Design and properties of mixed metal multinuclear molecules Part 1. Molecular structures of [Ag(PR3)(2)](2)[Ni(mnt)(2)] type complexes (R = Me, Et, Cy and mnt = maleonitriledithiolate) and [AgL](2)[Ni(mnt)(2)] type complexeswith chelating diphosphines (L = dppf and dppm)

The trinuclear complexes [Ag(PR3)(2)](2)[Ni(mnt)(2)] and [AgL](2)[Ni(mnt)(2 )] have been prepared by reactions of(NEt4)(2)[Ni(mnt)(2)] and Ag2SO4 with alkyl phosphines (PR3 = P(CH3)(3) (PMe3) for 1, P(C2H5)(3) (PEt3) for 2 and P(C6H11)(3) (PCy3) for 3), or with chelating diphosphines (L = 1,1'-bis(di phenylphosphino)ferrocene (dppf) for 4 and bis(diphenylphosphino)methane (d ppm) for 5). The structures of all the complexes have been determined by X- ray crystallography. Interactions between the [Ag(PR3)(2)](+) and [Ni(mnt)( 2)](2-) groups occur in compounds 1 and 2 with Ni-Ag distances of 3.063(4) and 2.9311(6) Angstrom, respectively. Only one sulfur atom of each mnt liga nd bridged [Ag(PR3)(2)](+) cations and [Ni(mnt)(2)](2-) anions in compound 1 through 3 with Ag-S distances of about 2.7 Angstrom. There is no interact ion between Ag and Ni in compound 3 due to the flexibility of the cyclohexy l groups. Interactions between [AgL](+) and [Ni(mnt)(2)](2-) groups also oc cur in compound 4 with a much shorter Ag-Ni distance of 2.7213(7) Angstrom, while silver atoms and the NiS4 plane in compound 4 make a chair conformat ion with Ag-S distances of about 2.8 Angstrom. In compound 5, dppm bridges two silver atoms, and interaction between silver atoms occurs at a distance of 2.9859(11) Angstrom, and only one sulfur atom of mnt is used to bridge Ni and Ag atoms with AE-S distances of 2.582(3) and 2.663(3) Angstrom. (C) 2000 Elsevier Science B.V. All rights reserved.