Characterization of Complexes Synthesized Using Schiff Base Ligands and Their Screening for Toxicity Two Fungal and One Bacterial Species on Rice Pathogens

Table 8

Characteristic IR data for the L2-BHEH (tridentate –O, –O, and –N) and its participation in complex formation with metal ions.

S. number	Complex	IR cm^−1 (s = sharp; b = broad; d = doublet; w = weak; vw = very weak)
		Coord water	vO–H^c	vN–H^c	vC=O^d	vC=N^d	vC=O phenolic^e	M–O or M–N or M–Cl^f
1	BHEH-L2^g	—	3330 (b)^a	3260 (b)^b	1650 (s)	1610 (s)	1240 (s)	—
2	[Cu(BHEH)Cl]	—	3460 (b)	3340 (b)	1600 (s)	1585 (s)	1255 (s)	690, 510, 270
3	[Ni(BHEH)2]	—	3600 (b)	3340 (b)	1620 (s)	1600 (s)	1255 (s)	500, 380
4	[Co(BHEH)2]	—	3450 (b)	3280 (s)	1620 (s)	1600 (s)	1255 (s)	650–400
5	[Fe(BHEH)(H2O)Cl]2	3500–3450 (b)	—	3340 (b)	1605 (s)	1580 (s)	1255 (s)	840 (s), 620, 580, 490
6	[Mn(BHEH)2]	—	3460 (b)	3280 (s)	1620 (d)	1600 (s)	1255 (s)	650–400
7	[VO(BHEH)Cl]2	—	3500 (w)	3260 (b)	1600 (s)	1590 (s)	1260 (s)	970 (V=O), 570, 520, 340

Intramolecular hydrogen bonding; ^bHydrogen bonding; ^cShift indicates cleavage of intramolecular H bonds after complex formation; ^dInvolvement of O of carbonyl group and N of azomethine group in complex formation, Watt and Dowes [95]; Truter and Rutherford [96]; Cotton and Wilkinson [97]; ^eDavison and Christie [98]; Kubo et al. [99]; indicates deprotonation of phenolic OH and binding to M;^fNakamoto [91, 100] and Selbin [94]; ^gNo change in vN–N at 1040 (w) cm⁻¹.