Facile transformation of isolated fragments to infinite chains in rhenium chalcocyanide clusters: Synthesis and structure of (Pr4N)(2)M(H2O)(5) [Re6X8(CN)(6)] center dot H2O and (Pr4N)(2)M(H2O)(4) [Re6S8(CN)(6)] (X= S, Se; M= Mn, Ni)

In this paper we report the synthesis of new compounds containing cluster a nions [Re6S8(CN)(6)](4-) and [Re6Se8(CN)(6)](4-). Interaction of aqueous so lutions of anions with transition metal cations in presence of Pr4N+ gives two type of compounds: (Pr4N)(2)M(H2O)(5)[Re6X8(CN)(6)] . H2O, X = S, Se (o rthorhombic phase) and (Pr4N)(2)M(H2O)(4)[Re6S8(CN)(6)] (tetragonal phase), X = S, Se, M = Mn, Ni. The structures of (Pr4N)(2)Mn(H2O)(4)[Re6S8(CN)(6)] . H2O (space group: P2(1)2(1)2(1), a = 18.286(2) Angstrom, b = 18.345(2) A ngstrom, c = 16.568(2) Angstrom, V = 5558(1) Angstrom(3), Z= 4) R1 = 0.0387 , wR2 = 0.0624), (Pr4N)(2)Mn(H2O)(4)[Re6S8(CN)(6)] (space group: I4/m, 13.2 55(2) Angstrom, 14.432(3) Angstrom, V = 2535.6(8) Angstrom(3), R1 = 0.0369, wR2 = 0,0960) and (Pr4N)(2)Ni(H2O)(4)[Re6S8(CN)(6)] (space group: I4/m, a = 13.247(4) Angstrom, c = 14.246(6) Angstrom, V = 2500(2) Angstrom(3), R1 = 0.0414, wR2 = 0.1004) were determined by X-ray single crystal analysis. Th e structure of (Pr4N)(2)Mn(H2O)(5)[Re6S8(CN)(6)] . H2O contains isolated fr agments {Mn(H2O)(5) [Re6Se8(CN)(6)]}(2-). The structures of (Pr4N)(2)M(H2O) (4)[Re6S8(CN)(6)] (M = Mn, Ni) contain {-Mn(H2O)(4)-[Re6S8(CN)(6)]-}(infini ty)(2-) infinite chains. When heated the (Pr4N)(2)M(H2O)(5)[Re6S8(CN)(6)] . H2O compounds transform into (Pr4N)(2)M(H2O)(4)[Re6S8(CN)(6)], the reactio n conditions depending on the nature of the metal. The formation and conver sion of the compounds are discussed in terms of substitution of water molec ules in coordination sphere of transition metal cations. It is shown that t he orthorhombic structure can be considered as a superstructure in respect to the tetragonal one. (C) 2000 Academic Press.