126
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Bjornsson R, Bühl M. Modeling Molecular Crystals by QM/MM: Self-Consistent Electrostatic Embedding for Geometry Optimizations and Molecular Property Calculations in the Solid. J Chem Theory Comput 2012; 8:498-508. [DOI: 10.1021/ct200824r] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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127
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Freitas MP, Bühl M, O'Hagan D. 1,2-Difluoroethane: the angular dependance on 1JCF coupling constants is independent of hyperconjugation. Chem Commun (Camb) 2012; 48:2433-5. [DOI: 10.1039/c2cc17180e] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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128
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Knight FR, Athukorala Arachchige KS, Randall RAM, Bühl M, Slawin AMZ, Woollins JD. Exploring hypervalency and three-centre, four-electron bonding interactions: Reactions of acenaphthene chalcogen donors and dihalogen acceptors. Dalton Trans 2012; 41:3154-65. [DOI: 10.1039/c2dt12031c] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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129
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Aschenbach LK, Knight FR, Randall RAM, Cordes DB, Baggott A, Bühl M, Slawin AMZ, Woollins JD. Onset of three-centre, four-electron bonding in peri-substituted acenaphthenes: a structural and computational investigation. Dalton Trans 2011; 41:3141-53. [PMID: 22175061 DOI: 10.1039/c1dt11697e] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two series of sterically crowded peri-substituted acenaphthenes have been prepared, containing mixed halogen-chalcogen functionalities at the 5,6-positions in A1-A6 (Acenap[X][EPh] (Acenap = acenaphthene-5,6-diyl; X = Br, I; E = S, Se, Te) and chalcogen-chalcogen moieties in A7-A12 (Acenap[EPh][E'Ph] (Acenap = acenaphthene-5,6-diyl; E/E' = S, Se, Te). The related dihalide compounds A13-A16 Acenap[XX'] (XX' = BrBr, II, IBr, ClCl) have also been prepared. Distortion of the acenaphthene framework away from the ideal was studied as a function of the steric bulk of the interacting halogen and chalcogen atoms occupying the peri-positions. The acenaphthene series experiences a general increase in peri-separation for molecules accommodating heavier congeners and maps the trends observed previously for the analogous naphthalene compounds N1-N12 (Nap[X][EPh], Nap[EPh][E'Ph] (X = Br, I; E/E' = S, Se, Te). The conformation of the aromatic ring systems and subsequent location of p-type lone-pairs dominates the geometry of the peri-region. The differences in peri-separations observed for compounds adopting differing conformations of the peri-substituted phenyl group can be correlated to the ability of the frontier orbitals of the halogen or chalcogen atoms to take part in attractive or repulsive interactions. Density-functional studies have confirmed these interactions and suggested the onset of formation of three-centre, four-electron bonding under appropriate geometric conditions.
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130
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Cao J, Bjornsson R, Bühl M, Thiel W, van Mourik T. Modelling zwitterions in solution: 3-fluoro-γ-aminobutyric acid (3F-GABA). Chemistry 2011; 18:184-95. [PMID: 22161781 DOI: 10.1002/chem.201101674] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Indexed: 12/18/2022]
Abstract
The conformations and relative stabilities of folded and extended 3-fluoro-γ-aminobutyric acid (3F-GABA) conformers were studied using explicit solvation models. Geometry optimisations in the gas phase with one or two explicit water molecules favour folded and neutral structures containing intramolecular NH···O-C hydrogen bonds. With three or five explicit water molecules zwitterionic minima are obtained, with folded structures being preferred over extended conformers. The stability of folded versus extended zwitterionic conformers increases on going from a PCM continuum solvation model to the microsolvated complexes, though extended structures become less disfavoured with the inclusion of more water molecules. Full explicit solvation was studied with a hybrid quantum-mechanical/molecular-mechanical (QM/MM) scheme and molecular dynamics simulations, including more than 6000 TIP3P water molecules. According to free energies obtained from thermodynamic integration at the PM3/MM level and corrected for B3LYP/MM total energies, the fully extended conformer is more stable than folded ones by about -4.5 kJ mol(-1). B3LYP-computed (3)J(F,H) NMR spin-spin coupling constants, averaged over PM3/MM-MD trajectories, agree best with experiment for this fully extended form, in accordance with the original NMR analysis. The seeming discrepancy between static PCM calculations and experiment noted previously is now resolved. That the inexpensive semiempirical PM3 method performs so well for this archetypical zwitterion is encouraging for further QM/MM studies of biomolecular systems.
