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Jonathan L Sessler - One of the best experts on this subject based on the ideXlab platform.
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tetrathiafulvalene diindolylquinoxaline a dual signaling anion receptor with phosphate selectivity
Chemical Communications, 2010Co-Authors: Christopher Bejger, Jung Su Park, Eric S Silver, Jonathan L SesslerAbstract:Incorporation of tetrathiafulvalene into the backbone of a known neutral phosphate receptor, diindolylquinoxaline, yields a dual optical-electrochemical chemosensor for Dihydrogen phosphate that functions in dichloromethane. This system shows selectivity for Dihydrogen phosphate over other small anions and can be used to detect the presence of this analyte via fluorescence quenching or cyclic voltammetry.
Robert H. Morris - One of the best experts on this subject based on the ideXlab platform.
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Dihydrogen dihydride and in between nmr and structural properties of iron group complexes
Coordination Chemistry Reviews, 2008Co-Authors: Robert H. MorrisAbstract:Abstract Tabulating the structures and characteristic NMR properties of 17 iron complexes, 98 ruthenium complexes and 70 osmium complexes that contain Dihydrogen or compressed dihydride ligands reveals a variety of trends. The H H bond lengths increase from similar Fe(II) to Ru(II) to Os(II) complexes. Iron(II) displays a narrow range of H H distances for stable complexes. Electronegative atoms Cl and O, when attached on the metal trans to the Dihydrogen ligand, result in elongation of the H H bond relative to more electropositive atoms H, C, P and N. The family of cyclopentadienyl ligands also causes this elongating effect. The Dihydrogen ligands with short H H distances and weak interactions with the metal, especially on iron and ruthenium are in the fast spinning regime. One exception is the biporphyrin complex of ruthenium with the side-on bridging H 2 ligand which has an H H distance of 118 pm but is in the fast spinning regime. There are some ruthenium complexes with H H distances greater than 110 pm that are in the slow motion regime and several complexes of osmium with H H distances greater than 130 pm that are in this regime. The large J HH due to quantum mechanical exchange coupling are observable for some of these osmium complexes with H H distances in the range of 140–160 pm. The Dihydrogen ligands in many complexes appear to have librational motions or other motions that place them in the intermediate motion regime. New equations to correlate J HD with H H distances for ruthenium Dihydrogen complexes and for osmium Dihydrogen complexes are introduced here.
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Non-classical Hydrogen Bonding along the Pathway to the Heterolytic Splitting of Dihydrogen
Recent Advances in Hydride Chemistry, 2001Co-Authors: Robert H. MorrisAbstract:Publisher Summary This chapter summarizes the heterolytic cleavage of Dihydrogen at a transition metal complex. Such a cleavage has unexpectedly interesting intermediates. These intermediates have nonclassical hydrogen bonding where the η 2 -Dihydrogen ligand is acting as a hydrogen bond donor or where the hydride ligand is acting as a hydrogen bond acceptor in a hydridic-protonic bond with d(H … H) 1.8 A˚. The former nonclassical bond is favored by an acidic Dihydrogen complex, while the latter is promoted by a basic hydride formed from a weak conjugate-acid hydride or Dihydrogen complex. The chapter also examines the efficient synthetic methods to many types of hydride complexes that are developed including anionic hydrides with (azacrown) potassium counter-cations. The latter displays strong 1.7–1.9 A˚ hydridic-protonic bonding in solid state and solution. NMR and IR characteristics are documented.
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1995 Alcan Award Lecture New intermediates in the homolytic and heterolytic splitting of Dihydrogen
Canadian Journal of Chemistry, 1996Co-Authors: Robert H. MorrisAbstract:Some of the research of the author and his research group into the structure and reactions of Dihydrogen complexes of transition metals is reviewed. The characterization of osmium complexes that can be regarded as having intermediate structures on the way to the homolytic splitting and to the heterolytic splitting of Dihydrogen is described. The properties of an iridium complex with novel short proton–hydride contacts is also reviewed. Key words: transition metal, Dihydrogen, hydride, complexes, NMR, neutron diffraction, osmium, iridium.
