Journal article
Nature and Hierarchy of Noncovalent Interactions in Gas-Phase Binary Complexes of Indole and Benzimidazole with Ethers
The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, Vol.121(46), pp.8815-8824
11/22/2017
DOI: 10.1021/acs.jpca.7b08627
PMID: 29064698
Abstract
Hierarchy among the weak noncovalent interactions such as van der Waals, electrostatic, hydrogen bonding, etc. dictates the secondary and tertiary structures of proteins as well as their interactions with various ligands. In this work, we investigate the competition between conventional (N-H···O) hydrogen bonds, unconventional (C-H···O) hydrogen bonds, and the van der Waals interaction in the model compounds of the chromophores of the amino acids, tryptophan, and histidine. These include indole (IND), benzimidazole (BIM), and its N-methylated analog (N-methylbenzimidazole, MBIM), which present multiple docking sites. The binary complexes of these molecules with ethers (dimethyl ether, diethyl ether, and tetrahydrofuran), which possess high proton affinity but lack acidic protons (thereby only act as hydrogen bond acceptors), are investigated. The complexes are formed in a supersonic jet and jointly studied by electronic and vibrational spectroscopy as well as quantum chemical calculations. Only the N-H···O bound structures are observed for the complexes of IND and BIM with ethers, although computations predict reasonably competent C-H···O type of structures. Remarkably, IND and BIM produce three (N-H···O) conformers with Me
O but single conformers with Et
O and THF. In the case of MBIM, which lacks a conventional hydrogen bond donor, no evidence for C(2)-H···O hydrogen bonds is seen; instead, the complexes are found to be bound purely by van der Waals interactions. The results indicate that strong N-H···O and even weak van der Waals interactions are thermodynamically favored over C(2)-H···O bound structures in these binary gas-phase complexes.
Details
- Title: Subtitle
- Nature and Hierarchy of Noncovalent Interactions in Gas-Phase Binary Complexes of Indole and Benzimidazole with Ethers
- Creators
- Aditi Bhattacherjee - Department of Chemical Sciences, Tata Institute of Fundamental Research , Homi Bhabha Road, Mumbai 400 005, IndiaSanjay Wategaonkar - Department of Chemical Sciences, Tata Institute of Fundamental Research , Homi Bhabha Road, Mumbai 400 005, India
- Resource Type
- Journal article
- Publication Details
- The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, Vol.121(46), pp.8815-8824
- DOI
- 10.1021/acs.jpca.7b08627
- PMID
- 29064698
- ISSN
- 1089-5639
- eISSN
- 1520-5215
- Grant note
- DOI: 10.13039/501100001405, name: Tata Institute of Fundamental Research
- Language
- English
- Date published
- 11/22/2017
- Academic Unit
- Chemistry
- Record Identifier
- 9984216589402771
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