Abstract
A cyanide-bridged coordination polymer, {[Ni(tren)][Ni(CN)4]} n (tren = tris(2-aminoethyl)amine), has been synthesized by self-assembly of cis-[Ni(tren)]2+ and [Ni(CN)4]2− building blocks. In the molecular structure, the paramagnetic cis-[Ni(tren)]2+ cations are bridged by diamagnetic [Ni(CN)4]2− anions through two cis-cyanides to form a 1-D helical chain of {[Ni(tren)][Ni(CN)4]} n . The compound crystallizes with a centrosymmetrical space group, P21 /n, in which the helical chains are packed in alternating right- and left-handed chiralities with a helical pitch of 10.2566(3) Å (equal to the length of the b-axis), leading to the formation of a racemic compound. The crystal packing is stabilized by moderately strong hydrogen-bonding between primary amines of tren and nitrogens of terminal cyanide.
Acknowledgments
The author thanks Prof. Pradyot Banerjee, Indian Association for the Cultivation of Science, Kolkata, for useful suggestions during the course of this work.