Further results on electron delocalization in 3d metal complexes probed by positronium atoms

Abstract

The rate constants, k_CR, of ortho–para-positronium conversion reactions promoted by Cr^III, Mn^II, Co^II and Ni^II complexes have, previously, been correlated with the corresponding delocalization of metal electrons as described by means of the ratio, β, between the interelectronic repulsion parameters in the complex, B, and that in the free gaseous ions, B₀. The parameters of the correlation lines have been improved by investigation of another eight conversion reactions. It was confirmed that the k_CR values for β→0 are proportional to the number of unpaired electrons of the metal ions, the newly determined proportionality constant, χ, being 3.0±0.2 dm3 mol^-1 ns^-1 electron^-1 (cf. previous value 3.7±0.6).