale;KurtisD. Hartlen;Abdolhamid Alizadeh ;MarkS. Workentin ;PaulJ. Ragogna
Chemistry - A European Journal 2010 Volume 16( Issue 30) pp:9068-9075
Publication Date(Web):
DOI:10.1002/chem.200902610
Abstract
The synthesis and characterization of several compounds representing a new class of multitask-specific phosphonium ionic liquids that contain a maleimide functionality is reported. The maleimide moiety of the ionic liquid (IL) is shown to undergo Michael-type additions with substrates containing either a thiol or amine moiety, thus, serving as a template to introduce wide structural diversity into the IL. Multitask-specific ILs are accessible by reaction of the maleimide with Michael donors that are capable of serving some function. As a model example to illustrate this concept, a redox active ferrocenyl thiol was incorporated and examined by cyclic voltammetry. Because the maleimide moiety is highly reactive to additions, the task-specific ionic liquids (TSILs) are prepared as the furan-protected Diels–Alder maleimide. The maleimide moiety can then be liberated when required by simple heating.
Co-reporter:Jason L. Dutton ; Paul J. Ragogna
Chemistry - A European Journal 2010 Volume 16( Issue 41) pp:12454-12461
Publication Date(Web):
DOI:10.1002/chem.201001447
Abstract
The synthesis and comprehensive characterization of the first dicationic tellurium analogues of N-heterocyclic carbenes (NHCs) has been reported, in both the +2 and +4 oxidation states. For the +2 oxidation state, a base-stabilized form of TeCl2 is used as the starting material. The dications are isolated by means of halide metathesis and the solid-state structures confirm the previously calculated diimine bonding arrangement. For TeIV, a diamine is used in a high-yielding dehydrohalogen coupling reaction from TeCl4. The dicationic NHC analogue is isolated in a base-stabilized form through halide abstraction and subsequent coordination by pyridine.
Co-reporter:Caleb D. Martin ; Christine M. Le ;Paul J. Ragogna
Journal of the American Chemical Society 2009 Volume 131(Issue 42) pp:15126-15127
Publication Date(Web):October 5, 2009
DOI:10.1021/ja9073968
Air-stable, chalcogen-centered dications have been synthesized and comprehensively characterized. These represent the first diiminopyridine (DIMPY) complexes of the chalcogens as well as the single nonmetallic (sulfur) complex of this ubiquitous ligand. Their stability under ambient conditions is a distinct contrast to other highly charged main-group cations.
Co-reporter:Jocelyn J. Tindale and Paul J. Ragogna
Chemical Communications 2009 (Issue 14) pp:1831-1833
Publication Date(Web):06 Mar 2009
DOI:10.1039/B821174D
A new class of highly fluorinated phosphonium ionic liquids (HFPILs) that are thermally stable, non-volatile, tuneable small molecules has been synthesized; they are uniquely suited for creating novel superhydrophobic coatings, offering a new paradigm in the application of ionic liquids.
Co-reporter:Jason L. Dutton ;Paul J. Ragogna
Inorganic Chemistry 2009 Volume 48(Issue 4) pp:1722-1730
Publication Date(Web):January 14, 2009
DOI:10.1021/ic801883e
A series of coordination complexes, where a heavy chalcogen (Se, Te) acts as the acceptor site, using a variety of electron rich Lewis bases (phosphine, imine, N-heterocyclic carbene), have been synthesized and comprehensively characterized. Each derivative is a representative example of a E→Ch coordinative bond, characterizing an efficient E-E bond forming methodology and a systematic investigation into the coordination chemistry of the chalcogens. The complexes are susceptible to classic ligand exchange reactions, verifying the dative E→Ch bonding motif.
