Bound and non-bound tetracyanoethylene radical anion (TCNE˙) in copper(I) triphenylphosphine complexes. The crystal structures of Cu(TCNE)(PPh3)3, [-(CN)Cu(PPh3)2(TCNE)Cu(PPh3)2-]nand [(PPh3)3Cu(CN)Cu(PPh3)3][TCNE]

Abstract
The reaction of the copper(II) complex [Cu(TCNE)]n with triphenylphosphine yields three different modes of incorporation of TCNE˙ into the products Cu(TCNE)(PPh3)31, [-(CN)Cu(PPh3)2(TCNE)Cu(PPh3)2-]n2 and [(PPh3)3Cu(CN)Cu(PPh3)3][TCNE]3. In 1, the TCNE˙ in 2, trans-N-bound TCNE˙ bridges alternate with CN bridges to produce a polymeric structure, and in 3 the TCNE˙ is un-coordinated.