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131
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Bühl M, Wipff G. Insights into Uranyl Chemistry from Molecular Dynamics Simulations. Chemphyschem 2011; 12:3095-105. [DOI: 10.1002/cphc.201100458] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 07/28/2011] [Indexed: 11/10/2022]
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132
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Bühl M, Kilian P, Woollins JD. Prediction of a New Delocalised Bonding Motif between Group 15 or Group 16 Atoms. Chemphyschem 2011; 12:2405-8. [DOI: 10.1002/cphc.201100423] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Indexed: 11/07/2022]
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133
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Bühl M, Früchtl H, André P. Computational thermochemistry of iron–platinum carbonyl clusters. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2011.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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134
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Bühl M, van Mourik T. NMR spectroscopy: quantum-chemical calculations. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2011. [DOI: 10.1002/wcms.63] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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135
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Hua G, Fuller AL, Bühl M, Slawin AMZ, Woollins JD. Selenation/Thionation of α-Amino Acids: Formation and X-ray Structures of Diselenopiperazine and Dithiopiperazine and Related Compounds. European J Org Chem 2011. [DOI: 10.1002/ejoc.201100226] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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136
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Somisara DMUK, Bühl M, Lebl T, Richardson NV, Slawin AMZ, Woollins JD, Kilian P. 1,2-diphosphaacenaphthene 1,2-dications: synthetic, stereochemical and computational study of the stabilising role of naphthalene-1,8-diyl backbone. Chemistry 2011; 17:2666-77. [PMID: 21274955 DOI: 10.1002/chem.201002259] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Indexed: 11/08/2022]
Abstract
Syntheses and full characterisation data (including single crystal diffraction) of three 1,2-diphosphonium dicationic species with the naphthalene-1,8-diyl (Nap) backbone are reported. The oxidation of Nap[P(NMe(2))(2)](2) with P(2)I(4) to its 1,2-dication was achieved. meso- and rac-forms of "all carbon" 1,2-diphosphonium dications were obtained in good yields and purity by double alkylation of the parent diphosphine (1,2-diphenyl-1,2-diphosphaacenaphthene) with methyl triflate or trimethyloxonium tetrafluoroborate. Each methylating reagent produces one of the rac- or meso-forms of the dication diastereospecifically. Structural parameters of the new dications are discussed with respect to other phosphorus 1,2-dications. DFT (B3LYP) computations revealed the significant role of the naphthalene backbone in stabilisation of the dicationic motif and helped to assess the energy cost of the steric clash of a variety of groups attached to the peri-positions of naphthalene. The synthesis and single crystal X-ray data of the extremely crowded Nap[P(Se)(OiPr)(2)](2) are discussed, and are contrasted with the unsuccessful synthesis of Nap(PtBu(2))(2) from NapLi(2) and ClPtBu(2).
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137
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138
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Bjornsson R, Früchtl H, Bühl M. 51V NMR parameters of VOCl3: static and dynamic density functional study from the gas phase to the bulk. Phys Chem Chem Phys 2011; 13:619-27. [DOI: 10.1039/c0cp01176b] [Citation(s) in RCA: 14] [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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139
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Fuentes JA, Wawrzyniak P, Roff GJ, Bühl M, Clarke ML. On the rate-determining step and the ligand electronic effects in rhodium catalysed hydrogenation of enamines and the hydroaminomethylation of alkenes. Catal Sci Technol 2011. [DOI: 10.1039/c1cy00026h] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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140
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Bühl M, Grenthe I. Binding modes of oxalate in UO2(oxalate) in aqueous solution studied with first-principles molecular dynamics simulations. Implications for the chelate effect. Dalton Trans 2011; 40:11192-9. [DOI: 10.1039/c1dt10796h] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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141
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Bühl M, Sieffert N, Chaumont A, Wipff G. Water versus Acetonitrile Coordination to Uranyl. Density Functional Study of Cooperative Polarization Effects in Solution. Inorg Chem 2010; 50:299-308. [DOI: 10.1021/ic101950d] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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142
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Ashbook S, Bühl M. MRC special edition on quantum-chemical computations of magnetic resonance parameters. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2010; 48 Suppl 1:S1. [PMID: 21104759 DOI: 10.1002/mrc.2672] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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143
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Bühl M, Wrackmeyer B. Density-functional computation of ⁹³Nb NMR chemical shifts. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2010; 48 Suppl 1:S61-S68. [PMID: 20552575 DOI: 10.1002/mrc.2624] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
93Nb chemical shifts of [NbX6](-) (X = Cl, F, CO), [NbXCl4](-) (X = O, S), Nb2(OMe)10, Cp*2Nb(κ2-BH4), (Cp*Nb)2(µ-B2H6)2, CpNb(CO)4, and Cp2NbH3 are computed at the GIAO (gauge-including atomic orbitals)-, BPW91- and B3LYP-, and CSGT (continuous set of gauge transformations)-CAM-B3LYP, -ωB97, and -ωB97X levels, using BP86-optimized or experimental (X-ray) geometries. Experimental chemical shifts are best reproduced at the GIAO-BPW91 level when δ(93Nb) values of inorganic complexes are referenced directly relative to [NbCl6](-) and those of organometallic species are first calculated relative to [Nb(CO)6](-). An inadvertent error in the reported δ(93Nb) values of cyclopentadiene borane complexes (H. Brunner et al., J. Organomet. Chem.1992, 436, 313) is corrected. Trends in the observed 93Nb NMR linewidths for anionic niobates [Nb(CO)5](3-), [Nb(CO)5H](2-), and [Nb(CO)5(NH3)](-) are rationalized in terms of computed electric field gradients at the metal.
