401
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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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402
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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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403
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Li Y, Wu D, Li ZR, Chen W, Sun CC. Do single-electron lithium bonds exist? Prediction and characterization of the H3C⋯Li–Y (Y=H, F, OH, CN, NC, and CCH) complexes. J Chem Phys 2006; 125:084317. [PMID: 16965022 DOI: 10.1063/1.2339020] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A new kind of single-electron lithium bonding complexes H(3)C...LiY (Y=H, F, OH, CN, NC, and CCH) was predicted and characterized in the present paper. Their geometries (C(3v)) with all real harmonic vibrational frequencies were obtained at the MP2/aug-cc-pVTZ level. For each H(3)C...LiY complex, single-electron Li bond is formed between the unpaired electron of CH(3) radical and positively charged Li atom of LiY molecule. Due to the formation of the single-electron Li bond, the C-H bonds of the CH(3) radical bend opposite to the LiY molecule and the Li-Y bond elongates. Abnormally, the three H(3)C...LiY (Y=CN, NC, and CCH) complexes exhibit blueshifted Li-Y stretching frequencies along with the elongated Li-Y bonds. Natural bond orbital analyses suggest ca. 0.02 electron transfer from the methyl radical (CH(3)) to the LiY moiety. In the single occupied molecular orbitals of the H(3)C...LiY complexes, it is also seen that the electron could of the CH(3) radical approaches the Li atom. The single-electron Li bond energies are 5.20-6.94 kcal/mol for the H(3)C...LiY complexes at the CCSD(T)aug-cc-pVDZ+BF (bond functions) level with counterpoise procedure. By comparisons with some related systems, it is concluded that the single-electron Li bonds are stronger than single-electron H bonds, and weaker than conventional Li bonds and pi-Li bonds.
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Affiliation(s)
- Ying Li
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, People's Republic of China
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404
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Alkorta I, Zborowski K, Elguero J, Solimannejad M. Theoretical Study of Dihydrogen Bonds between (XH)2, X = Li, Na, BeH, and MgH, and Weak Hydrogen Bond Donors (HCN, HNC, and HCCH). J Phys Chem A 2006; 110:10279-86. [PMID: 16928119 DOI: 10.1021/jp061481x] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The dihydrogen-bonded (DHB) complexes formed by (XH)2, with X = Li, Na, BeH, and MgH, with one, two, and four protonic molecules (HCN, HNC, and HCCH) have been studied. These complexes have been compared to those of the XH monomers with the same hydrogen bond donor molecules. The energetic results have been rationalized based on the electrostatic potential of the isolated hydridic systems. The electron density properties have been analyzed within the AIM methodology, both at the bond critical points and the integrated values at the atomic basins. Exponential relationships between several properties calculated at the bond critical points (rho,nabla2rho, lambdai, G, and V) and variation of integrated properties (energy, charge, and volume) vs the DHB distance have been obtained.
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Affiliation(s)
- Ibon Alkorta
- Instituto de Química Médica (CSIC), Juan de la Cierva, 3, 28006 Madrid, Spain.
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405
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Dunitz JD, Gavezzotti A. Molecular recognition in organic crystals: directed intermolecular bonds or nonlocalized bonding? Angew Chem Int Ed Engl 2006; 44:1766-87. [PMID: 15685679 DOI: 10.1002/anie.200460157] [Citation(s) in RCA: 376] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Molecules are held together mainly by forces acting between individual atoms. Does the same apply to molecular clusters? Does intermolecular cohesion depend on weak bonds between individual atoms in different molecules or on less localized, more diffuse interactions between molecules? We discuss these questions from several viewpoints and in particular compare interpretations based on the extension of Bader's atoms in molecules (AIM) theory to cover closed-shell intermolecular interactions with interpretations based on the new pixel method for the calculation of coulombic, polarization, dispersion, and repulsion energies from the electron density of molecular clusters.
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Affiliation(s)
- Jack D Dunitz
- Organic Chemistry Laboratory, Swiss Federal Institute of Technology, ETH-Hönggerberg HCI H333, 8093 Zurich, Switzerland.
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406
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Planas JG, Viñas C, Teixidor F, Light ME, Hursthouse MB. A boron–boron linked large metallacarborane cluster: Characterization and X-ray structure of 8,9′-[closo-{3-Co(η5-C5H5)-1,2-C2B9H10}]2. J Organomet Chem 2006. [DOI: 10.1016/j.jorganchem.2006.04.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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407
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Shi F. Theoretical Investigation on the Nature of Intramolecular Interactions in Aminocyclopentadienyl Ruthenium Hydride Complexes. Organometallics 2006. [DOI: 10.1021/om060330d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Fuqiang Shi
- College of Chemistry, Peking University, Beijing, 100871, People's Republic of China
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408
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Chen P, Xiong Z, Yang L, Wu G, Luo W. Mechanistic Investigations on the Heterogeneous Solid-State Reaction of Magnesium Amides and Lithium Hydrides. J Phys Chem B 2006; 110:14221-5. [PMID: 16854123 DOI: 10.1021/jp061496v] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Isothermal and non-isothermal kinetic measurements on the chemical reaction between Mg(NH2)(2) and LiH, as well as the thermal decomposition of Mg(NH(2))(2), give apparent activation energies of 88.1 and 130 kJ/mol, respectively, which reveal that the thermal decomposition of Mg(NH2)(2) is unlikely to be an elementary step in the chemical reaction of Mg(NH2)(2) and 2LiH. The H-D exchange between H(delta+) in Mg(NH2)(2) and D(delta-) in LiD gives evidence for the coordinated interaction between amide and hydride. The observed linear and nonlinear kinetic growth in the reaction of Mg(NH2)(2)-2LiH indicates that the reaction rate is controlled by the interface reaction in the early stage of the reaction and by mass transport through the imide layer in the later stage. Both particle size and degree of mixing of the reacting species affect the overall kinetics of the reactions.
