Table 4. Electronic Spectra of the Free Ligand and Its Zn(II) and Cu(II) Complexes.

compounds	absorption (nm)	transition
H2L	231, 261, 305, 408	(π → π*), (π → π*), (n → π*), and (n → π*)
1	231, 259, 303, 393	(π → π*), (π → π*), (n → π*), and (n → π*)
2	255, 351	(n → π*) and LMCT