A three-dimensional heterometallic Cu(I)/V(IV) 1,2-bis(1,2,4-triazol-4-yl)ethane framework: a new insight into the structure of vanadium oxyfluoride coordination hybrids.

The bitopic ligand 1,2-bis(1,2,4-triazol-4-yl)ethane (tr(2)eth) provides an unprecedented short-distance N(1):N(2)-triazole bridging of Cu(I) and V(IV) ions in poly[bis[mu(4)-1,2-bis(1,2,4-triazol-4-yl)ethane]di-mu(2)-fluorido-tetrafluoridodi-mu(2)-oxido-dicopper(I)divanadium(IV)], Cu(2)V(2)F(6)O(2)(C(6)H(8)N(6))(2). The Cu(I) ions and tr(2)eth linkers afford a two-dimensional square-grid topology involving centrosymmetric (tr)Cu(mu-tr)(2)Cu(tr) [tr is triazole; Cu-N = 1.9525 (16)-2.0768 (18) A] binuclear net nodes, which are expanded in a third dimension by centrosymmetric V(2)O(2)F(6) pillars. The concerted mu-tr and mu-O bridging between the Cu(I) and V(IV) ions allows a multi-centre accommodation of the vanadium oxyfluoride moiety on a cationic Cu/tr(2)eth matrix [Cu-O = 2.1979 (15) A and V-N = 2.1929 (17) A]. The distorted octahedral coordination of [VONF(4)] is completed by two terminal and two bridging F(-) ions [V-F = 1.8874 (14)-1.8928 (13) and 2.0017 (13)-2.1192 (12) A, respectively]. The resulting three-dimensional framework has a primitive cubic net topology and adopts a threefold interpenetration.