351
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Singh PC, Maity DK, Patwari GN. Infrared-optical double-resonance measurements on O-H...H-Ge dihydrogen-bonded phenol-triethylgermanium hydride complex in the gas phase. J Phys Chem A 2008; 112:5930-4. [PMID: 18529038 DOI: 10.1021/jp801035u] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Spectroscopic investigation of a dihydrogen-bonded complex between phenol and triethylgermanium hydride is reported here. Laser-induced fluorescence excitation, fluorescence-detected infrared, and IR-UV hole-burning spectroscopic studies were carried out in supersonic jet to investigate the complex formation between phenol and triethylgermanium hydride. The lowering of the O-H stretching frequency of the phenol moiety in the complex with triethylgermanium hydride clearly establishes the role of phenol as hydrogen bond donor. The experimental results together with the ab-initio calculations unambiguously confirm formation of an O-H...H-Ge dihydrogen-bonded complex between phenol and triethylgermanium hydride.
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Affiliation(s)
- Prashant Chandra Singh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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352
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Alkorta I, Blanco F, Elguero J. π-Systems as Simultaneous Hydride and Hydrogen Bond Acceptors. J Phys Chem A 2008; 112:6753-9. [DOI: 10.1021/jp803682z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ibon Alkorta
- Instituto de Química Médica (C.S.I.C.), Juan de la Cierva, 3, 28006-Madrid, Spain
| | - Fernando Blanco
- Instituto de Química Médica (C.S.I.C.), Juan de la Cierva, 3, 28006-Madrid, Spain
| | - Jose Elguero
- Instituto de Química Médica (C.S.I.C.), Juan de la Cierva, 3, 28006-Madrid, Spain
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353
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354
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355
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Jezierska A, Panek JJ, Koll A. Spectroscopic properties of a strongly anharmonic Mannich base N-oxide. Chemphyschem 2008; 9:839-46. [PMID: 18338342 DOI: 10.1002/cphc.200700769] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Car-Parrinello molecular dynamics simulations in vacuum and in the solid state are performed on a strongly anharmonic system, namely, 2-(N-diethylamino-N-oxymethyl)-4,6-dichlorophenol, to investigate its molecular and spectroscopic properties. The investigated compound contains two slightly different molecules in the crystal cell with very short intramolecular hydrogen bonds (of 2.400 and 2.423 A), as determined previously by neutron diffraction. The vibrational properties of the compound are studied on the basis of standard approaches, that is, Fourier transformation of the autocorrelation functions of the atomic velocities and dipole moments. Then, the trajectory obtained from ab initio molecular dynamics is sampled and the obtained snapshots are used to solve the vibrational Schrödinger equations and to calculate the O--H stretching envelope as a superposition of the 0-->1 transition. Using an envelope method, the a posteriori quantum effects are included in the O--H stretching. In addition, NMR spectra are calculated also using the obtained snapshots. One- and two-dimensional potentials of mean force (1D and 2D pmf) are derived to explain the details of the proton dynamics. The computational results are supported by NMR experimental data. In addition, the calculated results are compared with previously published X-ray, neutron diffraction, and spectroscopic descriptions. A detailed analysis of the bridged proton's dynamics is thus obtained. The application of 1D and 2D pmf in a system with a strong bridged-proton delocalization is also demonstrated.
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Affiliation(s)
- Aneta Jezierska
- University of Wrocław, Faculty of Chemistry, F. Joliot-Curie 14, 50-383 Wrocław, Poland.
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356
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Ghiasi R, Monajjemi M. Theoretical study of the dihydrogen bonded HMH…HB≡NH and HMH…HN≡BH complexes (M[dbnd]Be, Mg and Ca): properties and structures. MAIN GROUP CHEMISTRY 2008. [DOI: 10.1080/10241220802230666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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357
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Juárez-Pérez E, Viñas C, González-Campo A, Teixidor F, Sillanpää R, Kivekäs R, Núñez R. Controlled Direct Synthesis of C-Mono- and C-Disubstituted Derivatives of [3,3′-Co(1,2-C2B9H11)2]− with Organosilane Groups: Theoretical Calculations Compared with Experimental Results. Chemistry 2008; 14:4924-38. [DOI: 10.1002/chem.200702013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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358
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An X, Liu H, Li Q, Gong B, Cheng J. Influence of Substitution, Hybridization, and Solvent on the Properties of C−HO Single-Electron Hydrogen Bond in CH3−H2O Complex. J Phys Chem A 2008; 112:5258-63. [DOI: 10.1021/jp710414g] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xiulin An
- Science and Engineering College of Chemistry and Biology, Yantai University, Yantai 264005, and Department of Basic Agriculture, Hebei North Academy, Zhangjiakou 075131, China
| | - Haiping Liu
- Science and Engineering College of Chemistry and Biology, Yantai University, Yantai 264005, and Department of Basic Agriculture, Hebei North Academy, Zhangjiakou 075131, China
| | - Qingzhong Li
- Science and Engineering College of Chemistry and Biology, Yantai University, Yantai 264005, and Department of Basic Agriculture, Hebei North Academy, Zhangjiakou 075131, China
