TRANSITION-METAL-SUBSTITUTED DIPHOSPHENES .34. STUDIES ON THE REACTIVITY OF METALLODIPHOSPHENES (ETA(5)-C5R5)(CO)2M-P=P-MES(ASTERISK) OF IRON AND RUTHENIUM TOWARD HEXAFLUOROACETONE - X-RAY STRUCTURE ANALYSES OF (ETA(5)-C5ME5)(CO)M-P(=PMES-ASTERISK)OC(CF3)2C(O) (M=FE, RU), (ETA(5)-1,2,4-IPR3C5H2)(CO)RU-P(=PMES-ASTERISK)OC(CF3)2C(O), AND (ETA(5)-C5ME5)(CO)2FE-P-P(MES-ASTERISK)OC(CF3)2

Metallodiphosphenes (eta5-C5R5) (CO)2M-P=P-Mes* (C5R5 = C5Me5, C5Me4Et, 1,2,4-iPr3CrH2, 1,3-tBu2C5H3,1,3-(Me3Si)2C5H3; M = Fe,Ru) undergo reaction with anhydrous hexafluoroacetone to afford either the five-membered metallaheterocycles (eta5-C5R5)(CO)M-P(=PMes*)OC-(CF3)2C(O) or metalated 1-oxa-2,3-diphosphetanes (eta5-C5R5)(CO)2M-P-P(Mes*)OC(CF3)2. It is demonstrated that the l-oxa-2,3-diphosphetanes result from an intramolecular rearrangement of the metallaheterocycles. The course of the reaction and the nature of the products is largely influenced by the basicity of the cyclopentadienylmetal fragment. The molecular structures of (eta5-C5Me5) (CO)Fe-P(=PMes*)OC(CF3)2C(O) (9a) (P2(1)/c, a = 21.809(4) angstrom, b = 10.066(2) angstrom, c = 16.250(3) angstrom, beta = 95.87(1)-degrees, (eta5-C5Me5)(CO)Ru-P=P(Mes*)OC(CF3)2C(O) (10a) (P2(1)/c, a = 22.308(8) angstrom, b = 10.174(4) angstrom, c = 16.014(10) angstrom, beta = 96.62(4)-degrees), (eta5-1,2,4-iPr3C6H2)(CO)Ru-P-(=PMes*)OC(CF3)2C(O) (10c) (P1BAR, a = 9.416(5) angstrom, b = 9.784(6) angstrom, c = 24.40(2) angstrom, alpha = 92.74(5)-degrees, beta = 98.42(5)-degrees, gamma = 117.37(4)-degrees), and (eta5-C5Me5)(CO)2Fe-P-P(Mes*)OC(CF3)2 (11a) (C2/c, a = 46.79(3) angstrom, b = 9.316(5) angstrom, c = 16.611(5) angstrom, beta = 101.52(3)-degrees) were determined by single-crystal X-ray analyses.