ON THE CHEMISTRY OF GALLIUM .5. CYCLIC-COMPOUNDS OF GALLIUM AND INDIUM WITH THE ,2-DIMETHYL-1,3-BIS-[(TRIMETHYLSILYL)AMINO]PROPANE LIGAND

Reaction of hyl-N-lithio-1,3-bis[(trimethylsilyl)amino]propane (4a) wi th RGaBr(2) (R = Br, Mes) allows the isolation of the cyclic monomeric amine(amino)gallanes 5 and 6. The cyclic bis(amino)gallanes 7 and 9 a s well as the indium homologue 10 were obtained by reaction of gallium halides RGaCl(2) (R = Cl, Mes) or InCl3 with dilithiated 4. In the ca se of R = Mes the product is a monomer. In addition, the tetrakis(amin o)gallate 8 was isolated. Single-crystal X-ray diffraction studies con firmed the constitutions. Compound 5 has one short Ga-N single bond (1 84 pm) and a longer Ga-N dative bond (204 pm). Compound 7 exhibits a c entral asymmetrical four-membered Ga2N2 ring [d(Ga-N) = 199.4, 205.6 p m] with syn-oriented substituents. The terminal Ga-N bond length is 18 4.3 pm. Two nitrogen atoms bridge the Lithium and gallium atom in the gallate 8 [d(Li-N) = 206 pm]. Two Li-H contacts complete the coordinat ion sphere at the lithium atom.