| | - Baoan Gong
- Science and Engineering College of Chemistry and Biology, Yantai University, Yantai 264005, and Department of Basic Agriculture, Hebei North Academy, Zhangjiakou 075131, China
| | - Jianbo Cheng
- Science and Engineering College of Chemistry and Biology, Yantai University, Yantai 264005, and Department of Basic Agriculture, Hebei North Academy, Zhangjiakou 075131, China
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359
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360
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Wang GL, Lin YJ, Blacque O, Berke H, Jin GX. Helical Supramolecular Assemblies of {2,4,6-[Cp∗Rh(E2-1,2-C2B10H10)(NC5H4CH2S)]3(triazine)} (E = S, Se) Shaped by Cp∗−Toluene−Cp∗ π-Stacking Forces and BH−Pyridine Hydrogen Bonding. Inorg Chem 2008; 47:2940-2. [DOI: 10.1021/ic800105h] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Guo-Liang Wang
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Material Department of Chemistry, Fudan University, Shanghai 200433, People’s Republic of China, and Institute of Inorganic Chemistry, University of Zurich, Winterthurer Strasse 190, 8057 Zurich, Switzerland
| | - Yue-Jian Lin
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Material Department of Chemistry, Fudan University, Shanghai 200433, People’s Republic of China, and Institute of Inorganic Chemistry, University of Zurich, Winterthurer Strasse 190, 8057 Zurich, Switzerland
| | - Olivier Blacque
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Material Department of Chemistry, Fudan University, Shanghai 200433, People’s Republic of China, and Institute of Inorganic Chemistry, University of Zurich, Winterthurer Strasse 190, 8057 Zurich, Switzerland
| | - Heinz Berke
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Material Department of Chemistry, Fudan University, Shanghai 200433, People’s Republic of China, and Institute of Inorganic Chemistry, University of Zurich, Winterthurer Strasse 190, 8057 Zurich, Switzerland
| | - Guo-Xin Jin
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Material Department of Chemistry, Fudan University, Shanghai 200433, People’s Republic of China, and Institute of Inorganic Chemistry, University of Zurich, Winterthurer Strasse 190, 8057 Zurich, Switzerland
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361
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Krapp A, Frenking G, Uggerud E. Nonpolar Dihydrogen Bonds-On a Gliding Scale from Weak Dihydrogen Interaction to Covalent HH in Symmetric Radical Cations [HnE-H-H-EHn]+. Chemistry 2008; 14:4028-38. [DOI: 10.1002/chem.200701613] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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362
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Alkorta I, Elguero J, Grabowski SJ. How To Determine Whether Intramolecular H···H Interactions Can Be Classified as Dihydrogen Bonds. J Phys Chem A 2008; 112:2721-7. [PMID: 18311957 DOI: 10.1021/jp711387g] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Ibon Alkorta
- Instituto de Química Médica (CSIC), Juan de la Cierva, 3, 28006-Madrid, Spain, and Department of Crystallography and Crystal Chemistry, University of Łódź, 90-236 Łódź ul., Pomorska 149/153, Poland
| | - José Elguero
- Instituto de Química Médica (CSIC), Juan de la Cierva, 3, 28006-Madrid, Spain, and Department of Crystallography and Crystal Chemistry, University of Łódź, 90-236 Łódź ul., Pomorska 149/153, Poland
| | - Sławomir J. Grabowski
- Instituto de Química Médica (CSIC), Juan de la Cierva, 3, 28006-Madrid, Spain, and Department of Crystallography and Crystal Chemistry, University of Łódź, 90-236 Łódź ul., Pomorska 149/153, Poland
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363
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Structure of (Me2Cu)Li · 3DME and its oligomers [(Me2Cu)Li · 3DME] n (n = 2–5): a theoretical study. Russ Chem Bull 2008. [DOI: 10.1007/s11172-008-0075-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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364
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Wu Y, Feng L, Zhang X. Theoretical insights into the properties of the dihydrogen-bonded HXH···HCCH complexes (X=Be, Mg, and Ca). ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.theochem.2007.11.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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365
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Albrett AM, Conradie J, Ghosh A, Brothers PJ. DFT survey of monoboron and diboron corroles: regio- and stereochemical preferences for a constrained, low-symmetry macrocycle. Dalton Trans 2008:4464-73. [DOI: 10.1039/b718755f] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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366
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Trung NT, Hue TT, Nguyen MT, Zeegers-Huyskens T. Theoretical study of the interaction between HNZ (Z = O, S) and H2XNH2 (X = B, Al). Conventional and dihydrogen bonds. Phys Chem Chem Phys 2008; 10:5105-13. [DOI: 10.1039/b806346j] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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367
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Szymczak NK, Tyler DR. Aspects of dihydrogen coordination chemistry relevant to reactivity in aqueous solution. Coord Chem Rev 2008. [DOI: 10.1016/j.ccr.2007.06.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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368
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Chase PA, Jurca T, Stephan DW. Lewis acid-catalyzed hydrogenation: B(C6F5)3-mediated reduction of imines and nitriles with H2. Chem Commun (Camb) 2008:1701-3. [DOI: 10.1039/b718598g] [Citation(s) in RCA: 378] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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369