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Affiliation(s)
- Ping Chen
- Department of Physics, Faculty of Science, National University of Singapore, 10 Kent Ridge Crescent, Singapore 117542.
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409
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Filippov OA, Filin AM, Belkova NV, Tsupreva VN, Shmyrova YV, Sivaev IB, Epstein LM, Shubina ES. Competition between non-classical and classical hydrogen bonded sites in [BH3CN]−: Spectral, energetic, structural and electronic features. J Mol Struct 2006. [DOI: 10.1016/j.molstruc.2005.12.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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410
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Jing YQ, Li ZR, Wu D, Li Y, Wang BQ, Sun CC. Characteristics of Antiaromatic Ring π Multi-Hydrogen Bonds in (H2O)n−C4H4 (n = 1, 2) Complexes. J Phys Chem A 2006; 110:7470-6. [PMID: 16759137 DOI: 10.1021/jp060823w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
By counterpoise-corrected optimization method, the six antiaromatic ring pi multi-hydrogen bond structures with diversiform shapes for (H2O)n-C4H4 (n = 1,2) have been obtained at the MP2/aug-cc-pVDZ level. At the CCSD(T)/aug-cc-pVDZ level, the interaction energy obtained mainly depends on the numbers of H2O and fold numbers of the pi multi-hydrogen bond. The interaction energy order is -2.342 (1a with pi mono-hydrogen) < -2.777 (1b with pi bi-hydrogen) << -4.683 (2a with pi bi-hydrogen) < -4.734 (2b with pi tri-hydrogen) < -4.782 (2c with pi tri-hydrogen) < -5.009 kcal/mol (2d with pi tetra-hydrogen bond). Strangely, why is the interaction energy of the pi bi-hydrogen bond in 1b close to that of the pi mono-hydrogen bond in 1a (their difference is only 15.7%)? The reason is that a pi-type H-bond (as an accompanying interaction) between two lone pairs of the O-atom and a near pair of H-atoms of C4H4 exists shoulder by shoulder in structures 1a, 2a, 2b, and 2c and contributes to the interaction energy. Another accompanying interaction, a repulsive interaction between the pi H-bond (using the H-atom(s) of H2O) and the near pair of H-atoms of C4H4, is also found. For the structures and interaction energies, the pi-type H-bond produces four effects: bending the strong pi H-bond, attracting the pair of H-atoms of C4H4 so that they deviate from the C4 ring plane, showing the interaction energy contribution, and bringing the larger electron correlation contribution. The repulsive interaction also produces four effects: pushing the pair of H-atoms of C4H4 so that they deviate from its ring plane, elongating the distance of the pi H-bond, promoting the formation of pi-type H-bond, and slightly influencing the interaction energy. In the present paper, one C=C bond with two H2O (over and below the ring plane) forms a pi H-bond link in two ways: a strong-weak pi H-bond link and a strong-strong pi H-bond link. The stability contribution of the former is more favorable than the latter. One H2O forms a pi H-bond with C4H4 in two ways. One strong pi H-bond part (over or below the ring plane) always is accompanied by another H-bond part. The accompanying part is either a weak pi H-bond or pi-type H-bond.
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Affiliation(s)
- Ying-Qi Jing
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China
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411
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Fanfrlík J, Lepsík M, Horinek D, Havlas Z, Hobza P. Interaction of Carboranes with Biomolecules: Formation of Dihydrogen Bonds. Chemphyschem 2006; 7:1100-5. [PMID: 16671116 DOI: 10.1002/cphc.200500648] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Noncovalent interactions of the polyhedral carborane 1-carba-closo-dodecaborane (CB(11)H(12))(-) with building blocks of biomolecules, modelled by glycine (GLY), serine (SER), phenylalanine (PHE), glutamic acid (GLU), lysine (LYS) and arginine (ARG), were investigated in vacuo by molecular dynamics simulations with the UFF empirical potential. Selected structures were further studied by accurate ab initio quantum chemical procedures. Interactions with a peptide bond (GLY-SER dipeptide) and a nucleic acid building block (guanine) were also considered. The RESP and NPA charges of carboranes and small model systems are compared and their use is discussed. The dominant interaction between carboranes and biomolecules is the formation of unconventional proton-hydride hydrogen bonds (dihydrogen bonds) characterized by a short distance between hydrogen atoms (as close as 1.8 A) and an average strength in the range of 4.2-5.8 kcal mol(-1). The total stabilization energy of complexes investigated is rather large, and the largest value (approximately 15 kcal mol(-1)) was found for the carborane complexes with ARG and the GLY-SER dipeptide. These interactions are ubiquitous under geometrical constraints influencing the strength of the interaction. The carborane forms dihydrogen bonds with biomolecules preferably with the hydrogen atoms of its lower hemisphere (i.e. the part of the cage opposite to the carbon atom). These two geometrical factors can be used to explain the specificity of inhibition of HIV protease by carboranes.
