BENZOYLATION AND PROPERTIES OF 14-π NICKEL(Ⅱ)-TETRAAZAANNULENE COMPLEXES WITH SUBSTITUENTS ON THE PHENYL RING

다국어 초록 (Multilingual Abstract)

The benzoylated asymmetrical nickel(Ⅱ) complexes, 2,4,9,11 -tetramethyl-3,10-dibenzoyl- 1,5,8,12-([ 14]-Xbenzo)tetraazacyclotetradecinato(2-)nickel(II) (A_(1-4)) and 2,4,10,12-tetra- methyl3, l1-dibenzoyl-l,5,9,13-([15]-Xbenzo)tetraazacyclotetradecinato(2-)nickel(II) (B_(1-4)), wherein X=CH3 (A_(l) and B_(1)), H (A_(2) and B_(2)), C1 (A3 and B_(3)) and NO_(2) (A_(4) and B_(4)), have been synthesized and characterized by analysis, IR, electronic, ^(1)H- and ^(13)C-NMR spectra. An intense IR band due to C=O stretching is present in the range 1630-1650cm^(-1) upon benzoylation. Electronic spectra show bands at 375-390nm with ^(ε)max = 10000- 26000 M^(-1)cm^(-1) due to π → π^(*) transitions of macrocycles and at 500-550 nm with (ε)max = 10000- 5000 M^(-1)cm^(-1) attributable to LMCT for each of the complexes. The proton peaks of methine sites in the NMR spectra disappear on benzoylation. Results of the carbon-13 NMR spectra are compatible with those of the proton NMR. Cyclic voltammograms of the complexes in acetonitrile exhibit two successive and reversible (irreversible in DMSO) oxidation peaks for the macrocycle (Mc → Mc^(+) and Mc^(+) →Mc^(2+)) in the ranges +0.31-+0.51 and +0.60-+0.84V, respectively. In the reduction area, a reversible wave is followed by reduction of metal {Ni(II) → Ni(Ⅰ) at around -2.32V}. Unlike analogous complexes without the benzoyl group, those compounds are not electropolymerized by cyclic voltammetry.