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Dou J, Su F, Nie Y, Li D, Wang D. Self-assembled 2D supramolecular networks of copper(i) carborane complexes through C–H⋯H–B dihydrogen bonding interactions. Dalton Trans 2008:4152-6. [DOI: 10.1039/b801339j] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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370
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Wang H, Fröhlich R, Kehr G, Erker G. Heterolytic dihydrogen activation with the 1,8-bis(diphenylphosphino)naphthalene/B(C6F5)3 pair and its application for metal-free catalytic hydrogenation of silyl enol ethers. Chem Commun (Camb) 2008:5966-8. [DOI: 10.1039/b813286k] [Citation(s) in RCA: 264] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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371
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Lee HM, Kim D, Singh NJ, Kołaski M, Kim KS. Hydrated hydride anion clusters. J Chem Phys 2007; 127:164311. [DOI: 10.1063/1.2778423] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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372
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Li T, Bergner I, Haque FN, Zimmer-De Iuliis M, Song D, Morris RH. Hydrogenation of Benzonitrile to Benzylamine Catalyzed by Ruthenium Hydride Complexes with P−NH−NH−P Tetradentate Ligands: Evidence for a Hydridic−Protonic Outer Sphere Mechanism. Organometallics 2007. [DOI: 10.1021/om700783e] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tianshu Li
- Department of Chemistry, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
| | - Ines Bergner
- Department of Chemistry, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
| | - F. Nipa Haque
- Department of Chemistry, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
| | - Marco Zimmer-De Iuliis
- Department of Chemistry, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
| | - Datong Song
- Department of Chemistry, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
| | - Robert H. Morris
- Department of Chemistry, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
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373
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Kubas GJ. Fundamentals of H2 Binding and Reactivity on Transition Metals Underlying Hydrogenase Function and H2 Production and Storage. Chem Rev 2007; 107:4152-205. [DOI: 10.1021/cr050197j] [Citation(s) in RCA: 796] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Gregory J. Kubas
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
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374
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375
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Jacobsen GM, Shoemaker RK, McNevin MJ, Rakowski DuBois M, DuBois DL. Syntheses and Structural Characterizations of Iron(II) Complexes Containing Cyclic Diphosphine Ligands with Positioned Pendant Nitrogen Bases. Organometallics 2007. [DOI: 10.1021/om700601h] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- George M. Jacobsen
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, Washington 99352
| | - Richard K. Shoemaker
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, Washington 99352
| | - Michael J. McNevin
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, Washington 99352
| | - M. Rakowski DuBois
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, Washington 99352
| | - Daniel L. DuBois
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, Washington 99352
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376
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Grabowski SJ, Sokalski WA, Leszczynski J. Wide spectrum of H⋯H interactions: van der Waals contacts, dihydrogen bonds and covalency. Chem Phys 2007. [DOI: 10.1016/j.chemphys.2007.06.042] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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377
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Man ML, Lam KC, Sit WN, Ng SM, Zhou Z, Lin Z, Lau CP. Synthesis of heterobimetallic Ru-Mn complexes and the coupling reactions of epoxides with carbon dioxide catalyzed by these complexes. Chemistry 2007; 12:1004-15. [PMID: 16245376 DOI: 10.1002/chem.200500780] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The heterobimetallic complexes [(eta5-C5H5)Ru(CO)(mu-dppm)Mn(CO)4] and [(eta5-C5Me5)Ru(mu-dppm)(mu-CO)2Mn(CO)3] (dppm = bis-diphenylphosphinomethane) have been prepared by reacting the hydridic complexes [(eta5-C5H5)Ru(dppm)H] and [(eta5-C5Me5)Ru(dppm)H], respectively, with the protonic [HMn(CO)5] complex. The bimetallic complexes can also be synthesized through metathetical reactions between [(eta5-C5R5)Ru(dppm)Cl] (R = H or Me) and Li+[Mn(CO)5]-. Although the complexes fail to catalyze the hydrogenation of CO2 to formic acid, they catalyze the coupling reactions of epoxides with carbon dioxide to yield cyclic carbonates. Two possible reaction pathways for the coupling reactions have been proposed. Both routes begin with heterolytic cleavage of the RuMn bond and coordination of an epoxide molecule to the Lewis acidic ruthenium center. In Route I, the Lewis basic manganese center activates the CO2 by forming the metallocarboxylate anion which then ring-opens the epoxide; subsequent ring-closure gives the cyclic carbonate. In Route II, the nucleophilic manganese center ring-opens the ruthenium-attached epoxide to afford an alkoxide intermediate; CO2 insertion into the RuO bond followed by ring-closure yields the product. Density functional calculations at the B3LYP level of theory were carried out to understand the structural and energetic aspects of the two possible reaction pathways. The results of the calculations indicate that Route II is favored over Route I.