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Affiliation(s)
- Jindrich Fanfrlík
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic and Center for Biomolecules and Complex Molecular Systems, 166 10 Prague 6, Czech Republic
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412
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Ziółkowski M, Grabowski SJ, Leszczynski J. Cooperativity in Hydrogen-Bonded Interactions: Ab Initio and “Atoms in Molecules” Analyses. J Phys Chem A 2006; 110:6514-21. [PMID: 16706409 DOI: 10.1021/jp060537k] [Citation(s) in RCA: 277] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The H(2)CO...(HF)(n) (n = 1, ..., 9) complexes were investigated using the MP2 method and the following basis sets: 6-311++G(d,p), aug-cc-pVDZ and aug-cc-pVTZ. It was found that the cooperativity effect enhances significantly the F-H...O hydrogen bond; in some of cases one can detect the covalent nature of hydrogen bonding. To deepen the nature of the interactions investigated, the scheme of decomposition of the interaction energy was applied; for stronger H-bonds where the cooperativity is more important, the delocalization energy term increases. The ratio of delocalization energy to electrostatic energy increases for stronger hydrogen bonds where the proton...acceptor distance is shorter. The Bader theory was also applied, and it was found that for stronger H-bonds the electronic energy density at the proton...acceptor bond critical point is negative and may be attributed to the partly covalent interaction.
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Affiliation(s)
- Marcin Ziółkowski
- Department of Quantum Chemistry, Institute of Chemistry, Nicolaus Copernicus University, 7, Gagarin St., 87-100 Toruń, Poland
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413
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Solimannejad M, Alkorta I. Theoretical study of dihydrogen bonds in HnMH⋯HArF and HnMH⋯HKrF complexes (n=1–3; M=Be, Al, Ga, Si, Ge). Chem Phys 2006. [DOI: 10.1016/j.chemphys.2005.11.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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414
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Li Q, Wu G, Yu Z. The role of methyl groups in the formation of hydrogen bond in DMSO-methanol mixtures. J Am Chem Soc 2006; 128:1438-9. [PMID: 16448100 DOI: 10.1021/ja0569149] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
When examining the formation energetics of a hydrogen-bonded complex R-X-H...Y-R', focus has been almost always on the atoms directly involved, namely the atoms X, Y, and H. Little attention has been paid to the effects of the secondary alkyl groups R and R'. Taking dimethyl sulfoxide (DMSO)-methanol binary system as an example, we have studied the roles of the alkyl groups in stabilizing the hydrogen bonds by employing FTIR and NMR techniques and quantum chemical calculations. We found that methyl groups play different roles in response to the hydrogen-bonding interactions. The methyl groups of DMSO are electron-donating, whereas that of methanol is electron-withdrawing, both making positive contributions. The findings reveal non-negligible effects of secondary alkyl groups in hydrogen bonding interaction and may shed light on the understanding of other more complicated hydrogen-bonded systems in chemical and biological systems.
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Affiliation(s)
- Qingzhong Li
- Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
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415
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Solimannejad M, Amlashi LM, Alkorta I, Elguero J. XeH2 as a proton-accepting molecule for dihydrogen bonded systems: A theoretical study. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.02.070] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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416
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Yu W, Lin Z, Huang Z. Coexistence of Dihydrogen, Blue- and Red-Shifting Hydrogen Bonds in an Ultrasmall System: Valine. Chemphyschem 2006; 7:828-30. [PMID: 16526077 DOI: 10.1002/cphc.200500721] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Wenbo Yu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei 230026, P. R. China
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417
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Cybulski H, Tymińska E, Sadlej J. The Properties of Weak and Strong Dihydrogen-Bonded DH⋅⋅⋅HA Complexes. Chemphyschem 2006; 7:629-39. [PMID: 16477668 DOI: 10.1002/cphc.200500462] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The properties of six dihydrogen-bonded (DHB) dimers with the BeH2 molecule as a proton acceptor were calculated by MP2, CCSD(T) and B3LYP methods. The structural, energetic and spectroscopic parameters are presented and analyzed in terms of their possible correlation with the interaction energy and the intermolecular H...H separation. The symmetry-adapted perturbation theory (SAPT) calculations were performed to gain more insight into the nature of the H...H interactions. The studied complexes are divided into three groups based on the calculated intermolecular distances and the interaction energies which range from approximately -1 to -42 kJ mol(-1). The analysis of the interaction energy components indicates that, in contrast to conventional hydrogen bonds, the induction energy is the most important term in the BeH2NH4+ complex. On the other hand, there is no sharp boundary between the DHB complexes classified as hydrogen bonded and van der Waals systems. The complexation-induced changes in vibrational frequencies and in proton shielding constants show a relationship with the interaction energy. The values of the 2hJXH and 3hJBeX coupling constants correlate well with the interaction energy and with the intermolecular distance.
