“…Based on this concept, other metals were used and various complexes were developed: Ni(II), Pd(II), Cu(II), Co(III), Pt(II), or Zn(II) [ 160 , 161 , 162 , 163 , 164 , 165 , 166 , 167 , 168 , 169 ]. Most of these salphen or salen complexes display a square planar geometry except the square-based pyramidal salphen complexes based on Co(III) [ 168 ].…”