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Affiliation(s)
- Man Lok Man
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
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378
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Zhao GJ, Han KL. Novel infrared spectra for intermolecular dihydrogen bonding of the phenol-borane-trimethylamine complex in electronically excited state. J Chem Phys 2007; 127:024306. [PMID: 17640127 DOI: 10.1063/1.2752808] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The intermolecular dihydrogen bonding in the electronically excited states of the dihydrogen-bonded phenol-BTMA complex in gas phase was theoretically investigated using the time-dependent density functional theory method for the first time. It was theoretically demonstrated that the S(1) state of the dihydrogen-bonded phenol-BTMA complex is a locally excited state, in which only the phenol moiety is electronically excited. The infrared spectra of the dihydrogen-bonded phenol-BTMA complex in ground state and the S(1) state were calculated at both the O-H and B-H stretching vibrational regions. A novel infrared spectrum of the dihydrogen-bonded phenol-BTMA complex in the electronically excited state was found. The stretching vibrational absorption bands of the dihydrogen-bonded O-H and B-H groups are very strong in the ground state, while they are disappeared in the S(1) state. At the same time, a new strong absorption band appears at the C[Double Bond]O stretching region. From the calculated bond lengths, it was found that both the O-H and B-H bonds in the dihydrogen bond O-H...H-B are significantly lengthened in the S(1) state of the dihydrogen-bonded phenol-BTMA complex. However, the C-O bond in the phenol moiety is markedly shortened in the excited state, and then has the characteristics of C[Double Bond]O group. Furthermore, it was demonstrated that the intermolecular dihydrogen bonds in the electronically excited state of the dihydrogen-bonded phenol-BTMA complex are strengthened, since calculated H...H distance is drastically shortened in the S(1) state.
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Affiliation(s)
- Guang-Jiu Zhao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
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379
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380
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Ohta K, Yamazaki H, Kawahata M, Yamaguchi K, Pichierri F, Endo Y. Proton-driven conformational change in a 2-aryl-p-carborane constrained by an intramolecular C–H⋯O hydrogen bond. Tetrahedron Lett 2007. [DOI: 10.1016/j.tetlet.2007.05.135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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381
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A novel heterobidentate chiral phosphine and its coordination chemistry in transition metal clusters. J Organomet Chem 2007. [DOI: 10.1016/j.jorganchem.2007.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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382
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Urakawa A, Jutz F, Laurenczy G, Baiker A. Carbon Dioxide Hydrogenation Catalyzed by a Ruthenium Dihydride: A DFT and High-Pressure Spectroscopic Investigation. Chemistry 2007; 13:3886-99. [PMID: 17294492 DOI: 10.1002/chem.200601339] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Reaction pathways during CO(2) hydrogenation catalyzed by the Ru dihydride complex [Ru(dmpe)(2)H(2)] (dmpe=Me(2)PCH(2)CH(2)PMe(2)) have been studied by DFT calculations and by IR and NMR spectroscopy up to 120 bar in toluene at 300 K. CO(2) and formic acid readily inserted into or reacted with the complex to form formates. Two formate complexes, cis-[Ru(dmpe)(2)(OCHO)(2)] and trans-[Ru(dmpe)(2)H(OCHO)], were formed at low CO(2) pressure (<5 bar). The latter occurred exclusively when formic acid reacted with the complex. A RuHHOCHO dihydrogen-bonded complex of the trans form was identified at H(2) partial pressure higher than about 50 bar. The trans form of the complex is suggested to play a pivotal role in the reaction pathway. Potential-energy profiles along possible reaction paths have been investigated by static DFT calculations, and lower activation-energy profiles via the trans route were confirmed. The H(2) insertion has been identified as the rate-limiting step of the overall reaction. The high energy of the transition state for H(2) insertion is attributed to the elongated Ru--O bond. The H(2) insertion and the subsequent formation of formic acid proceed via Ru(eta(2)-H(2))-like complexes, in which apparently formate ion and Ru(+) or Ru(eta(2)-H(2))(+) interact. The bond properties of involved Ru complexes were characterized by natural bond orbital analysis, and the highly ionic characters of various complexes and transition states are shown. The stability of the formate ion near the Ru center likely plays a decisive role for catalytic activity. Removal of formic acid from the dihydrogen-bonded complex (RuHHOCHO) seems to be crucial for catalytic efficiency, since formic acid can easily react with the complex to regenerate the original formate complex. Important aspects for the design of highly active catalytic systems are discussed.
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Affiliation(s)
- Atsushi Urakawa
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Hönggerberg, HCI, 8093 Zurich, Switzerland
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383
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Huang Z, Lin Z, Song C. Protonation Processes and Electronic Spectra of Histidine and Related Ions. J Phys Chem A 2007; 111:4340-52. [PMID: 17474721 DOI: 10.1021/jp067280a] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A full structural assignment of the neutral, protonated, and deprotonated histidine conformers in the gas phase is presented. A total of 3024 unique trial structures were generated by all combinations of internal single-bond rotamers of these species and optimized at the B3LYP/6-311G* level and further optimized at the B3LYP/6-311++G** level. A set of unique conformers is found, and their relative energies, free energies, dipole moments, rotational constants, electron affinities, ionization energies, and harmonic frequencies are determined. The population ratio of histidine and its tautomer is 1:0.16 at 298 K. Massive conformational changes are observed due to protonation and deprotonation, and the intramolecular H-bonds are characterized with the atoms in molecules theory. The calculated proton dissociation energy, gas-phase acidity, proton affinity, and gas-phase basicity are in excellent agreement with the experiments. The deprotonation and protonation of gaseous histidine both occur on the imidazole ring, explaining the versatile biofunctions of histidine in large biomolecules. The UV spectra of neutral and singly and doubly protonated histidine are investigated with the TDDFT/B3LYP/6-311+G(2df,p) calculations. The S0-S1, S0-S2, and S0-S3 excitations of histidine are mixed pipi*/npi* transitions at 5.37, 5.44, and 5.69 eV, respectively. The three excitation energies for histidine tautomer are 4.85, 5.47, and 5.52 eV, respectively. The three excitations for protonated histidine are mainly npi* transitions at 5.45, 5.67, and 5.82 eV, respectively. The S0-S1 excitation of protonated histidine produces ImH-CbetaH2-CalphaH(COOH)-NH2+, while the S0-S2 and S0-S3 transitions produce ImH-CbetaH2-CalphaH(NH2)-(COOH)+. These data may help to understand the mechanisms of the UV fragmentation of biomolecules.