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Affiliation(s)
- Hubert Cybulski
- Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
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418
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Henry RM, Shoemaker RK, DuBois DL, DuBois MR. Pendant Bases as Proton Relays in Iron Hydride and Dihydrogen Complexes. J Am Chem Soc 2006; 128:3002-10. [PMID: 16506781 DOI: 10.1021/ja057242p] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The complex trans-[HFe(PNP)(dmpm)(CH(3)CN)]BPh(4), 3, (where PNP is Et(2)PCH(2)N(CH(3))CH(2)PEt(2) and dmpm is Me(2)PCH(2)PMe(2)) can be successively protonated in two steps using increasingly strong acids. Protonation with 1 equiv of p-cyanoanilinium tetrafluoroborate in acetone-d(6) at -80 degrees C results in ligand protonation and the formation of endo (4a) and exo (4b) isomers of trans-[HFe(PNHP)(dmpm)(CH(3)CN)](BPh(4))(2). The endo isomer undergoes rapid intramolecular proton/hydride exchange with an activation barrier of 12 kcal/mol. The exo isomer does not exchange. Studies of the reaction of 3 with a weaker acid (anisidinium tetrafluoroborate) in acetonitrile indicate that a rapid intermolecular proton exchange interconverts isomers 4a and 4b, and a pK(a) value of 12 was determined for these two isomers. Protonation of 3 with 2 equiv of triflic acid results in the protonation of both the PNP ligand and the metal hydride to form the dihydrogen complex [(H(2))Fe(PNHP)(dmpm)(CH(3)CN)](3+), 11. Studies of related complexes [HFe(PNP)(dmpm)(CO)](+) (12) and [HFe(depp)(dmpm)(CH(3)CN)](+) (10) (where depp is bis(diethylphosphino)propane) confirm the important roles of the pendant base and the ligand trans to the hydride ligand in the rapid intra- and intermolecular hydride/proton exchange reactions observed for 4. Features required for an effective proton relay and their potential relevance to the iron-only hydrogenase enzymes are discussed.
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Affiliation(s)
- Renee M Henry
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
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419
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Donghi D, Beringhelli T, D'Alfonso G, Mondini M. NMR Investigation of the Dihydrogen-Bonding and Proton-Transfer Equilibria between the Hydrido Carbonyl Anion [HRe2(CO)9]− and Fluorinated Alcohols. Chemistry 2006; 12:1016-25. [PMID: 16267862 DOI: 10.1002/chem.200500920] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The interaction of fluorinated alcohols with the anionic hydrido complex [HRe2(CO)9]- (1) has been investigated by NMR spectroscopy. According to the acidic strength of the alcohols, the interaction may result not only in the formation of dihydrogen-bonded ROH...[HRe2(CO)9]- adducts 2, but also in proton transfer to give the neutral species [H2Re2(CO)9] (3). With the weaker acid trifluoroethanol (TFE) evidence for the occurrence of the dihydrogen-bonding equilibrium was obtained by 2D 1H NOESY. The dependence of the hydride chemical shift on TFE concentration at different temperatures provided values for the constants of this equilibrium, from which the thermodynamic parameters were evaluated as deltaH(degrees) = -2.6(2) kcal mol(-1), deltaS(degrees) = -9.3(2) cal mol(-1) K(-1). This corresponds to a rather low basicity factor (E(j) = 0.64). Variable-temperature T1 measurements allowed the proton-hydride distance in adduct 2 a to be estimated (1.80 angstroms). In the presence of hexafluoroisopropyl alcohol (HFIP) simultaneous occurrence of both dihydrogen-bonding and proton-transfer equilibria was observed, and the equilibria shifted versus the protonated product 3 with increasing HFIP concentration and decreasing temperature. Reversible proton transfer between the alcohol and the hydrido complex occurs on the NMR timescale, as revealed by a 2D 1H EXSY experiment at 240 K. For the more acidic perfluoro-tert-butyl alcohol (PFTB) the protonation equilibrium was further shifted to the right. Thermal instability of 3 prevented the acquisition of accurate thermodynamic data for these equilibria. The occurrence of the proton-transfer processes (in spite of the unfavorable pK(a) values) can be explained by the formation of homoconjugated RO...HOR- pairs which stabilize the alcoholate anions.
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Affiliation(s)
- Daniela Donghi
- Università degli Studi di Milano, Facoltà di Farmacia, Dipartimento di Chimica Inorganica, Metallorganica e Analitica, Via Venezian 21, 20133 Milano, Italy
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420
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Kormos BL, Cramer CJ, Gladfelter WL. Pseudo-two-dimensional structures (HXYH)3n2H6n (XY = GaN, SiC, GeC, SiSi, or GeGe; n = 1-3): density functional characterization of structures and energetics. J Phys Chem A 2006; 110:494-502. [PMID: 16405321 DOI: 10.1021/jp051885+] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hybrid density functional calculations with effective core potential basis sets are performed for monomeric group 13/15 and group 14/14 analogues of cyclohexane, as well as for three different pseudo-two-dimensional structures that can be formed from expanding one and two concentric rings around the central one (trans-fused chairs, a rolling combination of trans- and cis-fused chairs, and cis-fused boats). Varying contributions from torsional strain, angle strain, electrostatics, and nontraditional H-H hydrogen bonding lead to different orderings and magnitudes of motif energies in the various systems: Homoatomic SiSi and GeGe systems prefer the trans-fused chair alternative and heteroatomic systems GaN, SiC, and GeC prefer the rolling chair. Decomposition of structure energies into characteristic fragment contributions indicates that pseudo-one-dimensional rods of poly(imidogallane) are thermodynamically more stable than any of the pseudo-two-dimensional structures.
