Akademik Veri Yönetim Sistemi
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY, cilt.268, ss.120678-120701, 2022 (SCI-Expanded)
Stable conformers of neutral balenine were scanned through molecular dynamics simulations and energy
minimizations using Allinger’s MM2 force field. For each of the found minimum-energy conformers,
geometry optimization and thermochemistry calculations were performed by using B3LYP, MP2,
G3MP2B3 methods, 6-31G(d), 6–311++G(d,p) and aug-cc-pvTZ basis sets. The calculation results have
indicated that balenine has about twenty stable conformers whose relative energies are in the range of
0–9.5 kcal/mol. Three of these are thought to provide the major contribution to matrix isolation IR spectra
of the molecule. Our solvent calculations using the polarized continuum model revealed the stable zwitterion
structures which are predicted to dominate IR spectra of balenine in water and heavy water (D2O)
solvents. Pulay’s SQM-FF method was used in scaling of the harmonic force constants and vibrational
spectral data calculated for the neutral and zwitterion structures. These refined calculation data together
with those obtained from anharmonic frequency calculations enabled us to correctly interpret the matrix
isolation IR spectrum of balenine and the tautomerism-based changes observed in its KBr IR and solution
(D2O) IR spectra. The results revealed the crucial role of conformation and zwitterionic tautomerism on
the structure and vibrational spectral data of the molecule.