REACTIONS OF TRANSITION-METAL SIGMA-ACETYLIDES .11. CYCLO-ADDITION REACTIONS WITH 1,1-DICYANO-2,2-BIS(TRIFLUOROMETHYL)ETHENE - X-RAY STRUCTURES OF W(C=CPHC(CF3)2C(CN)2)(CO)3(ETA-C5H5), MN(C=CPHC(CF3)2C(CN)2)(CO)3(DPPE), AND FE(C=CPHC(CF3)2C(CN)2)(CO)2(ETA-C5H5) AND OF A HYDRATION PRODUCT, W(NH=C(OH)C(CN)=CCPH=C(CF3)2)(CO)2(ETA-C5H5).H2O)