Synthesis and spectral studies on copper (II) complexes of two twelve-membered and tetradentate macrocyclic ligands

Copper (II) complexes of general composition Cu(L)X-2 (where L = dibenzo [e ,k] -2,3,8,9 -tetraphenyl- 1,4,7,10-tetraaza-cyclododeca-1,3,7,9-tetraene ( L-1) and dibenzo [e,k]-2,3,8,9-tetramethyl-1,4,7,10-tetraazacyclododeca-1,3 ,7,9-tetraene (L-2); X = Cl-, Br-, NO3-, ClO4-, MeCOO- for L-1 and Cl-, Br, NO3-, ClO4-, MeCOO- and 0.5 SO42- for L-2) have been synthesized. The comp lexes have been characterized on the basis of elemental analyses, molar con ductance, magnetic susceptibility, IR electronic and ESR spectral studies. The complexes are found to stabilize tetragonal geometry except Cu(L-2)SO4 which has been assigned a five coordinate square pyramidal geometry.