New basicity/nucleophilicity scale on the basis of parameters of formation of axial n,ν-complexes derived from tetraphenylporphyrinatozinc(II) and base/nucleophile as ligand

The stability constants of complexes derived from tetraphenylporphyrinatozinc(II) and various ligands in chloroform at 25°C were proposed as nucleophilicity/basicity parameters of the latter, which reflect the effects of electronic and steric factors. Supernucleophilicity of heteroaromatic N-oxides in reactions with electrophiles was interpreted in terms of sp 2–sp 3 rehybridization of the N-oxide oxygen atom.