N(1)-alkyl-2-(arylazo)imidazoles (RC6H4N=NC3H2N N(1)X; X=Me (a), Et (b); R=7-Me(L1), 7-OMe(L2), 7-Cl(L3), 7-NO2(L4) and 8-Me(L5)) yield perchlorate salts ofbis-chelated complexes with copper(I). The complexes are 1:1 electrolyte and the composition in supported by Jobs method of continuous variation. The N=N stretching is red shifted by 60–70 cm−1 compared to free ligand values suggesting efficient charge delocalization from Cu(I) to ligand centre. This is supported by high intense MLCT transitions in the visible region. The complexes show highly resolved symmetrical1H NMR spectra exhibiting C2-symmetry at least in the NMR time scale. In MeOH the complexes exhibit quasi-reversible CuL22+/CuL2+ couple at 0.4–0.5 Vvs SCE at 298 K. The high positive potential may be due to the distortion in the geometry of CuL2+.
Volume 134, 2022
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