Conjugated bond polymers with heteroatoms in the conjugated chain—XXI. Polymeric complexes of tetracyanoethylene

Abstract

IT WAS shown earlier that tetracyanoethylene (TCE) is capable of forming extremely heat-resistant polymeric complexes with metals possessing interesting magnetic and electrical properties [1-3]. In the present paper, experimental data on the production of polymers by the interaction of tetraeyanoethylene with metals or their salts and the results of an investigation of these polymers are considered. The selection of tetracyanoethylene as the starting material was dictated by the following considerations: (1) tetracyanoethylene has a plane structure, which makes it possible, when polymers are formed, to create conjugation along the chain of the macromolecule through the nitrile groups; (2) the presence in tetracyanoethylene of four nitrile groups and two carbon atoms may lead, under suitable conditions, to the formation of different cyclic structures, both with atoms of the metal in the ring and without them; (3) the polymeric compounds obtained from tetracyanoethy]ene and metals may be considered as almost the only example of inorganic maeromolecular compounds consisting of atoms of carbon, nitrogen, and metals linked to one another; and (4) the high vapour pressure and stability of monomeric tetraeyanoethylene at elevated temperatures makes it possible to form films of polymeric complexes directly on the surface of metals. The polymeric complexes were obtained by various methods: (1) by treatment of metallic sheets (copper, iron, nickel, aluminium, etc.) with tetracyanoethylene vapours at elevated temperatures; and (2)by heating a mixture of tetracyanoethylene with powdered metals or with acetylacetonates of the metals in a solvent (cyclohexanone, nitrobenzene, quinoline, etc.) or in the absence of a solvent. Treatment of metallic sheets with vapours of TCE at 150-450 ° for 5-20 hours led to the production of films of the polymeric complex which were black in eolour, as a rule, 10-6-10 -4 em thick, firmly bound to the metal, and insoluble in organic solvents, alkalis and acids. The reaction of powdered copper* with TCE takes place on heating the components in nitrobenzene at 190-200 °. The reaction of TCE with copper acetylacetonate (CAA) (2 : 1) (in solvents or with-