Novel Infinite Three-Dimensional Networks with Highly Conjugated Polynitrile Ligands: Syntheses, Crystal Structures, and Magnetic Properties of [Cu{C[C(CN)2]3}(H2O)2]n and [Cu{C[C(CN)2]3}(en)]n (en=NH2CH2CH2NH2)

An unprecedented coordination mode for the highly conjugated cyanocarbanion [C{C(CN)2}3]2− (1) is observed in the title complexes. This ligand employs four of its six CN groups in a μ4-η4 bridging mode to form two unique three-dimensional polymers.