Intermolecular potentials and force constants from ab initio energies - Application to the N-H…O=C hydrogen bonds in formamide dimers

Bleckmann, P.; Breitenbach, P.; Dickhut, K. U.; Keller, Detlef; Schwittek, Christoph

doi:10.1007/s002160050545

Cited by 6 publications

(2 citation statements)

References 3 publications

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“…Formamide is the simplest amide structure, and many calculations on the formamide dimer have been made to study NH···OC hydrogen bonds. − The most stable structure reported for the formamide dimer, both theoretically and experimentally, has two hydrogen bonds corresponding to the head-to-tail cyclic structure, 1 (see Chart ). The total electronic association energy for 1 has been calculated with the MP2 method, yielding values of −11.4 to −14.0 kcal/mol depending on the basis set used. ,, The highest level of basis set, cc-pV5Z, provides the highest interaction energy.…”

Section: Introductionmentioning

confidence: 99%

Strength of the NH···OC and CH···OC Bonds in Formamide andN-Methylacetamide Dimers

et al. 2001

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The structures of the dimers of formamide and N-methylacetamide have been calculated at the ab initio electronic structure theory level, second-order Møller-Plesset perturbation theory (MP2) with augmented correlation consistent basis sets. Five unique structures were optimized for the formamide dimers at the MP2/ aug-cc-pVDZ and MP2/aug-cc-pVTZ levels. At the optimized geometries obtained with the aug-cc-pVTZ basis set, MP2 energies were evaluated with the aug-cc-pVQZ basis set, allowing an extrapolation of the energies to the complete basis set limit. Four structures were found for the N-methylacetamide dimer at the MP2/aug-cc-pVDZ level, and single-point energies were calculated at the MP2/aug-cc-pVTZ level. In both systems, the basis set superposition error was estimated with the counterpoise method. The strength of the NsH‚‚‚OdC bond has a mean value of 7.1 kcal/mol in the formamide dimers and a mean value of 8.6 kcal/mol in the N-methylacetamide dimers. The difference in hydrogen bond strengths is attributed to differences in basicity at the carbonyl oxygen receptor site. In several dimers CsH‚‚‚OdC hydrogen bonds play an important role in stabilizing these intermolecular complexes, increasing the interaction energy by 1.1-2.6 kcal/mol per interaction.

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Section: Introductionmentioning

confidence: 99%

Strength of the NH···OC and CH···OC Bonds in Formamide andN-Methylacetamide Dimers

et al. 2001

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“…Formamide is the simplest amide structure, and many calculations about the formamides have been made to study NH···OC hydrogen bond 30–37. Taken as the primary step to dig into the cooperativity in biological systems, the studies of the cooperativity in NH···OC hydrogen bond chains are very important.…”

Section: Introductionmentioning

confidence: 99%

A scheme for rapid prediction of cooperativity in hydrogen bond chains of formamides, acetamides, andN‐methylformamides

Jiang¹,

Sun²,

Wang³

2009

J Comput Chem

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A scheme is proposed in this article to predict the cooperativity in hydrogen bond chains of formamides, acetamides, and N-methylformamides. The parameters needed in the scheme are derived from fitting to the hydrogen bonding energies of MP2/6-31+G** with basis set superposition error (BSSE) correction of the hydrogen bond chains of formamides containing from two to eight monomeric units. The scheme is then used to calculate the individual hydrogen bonding energies in the chains of formamides containing 9 and 12 monomeric units, in the chains of acetamides containing from two to seven monomeric units, in the chains of N-methylformamides containing from two to seven monomeric units. The calculation results show that the cooperativity predicted by the scheme proposed in this paper is in good agreement with those obtained from MP2/6-31+G** calculations by including the BSSE correction, demonstrating that the scheme proposed in this article is reasonable. Based on our scheme, a cooperativity effect of almost 240% of the dimer hydrogen bonding energy in long hydrogen bond formamide chains, a cooperativity effect of almost 190% of the dimer hydrogen bonding energy in long hydrogen bond acetamide chains, and a cooperativity effect of almost 210% of the dimer hydrogen bonding energy in long hydrogen bond N-methylformamide chains are predicted. The scheme is further applied to some heterogeneous chains containing formamide, acetamide, and N-methylformamide. The individual hydrogen bonding energies in these heterogeneous chains predicted by our scheme are also in good agreement with those obtained from Møller-Plesset calculations including BSSE correction.

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Rapid Prediction of the Hydrogen Bond Cooperativity inN‐methylacetamide Chains

Jiang

Wang

2009

ChemPhysChem

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A method is proposed to rapidly predict the hydrogen bond cooperativity in N-methylacetamide chains. The parameters needed are obtained from the fittings to the hydrogen bonding energies in the formamide chains containing 2 to 8 monomeric units. The scheme is then used to calculate the individual hydrogen bonding energies in N-methylacetamide chains containing 2 to 7 monomeric units. The cooperativity predicted is in good agreement with those obtained from MP2/6-31+G** calculations by including the BSSE correction. Our scheme is further employed to predict the individual hydrogen bonding energies in larger N-methylacetamide chains containing up to 200 monomeric N-methylacetamide units, to which the MP2 method cannot be applied. Based on our scheme, a cooperative effect of over 170% of the dimer hydrogen bonding energy in long N-methylacetamide chains is predicted. The method is also applied to heterogeneous chains containing formamide, acetamide, N-methylformamide, and N-methylacetamide. The individual hydrogen bonding energies in these heterogeneous chains are also in good agreement with those obtained from MP2 calculations with the BSSE correction, further demonstrating that our method is reasonable.

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Intermolecular potentials and force constants from ab initio energies - Application to the N-H…O=C hydrogen bonds in formamide dimers

Cited by 6 publications

References 3 publications

Strength of the NH···OC and CH···OC Bonds in Formamide andN-Methylacetamide Dimers

Strength of the NH···OC and CH···OC Bonds in Formamide andN-Methylacetamide Dimers

A scheme for rapid prediction of cooperativity in hydrogen bond chains of formamides, acetamides, andN‐methylformamides

Rapid Prediction of the Hydrogen Bond Cooperativity inN‐methylacetamide Chains

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