A5014262932- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Crystallography and molecular interactions
- Organometallic Complex Synthesis and Catalysis
- Metal complexes synthesis and properties
- Magnetism in coordination complexes
- Asymmetric Hydrogenation and Catalysis
- Metal-Catalyzed Oxygenation Mechanisms
- Metal-Organic Frameworks: Synthesis and Applications
- Crystal structures of chemical compounds
- Molecular Sensors and Ion Detection
- Lanthanide and Transition Metal Complexes
- Chemical Reactions and Mechanisms
- Polyoxometalates: Synthesis and Applications
- Catalytic Cross-Coupling Reactions
- Carbon dioxide utilization in catalysis
- Oxidative Organic Chemistry Reactions
- Organoboron and organosilicon chemistry
- Chemical Reaction Mechanisms
- Surfactants and Colloidal Systems
- Ammonia Synthesis and Nitrogen Reduction
- Nitric Oxide and Endothelin Effects
- Cyclopropane Reaction Mechanisms
- Chemical Reactions and Isotopes
- Molecular spectroscopy and chirality
University of Wyoming
2014-2024
Wyoming Department of Education
1994-2020
McGill University
2005-2008
Carnegie Mellon University
2006
Emory University
2005
University of California, Santa Cruz
2004
University of East Anglia
1999
University of Hyderabad
1990-1994
Water is essential for metabolism and all life processes. Despite this, many organisms distributed across the kingdoms of survive near-complete desiccation or anhydrobiosis. Increased intracellular viscosity, leading to formation a vitrified state necessary, but not sufficient, survival while dry. What properties system make it desiccation-tolerant -sensitive are unknown. We have analyzed 18 different in vitro systems, composed one three protective disaccharides (trehalose, sucrose, maltose)...
Atom transfer radical polymerization (ATRP) generally requires a catalyst/initiator molar ratio of 0.1 to 1 and catalyst/monomer 0.001 0.01 (i.e., catalyst concentration: 1000-10,000 ppm versus monomer). Herein, we report new copper-based complex CuBr/N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) as versatile highly active for acrylic, methacrylic, styrenic monomers. The mediated ATRP at 0.005 produced polymers with well-controlled molecular weights low polydispersities. occurred...
The synthesis and reactivity of a series Ru(II) complexes based on the strongly π-accepting pincer ligand 1,3-C6H3(CH2P(CF3)2)2 (CF3PCP) is reported. Thermolysis [Ru(cod)(η3-2-methylallyl)2] with CF3PCPH under H2 affords mixture three (μ-CF3PCPH)Ru(H)(μ-H)(μ-η6,κ3-CF3PCP)Ru(H), [(CF3PCP)Ru(H)]2(μ-CF3PCPH)2, (CF3PCP)Ru(cod)H, which were structurally characterized individually prepared in moderate yields. (CF3PCP)Ru(cod)H reacts (C2F5)2PCH2CH2P(C2F5)2 (dfepe) to give (CF3PCP)Ru(dfepe)H....
An increasing number of biological roles are ascribed to S-nitrosothiol compounds. Their inherent instability in multicomponent solutions is recognized as forming the basis for their physiological effects, such release nitric oxide or posttranslational modification protein cysteine residues. This reactivity also contributes lack fundamental physical and spectroscopic data that have been reported. We addressed this issue through characterization properties a group commonly used...
The iridium fluorinated pincer complex (CF3PCP)Ir(cod) (CF3PCP = 2,6-C6H3(CH2P(CF3)2)2) catalyzes hydrogen transfer from cyclooctane (coa) to tert-butylethylene (tbe) in 1/1 coa/tbe at 200 °C give cyclooctene (coe) and neohexane (tba) an initial rate of 40 TO h–1. In 5/1 coa/tbe, higher activity (155 h–1) turnovers (2580 TON's after 1450 min) are found. Samples 95% tbe contain significant amounts isoprene (2-methyl-1,3-butadiene), which reacts with initially form (CF3PCP)Ir(isoprene). Alkene...