Co-reporter:Jason L. Dutton ; Caleb D. Martin ; Michael J. Sgro ; Nathan D. Jones ;Paul J. Ragogna
Inorganic Chemistry 2009 Volume 48(Issue 7) pp:3239-3247
Publication Date(Web):March 2, 2009
DOI:10.1021/ic802320s
A series of N,C bound chalcogen heterocycles from the reaction of chalcogen halides (ChXn; Ch = S, Se Te; X = Cl, Br; n = 2, 4) with N-alkyl or N-aryl 1,4-diazabutadiene (DAB) ligands featuring methyl substituents on the backbone C−C linkage are reported. In contrast to what is observed for other p-block elements with the same ligand systems, which typically bind in an N,N′ fashion, the chalcogens react with the ligand in an unusual manner, forming N1C3Ch1 five-membered rings by incorporating a “backbone” methyl group. Solid state structures of the feature compounds have been confirmed by X-ray crystallographic studies. The reaction mechanism was probed by deuterium isotope labeling of the DAB ligand and analyzed using stopped-flow kinetics experiments, which supported attack by the olefin in the enamine form of the DAB ligand with concomitant loss of HX.
Co-reporter:CalebD. Martin;MichaelC. Jennings Dr.;MichaelJ. Ferguson Dr.;PaulJ. Ragogna
Angewandte Chemie International Edition 2009 Volume 48( Issue 12) pp:
Publication Date(Web):
DOI:10.1002/anie.200990054
Co-reporter:CalebD. Martin;MichaelC. Jennings Dr.;MichaelJ. Ferguson Dr.;PaulJ. Ragogna
Angewandte Chemie 2009 Volume 121( Issue 12) pp:
Publication Date(Web):
DOI:10.1002/ange.200990056
Co-reporter:JasonL. Dutton;GregoryJ. Farrar;MichaelJ. Sgro;TaylorL. Battista ;PaulJ. Ragogna
Chemistry - A European Journal 2009 Volume 15( Issue 39) pp:10263-10271
Publication Date(Web):
DOI:10.1002/chem.200901000
Abstract
The synthesis and comprehensive characterization of a series of base-stabilized ChX2 (Ch=Se, Te; X=Cl, Br) is reported using aryl-substituted diazabutadiene and 2,2′-bipyridine (bipy) as the ligands. In stark contrast to free ChX2 the complexes display excellent thermal stability. Their use as viable ChX2 reagents that may be stored for later use is demonstrated in principle. The syntheses are simple and high-yielding from commercially available or easily synthesized reagents. The bipy complexes are exceedingly rare examples of this ubiquitous ligand being utilized within Group 16 chemistry; the Se examples are the first to be characterized by X-ray crystallography, and the Te species are only the second.
Co-reporter:CalebD. Martin;MichaelC. Jennings Dr.;MichaelJ. Ferguson Dr.;PaulJ. Ragogna
Angewandte Chemie 2009 Volume 121( Issue 12) pp:2244-2247
Publication Date(Web):
DOI:10.1002/ange.200805198
Co-reporter:JasonL. Dutton;HeikkiM. Tuononen Adjunct Dr.;PaulJ. Ragogna
Angewandte Chemie 2009 Volume 121( Issue 24) pp:4473-4477
Publication Date(Web):
DOI:10.1002/ange.200901495
Co-reporter:CalebD. Martin;MichaelC. Jennings Dr.;MichaelJ. Ferguson Dr.;PaulJ. Ragogna
Angewandte Chemie International Edition 2009 Volume 48( Issue 12) pp:2210-2213
Publication Date(Web):
DOI:10.1002/anie.200805198
Co-reporter:PaulA. Rupar;Rajoshree Byopadhyay;BenjaminF.T. Cooper;MichaelR. Stinchcombe;PaulJ. Ragogna ;CharlesL.B. Macdonald ;KimM. Baines
Angewandte Chemie International Edition 2009 Volume 48( Issue 28) pp:5155-5158
Publication Date(Web):
DOI:10.1002/anie.200901351
Co-reporter:JasonL. Dutton;HeikkiM. Tuononen Adjunct Dr.;PaulJ. Ragogna
Angewandte Chemie International Edition 2009 Volume 48( Issue 24) pp:4409-4413
Publication Date(Web):
DOI:10.1002/anie.200901495
Co-reporter:Jason L. Dutton, Andre Sutrisno, Robert W. Schurko and Paul J. Ragogna
Dalton Transactions 2008 (Issue 26) pp:3470-3477
Publication Date(Web):20 Mar 2008
DOI:10.1039/B719779A
The synthesis and comprehensive characterisation of a series of 1,2,5-selenadiazolium salts, which were generated from the direct reaction between the neutral bidentate ligand tert-butyl-DAB and a variety of heavy chalcogen halides, are reported. The formation of the cationic heterocycle from the reaction of SeX4 (X = Cl, Br) and the ligand results in a two electron redox process where the chalcogen undergoes a two electron reduction concomitant with the elimination of X2, the oxidation by-product. A reaction pathway for this chemistry has been proposed necessitating several key intermediates. These species have been synthesized and used in a stepwise series of transformations that strongly supports this very unusual reactivity for the chalcogens. In contrast, the reaction between tert-butyl DAB and TeX4 (X = Cl, Br, I), does not result in redox, rather an octahedral Te(IV)·DAB complex is formed or no reaction was observed.
