Elucidating the secondary effect in the Lewis acid mediated anodic shift of electrochemical oxidation of a Cu(II) complex with a N2O2 donor unsymmetrical ligand

摘要: A metalloligand [CuL] (H2L = N-α-methylsalicylidene-N′-salicylidene-1,3-propanediamine) was reacted with a series (Li+, Na+, K+, Mg2+, Ca2+, Zn2+, Cd2+, Pr3+, Nd3+ and Sm3+) of redox-inactive metal ions (in excess) different Lewis acidities in acetonitrile to form heterometallic complexes situ. In the cases K+ single crystals were isolated from their respective solutions solved. The found be trinuclear phenoxido bridge between metals copper center having closest equilibrium distance. solution, some (Na+, Mg2+ Ca2+) formed predominantly 1 : 1 [CuL] : Mn+ adducts whereas others did not. Spectroscopic studies revealed that both energy intensity LMCT band at 363 nm influenced by acidity guest ions. blue shift hypochromic this showed linear dependence on corresponding only for adducts. combined EPR d–d transition spectral analysis these 298 K indicates there is change coordination geometry around Cu(II) proximal cation binding free [CuL]. correlation half wave potential (E1/2) first oxidation pKa metal(aqua)n+ ion as measure its potentials linearly dependent case other an unexpected deviation linearity observed. An incremental addition water mixtures decrease peak concomitant increase molar absorptivity. absorptivities E1/2 values show better suggesting modulation electron density regulates electrochemical metalloligand.