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The NHN + hydrogen bridge between 4,5‐dihydro‐1 H ‐imidazole and various amines
Author(s) -
Lankau Timm,
Yu ChinHui
Publication year - 2009
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.22159
Subject(s) - chemistry , hydrogen bond , van der waals force , low barrier hydrogen bond , imidazole , heteronuclear molecule , proton affinity , computational chemistry , affinities , proton , crystallography , hydrogen , stereochemistry , molecule , protonation , nuclear magnetic resonance spectroscopy , organic chemistry , ion , physics , quantum mechanics
The B3LYP/D95+(p,p) analysis of the NHN + bridge between 4,5‐dihydro‐1 H ‐imidazole and 23 amines covering a proton affinity range from 213 to 257 kcal/mol reveals a continues transition between different types of hydrogen bonding, Van der Waals bond, standard hydrogen bond, double well hydrogen bond, and low barrier hydrogen bond. The mismatch in the proton affinities ΔPA of 9 kcal/mol for an intrinsic low barrier hydrogen bond (LBHB) shows that the chemical environments of the bridge head nitrogen atoms differ significantly and that heteromolecular NHN + bridges have properties similar to heteronuclear OHN + LBHBs. The analysis further showed that the properties of NHN + LBHBs are similar to those observed in other hydrogen bonds and that the reliable classification of hydrogen bonds requires the careful analysis of all available data. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009