Co-reporter:Jason L. Dutton, Jocelyn J. Tindale, Michael C. Jennings and Paul J. Ragogna
Chemical Communications 2006 (Issue 23) pp:2474-2476
Publication Date(Web):03 May 2006
DOI:10.1039/B603777A
The reaction of SeCl4 with the ubiquitous tert-butyl-substituted diazabutadiene ligand results in the isolation of a rare example of a 1,2,5-selenadiazolium cation, representing a novel route to Se–N ring formation; these heterocycles can be derivatised at selenium, which has led to the identification of a short Se⋯N secondary bonding interaction.
Co-reporter:Jocelyn J. Tindale and Paul J. Ragogna
Chemical Communications 2009(Issue 14) pp:NaN1833-1833
Publication Date(Web):2009/03/06
DOI:10.1039/B821174D
A new class of highly fluorinated phosphonium ionic liquids (HFPILs) that are thermally stable, non-volatile, tuneable small molecules has been synthesized; they are uniquely suited for creating novel superhydrophobic coatings, offering a new paradigm in the application of ionic liquids.
Co-reporter:Jason L. Dutton, Andre Sutrisno, Robert W. Schurko and Paul J. Ragogna
Dalton Transactions 2008(Issue 26) pp:NaN3477-3477
Publication Date(Web):2008/03/20
DOI:10.1039/B719779A
The synthesis and comprehensive characterisation of a series of 1,2,5-selenadiazolium salts, which were generated from the direct reaction between the neutral bidentate ligand tert-butyl-DAB and a variety of heavy chalcogen halides, are reported. The formation of the cationic heterocycle from the reaction of SeX4 (X = Cl, Br) and the ligand results in a two electron redox process where the chalcogen undergoes a two electron reduction concomitant with the elimination of X2, the oxidation by-product. A reaction pathway for this chemistry has been proposed necessitating several key intermediates. These species have been synthesized and used in a stepwise series of transformations that strongly supports this very unusual reactivity for the chalcogens. In contrast, the reaction between tert-butyl DAB and TeX4 (X = Cl, Br, I), does not result in redox, rather an octahedral Te(IV)·DAB complex is formed or no reaction was observed.
Co-reporter:Preeti Chadha and Paul J. Ragogna
Chemical Communications 2011 - vol. 47(Issue 18) pp:NaN5303-5303
Publication Date(Web):2011/03/31
DOI:10.1039/C1CC11076D
The synthesis of novel Co(I) polymers featuring CpCo(C4R4) units are reported. The cyclopentadienyl ring on the CpCo(C4R4) unit has been functionalized with acrylate or methacrylate groups. Acrylate derivatives of these compounds were found to polymerize giving rise to the first example of polymers containing neutral, 18 e cobaltoarenocenes in the side chain.
