A New Approach to TCNQ-Based Coordination Polymers via TCNQH₂

Abstract

2,2′-(p-Phenylene)bis(propanedinitrile), (NC)2CH·C6H4·CH(CN)2 (referred to as TCNQH2), upon reaction with Cd(NO3)2, [(C6H5)3PMe]Br, and Li(CH3CO2) in MeOH/DMF at room temperature in air yields an air-stable product of composition (Ph3PMe)2[Cd2(TCNQ)3] in the form of rhombohedral single crystals amenable to X-ray diffraction studies. In the anionic three-dimensional (3D) {[Cd2(TCNQ)3]2−}∞ coordination network Cd centers are in an approximately octahedral coordination environment consisting of N atoms from six TCNQ2− units each of which is in turn attached to four Cd2+ centers at the corners of a quadrilateral that is almost a square. The disposition of the Cd centers is only very slightly distorted from primitive cubic. The results constitute a “proof of concept” for our proposition that easily accessible, air-stable TCNQH2 may afford a very convenient general entry into new types of coordination polymers based on the TCNQ2− anion and that these in turn may be amenable to redox intercalation to afford materials in which TCNQ is present either as the TCNQ− radical or in mixed oxidation states