Clark Timothy, Murray Jane S, Lane Pat, Politzer Peter
Computer-Chemie-Centrum, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nägelsbachstrasse 25, 91052, Erlangen, Germany.
J Mol Model. 2008 Aug;14(8):689-97. doi: 10.1007/s00894-008-0279-y. Epub 2008 May 6.
We have carried out B3PW91 and MP2-FC computational studies of dimethyl sulfoxide, (CH(3))(2)SO, and dimethyl sulfone, (CH(3))(2)SO(2). The objective was to establish quantitatively the basis for their high polarities and boiling points, and their strong solvent powers for a variety of solutes. Natural bond order analyses show that the sulfur-oxygen linkages are not double bonds, as widely believed, but rather are coordinate covalent single S(+)-->O(-) bonds. The calculated electrostatic potentials on the molecular surfaces reveal several strongly positive and negative sites (the former including sigma-holes on the sulfurs) through which a variety of simultaneous intermolecular electrostatic interactions can occur. A series of examples is given. In terms of these features the striking properties of dimethyl sulfoxide and dimethyl sulfone, their large dipole moments and dielectric constants, their high boiling points and why they are such good solvents, can readily be understood.
我们对二甲基亚砜（(CH(3))(2)SO）和二甲基砜（(CH(3))(2)SO(2)）进行了B3PW91和MP2-FC计算研究。目的是定量确定它们高极性、高沸点以及对多种溶质具有强溶解能力的基础。自然键序分析表明，硫-氧键并非如广泛认为的那样是双键，而是配位共价单键S(+)→O(-)。计算得到的分子表面静电势揭示了几个强正电和负电位点（前者包括硫上的σ-空穴），通过这些位点可以发生多种同时存在的分子间静电相互作用。给出了一系列示例。根据这些特征，二甲基亚砜和二甲基砜的显著性质，它们大的偶极矩和介电常数、高沸点以及为何它们是如此好的溶剂，都能够很容易地得到理解。