The preparation of a series four-coordinate complexes (CF3PCP)Ir(L) (L = CO, DBU, nbe, coe, MeP(C2F5)2 (dfmp)) and five-coordinate (CF3PCP)Ir(L)(L′) L′ dfmp, nbd, cod, (C2F5)2PCH2CH2P(C2F5)2 (dfepe); L PhCN, C2H4) from dehydrohalogenation (CF3PCP)Ir(C2H4)(H)Cl with Et3N in the presence trapping ligands is reported. (CF3PCP)Ir(L)2 for dfmp have been structurally characterized establish distorted-trigonal -bipyramidal coordination geometry bent PCP unit inequivalent axial equatorial sites....
The syntheses of Ir(I) and Ir(III) complexes incorporating the electron-poor pincer ligand (1,3-C6H3(CH2P(CF3)2)2) (CF3PCP) are reported. Under mild conditions, reaction CF3PCPH with [(cod)Ir(μ-Cl)]2 in benzene gave polymeric [(cod)IrCl(μ-CF3PCPH)]n, which was structurally characterized. Thermolysis [(coe)2Ir(μ-Cl)]2 or toluene at 120 °C resulted metalation to give not anticipated 16-electron (CF3PCP)Ir(H)Cl product but rather coordinatively saturated CF3PCPH-bridged dimer...
Abstract We report a nickel complex for catalytic oxidation of ammonia to dinitrogen under ambient conditions. Using the aryloxyl radical 2,4,6‐tri‐ tert ‐butylphenoxyl ( t Bu 3 ArO⋅) as H atom acceptor cleave N−H bond coordinated NH ligand up 56 equiv N 2 per Ni center can be generated. Employing ‐oxyl 2,2,6,6‐(tetramethylpiperidin‐1‐yl)oxyl (TEMPO⋅) H‐atom acceptor, 15 are formed. A bridging Ni‐hydrazine product identified by isotopic nitrogen N) studies and supported computational models...
Ligand formed by CN bond cleavage: Transition-metal-promoted heterolytic cleavage of the in 1 results formation five new complexes cis hyponitrite with Group 10 transition metals. The include [Ni(η2-O2N2)(dppf)] (dppf=1,1′-bis(diphenylphosphanyl)ferrocene) which is structurally characterized and thermal decomposition follows unimolecular kinetics.
Syntheses of osmium analogues acceptor pincer (CF3PCP)Ru(II) systems are reported. Treatment [Et4N]2OsCl6 with CF3PCPH at 130 °C in ethanol the presence Et3N gave coordinatively saturated anionic carbonyl complex HNEt3+[(CF3PCP)Os(CO)Cl2]−, which subsequently may be converted to cis-(CF3PCP)Os(CO)2Cl or cis-(CF3PCP)Os(CO)2H by reaction Me3SiOTf (Et3Si)2(μ-H)+B(C6F5)4–, respectively. (CF3PCP)Os(cod)H was obtained modest yields thermolysis Os(cod)(η3-2-methylallyl)2 neat cod under 3 atm H2 °C....
Cr(N 2 ) (diphosphine) complexes catalyze the reduction of dinitrogen at room temperature using SmI and ethylene glycol or H O to form hydrazine ammonia.
Gd(2)O(3) and Gd-doped HfO(2) films were deposited on p-type silicon substrates in a reducing atmosphere. Gd 4f photoexcitation peaks at roughly 7 5 eV below the valence band maximum have been identified using resonant photoemission of films, respectively. In case Gd(2)O(3), strong hybridization with O 2p is demonstrated, there evidence that weighted exhibits dispersion bulk structure. The rectifying (diode-like) properties HfO(2)-silicon Gd(2)O(3)-silicon heterojunctions are demonstrated.
