Interaction of bis(1,2,6,7-tetracyano-3,5-dihydro-3,5-diiminopyrrolizinide) metal complexes with phenazine and derivatives. Crystal structures of addition compounds of the nickel(II) complex with phenazine and 5,10-dimethyl-5,10-dihydrophenazine
Abstract
The charge-transfer compounds of the electron-acceptor moiety [NiL2](L = 1,2,6,7-tetracyano-3,5-dihydro-3,5-diiminopyrrolizinide) and the electron-donating phenazine derivatives [phenazine (phz), 5,10-dimethyl-5,10-dihydrophenazine (dmphz) and N-methylphenazinium cation (mphz+)] have been synthesized and characterized. The X-ray crystal structures of [NiL2]˙2phz˙2MeCN 1a and [NiL2]˙dmphz˙2MeCN 1b have been determined. Both compounds are monoclinic, mixed-stacked compounds, with planar acceptor and donor moieties alternating along the c axis [1a: space group P21/n, a= 14.687(1), b= 21.364(2), c= 7.8208(6)Å, β= 110.958(6)°, Z= 2; 1b: space group P21/c, a= 12.975(5), b= 19.838(7), c= 7.651(3)Å, β= 106.05(2)°, Z= 2]. While 1a, as expected, does not show any solid-state collective property, 1b is a semiconductor (single crystal ρ= 3.6 × 103Ω cm at room temperature; Ea= 0.28 eV); its degree of ionicity gradually increases, on lowering the temperature, from zero to a small amount corresponding to an effective magnetic moment (µeff)= of 0.28 µB per molecular formula. The cobalt derivative [CoL2]˙dmphz˙2MeCN has also been synthesized and characterized, which is isomorphous and isostructural with the nickel analogue, and qualitatively behaves likewise (single crystal ρ= 4.2 × 105Ω cm at room temperature; Ea= 0.26 eV); its magnetic measurements show a highspin metal configuration (S=, µeff= 4.13 µB). The N-methylphenazinium (mphz+) derivative, isolated as [NiL2]˙–˙mphz+˙2MeOH, is assumed to be a mixed-stacked radical anion salt from magnetic (µeff= 1.72 µB) and electrical (powder ρ= 5.5 × 106Ω cm at room temperature, Ea= 0.43 eV) measurements.