A study of H2CO•••HF Complex by Advanced Quantum Mechanical Methods

Abstract

Our research is focused on the ab initio calculations of the equilibrium structures, binding energies, harmonic and anharmonic vibrational frequencies of a hydrogen-bonded complex, which is formed between formaldehyde H2CO and hydrogen fluoride HF, using the Gaussian 09 package of programs with full 6311++G(3df, 3pd) basis sets in the MP2 second-order perturbation theory and CCSD(T) methods. Harmonic and anharmonic vibrational frequencies and intensities of the H2CO···HF complex were calculated by the Gaussian 16 package programs within the same approximation. Geometric changes and frequency shifts at the complex formation were evaluated. The H2CO···HF complex formation energy and the dipole moment were calculated in the CCSD(T)6311++G(3df, 3pd) approximation to be equal, respectively, to 7.78 kcal/mol and 4.2 D. Changes of the geometric, spectral, and energetic parameters of the complex proved the existence of a stable hydrogen bond F–H···O=CH2 between the components.

Investigation of the H2CO···HF complex in gas phase by the help of FTIR spectroscopy and computational methods

“…The band changes (blue or red) for the frequency, and intensity changes were explained in [4] in detail.…”

“…In [3] for (H 2 CO) 2 •••HF and H 2 CO•••(HF) 2 trimers the accurate spectral parameters were presented through very high level of quantum chemical calculations. The optimal geometry and harmonic spectral parameters and energetic evaluations of the H 2 CO•••HF complexes were presented in [4]. Formaldehyde dimer (CH 2 O) 2 has been investigated both experimentally and theoretically by THz spectroscopic and CCSD(T)-F12/aug-cc-pV5Z and MP2/aug-cc-pVQZ quantumchemical calculations in [5].…”