ROUTES TO BIS(AMINO)TIN DICHLORIDES - EXCHANGE-REACTIONS BETWEEN TIN(IV) CHLORIDE AND TIN(II) AND TIN(IV) AMIDES, AND THE SYNTHESIS OF A CYCLIC BIS(AMINO)TIN DICHLORIDE FROM TIN(IV) CHLORIDE AND N,N'-DI-TERT-BUTYL-1,3-DIAMINOPROPANE VIA HCL ELIMINATION

Monomeric non-cyclic and dimeric cyclic bis(amino)stannylenes react with tin(IV) chloride to give the corresponding bis(amino)tin dichlorides (1, 2) in essentially quantitative yield. By monitoring the exchange reaction between tin(IV) chloride and tetrakis(diethylamino)tin using Sn-119 NMR at low temperature, two intermediates (4, 5) were identified as binuclear complexes in which the tin atoms are bridged by two amino groups and one chloro ligand. The equilibrated 1:1 reaction mixture finally contains mainly bis(diethylamino)tin dichloride (3). The reaction between N,N'-di-tert-butyl-1,3-diaminopropane/triethylamine (1:2) and SnCl4 affords the cyclic bis(amino)tin dichloride (6) via elimination of HCl. The compounds 1-6 were characterized in solution by H-1, C-13, Si-29 and Sn-119 NMR. The solid state Sn-119 CP/MAS NMR spectrum of compound 6 proves that its monomeric character is retained also in the crystalline state.