Co-reporter:M. Azizpoor Fard, A. Rabiee Kenaree, P. D. Boyle, P. J. Ragogna, J. B. Gilroy and J. F. Corrigan
Dalton Transactions 2016 - vol. 45(Issue 7) pp:NaN2880-2880
Publication Date(Web):2016/01/21
DOI:10.1039/C5DT03962B
Ferrocene-based phosphines constitute an important auxiliary ligand in inorganic chemistry. Utilizing the (ferrocenylethyl)phosphines (FcCH2CH2)3−nHnP (Fc = ferrocenyl; n = 2, 1; n = 1, 2; n = 0, 3) the synthesis of a series of coordination complexes [(FcCH2CH2)3−nHnPCuCl]4 (n = 2, 1-CuCl; n = 0, 3-CuCl), [(FcCH2CH2)2HPCuCl] (2-CuCl), {[(FcCH2CH2)H2P]2AgCl}2 (1-AgCl), [(FcCH2CH2)2HPAgCl] (2-AgCl), [(FcCH2CH2)3PAgCl]4 (3-AgCl), [(FcCH2CH2)3PM(OAc)]4 (M = Cu, 3-CuOAc M = Ag, 3-AgOAc), [(FcCH2CH2)3−nHnPAuCl] (n = 1, 2-AuCl; n = 0, 3-AuCl), via the reaction between the free phosphine and MX (M = Cu, Ag and Au; X = Cl, OAc), is described. The reaction between the respective phosphine with a suspension of metal–chloride or -acetate in a 1:1 ratio in THF at ambient temperature affords coordinated phosphine-coinage metal complexes. Varying structural motifs are observed in the solid state, as determined via single crystal X-ray analysis of 1-CuCl, 3-CuCl, 1-AgCl, 3-AgCl, 3-CuOAc, 3-AgOAc, 2-AuCl and 3-AuCl. Complexes 1-CuCl and 3-CuCl are tetrameric Cu(I) cubane-like structures with a Cu4Cl4 core, whereas silver complexes with primary and tertiary phosphine reveal two different structural types. The structure of 1-AgCl, unlike the rest, displays the coordination of two phosphines to each silver atom and shows a quadrangle defined by two Ag and two Cl atoms. In contrast, 3-AgCl is distorted from a cubane structure via elongation of one of the Cl⋯Ag distances. 3-CuOAc and 3-AgOAc are isostructural with step-like cores, while complexes 2-AuCl and 3-AuCl reveal a linear geometry of a phosphine gold(I) chloride devoid of any aurophilic interactions. All of the complexes were characterized in solution by multinuclear 1H, 13C{1H} and 31P NMR spectroscopic techniques; the redox chemistry of the series of complexes was examined using cyclic voltammetry. This class of complexes has been found to exhibit one reversible Fe(II)/Fe(III) oxidation couple, suggesting the absence of electronic communication between the ferrocenyl units on individual phosphine ligands as well as between different phosphines on the polymetallic cores.
Co-reporter:Jason L. Dutton, Taylor L. Battista, Michael J. Sgro and Paul J. Ragogna
Chemical Communications 2010 - vol. 46(Issue 7) pp:NaN1043-1043
Publication Date(Web):2009/12/23
DOI:10.1039/B917841D
Alkyl and aryl substituted diazabutadiene ligands are shown to support a highly electrophilic “Se2+” synthon, which can be utilized in ligand exchange reactions to generate Se centred dicationic coordination complexes.
Co-reporter:Amir Rabiee Kenaree, Bradley M. Berven, Paul J. Ragogna and Joe B. Gilroy
Chemical Communications 2014 - vol. 50(Issue 73) pp:NaN10717-10717
Publication Date(Web):2014/08/01
DOI:10.1039/C4CC05296J
The synthesis and characterization of a novel class of highly-metallized, redox-active polyelectrolytes that employ phosphorus as a scaffold for the installation of transition metals is described. Pyrolysis of thin films of the title polyelectrolytes resulted in the production of magnetite crystallites and ill-defined carbon-, phosphorus- and oxygen-rich phases in char yields of nearly 50%.
Co-reporter:Allison L. Brazeau, Christine A. Caputo, Caleb D. Martin, Nathan D. Jones and Paul J. Ragogna
Dalton Transactions 2010 - vol. 39(Issue 45) pp:NaN11073-11073
Publication Date(Web):2010/10/21
DOI:10.1039/C0DT01029D
A bis(imino)acenaphthene (BIAN) ligand containing a pendant Lewis base has been used as a new framework to support a N-heterocyclic phosphenium cation (NHP). Reactivity studies demonstrate the ability of the ligand to act as a Lewis base, while the phosphorus centre provides a Lewis acidic site, giving new opportunities in NHP chemistry.
