New Cu^I₂(TCNQ^–II) and Cu^I₂(F₄TCNQ^–II) Coordination Polymers

Coordination polymer strips of composition ...Cu+2·lig2–·Cu+2·lig2–·Cu+2·lig2–... (where lig2– = TCNQ2– or its 2,3,4,5-tetrafluoro analogue) are observed with a wide range of coligands (monodentate, bidentate, and tridentate). Interdigitation of “thin”, planar N-heteroaromatic coligands on one strip with those on a neighbor is a common structural feature. Coligands too bulky to allow interdigitation give either non-interdigitating strips or 2D sheet structures. Both strips and sheets have 2-connecting Cu centers and 4-connecting tetracynano ligands. As a consequence of the great flexibility of the Cu/tetracyano ligand association, the geometries of the sheet structures vary widely from almost coplanar to highly corrugated and convoluted, despite which the same topology is present in all.