Modeling Vibrational Spectra of Ester Carbonyl Stretch in Water and DMSO Based on Molecular Dynamics Simulation.
On the basis of molecular dynamics simulation, we model the ester carbonyl stretch FTIR signals of methyl acetate in D2O and DMSO. An ab initio map is constructed at the B3LYP/6-311++G** level to relate the carbonyl stretch frequency to the external electric field. Using this map, fluctuating Hamiltonian of the carbonyl stretch is constructed from the MD simulation trajectory. The IR spectra calculated based on this Hamiltonian are found to be in good agreement with the experiment. For methyl acetate in D2O, hydrogen bonding on alkoxy oxygen causes a blue shift of frequency, while that on carbonyl oxygen causes a red shift. Two peaks observed in FTIR signals originate from the balance of these two effects. Furthermore, in both D2O and DMSO solutions, correlations are found between the instantaneous electric field on C═O and the frequencies. Broader line width of the signal in D2O suggests a more inhomogeneous electric field distribution due to the complicated hydrogen-bonding environment.
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , 457 Zhongshan Road, Dalian 116023, Liaoning, China.
Bin
B
Fang
Department of Chemistry, ShanghaiTech University , 19 Yueyang Road, Shanghai 200031, China.
Tianjun
T
Wang
Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), Department of Physics, Jilin University , 2699 Qianjin Street, ChangChun 130012, China.
Xian
X
Chen
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , 457 Zhongshan Road, Dalian 116023, Liaoning, China.
Tan
T
Jin
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , 457 Zhongshan Road, Dalian 116023, Liaoning, China.
Ruiting
R
Zhang
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , 457 Zhongshan Road, Dalian 116023, Liaoning, China.
Wei
W
Zhuang
D000085:Acetates / Q000737:chemistry*; D017666:Deuterium Oxide / Q000737:chemistry*; D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D004952:Esters / Q000737:chemistry; D006860:Hydrogen Bonding; D056004:Molecular Dynamics Simulation; D010100:Oxygen / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity; D014732:Vibration
D000085:Acetates; D004952:Esters; D012997:Solvents; D017666:Deuterium Oxide; D010100:Oxygen; C046923:methyl acetate; D004121:Dimethyl Sulfoxide