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Comparison of Hydrogen Bonds in FH—CO and FH—OC Weakly Bound Dimer Complexes
Author(s) -
Chen Cheng,
Chen ShyhJong,
Hong YawShun
Publication year - 2005
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200500120
Subject(s) - chemistry , dimer , hydrogen bond , monomer , bond length , bond energy , crystallography , gibbs free energy , equilibrium constant , binding energy , quadruple bond , density functional theory , ab initio , computational chemistry , molecule , bond order , thermodynamics , atomic physics , polymer , crystal structure , organic chemistry , physics
Weakly bound dimer complexes FH—CO and FH—OC were investigated using various ab initio and density function theory (DFT) methods. This study compares the strengths of the H—C H‐bond in FH—CO and the H—O H‐bond in FH—OC. The energy difference between dimers, the H‐bond energy, the inter‐monomer distance, the inter‐monomer vibration frequencies, the red shift of the HF stretching frequency, and the elongation of HF bond, all demonstrate that the H—C H‐bond is stronger than the related H—O H‐bond, according to all methods. The calculated Gibbs energies of the formation of the two dimers show that the weakly bound complexes are unstable at room temperature (T = 298 K) and ordinary pressure (P = 1 atm). However, decreasing T or increasing P monotonically decreases ΔG and increases the related equilibrium constant, K, of their dimer formation.