ABINITIO STUDY OF THE STRUCTURES, ROTATION INVERSION BARRIERS, FUNDAMENTAL FREQUENCIES, AND THERMODYNAMIC FUNCTIONS OF CH2CLCH2, CH3CHCL, AND CH3CCL2 RADICALS

被引:27
作者
CHEN, YH [1 ]
TSCHUIKOWROUX, E [1 ]
机构
[1] UNIV CALGARY, DEPT CHEM, CALGARY T2N 1N4, ALBERTA, CANADA
关键词
D O I
10.1021/j100197a026
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The equilibrium geometries, rotational and inversion barriers, and harmonic vibrational spectra for beta-chloroethyl (CH2ClCH2), alpha-chloroethyl (CH3CHCl), and alpha,alpha-dichloroethyl (CH3CCl2) radicals have been determined by ab initio molecular orbital techniques using the GAUSSIAN 88 system of programs at the UHF/6-31G* level of theory. For all three radicals only one distinguishable equilibrium conformation was found on the potential energy surface. The radical centers for all three species are nonplanar. The barriers for rotation about the C-C bond and inversion of the radical center were located for each compound by analytical methods. Electron correlation energy corrections were estimated by single-point UMP2/6-311G**//6-31G* calculations. Vibrational frequencies, as well as moments of inertia for overall and internal rotation, are reported for each species. Calculated heat capacities, entropies, enthalpy, and free energy functions are tabulated as a function of temperature. Several homodesmic reactions have been studied for the purpose of obtaining theoretical heats of formation. The theoretical DELTA-H-degrees(f,298) values thus evaluated are 22.44, 18.26, and 11.75 kcal/mol for CH2ClCH2, CH3CHCl, and CH3CCl2 radicals, respectively, which are in good agreement with available experimental values. Thermochemical quantities DELTA-H-degrees(f,T), DELTA-G-degrees(f,T), and log K(f,T) for all three radicals are reported as a function of temperature.
引用
收藏
页码:7266 / 7272
页数:7
相关论文
共 42 条
[21]   KINETICS OF THE REACTION OF CCL3 + BR-2 AND THERMOCHEMISTRY OF CCL3 RADICAL AND CATION [J].
HUDGENS, JW ;
JOHNSON, RD ;
TIMONEN, RS ;
SEETULA, JA ;
GUTMAN, D .
JOURNAL OF PHYSICAL CHEMISTRY, 1991, 95 (11) :4400-4405
[22]   A DETAILED CHEMICAL KINETIC MECHANISM FOR THE OXIDATIVE PYROLYSIS OF CH3CL [J].
KARRA, SB ;
SENKAN, SM .
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 1988, 27 (07) :1163-1168
[23]   P-P HOMOCONJUGATION IN BETA-CHLOROETHYL RADICAL [J].
KAWAMURA, T ;
KOCHI, JK ;
EDGE, DJ .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1972, 94 (05) :1752-&
[24]  
KERR JA, 1981, HDB BIMOLECULAR TERM, V1
[25]   SELF-CONSISTENT MOLECULAR-ORBITAL METHODS .20. BASIS SET FOR CORRELATED WAVE-FUNCTIONS [J].
KRISHNAN, R ;
BINKLEY, JS ;
SEEGER, R ;
POPLE, JA .
JOURNAL OF CHEMICAL PHYSICS, 1980, 72 (01) :650-654
[26]   APPROXIMATE 4TH-ORDER PERTURBATION-THEORY OF ELECTRON CORRELATION ENERGY [J].
KRISHNAN, R ;
POPLE, JA .
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, 1978, 14 (01) :91-100
[27]   CONTRIBUTION OF TRIPLE SUBSTITUTIONS TO THE ELECTRON CORRELATION-ENERGY IN 4TH ORDER PERTURBATION-THEORY [J].
KRISHNAN, R ;
FRISCH, MJ ;
POPLE, JA .
JOURNAL OF CHEMICAL PHYSICS, 1980, 72 (07) :4244-4245
[28]  
Lewis GN., 1961, THERMODYNAMICS
[29]   THEORETICAL INVESTIGATIONS OF THE ANAEROBIC REDUCTION OF HALOGENATED ALKANES BY CYTOCHROME-P450 .1. STRUCTURES, INVERSION BARRIERS, AND HEATS OF FORMATION OF HALOMETHYL RADICALS [J].
LUKE, BT ;
LOEW, GH ;
MCLEAN, AD .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1987, 109 (05) :1307-1317
[30]   KINETICS OF ALPHA-HYDROGEN AND BETA-HYDROGEN ABSTRACTION FROM C2H5CL BY BR ATOMS - ESTIMATE OF C-H BOND-DISSOCIATION ENERGIES AND HEATS OF FORMATION OF CH3CHCL AND CH2CH2CL RADICALS [J].
MIYOKAWA, K ;
TSCHUIKOWROUX, E .
JOURNAL OF PHYSICAL CHEMISTRY, 1990, 94 (02) :715-717