Molecular complexes. Part II. H nuclear magnetic resonance studies of complexes of some chloroethylenes with benzene

Abstract

The equilibrium constants and structures for the complexes of benzene with 1,1,2-trichloroethylene, 1,1-dichloroethylene, and cis- and trans-1,2-dichloroethylene are deduced from the ethylenic proton resonance shifts and their dependence on benzene concentration in chloroethylene–benzene–cyclohexane systems. The effects of self-association of the ethylene solute molecules are considered. Specific solute–benzene interaction in each system is considered to result in the formation of 1 : 1 molecular complexes, but with some reservation in the case of trans-1,2-dichloroethylene with benzene. For each complex the participant species are shown to have van der Waals contact separations.