Ni(bipy)(2)Ni(CN)(4), a new type of one-dimensional square tetracyano complex

The one-dimensional structure of catena-poly[[bis(2,2'-bipyridyl-1 kappa(2) N,N')-mu-cyano-1:2 kappa(2) N:C-dicyano-2 kappa(2) C-dinickel(II)]-mu-cyan o-C:N], [Ni-2 (CN)(4) (C10H8N2)(2)](n), consists of infinite zigzag chains running parallel to the c axis. The chains are composed of paramagnetic [Ni (bipy)(2)](2+) cations (bricks; nickel on a twofold axis) linked by diamagn etic [Ni(CN)(4)](2-) anions (mortar; nickel on an inversion center) via bri dging cyano groups. The bridging cyano groups occupy cis positions in the c ation and trans positions in the anion, giving rise to a new previously unk nown CT-type chain (i.e. cis-trans-type) among square tetracyano complexes. The coordination polyhedron of the paramagnetic Ni atom (twofold symmetry) is a slightly deformed octahedron with the two Ni-N(bipy) bonds in cis pos itions being somewhat longer [2.112 (3) Angstrom] than the remaining four N i-N bonds with a mean value of 2.065 (6) Angstrom. The bond distances and a ngles in the anion have typical values.