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The purpose of this study was to identify and correlate the microstructural and luminescence properties of europiumdoped Y 2 O 3 (Y 1-x Eu x ) 2 O 3 thin films deposited by metallorganic chemical vapor deposition (MOCVD), as a function of deposition time and temperature. The influence of deposition parameters on the crystallite size and microstructural morphology were examined, as well as the influence of these parameters on the photoluminescence emission spectra. (Y 1-x -Eu x ) 2 O 3 thin films were deposited onto (111) silicon and (001) sapphire substrates by MOCVD. The films were grown by reacting yttrium and europium tris(2,2,6,6-tetramethyl-3,5heptanedionate) precursors with an oxygen atmosphere at low pressures (5 torr (1.7 ؋ 10 3 Pa)) and low substrate temperatures (500°-700°C). The films deposited at 500°C were smooth and composed of nanocrystalline regions of cubic Y 2 O 3 , grown in a textured [100] or [110] orientation to the substrate surface. Films deposited at 600°C developed, with increasing deposition time, from a flat, nanocrystalline morphology into a platelike growth morphology with [111] orientation. Monoclinic (Y 1-x -Eu x ) 2 O 3 was observed in the photoluminescence emission spectra for all deposition temperatures. The increase in photoluminescence emission intensity with increasing postdeposition annealing temperature was attributed to the surface/grain boundary area-reduction effect.

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Reactions of M(allyl) 3 [M ) Rh, Ir] with a variety of donor ligands have been investigated. While both complexes are unreactive toward "hard" N-and O-donor ligands, "soft" ligands such as tolylisothiocyanate, tertiary phosphines, CO, and aryl isocyanides are readily added. Whereas ligand additions to Rh(allyl) 3 are often accompanied by reduction of the Rh(III) center, analogous reactions with Ir(allyl) 3 afford stable trivalent products containing σ-allyl ligands. The molecular structures of several derivatives are presented, including Ir(σ-allyl)-(π-allyl) 2 (PPh 3 ), Ir(σ-allyl) 2 (π-allyl)(PMe 3 ) 2 , and Ir(σ-allyl) 3 (CtN-2,6-Me 2 C 6 H 3 ) 3 .

Synthesis and Characterization of Bis( diphenylphosphido) bis( pentamethylcyclopentadieny1)-thorium ( I V ) , [ (q5-C5( CH&],Th( PPh,),The first diorganophosphido actinide complexes Cp*2Th(PRZ), (Cp* = T~-C~( C H~)~, R = Ph, Cy, Et) have been prepared by reaction of Cp*zThC12 with LiPR2. These complexes have been characterized spectroscopically, and Cp*zTh(PPh2)z has been structurally characterized by a complete single-crystal X-ray diffraction study. This compound crystallizes in the space group P2,/c with a = 35.071 (8) A, b = 15.203 (6) A, c = 21.840 (11) A, ( 3 = 92.97 ( 2 ) O , at T = -95 "C, and V = 11629.3 A3 and 2 = 12 (Mo Ka, radiation, X = 0.709 30 A). The structure refined to RF = 0.08 and RwF = 0.07. There are three crystallographically independent molecules in the asymmetric unit. All three molecules exhibit pseudotetrahedral geometry about the thorium atom with the pentamethylcyclopentadienyl ligands and two diphenylphosphido groups occupying the four coordination sites. While the angles about the phosphorus atoms are far from the tetrahedral, there is no evidence for significant Th-P multiple bonding. The average Th-P distance is 2.87 (2) A. (1) (a) Bruno, J. W.; Huffman, J. C.; Green, M. A.; Caulton, K. G. J . Am. Chem. SOC. 1984,106,8310. (b) Casey, C. P.; Jordan, R. F.; Rheingold, A. L. Ibid. 1983,105,665. (c) Wrobleski, D. A.; Day, C. S.; Goodman, B. A.; Rauchfuss, T. B. Ibid. 1984,106,5464. (d) Rosenburg, S.; Whittle, R. R.; Geoffroy, G. L. Ibid. 1984, 106,5934. (e) Breen, M. J.; Shulman, P. M.; Geoffroy, G. L.; Rheingold, A. L.; Fultz, W. C. Organometallics 1984, 3, 782. ( f ) Regragui, R.; Dixneuf, P. H.; Taylor, N. J.; Carty, A. J. Ibid. 1984,3,814. (9) Chandler, D. J.; Jones, R. A.; Stuart, A. L.; Wright, T. C.

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