Reactions of transition-metal cations with [Re6Te8(CN)6]4−: syntheses and structures of [Zn(NH3)4]2[Re6Te8(CN)6], [{Co(NH3)5}2Re6Te8(CN)6] · 4H2O, and [{Ni(NH3)5}2Re6Te8(CN)6] · 4H2O

The compounds [Zn(NH3)4]2[Re6Te8(CN)6](1), [{Co(NH3)5}2Re6Te8(CN)6] · 4H2O (2), and [{Ni(NH3)5}2Re6Te8(CN)6] · 4H2O (3) have been synthesized by the diffusion of an ammonia solution of Cs4[Re6Te8(CN)6] · 2H2O into a glycerol solution of ZnCl2 (for 1), CoCl2 · 6H2O (for 2), or NiCl2 · 6H2O (for 3). Compound 1 crystallizes in the trigonal space group with one formula in a unit cell of dimensions a=10.3776(8) Å, c=10.4322(11) Å, and V=972.97(15) Å3 (T=153 K). Compounds 2 and 3 crystallize with four formula units in space group C2/c with cells of dimensions a=20.808(2) Å, b=22.027(3) Å, c=10.3708(11) Å, β=110.958(2)°, and V=4438.9(8) Å3 (T=153 K) (for 2); a=20.7617(15) Å, b=22.0521(16) Å, c=10.3526(8) Å, β=110.692(1)°, and V=4434.1(6) Å3 (T=153 K) (for 3). Compound 1 is ionic whereas compounds 2 and 3, which are isostructural, are molecular comprising two M(NH3)5 groups (M=Co, Ni) bonded in a trans fashion to the Re6Te8(CN)6 cluster through M–N(cyanide) bonds.