Molecular orbital calculations at the ab initio STO-3G, 3-21G, 4-31G, and 6-31G* bases have been made for the relative proton affinities of an extended series of substituted cyanides, XCN. It is shown that geometry optimization at the 3-21G level is adequate and that 3-21G//3-21G calculations give very similar results to those obtained at the 6-31G*//3-21G level, except for X = Cl. Gas phase proton affinities are reported for many of the XCN compounds and these values are compared with the calculated results. Agreement between theory and experiment is excellent, except for some substituents which exert large field inductive effects.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Computational Theory and Mathematics
- Atomic and Molecular Physics, and Optics