GROUP-IB ORGANOMETALLIC CHEMISTRY .32. ARYLCOPPER COMPOUNDS ARNCUN AS INTERMEDIATES IN ORGANOMETALLIC SYNTHESIS - SINGLE-STEP SYNTHESIS AND DYNAMIC NMR-SPECTROSCOPY OF DIORGANOTIN DIHALIDES AR2-NRNSNX2(AR=2-ME2NCH2C6H4 OR (S)-2-ME2NCHMEC6H4-N=0 OR 1)

The selective, single-step synthesis of (2-Me2NCHZC6H4)RSnX2, in which Z H or Me, R Me or Ph and X Cl or Br, starting from the tetranuclear copper cluster compound (2-Me2NCHZC6H4)4Cu4 and RSnX3 is described. Reaction of (2-Me2NCH2C6H4)4Cu4 with SnBr4 in a 1/2 molar ratio afforded (2-Me2NCH2C6H4)2SnBr2 in almost quantitative yield. 1H NMR spectroscopic data of these novel compounds, which are monomeric in solution, indicate that: (i) intramolecular SnN coordination renders the Sn atom in (2-Me2NCHZC6H4)RSnX2 pentacoordinate, with the organo ligands residing in the equatorial plane of a trigonal bipyramidal structure, and the Sn atom in (2-Me2NCH2C6H4)2SnBr2 hexacoordinate, with trans organo groups and a cis arrangement for the Br and the N atoms; (ii) in pyridine the Sn atom in (2-Me2NCHZC6H4)RSnX2 becomes hexacoordinate by complex formation with the solvent but that intramolecular SnN coordination has been retained. The stereochemical lability of the pentacoordinate Sn center in the diorganotin dihalides (2-Me2NCHZC6H4)RSnX2, which contain a dissymmetrical equatorial plane, has been established on the basis of the dynamic NMR spectra of. © 1979.