Polydentate Schiff Base Ligands and Their La(III) Complexes: Synthesis, Characterization, Antibacterial, Thermal, and Electrochemical Properties

Table 6

Electrochemical data of the Schiff base ligands and their metal complexes.

Compound	Solvent	^i𝐸pa (V)	^i𝐸pc (V)	𝐸1/2 (mV)	Δ𝐸𝑝 (mV)	^ii𝐸pa (V)	^ii𝐸pc (V)	𝐸1/2 (mV)	Δ𝐸𝑝 (mV)
H2L^1	DMF	−0.55	−0.55	−550	−1100	−0.27	−0.67	—	−940
	DMSO	−0.29	−1.06	—	−770	−0.06	−1.15	—	−1210
H2L^2	DMF	1.00, −0.24	0.25, −0.19	−245	10	−0.35	0.06	—	−410
	DMSO	−0.47, 0.37, 1.04	0.41, −0.05, −0.62	—	−60	−0.36	−0.03, −0.58	—	220
H2L^3	DMF	0.93, −0.34	−0.05	—	−290	1.02, −0.31	0.09	—	−400
	DMSO	−0.51, −0.01, 0.50	0.39, 0.05, −0.63	—	120	−0.30, 0.09, 0.43	0.39, 0.10, −0.65	95	−10
H2L^4	DMF	−0.64, 0.42, 0.84	0.25, −0.57	—	−70	−0.50, 0.90	0.15, −0.63	—	130
	DMSO	−0.39, 0.43	0.35, −0.91	—	−40	−0.09	0.11, −1.01	10	−200
La2(L^1)(NO3)4(H2O)4	DMF	−0.43, −1.00	−0.65, −0.54, −0.41	—	−440	−0.80, −0.64, −0.25	−0.77, −1.20	—	−30
	DMSO	−0.29	−1.06	—	−770	−0.06	−1.15	—	1090
La(L^2)(NO3)(H2O)	DMF	−0.64, 0.42, 0.84	0.25, −0.57	—	−70	−0.85, −0.64, −0.31	−0.75, −1.25	—	−10
	DMSO	−0.47, 0.37, 1.04	0.41, −0.05, −0.62	−30	−60	−0.36	−0.03, −0.58	—	−357
La2(L^3)(NO3)4(H2O)4	DMF	−0.41, −0.18	−0.80, −0.61, −0.27	—	−225	−0.77, −1.28	−0.80, −0.61, −0.27	−78	−30
	DMSO	−0.41, 0.37, 1.04	0.41, −0.05, −0.62	—	−60	−0.36	−0.03, −0.58	—	−363
La2(L^4)(NO3)4(H2O)4	DMF	−0.57, −0.41	−0.22, −0.33	—	80	−0.80, −1.27	−0.78, −0.60, −0.30	−79	−20

Supporting electrolyte: [NBu₄](BF₄) (0.1 M); concentrations of the compounds: 1×10⁻³ M. All the potentials are referenced to Ag⁺/AgCl, where 𝐸_pa and 𝐸_pc are anodic and cathodic potentials, respectively. 𝐸_1/2=0.5×(𝐸_pa+𝐸_pc), Δ𝐸_𝑝=𝐸_pa−𝐸_pc. (i) These data have been obtained from scan rate 100 mVs⁻¹. Other data (ii) have been obtained by scan rate 100 mVs⁻¹.