Synthesis, Characterization, and Electrochemical Behaviour of Cobalt(II) and Nickel(II) Complexes with N_𝟐O_𝟐 Chelating Ligand 4,4′-(Biphenyl-4,4′-diyldinitrilo)dipentan-2-one

Table 3

Main spectroscopic IR data for the ligand (solid state) and its complexes (CH₂Cl₂ solution). For UV-visible both in DMF solution.

Compound	Infrared (cm^−1)					UV-vis (DMF solution)
	ν(N–H)	ν(O–H)	ν(C=N)	ν(C=O)	ν(C–O)	ν(M–O)	ν(M–N)	λ max (nm)
H2L	—	—	1570 s	1610 vs	—	—	—	351
([Co(H2L)]^4+)2	3296 b	—	1557 m	1626 s	—	516 w	473 w	299, 610, 678
([Ni(H2L)]^4+)2	3293 m	—	1551 m	1619 s	—	514 w	437 w	302
[(CoCl2)2(H2L)]^4+	3289 m	—	1550 m	1625 s	—	515 w	435 w	303, 608, 674
[(NiCl2)2L]^2+⋅2H2O	—	3378 b	1548 m	—	1370 m	514 w	448 w	300

vs: very strong; m: medium; b: broad; w: weak.