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144
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Hagan RM, Björnsson R, McMahon SA, Schomburg B, Braithwaite V, Bühl M, Naismith JH, Schwarz-Linek U. NMR spectroscopic and theoretical analysis of a spontaneously formed Lys-Asp isopeptide bond. Angew Chem Int Ed Engl 2010; 49:8421-5. [PMID: 20878961 PMCID: PMC3315829 DOI: 10.1002/anie.201004340] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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145
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Hagan RM, Björnsson R, McMahon SA, Schomburg B, Braithwaite V, Bühl M, Naismith JH, Schwarz-Linek U. NMR Spectroscopic and Theoretical Analysis of a Spontaneously Formed Lys-Asp Isopeptide Bond. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201004340] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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146
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Knight FR, Fuller AL, Bühl M, Slawin AMZ, Woollins JD. Synthetic and structural studies of 1,8-chalcogen naphthalene derivatives. Chemistry 2010; 16:7503-16. [PMID: 20468030 DOI: 10.1002/chem.200903523] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Four novel 1,8-disubstituted naphthalene derivatives 4-7 that contain chalcogen atoms occupying the peri positions have been prepared and fully characterised by using X-ray crystallography, multinuclear NMR spectroscopy, IR spectroscopy and MS. Molecular distortion due to noncovalent substituent interactions was studied as a function of the bulk of the interacting chalcogen atoms and the size and nature of the alkyl group attached to them. X-ray data for 4-7 was compared to the series of known 1,8-bis(phenylchalcogeno)naphthalenes 1-3, which were themselves prepared from novel synthetic routes. A general increase in the E...E' distance was observed for molecules containing bulkier atoms at the peri positions. The decreased S...S distance from phenyl-1 and ethyl-4 analogues is ascribed to a weaker chalcogen lone pair-lone pair repulsion acting in the ethyl analogue due to the presence of two equatorial S(naphthyl) ring conformations. Two novel peri-substituted naphthalene sulfoxides of 1, Nap(O=SPh)(SPh) 8 and Nap(O=SPh)(2) 9, which contain different valence states of sulfur, were prepared and fully characterised by using X-ray crystallography and multinuclear NMR spectroscopy, IR spectroscopy and MS. Molecular structures were analysed by using naphthalene ring torsions, peri-atom displacement, splay angle magnitude, S...S interactions, aromatic ring orientations and quasi-linear O=S...S arrangements. The axial S(naphthyl) rings in 8 and 9 are unfavourable for S...S contacts due to stronger chalcogen lone pair-lone pair repulsion. Although quasi-linear O=S...S alignments suggest attractive interaction is conceivable, analysis of the B3LYP wavefunctions affords no evidence for direct bonding interactions between the S atoms.
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147
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Knight FR, Fuller AL, Bühl M, Slawin AMZ, Woollins JD. Hypervalent Adducts of Chalcogen-Containing peri-Substituted Naphthalenes; Reactions of Sulfur, Selenium, and Tellurium with Dihalogens. Inorg Chem 2010; 49:7577-96. [DOI: 10.1021/ic101086h] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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148
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Waddell PG, Slawin AMZ, Sieffert N, Bühl M, Woollins JD. The Preparation and Structure of [Pt(S
2
N
2
){P(OR)
n
R′
3–
n
}
2
] and [Pt(SeSN
2
){P(OMe)
n
Ph
3–
n
}
2
] (
n
= 0–3). Eur J Inorg Chem 2010. [DOI: 10.1002/ejic.201000329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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149
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Knight FR, Fuller AL, Bühl M, Slawin AMZ, Woollins JD. Sterically Crowded peri-Substituted Naphthalene Phosphines and their PV Derivatives. Chemistry 2010; 16:7617-34. [PMID: 20496359 DOI: 10.1002/chem.201000454] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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150
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Sieffert N, Bühl M. Hydrogen Generation from Alcohols Catalyzed by Ruthenium−Triphenylphosphine Complexes: Multiple Reaction Pathways. J Am Chem Soc 2010; 132:8056-70. [PMID: 20481632 DOI: 10.1021/ja101044c] [Citation(s) in RCA: 206] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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