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Affiliation(s)
- Zhijian Huang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science and Technology of China, Hefei, China 230026
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384
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Hugas D, Simon S, Duran M. Electron density topological properties are useful to assess the difference between hydrogen and dihydrogen complexes. J Phys Chem A 2007; 111:4506-12. [PMID: 17455920 DOI: 10.1021/jp070080u] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
B3LYP/6-31++G(d,p) and MP2/6-31++G(d,p) calculations for a series of hydrogen- and dihydrogen-bonded systems have been carried out in order to analyze the topology of the electron density and the energy densities at the respective energy-optimized bond critical points. Even though there are no significant differences when these properties are represented as a function of the dimerization energy, they can be separated into two well-defined sets if those properties are correlated with intermolecular distances. When analyzing the dependence of various properties with equilibrium bond lengths, the specific trends of dihydrogen bond systems consist of (a) lower electron density at the bond critical point, and (b) lower concentration/depletion of that density which can be translated in a different behavior for the Laplacian components. Furthermore, the sets of molecules form two different plots which allow for a valuable classification between hydrogen- and dihydrogen-bonded systems.
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Affiliation(s)
- David Hugas
- Institut de Química Computacional and Departament de Química, Universitat de Girona, 17071-Girona, Catalonia, Spain
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385
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Matus MH, Anderson KD, Camaioni DM, Autrey ST, Dixon DA. Reliable Predictions of the Thermochemistry of Boron−Nitrogen Hydrogen Storage Compounds: BxNxHy, x = 2, 3. J Phys Chem A 2007; 111:4411-21. [PMID: 17444621 DOI: 10.1021/jp070931y] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thermochemical data calculated using ab initio molecular orbital theory are reported for 16 BxNxHy compounds with x = 2, 3 and y > or = 2x. Accurate gas-phase heats of formation were obtained using coupled cluster with single and double excitations and perturbative triples (CCSD(T)) valence electron calculations extrapolated to the complete basis set (CBS) limit with additional corrections including core/valence, scalar relativistic, and spin-orbit corrections to predict the atomization energies and scaled harmonic frequencies to correct for zero point and thermal energies and estimate entropies. Computationally cheaper calculations were also performed using the G3MP2 and G3B3 variants of the Gaussian 03 method, as well as density functional theory (DFT) using the B3LYP functional. The G3MP2 heats of formation are too positive by up to approximately 6 kcal/mol as compared with CCSD(T)/CBS values. The more expensive G3B3 method predicts heats of formation that are too negative as compared with the CCSD(T)/CBS values by up to 3-4 kcal/mol. DFT using the B3LYP functional and 6-311+G** basis set predict isodesmic reaction energies to within a few kcal/mol compared with the CCSD(T)/CBS method so isodesmic reactions involving BN compounds and the analogous hydrocarbons can be used to estimate heats of formation. Heats of formation of c-B3N3H12 and c-B3N3H6 are -95.5 and -115.5 kcal/mol at 298 K, respectively, using our best calculated CCSD(T)/CBS approach. The experimental value for c-B3N3H6 appears to be approximately 7 kcal/mol too negative. Enthalpies, entropies, and free energies are calculated for many dehydrocoupling and dehydrogenation reactions that convert BNH6 to alicyclic and cyclic oligomers and H2(g). Generally, the reactions are highly exothermic and exergonic as well because of the release of 1 or more equivalents of H2(g). For c-B3N3H12 and c-B3N3H6, available experimental data for sublimation and vaporization lead to estimates of their condensed phase 298 K heats of formation: DeltaHf degrees [c-B3N3H12(s)] = -124 kcal/mol and DeltaHf degrees [c-B3N3H6(l)] = -123 kcal/mol. The reaction thermochemistries for the dehydrocoupling of BNH6(s) to c-B3N3H12(s) and the dehydrogenation of c-B3N3H12(s) to c-B3N3H6(l) are much less exothermic compared with the gas-phase reactions due to intermolecular forces which decrease in the order BNH6 > cyclo-B3N3H12 > cyclo-B3N3H6. The condensed phase reaction free energies are less negative compared with the gas-phase reactions but are still too favorable for BNH6 to be regenerated from either c-B3N3H12 or c-B3N3H6 by just an overpressure of H2.
