Single-crystal ESR spectra of copper(II) complexes with geometries intermediate between a square pyramid and a trigonal bipyramid

The single-crystal ESR spectra of copper( 11)-doped bis(N-methylsalicylaldiminato)zinc(II) and (bis(3-salicylaldiminatopropyl) methylamine)zinc(II) have been recorded. Both the complexes are five-coordinate with geometries intermediate between a square pyramid and a trigonal bipyramid The g and A values of these complexes are discussed on the basis of an angular overlap model. Criteria are suggested for recognizing the ESR spectra of distorted five-coordinate complexes in diluted powders or frozen solutions.