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Articles 1 - 5 of 5
Full-Text Articles in Chemistry
Dft Analysis Into The Intermediates Of Nickel Pyridenthiolate Catalysed Proton Reduction, Carolyn N. Virca, Theresa M. Mccormick
Dft Analysis Into The Intermediates Of Nickel Pyridenthiolate Catalysed Proton Reduction, Carolyn N. Virca, Theresa M. Mccormick
Chemistry Faculty Publications and Presentations
Nickel pyridine 2-thiolate (Ni(PyS)3 −) has shown good stability and activity as a H2 generation catalyst for use in solar energy storage. The experimentally proposed catalytic pathway is explored using DFT calculations. Free energy changes along the reaction coordinate, spin states, localization of charge and geometry of the intermediates were explored. Calculations were performed using Gaussian 09 with a B3P86/ 6-31+G(d) basis set and a CPCM water solvation model. Of particular interest were our findings that the first reduction occurs at the nickel rather than through non-innocent ligands and that water coordination is not favourable although protonation of …
Solid State And Solution Dynamics Of Pyridine Based Tetraaza- Macrocyclic Lanthanide Chelates Possessing Phosphonate Ligating Functionality (Ln-Pctmb): Effect On Relaxometry And Optical Properties, Garry Kiefer, Mark Woods
Solid State And Solution Dynamics Of Pyridine Based Tetraaza- Macrocyclic Lanthanide Chelates Possessing Phosphonate Ligating Functionality (Ln-Pctmb): Effect On Relaxometry And Optical Properties, Garry Kiefer, Mark Woods
Chemistry Faculty Publications and Presentations
The macrocyclic ligand 3,6,9-tris(methylenebutyl phosphonic acid)-3,6,9−15-tetraazabicyclo [9.3.1]pentadeca-1(15),11,13-triene (PCTMB) was synthesized and complexes of Eu3+, Tb3+, and Gd3+ studied by X-ray crystallography, luminescence, and relaxometry. In the crystal these complexes are dimeric and possess 8-coordinate Ln3+ centers that are linked by bridging phosphonates. The rigidity introduced by the pyridyl nucleus forces the EuPCTMB and TbPCTMB to adopt a twisted snub disphenoid (TSD) coordination geometry. Examination of the 5D0 → 7F0 luminescent transition of EuPCTMB in the solid state confirmed the existence of a single distinct Eu3+ coordination environment, whereas two …
Synthesis And Evaluation Of Lanthanide Ion Dota-Tetraamide Complexes Bearing Peripheral Hydroxyl Groups, Azhar Pasha, Mai Lin, Gyula Tircso, Cynthia L. Rostollan, Mark Woods, Garry Kiefer, A. Dean Sherry, Xiankai Sun
Synthesis And Evaluation Of Lanthanide Ion Dota-Tetraamide Complexes Bearing Peripheral Hydroxyl Groups, Azhar Pasha, Mai Lin, Gyula Tircso, Cynthia L. Rostollan, Mark Woods, Garry Kiefer, A. Dean Sherry, Xiankai Sun
Chemistry Faculty Publications and Presentations
The use of lanthanide-based contrast agents for magnetic resonance imaging has become an integral component of this important diagnostic modality. These inert chelates typically possess high thermodynamic stability constants that serve as a predictor for in vivo stability and low toxicity. Recently, a new class of contrast agents was reported having a significantly lower degree of thermodynamic stability while exhibiting biodistribution profiles indicative of high stability under biological conditions. These observations are suggestive that the nature of contrast agent stability is also dependent upon the kinetics of complex dissociation, a feature of potential importance when contemplating the design of new …
Potentiometric And Relaxometric Properties Of A Gadolinium-Based Mri Contrast Agent For Sensing Tissue Ph, Ferenc K. Kálmán, Mark Woods, Peter Caravan, Paul Jurek, Marga Spiller, Gyula Tircso, Róbert Király, Ernő Brücher, A. Dean Sherry
Potentiometric And Relaxometric Properties Of A Gadolinium-Based Mri Contrast Agent For Sensing Tissue Ph, Ferenc K. Kálmán, Mark Woods, Peter Caravan, Paul Jurek, Marga Spiller, Gyula Tircso, Róbert Király, Ernő Brücher, A. Dean Sherry
Chemistry Faculty Publications and Presentations
The pH-sensitive contrast agent, GdDOTA-4AmP (Gd1) has been successfully used to map tissue pH by MRI. Further studies now demonstrate that two distinct chemical forms of the complex can be prepared depending upon the pH at which Gd3+ is mixed with ligand 1. The desired pH-sensitive form of this complex, referred to here as a Type II complex, is obtained as the exclusive product only when the complexation reaction is performed above pH 8. At lower pH values, a second complex is formed that, by analogy with an intermediate formed during the preparation of GdDOTA, we tentatively assign …
Structural And Chiroptical Properties Of The Two Coordination Isomers Of Ybdota-Type Complexes, Lorenzo Di Bari, Gennaro Pescitelli, A. Dean Sherry, Mark Woods
Structural And Chiroptical Properties Of The Two Coordination Isomers Of Ybdota-Type Complexes, Lorenzo Di Bari, Gennaro Pescitelli, A. Dean Sherry, Mark Woods
Chemistry Faculty Publications and Presentations
Studies of the structural, physical, and chemical properties of the lanthanide(III) complexes of DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) and related ligands are often complicated by the presence of two coordination isomers in solution. Since these coordination isomers are in exchange and cannot be separated, many techniques offer information only on the weighted average of the two isomers. Lanthanide ion complexes formed with the ligands S(RRRR)NO2BnDOTMA and S(SSSS)NO2BnDOTMA preferentially adopt only one of the two common coordination isomers in solution, so the ytterbium complexes of these ligands offer a unique opportunity to study …