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Affiliation(s)
- Myrna H Matus
- Department of Chemistry, The University of Alabama, Tuscaloosa, AL 35487-0336, USA
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386
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Wang FF, Hou JH, Li ZR, Wu D, Li Y, Lu ZY, Cao WL. Unusual halogen-bonded complex FBrδ+⋯Brδ+F and hydrogen-bonded complex FBrδ+⋯Hδ+F formed by interactions between two positively charged atoms of different polar molecules. J Chem Phys 2007; 126:144301. [PMID: 17444706 DOI: 10.1063/1.2715559] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using ab initio calculations, the authors' predicted for the first time that the halogen-bonded complex FBrdelta+...delta+BrF and hydrogen-bonded complex FBrdelta+...delta+HF formed by the interactions between two positively charged atoms of different polar molecules can be stable in gas phase. It shows that halogen bond or hydrogen bond not only exists between oppositely charged atoms but also between like-charged atoms. That the attraction arising from the special halogen bond or hydrogen bond can exceed the electrostatic repulsion between two contact positively charged atoms stabilizes the complex. Of course, from the point of view of physics they can consider the interactions in FBrdelta+...delta+BrF and FBrdelta+...delta+HF as mainly the sum of the long range molecular interactions, namely, electrostatic, induction, and dispersion with some short-range repulsion. They found that the intermolecular electron correlation contribution representing dispersion interaction plays a crucial role in the stabilities of seemingly repulsive complexes FBrdelta+...delta+BrF and FBrdelta+...delta+HF.
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Affiliation(s)
- Fang-Fang Wang
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China
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387
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Giner Planas J, Teixidor F, Viñas C, Light ME, Hursthouse MB. Self-Assembly of Halogenated Cobaltacarborane Compounds: Boron-Assisted CH⋅⋅⋅XB Hydrogen Bonds? Chemistry 2007; 13:2493-502. [PMID: 17200917 DOI: 10.1002/chem.200601297] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Full structural characterisation and complete synthetic procedures for three monohalogenated cobaltacarborane compounds closo-[3-Co(eta5-C5H5)-8-X-1,2-C2B9H10] (X=Cl (1), Br (2), I (3)) and the dibromo derivative closo-[3-Co(eta5-C5H5)-8,9-Br2-1,2-C2B9H9] (4) are reported. The supramolecular structures of 1, 3, and 4 reveal the existence of intermolecular C--HX--B interactions. The role of these interactions has been investigated through a CSD search and subsequent analysis of the reported crystalline compounds. The results show that halogens become reasonably good hydrogen-bond acceptors when bonded to boron and, in this respect, are comparable in strength to metal-bound halogens.
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Affiliation(s)
- José Giner Planas
- Institut de Ciència de Materials de Barcelona (CSIC), Campus U.A.B., 08193 Bellaterra, Spain
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388
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Leung CW, Zheng W, Wang D, Ng SM, Yeung CH, Zhou Z, Lin Z, Lau CP. Catalytic H/D Exchange between Organic Compounds and D2O with TpRu(PPh3)(CH3CN)H (Tp = hydro(trispyrazolyl)borate). Reaction of TpRu(PPh3)(CH3CN)H with Water to Form Acetamido Complex TpRu(PPh3)(H2O)(NHC(O)CH3). Organometallics 2007. [DOI: 10.1021/om061045x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chung Wing Leung
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, People's Republic of China, and Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People's Republic of China
| | - Wenxu Zheng
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, People's Republic of China, and Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People's Republic of China
| | - Dexian Wang
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, People's Republic of China, and Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People's Republic of China
| | - Siu Man Ng
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, People's Republic of China, and Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People's Republic of China
| | - Chi Hung Yeung
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, People's Republic of China, and Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People's Republic of China
| | - Zhongyuan Zhou
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, People's Republic of China, and Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People's Republic of China
| | - Zhenyang Lin
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, People's Republic of China, and Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People's Republic of China
| | - Chak Po Lau
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, People's Republic of China, and Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People's Republic of China
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389
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Polyakova IN, Zhizhin KY, Kuznetsov NT. Crystal structure of tetraphenylphosphonium 2-{[(Z)-Hydroxy(phenyl)methylene]ammonio}nonahydro-closo-Decaborate: The intramolecular O-H···B3 hydrogen bond in the [B10H9NHC(OH)Ph]− anion. CRYSTALLOGR REP+ 2007. [DOI: 10.1134/s1063774507020186] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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390
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Filippov OA, Filin AM, Tsupreva VN, Belkova NV, Lledós A, Ujaque G, Epstein LM, Shubina ES. Proton-transfer and H2-elimination reactions of main-group hydrides EH4- (E = B, Al, Ga) with alcohols. Inorg Chem 2007; 45:3086-96. [PMID: 16562965 DOI: 10.1021/ic052028n] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The reaction of the isostructural anions of group 13 hydrides EH4- (E = B, Al, Ga) with proton donors of different strength (CH3OH, CF3CH2OH, and CF3OH) was studied with different theoretical methods [DFT/B3LYP and second-order Møller-Plesset (MP2) using the 6-311++G(d,p) basis set]. The results show the general mechanism of the reaction: the dihydrogen-bonded (DHB) adduct (EH...HO) formation leads through the activation barrier to the next concerted step of H2 elimination and alkoxo product formation. The structures, interaction energies (calculated by different approaches including the energy decomposition analysis), vibrational E-H modes, and electron-density distributions were analyzed for all of the DHB adducts. The transition state (TS) is the dihydrogen complex stabilized by a hydrogen bond with the anion [EH3(eta2-H2)...OR-]. The single exception is the reaction of BH4- with CF3OH exhibiting two TSs separated by a shallow minimum of the BH3(eta2-H2)...OR- intermediate. The structures and energies of all of the species were calculated, leading to the establishment of the potential energy profiles for the reaction. A comparison is made with the mechanism of the proton-transfer reaction to transition-metal hydrides. The solvent influence on the stability of all of the species along the reaction pathway was accounted for by means of polarizable conductor calculation model calculations in tetrahydrofuran (THF). Although in THF the DHB intermediates, the TSs, and the products are destabilized with respect to the separated reactants, the energy barriers for the proton transfer are only slightly affected by the solvent. The dependence of the energies of the DHB complexes, TSs, and products as well as the energy barriers for the H2 release on the central atom and the proton donor strength is also discussed.
