Reactions of niobium and tantalum hexanuclear halide clusters with cadmium(II) halides, diamagnetic and paramagnetic clusters with semiconducting properties

The diamagnetic [Ta6Cl12(H2O)6][CdCl2X2]·12H2O (X = Br, I) 1, 2 and [M6Br12(H2O)6][CdBr2X2]·12H2O (M = Nb, Ta; X = Cl, Br, I) 3–8 clusters as well as paramagnetic [(Ta6Cl12)Cl(H2O)5][CdBr4]·6H2O 9 have been isolated. The crystal structures have been determined for [Nb6Br12(H2O)6][CdBr4]·12H2O 4, [Ta6Br12(H2O)6][CdBr4]·12H2O 7 and [(Ta6Cl12)Cl(H2O)5][CdBr4]·6H2O 9. Octahedral cluster cations [M6Br12(H2O)6]2+ in 4, 7 and [(Ta6Cl12)Cl(H2O)5]2+ in 9, together with [CdBr4]2− anion as discrete units are main structural building blocks. The crystal packing of the cations and anions in a three-dimensional network in 4 and 7 is realized via hydrogen bonds involving crystal and coordinated water molecules and Br− atoms from [CdBr4]2− anions. The paramagnetic cluster 9 displays the quazionedimensional magnetic properties with intrachain antiferromagnetic interaction J = 68 K and the interchain interaction J’ = 21 K. All compounds show semiconducting properties. The respective activation energies, Ea1 = 0.23 eV and Ea2 = 0.19 eV (the same values for 7 and 9) have been found.