Self-consistent molecular orbital methods. XV. Extended Gaussian-type basis sets for lithium, beryllium, and boron

Dill, James D.; Pople, John A.

doi:10.1063/1.430801

Cited by 711 publications

(279 citation statements)

References 4 publications

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“…The geometries obtained at this degree of accuracy served as starting points for further optimization with the split valence 3-21 G [18] and 6-31 G [19][20][21] sets of basis functions and the polarized 6-31 G* basis set [22], which includes one set of d functions for all heavy atoms. In addition we used the 6-311G basis set, which has a triple split in the valence s and p shells, combined with an inner shell representation by a single function with six gaussians [23] (valence triple zeta).…”

Section: Methodsmentioning

confidence: 99%

The Structure of Lithiated Aminonitriles in Solution: Interpretation of their Experimental IR Spectra by Means of ab initio Calculations

Raabe

Zobel

Fleischhauer

et al. 1991

Zeitschrift Für Naturforschung A

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Quantum chemical calculations of relative energies and vibrational frequencies have been per formed in order to elucidate the structure of metalated aminonitriles (1R2RN)3RC2NLi formed upon lithiation of (1R2RN)3RCH-CN in tetrahydrofuran at -78 °C. For the sake" of feasibility the calculations have been performed on model compounds where the heavy substituents 'R, 2R and 3R and in some cases even the complete amino group ('R2RN) and 3R have been replaced by hydrogen atoms.In the gasphase a lithium-bridged (nonclassical) monomer, whose lithium atom is within bonding distance to the atoms of the cyano group and the adjacent carbon atom, was found to be about 9 kcal/mol lower in energy than the most stable isomer of the corresponding nitrogen metalated ketenimine with amost linear CNLi moiety. However, the relative stability of the two structures will most likely be reversed under the influence of a solvent (modeled by H20).Dimerization of H2C2NLi, yielding a product of D2h symmetry with a four-membered (LiN)2 ring, turned out to be exothermic by about 41 kcal/mol in the gasphase and 15 kcal/mol when the model solvent is present.While in the case of the lithiated amino ketenimine with almost linear CNLi segment the structure obtained with the semiempirical MNDO method widely parallels the ab initio results, the semiempirical method seems to perform less reliably for the nonclassical monomer.Formation of the trapping products obtained with methyl iodide and acetyl chloride is explained in terms of orbital-and charge control, respectively. According to this analysis, the results of trapping experiments are compatible with presence of a dimer, of a monomer with almost linear CNLi moiety, or of a monomer with lithium in a bridging position. However, comparison of observed and computed vibrational frequencies and of the calculated energies of classical and nonclassical structures led to the conclusion that the observed IR spectra are not due to nonclassical molecules with lithium in a bridging position. Taking into account the results of recent cryoscopic measurements we assign the characteristic absorptions in the experimental IR spectra to keteniminelike monomers and their dimers.

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Section: Methodsmentioning

confidence: 99%

The Structure of Lithiated Aminonitriles in Solution: Interpretation of their Experimental IR Spectra by Means of ab initio Calculations

Raabe

Zobel

Fleischhauer

et al. 1991

Zeitschrift Für Naturforschung A

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“…The model was described by M06 [73], B3LYP [74][75][76], BP86 [77], and PBE0 [78] methods with spin-state-corrected s6-31G(d) [79] basis set for Cu atom and 6-311++G(d,p) for atoms of the BH 4 − and alcohol OH-groups [80,81]; 6-31G(d) for the phosphorus atoms [82]; and 6-31G for the carbon and hydrogen atoms of dppm ligand [80,83,84]. For B3LYP, BP86 and PBE0 functionals empirical dispersion correction suggested by Grimme (GD2 [85] and GD3BJ [86,87]) was applied.…”

Section: Computational Detailsmentioning

confidence: 99%

Binuclear Copper(I) Borohydride Complex Containing Bridging Bis(diphenylphosphino) Methane Ligands: Polymorphic Structures of [(µ2-dppm)2Cu2(η2-BH4)2] Dichloromethane Solvate

et al. 2017

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Bis(diphenylphosphino)methane copper(I) tetrahydroborate was synthesized by ligands exchange in bis(triphenylphosphine) copper(I) tetrahydroborate, and characterized by XRD, FTIR, NMR spectroscopy. According to XRD the title compound has dimeric structure, [(µ 2 -dppm) 2 Cu 2 (η 2 -BH 4 ) 2 ], and crystallizes as CH 2 Cl 2 solvate in two polymorphic forms (orthorhombic, 1, and monoclinic, 2) The details of molecular geometry and the crystal-packing pattern in polymorphs were studied. The rare Twisted Boat-Boat conformation of the core Cu 2 P 4 C 2 cycle in 1 is found being more stable than Boat-Boat conformation in 2.

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“…The M06/M06L functional is specially parameterized to include dispersion interactions-an important bonding factor in the complexes studied here [36]. A Pople-type 6-31G(d) basis sets [38] was used throughout the study. The Gaussian 09 suite of programs [39] was used for most calculations reported.…”

Section: Quantum Chemistry Calculationsmentioning

confidence: 99%

What Happens to Hydrophobic Interactions during Transfer from the Solution to the Gas Phase? The Case of Electrospray-Based Soft Ionization Methods

Barylyuk

Balabin

Grünstein

et al. 2011

J. Am. Soc. Mass Spectrom.

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The disappearance of the hydrophobic effect in the gas phase due to the absence of an aqueous surrounding raises a long-standing question: can noncovalent complexes that are exclusively bound by hydrophobic interactions in solution be preserved in the gas phase? Some reports of successful detection by mass spectrometry of complexes largely stabilized by hydrophobic effect are questionable by the presence of electrostatic forces that hold them together in the gas phase. Here, we report on the MS-based analysis of model supramolecular complexes with a purely hydrophobic association in solution, β-cyclodextrin, and synthetic adamantyl-containing ligands with several binding sites. The stability of these complexes in the gas phase is investigated by quantum chemical methods . Compared with the free interaction partners, the inclusion complex between β-cyclodextrin and adamantyl-containing ligand is shown to be stabilized in the gas phase by ΔG = 9.6 kcal mol -1 . The host-guest association is mainly enthalpy-driven due to strong dispersion interactions caused by a large nonpolar interface and a high steric complementarity of the binding partners. Interference from other types of noncovalent binding forces is virtually absent. The complexes are successfully detected via electrospray ionization mass spectrometry, although a high dissociation yield is also observed. We attribute this pronounced dissociation of the complexes to the collisional activation of ions in the atmospheric interface of mass spectrometer. The comparison of several electrospray-based ionization methods reveals that cold spray ionization provides the softest ion generation conditions for these complexes.

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Self-consistent molecular orbital methods. XV. Extended Gaussian-type basis sets for lithium, beryllium, and boron

Cited by 711 publications

References 4 publications

The Structure of Lithiated Aminonitriles in Solution: Interpretation of their Experimental IR Spectra by Means of ab initio Calculations

The Structure of Lithiated Aminonitriles in Solution: Interpretation of their Experimental IR Spectra by Means of ab initio Calculations

Binuclear Copper(I) Borohydride Complex Containing Bridging Bis(diphenylphosphino) Methane Ligands: Polymorphic Structures of [(µ2-dppm)2Cu2(η2-BH4)2] Dichloromethane Solvate

What Happens to Hydrophobic Interactions during Transfer from the Solution to the Gas Phase? The Case of Electrospray-Based Soft Ionization Methods

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