Addition of KN(R)Ph to írans-CPMeskPdCR')! (R = H, Me; R' = Ph, Me) results in the formation of the monomeric anilide complexes ircms-CPMeghPdCRONCRiPh in good yield. A single-crystal X-ray diffraction study of #rans-(PMe3)2Pd(Ph)N(H)Ph (1) reveals that it crystallizes in the space group PI with a = 8.423(3) Á, h = 10.768(4) Á, c = 12.565 Á, a = 68.81(3)°, ß -71.90(3)°, y = 87.65(3)°, V -1006.7(7) Á3, and Z = 2. There is no evidence for significant interaction between the N lone pair and the metal center, though a shortened N-C distance (1.32(2) Á) may indicate interaction between the N lone pair and the phenyl ring. Thermolysis of 1 at 90 °C in the solid state results in loss of PMes and formation of the dimeric complex [(PMe3)Pd(Ph)(w-NHPh)]2 (9), which was also characterized with a singlecrystal X-ray structure study. Compound 9 crystallizes in the space group PI with a = 6.805(1) Á, b = 12.186(2) Á, c = 18.943(3) Á, a -89.56(1)°, ß = 85.17(1)°, y = 87.67(1)°, V -1564.0(4) Á3, and Z = 2. The PMes groups are anti with respect to the Pd-Pd vector, while the phenyl groups of the anilides are anti with respect to the Pd2N2P2C2 coordination plane. In solution at 25 °C, 9 undergoes an isomerization equilibrium to form two new isomers. Spectroscopic data suggest that these two new isomers are consistent with syn PMes groups and syn anilide groups. Prolonged heating (110 °C, 12 h) of 9 results in reductive elimination of diphenylamine. 1991, 10, 2969.

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From the corresponding TpMo(CO) 2 (π-allyl) complexes, four symmetrically substituted TpMo(CO)(NO)(π-allyl) + complexes (π-allyl ) propenyl, 2-methylpropenyl, cyclohexenyl, and cyclooctenyl) were prepared and characterized by IR, by 1 H and 13 C NMR spectroscopy, and in one case by X-ray crystallography. The BF 4 -salts of the cationic nitrosyl complexes were unstable in solution; however, using the noncoordinating counterion [(3,5-(CF 3 ) 2 C 6 H 3 ) 4 B] -

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Cyclic and acyclic dicarbonyl[hydrotris(1-pyrazolyl)borato][η 3 -1-((tert-butyldimethylsilyl)oxy)allyl]molybdenum complexes and a variety of their 1-acetoxy and 1-alkoxy (RO ) MeO, i-PrO) analogues were prepared and characterized by IR and 1 H and 13 C NMR spectroscopy and, in the case of [TpMo(CO) 2 [η-(1,2,3)-(()-(1R,2S,3S)-1-methoxy-2-cyclohexen-1-yl], by X-ray crystallography. These complexes were prepared in moderate to excellent yields by the tert-butyldimethylsilyl chloride promoted oxidative addition of R,β-unsaturated aldehydes and acyclic and cyclic ketones to (DMF) 3 Mo(CO) 3 followed by ligand metathesis with potassium hydrotris(1-pyrazolyl)borate. The 1-tert-butyldimethylsiloxy-and the 1-methoxyand 1-isopropoxy-substituted acyclic complexes were formed solely as the syn isomer; however, the 1-acetoxy analogue underwent isomerization to a thermodynamic mixture of the syn and anti isomers in which the anti isomer predominated (3.7 : 1). The 1-((tertbutyldimethylsilyl)oxy)-3-alkyl-or 1-alkoxy-3-alkyl-disubstituted acyclic complexes were formed with syn-silyloxy/anti-alkyl or syn-alkoxy/anti-alkyl stereochemistry, while the disubstituted allyls bearing a 1-acetoxy substituent existed as mixtures of both possible syn/ anti isomers and the syn/syn and anti/anti isomers. The conformation and configuration of the isomers was confirmed through nOe studies on several complexes and by X-ray crystallography in the case of [TpMo(CO) 2 [η-(1,2,3)-(()-(1R,2S,3S)-1-methoxy-2-cyclohexen-1-yl].

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