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Affiliation(s)
- Bethany L Kormos
- Department of Chemistry and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, USA
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421
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Solimannejad M, Boutalib A. Theoretical investigation of the weakly dihydrogen bonded dimers H2−nXnAlH⋯HArF and H2−nXnAlH⋯HKrF (n=0–2; X=F, Cl). Chem Phys 2006. [DOI: 10.1016/j.chemphys.2005.07.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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422
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Canal JP, Ramnial T, Dickie DA, Clyburne JAC. From the reactivity of N-heterocyclic carbenes to new chemistry in ionic liquids. Chem Commun (Camb) 2006:1809-18. [PMID: 16622493 DOI: 10.1039/b512462j] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
N-Heterocyclic carbenes have numerous applications in synthetic chemistry. We detail the reactivity and chemistry of these molecules including investigations into their reactions with small reagents, their use for the preparation of polarised azines and their potential application as NLO materials. The chemistry of imidazolium salts, which are related to NHCs by the addition of a proton, is also discussed. New chemistry for ionic liquids is also revealed.
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Affiliation(s)
- John P Canal
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
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423
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424
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Sobczyk L, Grabowski SJ, Krygowski TM. Interrelation between H-bond and Pi-electron delocalization. Chem Rev 2005; 105:3513-60. [PMID: 16218560 DOI: 10.1021/cr030083c] [Citation(s) in RCA: 528] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lucjan Sobczyk
- Faculty of Chemistry, University of Wrocław, Joliot-Curie 14, 50 383 Wrocław, Poland
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425
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Wilson AD, Newell RH, McNevin MJ, Muckerman JT, Rakowski DuBois M, DuBois DL. Hydrogen Oxidation and Production Using Nickel-Based Molecular Catalysts with Positioned Proton Relays. J Am Chem Soc 2005; 128:358-66. [PMID: 16390166 DOI: 10.1021/ja056442y] [Citation(s) in RCA: 419] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Highly efficient electrocatalysts for both hydrogen evolution and hydrogen oxidation have been designed, synthesized, and characterized. The catalysts in their resting states are air-stable, mononuclear nickel(II) complexes containing cyclic diphosphine ligands with nitrogen bases incorporated into the ligand backbone. X-ray diffraction studies have established that the cation of [Ni(P(Ph)(2)N(Ph)(2))(2)(CH(3)CN)](BF(4))(2), 6a, (where P(Ph)(2)N(Ph)(2) is 1,3,5,7-tetraphenyl-1,5-diaza-3,7-diphosphacyclooctane) is a trigonal bipyramid with bonds to four phosphorus atoms of the two bidentate diphosphine ligands and the nitrogen atom of an acetonitrile molecule. Two of the six-membered rings formed by the diphosphine ligands and Ni have boat conformations with an average Ni- - -N distance to the two pendant bases of 3.4 A. The cation of [Ni(P(Cy)(2)N(Bz)(2))(2)](BF(4))(2), 6b, (where Cy = cyclohexyl and Bz = benzyl) is a distorted square planar complex. For 6b, all four six-membered rings formed upon coordination of the diphosphine ligands to the metal are in the boat form. In this case, the average Ni- - -N distance to the pendant base is 3.3 A. Complex 6a is an electrocatalyst for hydrogen production in acidic acetonitrile solutions, and compound 6b is an electrocatalyst for hydrogen oxidation in basic acetonitrile solutions. It is demonstrated that the high catalytic rates observed with these complexes are a result of the positioning of the nitrogen base so that it plays an important role in the formation and cleavage of the H-H bond.
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Affiliation(s)
- Aaron D Wilson
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
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426
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Solimannejad M, Scheiner S. Theoretical Investigation of the Dihydrogen Bond Linking MH2 with HCCRgF (M = Zn, Cd; Rg = Ar, Kr). J Phys Chem A 2005; 109:11933-5. [PMID: 16366645 DOI: 10.1021/jp0563383] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An ab initio computational study of the properties of four linear dihydrogen-bonded complexes pairing MH2 (M = Zn, Cd) with HCCRgF (Rg = Ar, Kr) was undertaken at the MP2/DGDZVP level of theory. The calculated complexation energies of the linear complexes vary between 6.5 kJ/mol for M = Zn to 8.5 kJ/mol for M = Cd. Equilibrium interatomic H...H distances are roughly 2.07 A for all four complexes. The red shifts of the H-C stretching frequency of HCCRgF correlate nicely with the interaction energies.
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Affiliation(s)
- Mohammad Solimannejad
- Quantum Chemistry Group, Department of Chemistry, Arak University, 38156-879 Arak, Iran.
