Syntheses and structures of metal tetrazole coordination polymers

Abstract

Two salts and seven copper(I/II) and silver(I) coordination polymers containing tetrazolyl ligands have been hydro(solvo)thermal synthesized by metal salts, NaN₃ and various nitriles generated via [2 + 3] cycloaddition reactions of organonitriles and sodium azide. The study also shows that in some cases the azide can play a dual role in the in situ syntheses of metal tetrazole complexes, namely, starting material for tetrazole ligand and co-ligand in the tetrazole-based coordination complexes. Compounds 1 and 2 are simple salts of ammonium and sodium 5-methyltetrazolate. Compound 3 has a 3-D framework with intersecting channel and unprecedented (4⁹.6⁶) topology constructed from mixed-valent Cu₈ clusters. Compounds 4 and 5 are isomorphous, and have 3-D organic–inorganic frameworks constructed by [M₂(mtta)]⁺ (Hmtta = 5-methyltetrazole) ribbon and [M₂(N₃)]⁺ (M = Cu, Ag) layer two types of structural motifs, which contains an µ₄-1,1,1,3 azide. Compound 6 is a 3-D four-connected chiral complex with (4².8⁴)_Cu(4².8².10²)_tta topology. The structure of 7 consists of 2-D three-connected layers that are linked by ligand-unsupported Ag(I)⋯Ag(I) interactions to form a 3-D supramolecular array. Compound 8 shows a 3-D chiral framework containing tetrahedrally and linearly coordinated Ag(I) ions and µ₃- and µ₄-two types of 5-propyltetrazolate. Compound 9 has a 2-D layered structure formed by linkage of [Ag(tetrazolyl)] ribbons via C–C and N–Ag bonds. Magnetic measurement confirmed that there are two Cu(II) ions and six Cu(I) ions per Cu₈ unit consistent with a mixed-valent Cu(I,II) complex.