Inorganic Chemistry, Vol.50, No.24, 12315-12325, 2011
Preparation, Characterization, and Theoretical Analysis of Group 14 Element(I) Dimers: A Case Study of Magnesium(I) Compounds as Reducing Agents in Inorganic Synthesis
A synthetic route to the new amidine (DipNH)(DipN)-C(C6H4But-4) (ButisoH; Dip = C6H3Pr2i-2,6) has been developed. Its deprotonation with either LiBun or KN(SiMe3)(2) yields the amidinate complexes [M(Butiso)] (M = Li or K). Their reactions with group 14 element halides/pseudohalides afford the heteroleptic group 14 complexes [(Butiso)SiCl3], [(Butiso)ECI] (E = Ge or Sn), and [{(Butiso)-Pb(mu-O3SCF3)(THF)}(infinity)], all of which have been crystallographically characterized. In addition, the synthesis and spectroscopic characterization of the homoleptic complex [Pb(Butiso)(2)] is reported. Reductions of the heteroleptic complexes with a soluble magnesium(I) dimer, [{((Mes)Nacnac)Mg}(2)] ((Mes)Nacnac = [(MesNCMe)(2)CH](-); Mes = mesityl), have given moderate-to-high yields of the group 14 element(I) dimers [{(Butiso)E}(2)] (E = Si, Ge, or Sn), the X-ray crystallographic studies of which reveal trans-bent structures. The corresponding lead(I) complex could spectroscopic and theoretical analyses of [{(Butiso)E}(2)] have allowed their properties to be compared. All complexes possess E-E single bonds and can be considered as intramolecularly base-stabilized examples of ditetrelynes, REER. Taken as a whole, this study highlights the synthetic utility of soluble and easy to prepare magnesium(I) dimers as valuable alternatives to the harsh, and often insoluble, alkali-metal reducing agents that are currently widely employed in the synthesis of low-oxidation-state organometallic/inorganic complexes.