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427
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Boily JF, Seward TM. On the Dissociation of Methyl Orange: Spectrophotometric Investigation in Aqueous Solutions from 10 to 90 ∘C and Theoretical Evidence for Intramolecular Dihydrogen Bonding. J SOLUTION CHEM 2005. [DOI: 10.1007/s10953-005-8514-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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428
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Guilera G, McGrady GS, Steed JW, Jones AL. Complex Formation and Rearrangement Reactions of the Phosphine Hydride Anions [OsH3(PPh3)3]- and [IrH2(PPh3)3]-. Organometallics 2005. [DOI: 10.1021/om050391w] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gemma Guilera
- European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, Grenoble Cedex 9, France, Department of Chemistry, University of New Brunswick, Fredericton, N.B. E3B 6E2, Canada, and Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, U.K
| | - G. Sean McGrady
- European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, Grenoble Cedex 9, France, Department of Chemistry, University of New Brunswick, Fredericton, N.B. E3B 6E2, Canada, and Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, U.K
| | - Jonathan W. Steed
- European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, Grenoble Cedex 9, France, Department of Chemistry, University of New Brunswick, Fredericton, N.B. E3B 6E2, Canada, and Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, U.K
| | - Aled L. Jones
- European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, Grenoble Cedex 9, France, Department of Chemistry, University of New Brunswick, Fredericton, N.B. E3B 6E2, Canada, and Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, U.K
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429
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Shukla MK, Leszczynski J. Effect of Hydration on the Lowest Singlet ππ* Excited-State Geometry of Guanine: A Theoretical Study. J Phys Chem B 2005; 109:17333-9. [PMID: 16853213 DOI: 10.1021/jp0520751] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An ab-initio computational study was performed to investigate the effect of explicit hydration on the ground and lowest singlet PiPi* excited-state geometry and on the selected stretching vibrational frequencies corresponding to the different NH sites of the guanine acting as hydrogen-bond donors. The studied systems consisted of guanine interacting with one, three, five, six, and seven water molecules. Ground-state geometries were optimized at the HF level, while excited-state geometries were optimized at the CIS level. The 6-311G(d,p) basis set was used in all calculations. The nature of potential energy surfaces was ascertained via the harmonic vibrational frequency analysis; all structures were found minima at the respective potential energy surfaces. The changes in the geometry and the stretching vibrational frequencies of hydrogen-bond-donating sites of the guanine in the ground and excited state consequent to the hydration are discussed. It was found that the first solvation shell of the guanine can accommodate up to six water molecules. The addition of the another water molecule distorts the hydrogen-bonding network by displacing other neighboring water molecules away from the guanine plane.
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Affiliation(s)
- M K Shukla
- Computational Centre for Molecular Structure and Interactions, Department of Chemistry, Jackson State University, Jackson, MS 39217, USA
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430
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431
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Hayashi A, Shiga M, Tachikawa M. Ab initio path integral molecular dynamics simulation study on the dihydrogen bond of NH4+⋯BeH2. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.05.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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432
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Solimannejad M, Scheiner S. Theoretical Investigation of the Weakly Dihydrogen Bonded Complexes FArCCH···HBeX (X = H, F, Cl, Br). J Phys Chem A 2005; 109:6137-9. [PMID: 16833952 DOI: 10.1021/jp052534y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An ab initio computational study of the properties of four linear dihydrogen-bonded complexes formed between the first compound with an Ar-C chemical bond (FArCCH) and HBeX (X = H, F, Cl, and Br) molecules was undertaken at the MP2/6-311++G(2d,2p) level of theory. The calculated complexation energy at MP2 and G2(MP2) levels decreases in the order HBeH...HCCArF > BrBeH...HCCArF > ClBeH...HCCArF > FBeH...HCCArF. The intermolecular stretching frequency, and shifts within the monomers, are compared with the energetic strength of complexation.
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433
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Di Saverio A, Focante F, Camurati I, Resconi L, Beringhelli T, D'Alfonso G, Donghi D, Maggioni D, Mercandelli P, Sironi A. Oxygen-Bridged Borate Anions from Tris(pentafluorophenyl)borane: Synthesis, NMR Characterization, and Reactivity. Inorg Chem 2005; 44:5030-41. [PMID: 15998031 DOI: 10.1021/ic0502168] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The previously known anion [(C6F5)3B(mu-OH)B(C6F5)3]- (2) has been prepared by a two-step procedure, involving deprotonation of (C6F5)3BOH2 to give [B(C6F5)3OH]- (1), followed by addition of B(C6F5)3. The solution structure and the dynamics of 2 have been investigated by 1H and 19F NMR spectroscopy. The reaction of [NHEt3]2 with NEt3 resulted in the formation of [NHEt3]+ [(C6F5)3BOH]-, [NHEt3]+ [(C6F5)3BH]-, and (C6F5)3B- (CH2CH=N+ Et2). This indicates that in the presence of a nucleophile anion 2 can dissociate to B(C6F5)3 and 1. The reaction of [HDMAN]2 with 1,8-bis(dimethylamino)naphthalene (DMAN) confirmed this trend. In the presence of water, 2 transformed into the adduct [(C6F5)3BO(H)H...O(H)B(C6F5)3]- (3), containing the borate 1 hydrogen-bonded to a water molecule coordinated to B(C6F5)3. The same compound is formed by treating (C6F5)3BOH2 with 0.5 equiv of a base. A competition study established that for 1 the Lewis acid-base interaction with B(C6F5)3 is about 5 times preferred over H-bonding to (C6F5)3BOH2. The X-ray single-crystal analysis of [2-methyl-3H-indolium]3 provided the first experimental observation of an asymmetric H-bond in the [H3O2]- moiety, the measured O-H and H...O bond distances being significantly different [1.14(2) vs 1.26(2) A]. The reaction of NEt3 with an equimolar mixture of B(C6F5)3 and bis(pentafluorophenyl)borinic acid, (C6F5)2BOH, afforded the novel borinatoborate salt [NHEt3]+ [(C6F5)3BOB(C6F5)2]- ([NHEt3]4). X-ray diffraction showed that the B-O bond distances are significantly shorter than in [(C6F5)3B(mu-OH)B(C6F5)3]-. Variable-temperature 19F NMR revealed high mobility of the five aryl rings, at variance with the more crowded anion 2. 2D NMR correlation experiments showed that in CD2Cl2 the two anions [(C6F5)3BOH]- and [(C6F5)3BH]- form tight ion pairs with [NHEt3]+, in which the NH proton establishes a conventional (BO...HN) or an unconventional (BH...HN), respectively, hydrogen bond with the anion. The diborate anions 2-4, on the contrary, gave loose ion pairs with the ammonium cation, due both to the delocalized anionic charge and to the more sterically encumbered position of the oxygen atoms that should act as H-bond acceptors.