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Affiliation(s)
- Oleg A Filippov
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov strasse, 119991 Moscow, Russia
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391
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Welch GC, Stephan DW. Facile Heterolytic Cleavage of Dihydrogen by Phosphines and Boranes. J Am Chem Soc 2007; 129:1880-1. [PMID: 17260994 DOI: 10.1021/ja067961j] [Citation(s) in RCA: 678] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gregory C Welch
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4
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392
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Nguyen MT, Nguyen VS, Matus MH, Gopakumar G, Dixon DA. Molecular Mechanism for H2 Release from BH3NH3, Including the Catalytic Role of the Lewis Acid BH3. J Phys Chem A 2007; 111:679-90. [PMID: 17249759 DOI: 10.1021/jp066175y] [Citation(s) in RCA: 151] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electronic structure calculations using various methods, up to the coupled-cluster CCSD(T) level, in conjunction with the aug-cc-pVnZ basis sets with n = D, T, and Q, extrapolated to the complete basis set limit, show that the borane molecule (BH3) can act as an efficient bifunctional acid-base catalyst in the H2 elimination reactions of XHnYHn systems (X, Y = C, B, N). Such a catalyst is needed as the generation of H2 from isoelectronic ethane and borane amine compounds proceeds with an energy barrier much higher than that of the X-Y bond energy. The asymptotic energy barrier for H2 release is reduced from 36.4 kcal/mol in BH3NH3 to 6.0 kcal/mol with the presence of BH3 relative to the molecular asymptote. The NH3 molecule can also participate in a similar catalytic process but induces a smaller reduction of the energy barrier. The kinetics of these processes was analyzed by both transition-state and RRKM theory. The catalytic effect of BH3 has also been probed by an analysis of the electronic densities of the transition structures using the atom-in-molecule (AIM) and electron localization function (ELF) approaches.
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Affiliation(s)
- Minh Tho Nguyen
- Department of Chemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, USA
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393
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Hayashi A, Shiga M, Tachikawa M. H / D isotope effect on the dihydrogen bond byab initiopath integral molecular dynamics simulation. MOLECULAR SIMULATION 2007. [DOI: 10.1080/08927020601052963] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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394
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Stephens FH, Pons V, Tom Baker R. Ammonia–borane: the hydrogen source par excellence? Dalton Trans 2007:2613-26. [PMID: 17576485 DOI: 10.1039/b703053c] [Citation(s) in RCA: 609] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Ammonia-borane, H3NBH3, is an intriguing molecule for chemical hydrogen storage applications. With both protic N-H and hydridic B-H bonds, three H atoms per main group element, and a low molecular weight, H3NBH3 has the potential to meet the stringent gravimetric and volumetric hydrogen storage capacity targets needed for transportation applications. Furthermore, devising an energy-efficient chemical process to regenerate H3NBH3 from dehydrogenated BNHx material is an important step towards realization of a sustainable transportation fuel. In this perspective we discuss current progress in catalysis research to control the rate and extent of hydrogen release and preliminary efforts at regeneration of H3NBH3.
