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 119 Sn 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 SnCl 4 affords the cyclic bis(amino)tin dichloride ( 6 ) via elimination of HCl. The compounds 1–6 were characterized in solution by 1 H, 13 C, 29 Si and 119 Sn NMR. The solid state 119 Sn CP/MAS NMR spectrum of compound 6 proves that its monomeric character is retained also in the crystalline state.