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434
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Hugas D, Simon S, Duran M. MH⋅sHX Dihydrogen Bond with M≡Li, Na and X≡F, Cl, Br: A CP-Corrected PES Calculation and an AIM Analysis. Struct Chem 2005. [DOI: 10.1007/s11224-005-4456-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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435
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Filippov OA, Filin AM, Teplitskaya LN, belkova NV, shmyrova YV, sivaev IB, bregadze VI, epstein LM, shubina ES. Hydrogen bonding of the undecahydro-thiocyanato-closo-dodecaborate anion with proton donors. MAIN GROUP CHEMISTRY 2005. [DOI: 10.1080/10241220500106747] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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436
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Jiménez-Tenorio M, Palacios MD, Puerta MC, Valerga P. TpRu Hydride and Dihydrogen Complexes Bearing Bidentate Phosphinoamine Ligands. NMR Study of Proton Transfer to [TpRuH(L)] (L = R,R-dippach, dippae; Tp = Hydrotris(pyrazolyl)borate). Organometallics 2005. [DOI: 10.1021/om050199u] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Manuel Jiménez-Tenorio
- Departamento de Ciencia de Materiales e Ingeniería Metalúrgica y Química Inorgánica, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain
| | - M. Dolores Palacios
- Departamento de Ciencia de Materiales e Ingeniería Metalúrgica y Química Inorgánica, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain
| | - M. Carmen Puerta
- Departamento de Ciencia de Materiales e Ingeniería Metalúrgica y Química Inorgánica, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain
| | - Pedro Valerga
- Departamento de Ciencia de Materiales e Ingeniería Metalúrgica y Química Inorgánica, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain
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437
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Grabowski SJ, Sokalski WA, Leszczynski J. How Short Can the H···H Intermolecular Contact Be? New Findings that Reveal the Covalent Nature of Extremely Strong Interactions. J Phys Chem A 2005; 109:4331-41. [PMID: 16833763 DOI: 10.1021/jp0444215] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ab initio calculations at the MP2/6-311++G(d,p) and MP2/aug-cc-pVDZ//MP2/aug-cc-pVTZ levels have been performed for the following complexes: H2OH+...HBeH, H2OH+...HBeBeH, H2OH+...HBeF, HClOH+...HBeH, Cl2OH+...HBeH, and Cl2OH+...HBeF. For all dimers considered, extremely short H...H intermolecular contacts (1.0-1.3 A) were obtained. These are the shortest intermolecular distances which have ever been reported, with binding energies within the range of 13.7-24.3 kcal/mol (MP2/aug-cc-pVDZ//MP2/aug-cc-pVTZ level). The interaction energies of the complexes analyzed were also extrapolated to the complete basis set (CBS) limit. To explain the nature of such strong interactions, the Bader theory was applied, and the characteristics of the bond critical points (BCPs) were analyzed. It was pointed out that for the major part of the H...H contacts considered here the Laplacian of the electron density at H...H BCP is negative indicating the partly covalent nature of such a connection. The term "covalent character of the hydrogen bond" used sometimes in recent studies is discussed. An analysis of the interaction energy components for dihydrogen bonded systems considered indicates that in contrast to conventional hydrogen bonded systems the attractive electrostatic term is outweighed by the repulsive exchange energy term and that the higher order delocalization energy term is the most important attractive term.
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Affiliation(s)
- Sławomir J Grabowski
- Department of Crystallography and Crystal Chemistry, University of Łódź, 90-236 Łódź, ul. Pomorska 149/153, Poland.
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438
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Henry RM, Shoemaker RK, Newell RH, Jacobsen GM, DuBois DL, Rakowski DuBois M. Stereochemical Control of Iron(II) Complexes Containing a Diphosphine Ligand with a Pendant Nitrogen Base. Organometallics 2005. [DOI: 10.1021/om050071c] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Renee M. Henry
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
| | - Richard K. Shoemaker
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
| | - Rachel H. Newell
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
| | - George M. Jacobsen
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
| | - Daniel L. DuBois
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
| | - M. Rakowski DuBois
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
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439
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Dunitz JD, Gavezzotti A. Molekulare Erkennung in organischen Kristallen: gerichtete intermolekulare oder nichtlokalisierte Bindungen? Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200460157] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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440
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441
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Patwari GN. Proton Affinities of Borane−Amines: Consequences on Dihydrogen Bonding. J Phys Chem A 2005; 109:2035-8. [PMID: 16838971 DOI: 10.1021/jp044445b] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The calculated proton affinities of four borane-amines using Gaussian-2 theory have been found to be comparable to conventional bases such as water, methanol, and ammonia. On the other hand the structure of protonated borane-ammonia, [HBH(3)-NH(3)](+), is found to be drastically different from that of protonated ammonia, [HNH(3)](+), and can appropriately be described as a eta(2)-H(2) complex with [BH(2)-NH(3)](+) molecular cation. Further, the proton affinities of borane-amines are related to the ease of H(2) elimination.
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442
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Bakhmutov VI. Proton Transfer to Hydride Ligands with Formation of Dihydrogen Complexes: A Physicochemical View. Eur J Inorg Chem 2005. [DOI: 10.1002/ejic.200400697] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Vladimir I. Bakhmutov
- Department of Chemistry, Texas A&M University, College Station, Texas 77843‐3255, USA
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443
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Abstract
Using theoretical calculations we predict a novel family of compounds, which might serve for hydrogen storage, and for chemical vapour deposition of titanium carbide coatings.
