A microscopic view of substitution reactions solvated by ionic liquids

被引:18
作者
Arantes, Guilherme M. [1 ]
Ribeiro, Mauro C. C. [1 ]
机构
[1] Univ Sao Paulo, Inst Quim, Lab Espectroscopia Mol, CP 26077, BR-05513 Sao Paulo, Brazil
基金
巴西圣保罗研究基金会;
关键词
D O I
10.1063/1.2890042
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 solvation effect of the ionic liquid 1-N-butyl-3-methylimidazolium hexafluorophosphate on nucleophilic substitution reactions of halides toward the aliphatic carbon of methyl p-nitrobenzenesulfonate (pNBS) was investigated by computer simulations. The calculations were performed by using a hybrid quantum-mechanical/molecular-mechanical (QM/MM) methodology. A semiempirical Hamiltonian was first parametrized on the basis of comparison with ab initio calculations for Cl- and Br- reaction with pNBS at gas phase. In condensed phase, free energy profiles were obtained for both reactions. The calculated reaction barriers are in agreement with experiment. The structure of species solvated by the ionic liquid was followed along the reaction progress from the reagents, through the transition state, to the final products. The simulations indicate that this substitution reaction in the ionic liquid is slower than in nonpolar molecular solvents proper to significant stabilization of the halide anion by the ionic liquid in comparison with the transition state with delocalized charge. Solute-solvent interactions in the first solvation shell contain several hydrogen bonds that are formed or broken in response to charge density variation along the reaction coordinate. The detailed structural analysis can be used to rationalize the design of new ionic liquids with tailored solvation properties. (c) 2008 American Institute of Physics.
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页数:9
相关论文
共 52 条
[1]   Elucidation of rate variations for a Diels-Alder reaction in ionic liquids from QM/MM simulations [J].
Acevedo, Orlando ;
Jorgensen, William L. ;
Evanseck, Jeffrey D. .
JOURNAL OF CHEMICAL THEORY AND COMPUTATION, 2007, 3 (01) :132-138
[2]  
Allen M. P., 2009, Computer Simulation of Liquids
[3]   Specific parametrisation of a hybrid potential to simulate reactions in phosphatases [J].
Arantes, GM ;
Loos, M .
PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 2006, 8 (03) :347-353
[4]   EVIDENCE FOR HYDROGEN-BONDING IN SOLUTIONS OF 1-ETHYL-3-METHYLIMIDAZOLIUM HALIDES, AND ITS IMPLICATIONS FOR ROOM-TEMPERATURE HALOGENOALUMINATE(III) IONIC LIQUIDS [J].
AVENT, AG ;
CHALONER, PA ;
DAY, MP ;
SEDDON, KR ;
WELTON, T .
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1994, (23) :3405-3413
[5]   DENSITY-FUNCTIONAL THERMOCHEMISTRY .3. THE ROLE OF EXACT EXCHANGE [J].
BECKE, AD .
JOURNAL OF CHEMICAL PHYSICS, 1993, 98 (07) :5648-5652
[6]   Computational study of room temperature molten salts composed by 1-alkyl-3-methylimidazolium cations-force-field proposal and validation [J].
de Andrade, J ;
Böes, ES ;
Stassen, H .
JOURNAL OF PHYSICAL CHEMISTRY B, 2002, 106 (51) :13344-13351
[7]   THE DEVELOPMENT AND USE OF QUANTUM-MECHANICAL MOLECULAR-MODELS .76. AM1 - A NEW GENERAL-PURPOSE QUANTUM-MECHANICAL MOLECULAR-MODEL [J].
DEWAR, MJS ;
ZOEBISCH, EG ;
HEALY, EF ;
STEWART, JJP .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1985, 107 (13) :3902-3909
[8]   SELF-CONSISTENT MOLECULAR-ORBITAL METHODS .9. EXTENDED GAUSSIAN-TYPE BASIS FOR MOLECULAR-ORBITAL STUDIES OF ORGANIC MOLECULES [J].
DITCHFIELD, R ;
HEHRE, WJ ;
POPLE, JA .
JOURNAL OF CHEMICAL PHYSICS, 1971, 54 (02) :724-+
[9]   Ionic liquid (molten salt) phase organometallic catalysis [J].
Dupont, J ;
de Souza, RF ;
Suarez, PAZ .
CHEMICAL REVIEWS, 2002, 102 (10) :3667-3691
[10]  
Field MJ, 2000, J COMPUT CHEM, V21, P1088, DOI 10.1002/1096-987X(200009)21:12<1088::AID-JCC5>3.0.CO