ALTERNATIVE LIGANDS .34. SYNTHESIS AND LI GATING PROPERTIES OF P-DONOR SN-ACCEPTOR LIGANDS/

Donor/acceptor ligands of the type Me(2)PCH(R)OSnMe(3) [R = H(5), Me ( 6), Ph (7)] have been prepared by reaction of Me(3)SnCl with HOCH(R)PM e(2) and insertion of RCHO into the SnP bond of the stannyl phosphane Me(3)SnPMe(2), respectively. The new ligands, including the ethylen-br idged analogue Me(2)PCH(2)CH(2)SnMe(3) (1), were used for the synthesi s of the pentacarbonyl chromium complexes Cr(CO)(5)Me(2)PCH(2)CH(2)SnM e(3) (11) and Cr(CO)(5)Me(2)PCH(R)OSnMe(3) [R = H (12), Me (13), Ph (1 4)]. In addition, different routes were investigated to prepare the li gand 5-7 in the coordination sphere of the Cr(CO)(5)-fragment. For thi s purpose the ligands Me(2)PCH(R)OH [R = H (5'), Me (6'), Ph (7)] and the complexes Cr(CO)(5)Me(2)PCH(R)OH [R = H (15), Me (16), Ph (17)], C r(CO)(5)Me(2)PSnMe(3) (18) and Cr(CO)(5)PMe(2)H (19) were prepared. Su itable pathways were found in the two-step process of 15-17 with (n)Bu Li to give Cr(CO)(5)Me(2)PCH(R)OLi, followed by reaction with Me(3)SnC l, and the condensation of 15-17 with Me(3)SnCl using NEt(3) as base. Besides ligands 5-7 were transformed to the corresponding phosphane su lfides Me(2)P(S)CH(R)OSnMe(3) [R = H (8), Me (9), Ph (10)] by reaction with sulfur. Analytical (C, H) and spectroscopic investigations (NMR, IR, MS, Mossbauer), in addition to an X-ray diffraction study of 7, w ere performed to characterize the new compounds and to deduce informat ion on structure and bonding.