TRIMETHYLGALLIUM-INDUCED TRIMERIZATION OF ACETONITRILE

The reaction of GaMe3 in acetonitrile in the presence of halide ions, F-, Cl-,and Br-, at 60 degrees C gives the heterocycle [Me2Ga{HNC(Me)} (2)C(CN)] (1). Further reaction with GaMe3 and MeCN leads to a hexanuc lear gallium complex [(Me2Ga)(4)(MeGa)(2){HNC(Me)C(CN)CH(NCMe)(2)}(2)] (2). In addition to 2, 2.3MeCN and 2.2GaMe(3) can be obtained under s pecial conditions. 1 and 2 have been characterized by their NMR, IR,an d MS spectra, X-ray analyses were performed with 1, 2, 2.3MeCN, and 2. 2GaMe(3). Compound 1 consists of six-membered heterocycles, which are connected by hydrogen bridges to zigzag chains along the direction [01 0]. 2 contains 10 units of acetonitrile and six gallium centers formin g a centrosymmetric eight-membered Ga-N ring. The structure of 2 .3MeC N exhibits two hydrogen-bridged MeCN molecules and one acetonitrile mo lecule which is not connected to another component of the unit cell. I n 2.2GaMe(3) two units of GaMe3 are coordinated to the CN groups of 2 creating weakly pyramidalized GaMe3 fragments.