The synthesis of perfluoroalkyl-substituted "pincer"-type PCP ligands, 1,3-C6H4(CH2P(Rf)2)2 (Rf = CF3, C2F5), and platinum coordination studies CF3) are reported. 1,3-C6H4(CH2P(CF3)2)2 (CF3PCPH) reacts at ambient temperatures with (cod)Pt(Me)Cl (cod 1,5-cyclooctadiene) (cod)PtMe2 to afford unmetalated PCPH-bridged products [(CF3PCPH)Pt(Me)Cl]x cis-[(CF3PCPH)PtMe2]2, respectively. cis-[(CF3PCPH)PtMe2]2 is soluble has been spectroscopically crystallographically characterized. Thermolysis these...
The synthesis, structure, and spectroscopic signatures of a series four-coordinate iron(II) complexes β-ketoiminates their zinc(II) analogues are presented. An unusual five-coordinate triflate with three oxygen bound protonated β-ketoimines is also synthesized structurally characterized. Single-crystal X-ray crystallographic analysis reveals that the deprotonated bis(chelate)metal various degrees distortion depending on degree steric bulk electronics metal center. Each high-spin centers...
The syntheses of isomeric helical viologens that have potential applications in supramolecular chemistry and catalysis been developed. structures the molecules their solid-state packing motifs determined by X-ray crystallography. Computational studies demonstrate magnitude racemization barriers is primarily identity scaffold insensitive to placement viologen functional group. isomers are similar photophysical behavior but very different photochemical behavior.
A new coordination polymer {[Zn(TIPA)(seb)0.5](NO3)·3.5H2O} n (1) (TIPA = tris(4-(1H-imidazol-1-yl)phenyl)amine, seb sebacic acid) is prepared and characterized by elemental analysis, Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD) single crystal diffraction. Complex 1 has a three-dimensional (3D) 2-fold interpenetrating diamondoid network, can be represented the Schläfli symbol {33·43·54·64·7}. The luminescent, optical, thermal properties of in solid state are...
Synthetic strategies toward the synthesis of electron-poor pincer complexes (CF3PCP)PtH and (CF3PCP)Pt(η2-H2)+ are described. Metathesis (CF3PCP)PtCl with hydride reagents does not lead to (CF3PCP)PtH; KH in tetrahydrofuran (THF) afforded an unusual metallated bimetallic product (CF3PCP)Pt[κ1-C,κ3−P,C,P-2,6-(CHP(CF3)2)(CH2P(CF3)2)-C6H3]PtCl, which has been structurally characterized. Chloride abstraction from or protonolysis (CF3PCP)PtMe presence H2 gives characterized hydride-bridged dimer...
The synthesis of the organochromium(II) complexes [POCOP
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMononuclear Iron(II), Manganese(II), and Nickel(II) Tetranuclear Iron(III) Complexes of a New Hexadentate LigandNavamoney Arulsamy, Joergen Glerup, Derek J. HodgsonCite this: Inorg. Chem. 1994, 33, 14, 3043–3050Publication Date (Print):July 1, 1994Publication History Published online1 May 2002Published inissue 1 July 1994https://pubs.acs.org/doi/10.1021/ic00092a006https://doi.org/10.1021/ic00092a006research-articleACS PublicationsRequest reuse...
The first helical viologen (4,4'-bipyridinium salt) has been prepared and characterized. Its reduction to the radical cation at -0.22 V vs SCE makes it most easily reduced redox-active helicene known. It exhibits absorption 397 nm for S1 ← S0 transition, is luminescent allowing measurement of both its singlet (59.3 ± 0.1 kcal/mol) triplet (54 1 energies. In contrast neutral helicenes, not aromatic π-stacked in crystal a shortest interdication distance 4.977 Å. racemization barrier calculated...
The ligand-to-metal charge transfer state (LMCT) of [(dmpe)3Re](2+) (dmpe = 1,2-bis(dimethylphosphino)ethane) has been demonstrated to be a potent oxidant (E(0)(Re(2+*)/Re(+)) 2.61 V vs standard calomel electrode). This complex traditionally prepared by nontrivial routes in low yields, and very little achieved optimizing the ground emission energy properties general class complexes [(PP)3Re](2+) (PP chelating diphosphine) through phosphine modification. Improved syntheses for Re(I)...