Komplexchemie P-reicher Phosphane und Silylphosphane. IX. Chromcarbonyl-Komplexe silyliert-alkylierter Triphosphane

Transition Metal Complexes of P-rich Phosphanes and Silylphosphanes. IX. Chromium Carbonyl Complexes of Silylated and Alkylated Triphosphanes . To investigate the influence of the substituents on the formation of complex compounds of triphosphanes several derivatives were synthesized which differ in the number and position of the Me₃Si and tBu groups at the primary P atoms and which bear H, Me₃Si, Me of Ph groups at the secondary P atom. These are [(Me₃Si)₂P]₂PH 1 , [(Me₃Si)₂P]₂P(SiMe₃) 2 , (MeSi)(tBu)P? P(H)? P(SiMe₃)₂ 3 , (tBu)₂P? P(SiMe₃)? P(tBu)(SiMe₃) 4 , [(tBu)₂P]₂PH 5 , [(tBu)₂P]₂P(SiMe₃) 6 , [(Me₃Si)₂P]₂PMe 7 , [(Me₃Si)₂P]₂P(Ph) 8 . When reacting these compounds with Cr(CO)₅THF 9 the following groups of products are obtained: Compounds 1, 3, 5, 7 and 8 at first yield products of group A and react on to B; however this second step is not important for 7 and even less for 8. Compounds 2, 4 and 6 bearing a Me₃Si group at the secondary P atom yield C, but their reactivity is strongly reduced and they tend to give byproducts. Using a molar ratio of triphosphane: Cr(CO),THF 9 = 1 : 2 A forms also D in addition to B . Further reactions may occur from A and B , e. g., at 50°C 1 b ( B ) decomposes to 1 and lc (E). With Cr(CO),NBD the compounds 1, 5, 7 and 8 form products of groups E and F. At ?18°C 7 forms 7c (E) which rearranges at 75°C to 7d (F). The compounds are characterized by ³¹P and ¹H NMR spectra, mass spectra and elemental analysis.