Studies on Oligomer Metal Complexes Derived from Bisamic Acid of Pyromellitic Dianhydride and 4-Bromoaniline

Table 2

FT-IR frequencies and electronic spectral data of the ligand and its oligomer metal complexes.

Compound		−COOH	−CONH	−OH	−C=O	−CONH	COO^−	C–O	M–O	M–N	Electronic spectral data
											cm^−1	Transitions
1	L	3555	3237	—	1712	1688	1465	1047	—	—	—	—
2a	[Mn–L–	—	3212	2982	1692	1665	1453	1029	623	528	16,486,; 17,769,; 23,140	6A1g → 4T1g(4G),; 6A1g → 4T2g(4G); 6A1g → 4A1g, 4Eg
2b	[Fe–L–	—	3220	2979	1694	1673	1455	1026	628	531	19011; 36062	5T2g(F) → 3Eg; 5T2g(F) → 3T1g
2c	[Co–L–	—	3211	2983	1690	1672	1447	1028	630	529	9,845; 15,553; 22,948	4T1g(F) → 4T2g(F); 4T1g(F) → 4A2g(F); 4T1g(F) → 4T1g(P)
2d	[Ni–L–	—	3214	2977	1695	1669	1449	1025	634	526	9,851; 15,570; 22,934	3A2g → 3T2g; 3A2g → 3T1g(F); 3A2g → 3T1g(P)
2e	[Cu–L–	—	3225	2969	1689	1671	1450	1027	629	532	15,949; 22,746	2T2g → 2Eg; charge transfer
2f	[Zn–L–	—	3213	2973	1687	1668	1446	1026	632	527	—	—