Formation of high nuclearity mixed-valent polyoxovanadates in the presence of copper amine complexes

Two new Muller-type clusters, a one-dimensional solid {Cu(en)(2)}(4)[Cl subset of V15O36](.)12H(2)O 1, and a three-dimensional solid (Cu(pn)(2))(4)[Cl subset of V18O42](.)12H(2)O 2, have been synthesised by employing identical hydrothermal conditions except varying the nature of organic diamine. I crystallised in a chiral space group P2(1)2(1)2(1) with a = 12-757(1), b = 18.927(2) and c = 28.590(3) angstrom, and Z = 4.2 crystallised in a tetragonal system with space group P4/nnc, a = 15-113(1) and c = 18-542(3) angstrom, and Z = 2. Mixed-valent vanadium ions in structures 1 and 2 have been established both by magnetisation and bond-length bond-valence measurements. Chemistry of formation of high nuclearity polyoxovanadate clusters is discussed.