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Affiliation(s)
- Wojciech Grochala
- Department of Chemistry, University of Warsaw, Pasteur 1, 02093 Warsaw, Poland.
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444
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Ferrando-Miguel G, Wu P, Huffman JC, Caulton KG. New d4dihydrides of Ru(iv) and Os(iv) with π-donor ligands: M(H)2(chelate)(PiPr3)2with chelate = ortho-XYC6H4with X, Y = O, NR; R = H or CH3. NEW J CHEM 2005. [DOI: 10.1039/b411487f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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445
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Marincean S, Custelcean R, Stein RS, Jackson JE. Structural Reinvestigation of Ammonium Hypophosphite: Was Dihydrogen Bonding Observed Long Ago? Inorg Chem 2004; 44:45-8. [PMID: 15627359 DOI: 10.1021/ic048657z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The past decade has seen the explosive emergence of "dihydrogen bonds", interactions between the electrons of M-H sigma-bonds, where M is less electronegative than H (M = Al, B, Ga, Ir, Mo, Mn, Os, Re, Ru, W) and traditional proton donors. But 70 years ago, such an interaction was proposed by Zachariasen and Mooney [J. Chem. Phys. 1934, 2, 34-37] on the basis of their single-crystal X-ray diffraction structure (heavy atoms positions only) of ammonium hypophosphite (NH(4)H(2)PO(2)). We redetermined this structure at high resolution with a focus on the hydrogen atoms, using a modern diffractometer equipped with a CCD detector. Molecular orbital calculations were performed to investigate the charge density and the bond polarity of the P-H bonds and to assess their potential for participation in dihydrogen bonds. Neither the theory nor the X-ray structure supports the original claim of H...H interactions in this salt.
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Affiliation(s)
- Simona Marincean
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, USA
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446
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Li RY, Li ZR, Wu D, Li Y, Chen W, Sun CC. Characteristic of structures and π-hydrogen bond of dimers C2H4−nFn-HF (n=0,1,2). J Chem Phys 2004; 121:8775-81. [PMID: 15527341 DOI: 10.1063/1.1799615] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
By the counterpoise-correlated potential energy surface method (interaction energy optimization), five structures of the C(2)H(4-n)F(n)-HF (n = 0,1,2) dimers with all real frequencies have been obtained at MP2/aug-cc-pVDZ level. The influence of F substituent effect on the structure and pi-hydrogen bond of dimer has been discussed. For C(2)H(4-n)F(n)-HF (n = 1,2), the pi-hydrogen bonds are elongated comparing with that for C(2)H(4)-HF. For C(2)H(3)F-HF, g-C(2)H(2)F(2)-HF, cis-C(2)H(2)F(2)-HF, the pi-hydrogen bonds are further deformed. These changes (elongate, shift, and deformation) of pi-hydrogen bond mainly come from deformation of pi-electron cloud of C=C bond. The pi-electron cloud is pushed towards the one C atom, the pi H-bond shift also to the C direction. Since the two lobes of pi-electron cloud have deviated slightly from the molecular vertical plane passing through C=C bond, the pi-hydrogen bond is sloped. Intermolecular interaction energies of the dimers are calculated to be -3.9 for C(2)H(4)-HF, -2.8 for C(2)H(3)F-HF, -2.1 for g-C(2)H(2)F(2)-HF, -1.6 for cis-C(2)H(2)F(2)-HF, -1.3 kcal/mol for trans-C(2)H(2)F(2)-HF, at CCSD(T)/aug-cc-pVDZ level.
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Affiliation(s)
- Rui-Yan Li
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, People's Republic of China
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447
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448
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McDowell SAC. A computational study of the dihydrogen bonded complexes HBeH⋯HArF and HBeH⋯HKrF. J Chem Phys 2004; 121:5728-32. [PMID: 15366996 DOI: 10.1063/1.1784449] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We report an ab initio computational study of the properties of two linear dihydrogen-bonded complexes of HBeH with the recently discovered rare gas compounds HArF and HKrF at the MP2(full)/6-311++G(2d,2p) level of theory. The HBeH ... HArF and HBeH ... HKrF complexes were found to have zero-point energy corrected binding energies of 27 and 12 kJ mol(-1), respectively. Large red shifts of the H-Rg vibrational stretching frequency in both complexes were also predicted. The electron density rearrangement of the rare gas compounds on complexation was also examined. We also consider the relative stabilities of D-containing isotopomers of the complexes by comparison of their computed zero-point vibrational energies.
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Affiliation(s)
- Sean A C McDowell
- Department of Biological and Chemical Sciences, University of the West Indies, Cave Hill Campus, P.O. Box 64, Bridgetown, Barbados
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449
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Belkova N, Filippov O, Filin A, Teplitskaya L, Shmyrova Y, Gavrilenko V, Golubinskaya L, Bregadze V, Epstein L, Shubina E. Interaction of the [GaH4]− Anion with Weak XH Acids− A Spectroscopic and Theoretical Study. Eur J Inorg Chem 2004. [DOI: 10.1002/ejic.200400084] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Gil A, Sodupe M, Bertran J. Unusual hydrogen bonds in [AH3–H3O]+ radical cations (A=C, Si, Ge, Sn and Pb). Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.07.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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