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Effect of CH···O hydrogen bond length on the geometric and spectroscopic features of the peptide unit of proteins
Author(s) -
Scheiner Steve
Publication year - 2010
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.22756
Subject(s) - chemistry , hydrogen bond , crystallography , bond length , intermolecular force , intramolecular force , dipeptide , molecule , covalent bond , proton , chemical shift , blueshift , molecular geometry , chemical bond , formamide , computational chemistry , stereochemistry , peptide , crystal structure , materials science , organic chemistry , biochemistry , physics , optoelectronics , quantum mechanics , photoluminescence
A formamide molecule is allowed to form a CH ··· O H‐bond with a glycine dipeptide in both its C5 and C7 internal conformations. As this intermolecular H‐bond is elongated, the contraction of the CH covalent bond is monitored, as is its vibrational stretching frequency and intensity, along with NMR chemical shifts of the atoms involved in the H‐bond. The degree of shortening of the CH bond becomes progressively smaller as the proton acceptor is moved further away, as does the blue shift of the CH stretching frequency, and the chemical shift of the bridging proton. These changes are monotonic and regular enough that experimental evaluation of CH bond length or blue shift or proton NMR chemical shift may be used to accurately predict the energetics of the H‐bond for any particular geometry. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010