SYNTHESIS AND STRUCTURE-ANALYSIS OF (TBUP )(4)SN(CH3)(2) AND(CH3)(2)SN[(TBU)P-P(TBU)]SN-2(CH3)(2)

The diphosphides K-2[(tBu)P-(tBuP)(2)-P(tBu)] 7 or K-2[(tBu)P-P(tBu)] 8 react with (CH3)(2)SnCl2 in a molar ratio of 1:1 to form the binary 5-membered ring system P4Sn 4a and the 6-membered ring system Sn(P-2)( 2)Sn 5a respectively. When (CH3)(2)SnCl2, however, is treated with 8 i n a molar ratio of 2:1 the 4-membered ring system P3Sn 2a is formed wh ich includes the fragmentation of the intermediate K-2[(CH3)(2)Sn ((tB u)P-P(tBu))(2)] 9. 4a and 5a could be obtained in a pure form and char acterized NMR spectroscopically and by X-ray structure analyses; 2a wa s identified only NMR spectroscopically.