A study of van der Waals complexes of 1,2-dichloroethane in paraffin oil by FTIR spectroscopy and ab initio calculations.
Weak molecular interactions of 1,2-dichloroethane dissolved in paraffin oil were investigated by FTIR spectroscopy. Occurrence of isosbestic points in the spectra along with the factor analysis showed that DCE⋯DCE dimers are formed in solutions at DCE concentrations between 7 and 15 vol.%. It was found that both trans and gauche conformers are involved in the complexation, forming a tg-dimer. From the spectra collected at 200-222 K, the complexation enthalpy was determined: -4.2±0.4 kcal mol(-1). The equilibrium geometry of tg-dimer and the vibrational frequencies were determined from the density functional calculations performed at B3LYP/6-311++G(d,p) and 6-31G(d,p) levels. The C-C bonds of the two molecules involved in tg-dimers were found to be oriented nearly perpendicular to each other. The complexation energy calculated using 6-31G(d,p) and 6-311++G(d,p) basis sets was found to be -1.59 and -1.52 kcal mol(-1), respectively.
Kazan Federal University, Institute of Physics, Kremlevskaya str. 18, Kazan 420008, Russia. Electronic address: aif@kpfu.ru.
A I
AI
Fishman
Kazan Federal University, Institute of Physics, Kremlevskaya str. 18, Kazan 420008, Russia.
A I
AI
Noskov
Kazan Federal University, Institute of Physics, Kremlevskaya str. 18, Kazan 420008, Russia.
R M
RM
Aminova
Kazan Federal University, Institute of Physics, Kremlevskaya str. 18, Kazan 420008, Russia.
R A
RA
Skochilov
D019281:Dimerization; D005025:Ethylene Dichlorides / Q000737:chemistry*; D008956:Models, Chemical; D008968:Molecular Conformation; D009821:Oils / Q000737:chemistry*; D010232:Paraffin / Q000737:chemistry*; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D013816:Thermodynamics
D005025:Ethylene Dichlorides; D009821:Oils; D012996:Solutions; C024565:ethylene dichloride; D010232:Paraffin; C015418:paraffin oils
1,2-Dichloroethane; FTIR spectroscopy; Factor analysis; Glass transition; Isosbestic point; Van der Waals complex