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395
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Planas JG, Viñas C, Teixidor F, Light ME, Hursthouse MB. Polymorphism and phase transformations in cobaltacarborane molecular crystals. CrystEngComm 2007. [DOI: 10.1039/b704833e] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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396
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Barba C, Carmona D, García JI, Lamata MP, Mayoral JA, Salvatella L, Viguri F. Conformational Preferences of Methacrolein in Diels−Alder and 1,3-Dipolar Cycloaddition Reactions. J Org Chem 2006; 71:9831-40. [PMID: 17168603 DOI: 10.1021/jo062200k] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A B3LYP/6-31G* study has been carried out for the reactions of methacrolein with cyclopentadiene, parent nitrone, 1-pyrroline-1-oxide, and (Z)-C,N-diphenylnitrone, in which the coordination of a Lewis acid (borane) and the solvent polarity (dichloromethane) have been taken into account. Calculated activation parameters, regioselectivities (for 1,3-dipolar cycloaddition reactions), and endo/exo stereoselectivities show good agreement with available experimental data. Gas-phase calculations show a varied behavior of the s-cis/s-trans TS stability for noncatalyzed reactions (from the systematic s-cis preference for the cyclopentadiene reaction to the systematic s-trans predilection encountered in the diphenylnitrone cycloaddition). BH3 coordination leads to a preferential stabilization of s-trans TSs in the reactions of cyclopentadiene (exo approach) and diphenylnitrone but a larger stabilization of s-cis structures in the processes involving the parent nitrone or 1-pyrroline-1-oxide. Additionally, a rather systematic preferential stabilization of s-trans structures is induced by solvent polarity in most reactions. As a consequence, an s-trans preference is predicted in solution for both thermal and catalyzed types of reactions in most approaches. Such a conclusion is consistent with some experimental results suggesting a preference for a particular conformation of the methacrolein-Lewis acid complexes.
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Affiliation(s)
- Carmen Barba
- Departamento de Química InorgAnica, Instituto de Ciencia de Materiales de Aragón, Instituto Universitario de CatAlisis Homogénea, Facultad de Ciencias, Universidad de Zaragoza-CSIC, Pedro Cerbuna 12, E-50009 Zaragoza, Spain
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397
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Hayashi A, Shiga M, Tachikawa M. H∕D isotope effect on the dihydrogen bond of NH4+⋯BeH2 by ab initio path integral molecular dynamics simulation. J Chem Phys 2006; 125:204310. [PMID: 17144703 DOI: 10.1063/1.2388257] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In order to investigate the HD isotope effect on a dihydrogen bonded cation system, we have studied NH+4...BeH2 and its isotopomers by ab initio path integral molecular dynamics. It is found that the dihydrogen bond can be exchanged by NH+(4) rotation. The deuterated isotopomer (ND+(4)...BeD(2); DD) can exchange the dihydrogen bond more easily than other isotopomers such as (NH+4...BeH2; HH). This unusual isotope effect is ascribed to the "quantum localization" which occurs when the effective energy barrier for the rotational mode becomes higher by the zero point energy of other modes. We also found that the binding energy of dihydrogen bonds for DD species is the smallest among the isotopomers.
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Affiliation(s)
- Aiko Hayashi
- Quantum Chemistry Division, Graduate School of Science, Yokohama City University, Seto 22-2, Kanazawa-ku, Yokohama 236-0027, Japan
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398
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Dem‘yanov PI, Gschwind RM. Formation of Hydrogen Bonds in Complexes between Dimethylcuprate(I) Anion and Methane, Propane, or Dimethyl Ether. A Theoretical Study. Organometallics 2006. [DOI: 10.1021/om0604066] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Piotr I. Dem‘yanov
- Chemistry Department, Moscow State University, Lenin Hills 1, Building 3, Moscow, 119992 GSP-2, Russian Federation, and Institut für Organische Chemie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - Ruth M. Gschwind
- Chemistry Department, Moscow State University, Lenin Hills 1, Building 3, Moscow, 119992 GSP-2, Russian Federation, and Institut für Organische Chemie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
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399
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Ling S, Yu W, Huang Z, Lin Z, Harañczyk M, Gutowski M. Gaseous Arginine Conformers and Their Unique Intramolecular Interactions. J Phys Chem A 2006; 110:12282-91. [PMID: 17078626 DOI: 10.1021/jp0645115] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Extensive ab initio calculations were employed to characterize stable conformers of gaseous arginine, both the canonical and zwitterionic tautomers. Step-by-step geometry optimizations of possible single-bond rotamers at the B3LYP/6-31G(d), B3LYP/6-31++G(d,p), and MP2/6-31++G(d,p) levels yield numerous structures that are more stable than any known ones. The final electronic energies of the conformers were determined at the CCSD/6-31++G(d,p) level. The lowest energies of the canonical and zwitterionic structures are lower than the existing values by 2.0 and 2.3 kcal/mol, respectively. The relative energies, rotational constants, dipole moments, and harmonic frequencies of the stable conformers remain for future experimental verification. The conformational distributions at various temperatures, estimated according to thermodynamic principles, consist almost exclusively of the newly found structures. One striking feature is the occurrence of blue-shifting hydrogen bonds in all six of the most stable conformers. A unique feature of important conformations is the coexistence of dihydrogen and blue- and red-shifting hydrogen bonds. In addition to the hydrogen bonds, the stereoelectronic effects were also found to be important stabilization factors. The calculated and measured proton affinities agree within the theoretical and experimental uncertainties, affirming the high quality of our conformational search. The theoretical gas-phase basicity of 245.9 kcal/mol is also in good agreement with the experimental value of 240.6 kcal/mol. The extensive searches establish firmly that gaseous arginine exists primarily in the canonical and not the zwitterionic form.
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Affiliation(s)
- Sanliang Ling
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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400
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Wang S, Gong W, Liu X, Gao B, Yue Q. Removal of fulvic acids using the surfactant modified zeolite in a fixed-bed reactor. Sep Purif Technol 2006. [DOI: 10.1016/j.seppur.2006.02.019] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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