Co-reporter:Caleb D. Martin and Paul J. Ragogna
Dalton Transactions 2011 - vol. 40(Issue 44) pp:NaN11980-11980
Publication Date(Web):2011/10/10
DOI:10.1039/C1DT11111F
The direct reactions of PI3 with –H or –C6H5 substituted diiminopyridine ligands yield the N,N′,N′′-chelated P(I) cations. The analogous chemistry with the ubiquitous –CH3 substituted derivative produces a complex mixture of products underscoring the importance of the substitution on the α-carbon atom. The I3− counteranion of the compounds could be easily exchanged with the more robust B12Cl122− dianion. Reactions of PCl3 and PBr3 with –CH3 and –C6H5 substituted ligands led to indiscernible mixtures or no reaction. However, heating PBr3 with the –H derivative in the presence of a halide trap produced the corresponding phosphorus(I) cation as the bromide salt. These species represent the first phosphorus diiminopyridine complexes reported.
Co-reporter:Ryan Guterman, Elizabeth R. Gillies and Paul J. Ragogna
Dalton Transactions 2015 - vol. 44(Issue 35) pp:NaN15670-15670
Publication Date(Web):2015/07/30
DOI:10.1039/C5DT02364E
Air-sensitive and air-stable primary phosphines (RPH2) were compared for their ability to undergo photoinitiated phosphane–ene chemistry with 1-hexene. Despite their increased air-stability, the primary phosphines displayed equal to or greater reactivity when compared to air-sensitive alkyl or aryl analogues. The phosphane–ene reaction was also performed in the presence of 1-octanethiol to determine whether thiol–ene and phosphane–ene chemistries could proceed simultaneously. It was determined that the phosphane–ene process takes precedence over thiol–ene as P–H bond conversion was independent of thiol concentration. Tertiary phosphine (R3P) and some secondary phosphine (R2PH) products were found to react with thiols under experimental conditions to create phosphine–sulfides (P–S), but this chemistry only proceeded at low P–H bond concentrations. These results suggests that hydrogen transfer reactions take precedence over P–S formation and demonstrate the unique relationship between phosphane–ene and thiol–ene chemistry.
Co-reporter:Jonathan W. Dube, Zachary D. Brown, Christine A. Caputo, Philip P. Power and Paul J. Ragogna
Chemical Communications 2014 - vol. 50(Issue 16) pp:NaN1946-1946
Publication Date(Web):2013/12/09
DOI:10.1039/C3CC48933G
The reaction of phosphine gas with a low coordinate diaryl germylene or diarylstannylene results in both oxidative addition and arene elimination at the group 14 atom. The products were characterised by 31P NMR spectroscopy and X-ray crystallography, and represent the first P–H bond activation by a heavy group 14 element compound.
Co-reporter:Allison L. Brazeau, Anton S. Nikouline and Paul J. Ragogna
Chemical Communications 2011 - vol. 47(Issue 16) pp:NaN4819-4819
Publication Date(Web):2011/03/21
DOI:10.1039/C1CC10949A
A bulky guanidinate ligand has been utilized in supporting a dichloroarsine, which is an excellent precursor to an arsenium cation and a 2,2′-bipyridine base stabilised arsetidinium dication.
Co-reporter:T. J. Cuthbert, E. Evoy, J. P. J. Bow, R. Guterman, J. M. Stubbs, E. R. Gillies, P. J. Ragogna and J. M. Blacquiere
Catalysis Science & Technology (2011-Present) 2017 - vol. 7(Issue 13) pp:NaN2688-2688
Publication Date(Web):2017/06/01
DOI:10.1039/C7CY00391A
A soft polymer network prepared through a phosphane–ene reaction successfully sequestered Rh and Ru from hydrogenation and ring closing metathesis reactions, respectively. Scavenging effectively quenches catalytic activity and ultimately removes >98% of the metal.
Co-reporter:Allison L. Brazeau, Nathan D. Jones and Paul J. Ragogna
Dalton Transactions 2012 - vol. 41(Issue 26) pp:NaN7896-7896
Publication Date(Web):2012/03/02
DOI:10.1039/C2DT30171G
Cobaltocene has been used as a one-electron reductant in a facile route to generate pnictogen(I) (P, As) synthons. These subsequently undergo a formal 4 + 2 cycloaddition with a pyridyl tethered 1,2-bis(imino)acenaphthene “clamshell” ligand to yield N-heterocyclic chlorophosphines and -arsines, which are precursors to the corresponding N-heterocyclic pnictenium cations. In the absence of a reductant the “clamshell” ligand can be used in forming hypervalent donor–acceptor complexes with heavy main group elements (Sn, Sb and Bi).
