177702-89-5Relevant academic research and scientific papers
Formation of Metal Clusters or Nitrogen-Bridged Adducts by Reaction of a Bis(amino)stannylene with Halides of Two-Valent Transition Metals
Veith, Michael,Müller, Alice,Stahl, Lothar,N?tzel, Martin,Jarczyk, Maria,Much, Volker
, p. 3848 - 3855 (1996)
When the cyclic bis(amino)stannylene Me2Si(NtBu)2Sn is allowed to react with metal halides MX2 (M = Cr, Fe, Co, Zn; X = Cl, Br [Zn]) adducts of the general formula [Me2Si(NtBu)2Sn-MX2]n are obtained. The compounds are generally dimeric (n = 2) except the ZnBr2 adduct, which is monomeric in benzene. The crystal structures of [Me2Si(NtBu)2Sn-CoCl2]2 (triclinic, space group P?1; a = 8.620(9) ?, b = 9.160(9) ?, c = 12.280(9) ?, α = 101.2(1)°, β = 97.6(1)°, γ = 105.9(1)°, Z = 1) and of [Me2Si(NtBu)2Sn-ZnCl2]2 (monoclinic, space group P21/c; a = 8.156(9) ?, b = 16.835(12) ?, c = 13.206(9) ?, β= 94.27(6)°, Z = 2) were determined by X-ray diffraction techniques. The two compounds form similar polycyclic, centrosymmetrical assemblies of metal atoms bridged by chlorine or nitrogen atoms. While in the case of the cobalt compound Co is pentacoordinated by three chlorine and two nitrogen atoms, in the zinc derivative Zn is almost tetrahedrally coordinated by three chlorine atoms and one nitrogen atom. The iron derivative [Me2Si(NtBu)2Sn·FeCl2]2 seems to be isostructural with the cobalt compound as can be deduced from the crystal data (triclinic, a = 8.622(7) ?, b = 9.158(8) ?, c = 12.353(8) ?, α = 101.8(1)°, β= 96.9(1)°, γ = 105.9(1)°, Z = 1). If NiBr2, PdCl2, or PtCl2 is combined with the stannylene, the reaction product is totally different: 4 equiv of the stannylene are coordinating per metal halide, forming the molecular compound [Me2Si(NtBu)2Sn]4MX2, which crystallizes with half a mole of benzene per molecular formula. The crystal structures of [Me2Si(NtBu)2Sn]4·NiBr 2·l/2C6H6 (tetragonal, space group I41/a, a = b = 43.86(4) ?, c = 14.32(2) ?, Z = 16) and [Me2Si(NtBu)2Sn44·PdCl 2·1/2C6H6 (tetragonal, space group I41/a, a = b = 43.99(4) ?, c = 14.318(14) ?, Z = 16) reveal the two compounds to be isostructural. The molecules have an inner Sr4M pentametallic core (mean distances: Sn-Ni 2.463 ?, Sn-Pd 2.544 ?) with the transition metal in the center of a slightly distorted square formed by the four tin atoms, the distortion from planarity resulting in a weak paramagnetism of 0.2 μB for the nickel compound. The halogen atoms form bridges between two of the tin atoms and have no bonding interaction with the transition metal. The nickel compound has also been prepared by direct interaction of Br2 or NR4Br3 with [Me2Si(NtBu)2Sn]4Ni as a minor product, the main products being Me2Si(NtBu)2Sn(NtBu)2SiMe2, Me2Si(NtBu)2SnBr2, NiBr2 and SnBr2 . Other metal clusters have been obtained by the reaction of Me2Si(NtBu)2Sn with tetrakis(triphenyphosphine)palladium or by the reaction of Me2Si(NtBu)2Ge with RhCl(PPh3)3. In the first case Ph3PPd[Sn(NtBu)2SiMe2]3PdPPh 3 (rhombohedral, space group R3c, a = b = 21.397(12) ?, c = 57.01(5) ?, α = β= 90°, γ = 120°, Z = 12) is formed and is characterized by X-ray techniques to be composed of a central PdSn3Pd trigonal bipyramid with the tin atoms occupying the equatorial positions (Pd - Sn = 2.702(5) ?). In the second reaction all the triphenylphosphine ligands are replaced from rhodium and Rh[Ge(NtBu)2SiMe2]2Cl is formed (monoclinic, space group P21/n, a = 12.164(2) ?, b = 23.625(5) ?, c = 24,128(5) ?, β = 102.74(3)°, Z = 4). The central core of this molecule is made up of a rhodium atom which is almost square planarly coordinated by the germanium atoms, two of which are bridged by chlorine (mean Ge -Rh = 2.355 ?).
