Table 3.

Absorption data, band assignments of BEB ligand and its Cu(II) complexes.

Compounds		Absorption Transition, λmax (nm, DMF)	Band Assignments
BEB	C18H20N2O4	277, 309, 381	π-π*, π-π*, n-π*
[Cu(BEB)Cl]·2H2O	C18H20N2O5Cu	325, 345, 375, 545	π-π*, L → M (LMCT), 2B1g → 2A1g
[Cu(BEB)Br]·H2O	C18H22N2O6Cu	335, 395, 565	π-π*, L → M (LMCT), 2B1g → 2A1g
[Cu(BEB)SCN]·2H2O	C18H22N2O6Cu	330, 380, 547	π-π*, L → M (LMCT), 2B1g → 2A1g
[Cu(BEB)NO3]·3H2O	C18H22N2O6Cu	335, 395, 570	π-π*, L → M (LMCT), 2B1g → 2A1g