Quantum chemical investigation of linear hydrogen bonding in ONCCN···HX (X = F, Cl, Br) dimers

Varadwaj, Pradeep R.

doi:10.1002/qua.21238

Cited by 2 publications

(1 citation statement)

References 33 publications

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“…No systematic trend in the halide series is observed between the binding energy and the intermolecular bond length, as normally expected,[24–26, 63] as c‐C 3 H 2 ···HCl is predicted to be the least stable complex, and the intermolecular distance was found to increase in the order F > Cl > Br. Whereas the effect of deformation of c‐C 3 H 2 on the energetics is negligible ( E D < 0.2 kcal mol −1 ), that of the hydrogen halides is somewhat more pronounced (the largest being 3 kcal mol −1 for HBr with MP2/aug‐cc‐pVQZ) as a result of significant electronic structure changes on H‐bond formation.…”

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confidence: 60%

An electronic structure theory investigation of the physical chemistry of the intermolecular complexes of cyclopropenylidene with hydrogen halides

Varadwaj

Peslherbe

2012

J Comput Chem

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The proton accepting and donating abilities of cyclopropenylidene (c-C(3)H(2)) on its complexation with hydrogen halides H-X (X = F, Cl, Br) are analyzed using density-functional theory with three functionals (PBE0, B3LYP, and B3LYP-D) and benchmarked against second-order Møller-Plesset (MP2) theory. Standard signatures including, inter alia, dipole moment enhancement, charge transfer from the carbenic lone pair to the antibonding σ*(H-X) orbital, and H-X bond elongation are examined to ascertain the presence of hydrogen bonding in these complexes. The latter property is found to be accompanied with a pronounced red shift in the bond stretching frequency and with a substantial increase in the infrared intensity of the band on complex formation. The MP2/aug-cc-pVTZ c-C(3)H(2)···H-F complex potential energy surface turns out to be an asymmetric deep single well, while asymmetric double wells are found for the c-C(3)H(2)···H-Cl and c-C(3)H(2)···H-Br complexes, with an energy barrier of 4.1 kcal mol(-1) for proton transfer along the hydrogen bond in the latter complex. Hydrogen-bond energy decomposition, with the reduced variational space self-consistent field approach, indicates that there are large polarization and charge-transfer interactions between the interacting partners in c-C(3)H(2)···H-Br compared to the other two complexes. The C···H bonds are found to be predominantly ionic with partial covalent character, unveiled by the quantum theory of atoms in molecules. The present results reveal that the c-C(3)H(2) carbene divalent carbon can act as a proton acceptor and is responsible for the formation of hydrogen bonds in the complexes investigated.

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Section: Resultssupporting

confidence: 60%

An electronic structure theory investigation of the physical chemistry of the intermolecular complexes of cyclopropenylidene with hydrogen halides

Varadwaj

Peslherbe

2012

J Comput Chem

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Hydrogen bonding interactions in PN···HX complexes: DFT and ab initio studies of structure, properties and topology

Varadwaj

2009

J Mol Model

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Spin-restricted DFT (X3LYP and B3LYP) and ab initio (MP2(fc) and CCSD(fc)) calculations in conjunction with the Aug-CC-pVDZ and Aug-CC-pVTZ basis sets were performed on a series of hydrogen bonded complexes PN...HX (X = F, Cl, Br) to examine the variations of their equilibrium gas phase structures, energetic stabilities, electronic properties, and vibrational characteristics in their electronic ground states. In all cases the complexes were predicted to be stable with respect to the constituent monomers. The interaction energy (Delta E) calculated using a super-molecular model is found to be in this order: PN...HF > PN...HCl > PN...HBr in the series examined. Analysis of various physically meaningful contributions arising from the Kitaura-Morokuma (KM) and reduced variational space self-consistent-field (RVS-SCF) energy decomposition procedures shows that the electrostatic energy has significant contribution to the over-all interaction energy. Dipole moment enhancement (Delta mu) was observed in these complexes expected of predominant dipole-dipole electrostatic interaction and was found to follow the trend PN...HF > PN...HCl > PN...HBr at the CCSD level. However, the DFT (X3LYP and B3LYP) and MP2 levels less accurately determined these values (in this order HF < HCl < HBr). Examination of the harmonic vibrational modes reveals that the PN and HX bands exhibit characteristic blue- and red shifts with concomitant bond contraction and elongation, respectively, on hydrogen bond formation. The topological or critical point (CP) analysis using the static quantum theory of atoms in molecules (QTAIM) of Bader was considered to classify and to gain further insight into the nature of interaction existing in the monomers PN and HX, and between them on H-bond formation. It is found from the analysis of the electron density rho ( c ), the Laplacian of electron charge density nabla(2)rho(c), and the total energy density (H ( c )) at the critical points between the interatomic regions that the interaction N...H is indeed electrostatic in origin (rho(c) > 0, nabla(2)rho(c) > 0 and H(c) > 0 at the BCP) whilst the bonds in PN (rho(c) > 0, nabla(2)rho(c) > 0 and H(c) < 0) and HX ((rho(c) > 0, nabla(2)rho(c) < 0 and H(c) < 0)) are predominantly covalent. A natural bond orbital (NBO) analysis of the second order perturbation energy lowering, E((2)), caused by charge transfer mechanism shows that the interaction N...H is n(N) --> BD*(HX) delocalization.

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Quantum chemical investigation of linear hydrogen bonding in ONCCN···HX (X = F, Cl, Br) dimers

Cited by 2 publications

References 33 publications

An electronic structure theory investigation of the physical chemistry of the intermolecular complexes of cyclopropenylidene with hydrogen halides

An electronic structure theory investigation of the physical chemistry of the intermolecular complexes of cyclopropenylidene with hydrogen halides

Hydrogen bonding interactions in PN···HX complexes: DFT and ab initio studies of structure, properties and topology

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