Inorganic Chemistry, Vol.37, No.18, 4607-4610, 1998
A novel mixed macrocycle complex of nickel : Synthesis, structure, and redox chemistry of [Ni-II([9]aneN(3))([9]aneS(3))](ClO4)(2)center dot CHCl3 ([9]aneN(3) = 1,4,7-triazacyclononane and [9]aneS(3) = 1,4,7-trithiacyclononane)
The mixed macrocycle cation, [Ni([9]aneN(3))([9]aneS(3))](2+) (where [9]aneN(3) = 1,4,7-triazacyclononane and [9]aneS(3) = 1,4,7-trithiacyclononane), has been prepared by stepwise complexation of [9]aneN(3) and [9]aneS(3), respectively, to Ni(II) cation. The intermediate [Ni([9]aneN3)(CH3NO2)(3)](2+) has been isolated and characterized by mass spectrometry and UV - visible spectroscopy. Cyclic voltammetry of [Ni([9]aneN(3))(CH3NO2)(3)](2+) shows a quasireversible wave for the Ni-II/III couple (E-1/2 = 0.73V vs Fc(+/0)), and the Ni(III) species exhibits an axial ESR spectrum (g(perpendicular to) = 2.101 and g(parallel to) = 1.985). The structure of [Ni([9]aneN(3))([9]aneS(3))](ClO4)(2). CHCl3 has been determined. It crystallizes in monoclinic space group P2(1)/c with a = 13.3911(8) Angstrom, b = 14.4430(9) Angstrom, c = 13.6116(8) Angstrom, beta = 107.2090(10)degrees, V = 2514.7(3) Angstrom(3), and Z = 4. Of the 15 047 reflections collected, 5765 reflections (I > 2 sigma(I)) were used in the refinement to obtain a final R-w = 0.0278 and R-F = 0.0368. In the cation [Ni([9]aneN(3))([9]aneS(3))](2+), the two macrocycles occupy the trigonal faces of the Ni2+ ion, imposing a distorted octahedral geometry. Cyclic voltammetry of the complex in CH3CN (Pt electrodes, 0.1 M n-Bu4NClO4, 500 mV) shows a quasireversible wave for the Ni-II/Ni-III couple (E-1/2 = 0.86V vs Fc(+/0)). Chemical oxidation by NOPF6 of the cation [Ni([9]aneN(3))([9]aneS(3))](2+) generates a NI(III) species that shows axial ESR spectrum with g(perpendicular to) = 2.106 and g(parallel to) = 2.063. No characteristic reduction wave was observed in either CH3CN or CH3NO2 media.