870 ARLAND. NORMAN
IpLorganic Chemistry CONTRIBUTION FROM THE DEPARTMENT O F CHEMISTRY, UNIVERSITY O F COLORADO, BOULDER, COLORADO 80302
The Preparation and Properties of Methyl(phosphino)silanes and -germanesl BY ARLAN D. KORMAN Received September 26, 1969 A series of new methyl(phosphin0 jgermanes and -silanes-( CH3)3GePH2, (CH$),Ge(PH2)2,and (CH3)2Si(PH2)Z-has been synthesized by the reaction of LiAl(PH2)d with the appropriate halogermane or -silane. The previously reported (CHS)BSiPHi has also been obtained in high yield. Mixed reduction-phosphination products, (CHs)aGe(PH2)H and ( CE13)2Si(PH%)H,have been prepared by the reaction of nominally equimolar LiAIH?-LiAI( PH2)d mixtures with ( CH3)2GeC12and (CH3j~SiC12, respectively. The new compounds have been characterized by elemental analyses, molecular weight measurenmr, ir, and mass spectral data are also reported for the compounds. ments, and vapor tension data. Proton and 31P
Introduction The preparation and characterization of the new methyl(phosphin0) silanes and -germanes were carried out in connection with a program involving reactions of silicon-phosphorus and germanium-phosphorus compounds with boranes. In this study, both mono- and bisphosphino derivatives were needed. Because of our recent success in preparing unsubstituted phosphinosilanes and -germanes by direct phosphination of halosilanes and -germanes with LiL41(PH2)42-4 and the importance of establishing the generality of this phosphination method, this reaction was used to prepare the compounds of interest. Three new monophosphino compounds, (CH3)3GePH2, (CH3)2Ge(PH2)H, and (CH3)&(PH2)Hj and the previously reported (CH3)3SiPH25 have been prepared in high yields. Also, two new bisphosphino compounds, (CH&Si( PH2)2 and (CH3)2Ge(PH2)2, have been obtained.
Results Trimethylsilylphosphine and (CH3)3GePH2 are formed in high yield from reactions of (CH3)3SiCland (CH3)3GeCl, respectively, with triglyme solutions of LiAI(PH2)4 (eq I). Similarly, reactions of (CH&SiC12 4(CH3)3MC1
+ LiAI(PH2)4+ LiCl
+ AICh -I-4(CH3)3MPH2 (1)
and (CH3)2GeC12with LiA1(PH2)4yield the bisphosphino compounds, (CH3)2Si(PH2)2and (CH3)zGe(PH2)2 (eq 2). I n every reaction, formation of the 2(CH3)2MC12
+ LiAl(PW2)a -+
LiCl 2(CHa)zM(PHn)2
+ A1Ch + (M
=
Si or Ge)
(2)
desired product is accompanied by small quantities of the reduced halide and varying quantities of PH3. Reduction of the halosilane or -germane concomitant with phosphination is not unexpected since the LiA1(PHJ4 solutions invariably contained a small quantity (
