New GaE and InE four membered ring compounds: Syntheses and crystal structures of [Et2InE(SiMe3)(2)](2) and [GaCl(PtBu2Me)E(SiMe3)](2) (E = P, As)

Et3In . PR3 (R = Et, iPr) reacts with H2ESiMe3 under liberation of C2H6 and EH3 to form the cyclic compounds [Et2InE(SiMe3)(2)](2) (1a: E = P, 1b: E = As). 1 consists of a planar four membered In2E2 ring in which the indium a nd phosphorus or arsenic atoms are four coordinated. In contrast, the phosp horusiarsenic atoms in [GaCl(PtBu2Me)-E(SiMe3)](2) (2 a: E = P, 2 b: E = As ) only have the coordination number three. 2 results from the reaction of G aCl3. Pt-Bu2Me with As(SiMe3)(3) or Li2PSiMe3 respectively, and displays a folded four membered Ga2E2 ring as central structural motif. 1 and 2 have b een characteriscd by single crystal X-ray diffraction analysis as well as H -1 and P-31{H-1} NMR spectroscopy.