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Reactions of transition metal Dihydrogen complexes
Coordination Chemistry Reviews, 1992Co-Authors: Philip G. Jessop, Robert H. MorrisAbstract:A. Introduction (i) The scope of the review (ii) The preparation of Dihydrogen complexes (a) Preparation from Dihydrogen gas (b) Protonation of a hydride complex (c) Other methods of preparation B. Homolytic splitting of coordinated Dihydrogen (i) Introduction (ii) Observing the Dihydrogen-dihydride equilibrium (iii) Factors influencing the Dihydrogen-dihydride equilibrium (iv) Thermodynamics of the Dihydrogen-dihydride equilibrium (v) Kinetics of the Dihydrogen-dihydride equilibrium (vi) Rapid Dihydrogen-dihydride equilibrium or elongated H ... H ligand? ..... (vii) Other Dihydrogen to dihydride reactions (viii) Intermolecular homolytic cleavage of a Dihydrogen ligand C. Exchange of H atoms between Dihydrogen and other hydrogen-donor ligands .... (i) Introduction (ii) Intramolecular H atom exchange for a three-hydrogen system M(H,)H ..... (a) Mechanisms of H atom exchange (b) Observing H atom exchange for a three-hydrogen system M(H,)H .... (c) Complete line-shape analysis (d) Activation parameters from complete line-shape studies (e) Slow exchange with incomplete T, averaging (f) Line-shape coalescence (g) No line-shape decoalescence (h) Intramolecular exchange of isotopes (iii) Intramolecular H atom exchange for Dihydrogenpolyhydride systems M(H,)H, (a) Mechanisms (b) Line-shape coalescence (c) No line-shape decoalescence (d) Intramolecular exchange of isotopes (iv) H/D exchange in the reaction of M(H,)L, with D, (v) Intramolecular H atom exchange in bimetallic systems D. Heterolytic cleavage of the Dihydrogen ligand 159 160 161 162 162 163 163 163 164 170 174 178 182 185 187 188 188 189 189 193 194 197 198 201 203 203 206 206 207 209 211 212 214 215
B Fultz - One of the best experts on this subject based on the ideXlab platform.
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spin state effects on the thermal Dihydrogen release from solid state mh η2 h2 dppe2 m fe ru os organometallic complexes for hydrogen storage applications
Journal of Physical Chemistry C, 2014Co-Authors: David G Abrecht, J A Munoz, Hillary L Smith, B FultzAbstract:Mossbauer spectroscopy, experimental thermodynamic measurements, and computational studies were performed to investigate the properties of molecular hydrogen binding to the organometallic fragments [MHdppe2]+ (M = Fe, Ru, Os; dppe =1,2-bis(diphenylphosphino)ethane) to form the Dihydrogen complex fragments [MH(η2-H2)dppe2]+. Mossbauer spectroscopy showed that the dehydrogenated complex [FeHdppe2]+ adopts a geometry consistent with the triplet spin state, transitioning to a singlet state complex upon addition of the Dihydrogen molecule in a manner similar to the previously studied dinitrogen complexes. From simulations, this spin transition behavior was found to be responsible for the strong binding behavior experimentally observed in the iron complex. Spin-singlet to spin-singlet transitions were found to exhibit thermodynamics consistent with the 5d > 3d > 4d binding trend observed for other transition metal Dihydrogen complexes. Finally, the method for distinguishing between Dihydrogen and dihydride comp...
Jongmin Kang - One of the best experts on this subject based on the ideXlab platform.
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Dihydrogen Phosphate Selective Anion Receptor Based on Acylhydrazone
Bulletin of the Korean Chemical Society, 2014Co-Authors: T. Senthil Pandian, Jongmin KangAbstract:Anion receptor 1 based on acylhydrazone has been designed and synthesized. UV–vis and H NMR titration showed that receptor 1 is selective receptor for Dihydrogen phosphate (H2PO4 −). Dihydrogen phosphate was complexed by the receptor 1 via at least 4 hydrogen bonding interactions, contributing from two amide N-Hs and two imine C-Hs. In addition, nitrogen in the aromatic ring could make 2 additional hydrogen bondings with OH groups in the Dihydrogen phosphate. However, the receptor 1 could make only 4 hydrogen bonds with halides. Therefore, receptor 1 could bind anions through hydrogen bonds with a selectivity in the order of H2PO4 − > Br− > Cl− in highly polar solvent such as DMSO.
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A new Dihydrogen phosphate selective anion receptor utilizing carbazole and indole
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2012Co-Authors: Sung Kyu Lee, Yeunkun Han, Yusun Choi, Jongmin KangAbstract:Dihydrogen phosphate selective anion receptor 2 based on one carbazole and two indole moieties was designed and synthesized. Fluorescence and 1H NMR titration clearly showed that receptor 2 was a good sensor in the selective recognition for Dihydrogen phosphate over other anions. Receptor 2 utilized two amide hydrogens, three amine hydrogens to bind anions. These five hydrogens formed concave structure for the selective recognition of Dihydrogen phosphate.
Christopher Bejger - One of the best experts on this subject based on the ideXlab platform.
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tetrathiafulvalene diindolylquinoxaline a dual signaling anion receptor with phosphate selectivity
Chemical Communications, 2010Co-Authors: Christopher Bejger, Jung Su Park, Eric S Silver, Jonathan L SesslerAbstract:Incorporation of tetrathiafulvalene into the backbone of a known neutral phosphate receptor, diindolylquinoxaline, yields a dual optical-electrochemical chemosensor for Dihydrogen phosphate that functions in dichloromethane. This system shows selectivity for Dihydrogen phosphate over other small anions and can be used to detect the presence of this analyte via fluorescence quenching or cyclic voltammetry.