ISOLATION AND X-RAY STRUCTURAL-ANALYSIS OF FAC AND MER ISOMERS OF PRSNCL3.2DMF

By crystallization in N,N-dimethlformamide and silica gel, respectively, it was possible to isolate both the mer- and the fac-isomer of the compound iPrSnCl3.2DMF. The conformations of these octahedral complexes with a cis-arrangement of the two solvent molecules were confirmed by single crystal X-ray diffraction experiments. This example shows that the predominant formation of only a special stereoisomer which is often observed in octahedral 1:2 adducts of monoorganotin trihalides is caused by reaction conditions more than by sterical and/or electronical effects of the several complex ligands. In both complexes the bonds trans to the isopropyl group are shortened.