Synthesis and structure of the first η3-1,2-diphosphaallyl complexes [(η5-C5H5)(CO)2M{η3-RPPC(SiMe3)2}] (M = Mo, R = tBu, Cy;: M = W, R = tBu) from [(η5-C5H5)(CO)2M=P=C(SiMe3)2] (M = Mo, W) and inversely polarized phosphaalkenes RP=C(NMe2)2 (R = tBu, Cy)

Reaction of [(eta(5)-C5H5)(CO)(2)M=P=C(SiMe3)(2)] [where M = Mo (2), W (5)] with the phosphaalkene tBuP=C(NMe2)(2) (1a) afforded the eta(3)-1,2-diphosphaallyl complexes [(eta(5)-C5H5)-(CO)(2)M(eta(3)-tBuPPC(SiMe3)(2)}], [where M = Mo (3a); M = W (6)]. Similarly, 2 and CyP=C(NMe2)(2) (1b; where Cy = cyclohexyl) gave rise to the formation of [(eta(5)-C5H5)(CO)(2)Mo-CyPPC(SiMe3)(2))] (3b) by a phosphinidene transfer process. Small amounts of [{eta(5) -C5H5)(CO)(2)Mo}(2)(eta(2):eta(2) -Cy3P5)] (4) were formed as a minor product. However, treatment of 2 and 5 with HP=C(NMe2)(2) (1c) yielded the complexes [(eta(5)-C5H5)(CO)(2)M{eta(2)-(Me3Si)(2)CH-P=P-C(NMe2)(2)}] [where M = Mo (9), W (10)]. The novel compounds 3a, 3b, 9 and 10 were characterized by means of spectroscopy (IR, H-1, C-13{H-1}, P-31{H-1} NMR, MS). Moreover, the molecular structures of 3a, 3b, 4, 6 and 10 were determined by X-ray diffraction analysis. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)