Nucleophilicities of the simplest saturated and unsaturated hydrocarbons

Abstract

Nucleophilicities NB of prototype saturated and unsaturated hydrocarbons methane, ethane, cyclopropane, ethyne and ethene when acting as Lewis bases were determined from the dissociation energies De of the hydrogen-bond complexes B…HX calculated ab initio, where B is the hydrocarbon and HX is variously HF, HCl, HBr, HI, HCN, HCCH and HCP. The values of NB obtained were 0.712(31), 0.736(32), 0.283(44), 2.561(73), 2.604(51) for methane, ethane, cyclopropane, ethyne and ethene, respectively. The inductive effect of the methyl group when ethyne is methylated was also investigated.