The properties of transition-metal complexes of dipyrromethenes. Part II. Dipyrromethenes as unidentate ligands

Abstract

Complexes of the form M(PMH)₂X₂ can be isolated where M = Cu^II, Co^II, Ni^II, Zn^II, or Cd^II; PMH = 4,4′-di-ethoxycarbonyl-3,3′,5,5′-tetramethyldipyrromethene and X = Cl^–, Br^–, I^–, CNS^–, or NO₃^–. The presence of N–H bonds can be detected spectroscopically, indicating that co-ordination occurs through the basic pyrrole nitrogen. A number of the Cu, Ni, and Co complexes behave as 1:1 electrolytes in acetone. Magnetic and spectral results suggest tetrahedral structures for the cobalt and possibly nickel complexes.