The Tetracyanopyrrolide Anion as Ligand in Transition Metal Complexes

Two isotypic mononuclear discrete complexes [Co(MeCN)(4)(tcp)(2)]center dot 2MeCN (1) and [Ni(MeCN)(4)(tcp)(2)]center dot 2MeCN (2) containing the tetracyanopyrrolide anion [C-4(CN)(4)N](-) (tcp) were synthesized from [Me4N] tcp and the respective metal perchlorates in acetone/acetonitrile. Tcp coordinates to the transition metal atoms in eta(1) fashion via the nitrogen atom of the pyrrole ring. No coordination via the cyano groups is observed. Both complexes show nearly ideal paramagnetic behavior according to the Curie law with magnetic moments of 4.98 mu(B) for 1 and 3.09 mu(B) for 2. In the presence of Cu2+ ions tcp reacts with traces of water under hydrolysis of one cyano group to tricyanopyrrole-2-carboxamide (NC4(CN)(3)C(O)NH2)(-) (tcpc). From solutions in DMF the complex [Cu(tcpc)(2)(DMF)(2)] (3) is isolated.