Table 2.

Significant IR frequencies (cm⁻¹) for HL Schiff base and its complexes.

Compound	υ(H2O, OH, NH)	υ(C=O)	υ(C=N)	υ NO3	υ M-O	υ M-N
HL	3500–2900 m, br	1622 w	1576 s	---	---	---
[Cu(L)(H2O)]Cl.H2O	3740–3000 m, br	1627 w	1539 sh	---	653 w	580 w
[Ni(L)2]	3800–3030 m, br	1603 w	1520 sh	---	612 w	584 w
[Co(L)2]1/2H2O	3830–2990 m, br	1632 w	1530 sh	---	608 w	545 w
[Gd(L)2(H2O)2](NO3).3/2H2O	3800–2990 m, br	1612 w	1528 sh	1384 s	641 w	584 w
[Sm(L)2(H2O)2](NO3).2H2O	3700–3100 m, br	1609 w	1539 sh	1384 s	588 w	578 w

s: strong, m: medium, w: weak, br: broad, and sh: shoulder.