Isolation of p-tricyanovinylphenyldicyanomethide ion via a [2+2] cycloaddition of 7,7,8,8-tetracyanoquinodimethane (TCNQ) molecules

In the presence of CoCl2·6H2O and dppm, the reaction of TCNQ (7,7,8,8-tetracyanoquinodimethane) molecules by [2+2] cycloaddition forms a p-tricyanovinylphenyldicyanomethide ion (PCQ−), which has been obtained as one anion unit in one new compound [Co(dppmdo)3][PCQ−]2·H2O 1 (dppmdo = bis(diphylphospine oxide) methane). Its structure was determined by X-ray crystallography: 1 crystallizes in P1¯ with a = 14.174(3) Å, b = 19.553(4) Å, c = 19.776(4) Å, α = 112.72(3)°, β = 95.43(3)°, γ = 110.79(3)°, and Z = 2. It was characterized by IR spectra, UV-Vis spectra, and cyclic voltammogram. Magnetic properties indicate that no magnetic coupling between PCQ− and [Co(dppmdo)3]2+ unit.