Papers by Shin-guang Shyu
Organometallics, 1998
The heterobimetallic phosphido-bridged complexes CpMo(CO) 2 (µ-PPh 2 )Fe(CO) 4 (1) and CpMo(CO) 3... more The heterobimetallic phosphido-bridged complexes CpMo(CO) 2 (µ-PPh 2 )Fe(CO) 4 (1) and CpMo(CO) 3 (µ-PPh 2 )Fe(CO) 4 (2) were prepared by the reaction of CpMo(CO) 3 PPh 2 with Fe 2 -(CO) 9 . The reaction between 1 and Lewis bases L (L ) P(OMe) 3 , PPh 2 H, PPh 3 ) at ambient temperatures produced CpMo(CO) 2 (µ-PPh 2 )Fe(CO) 3 (L) (3) with L regiospecifically coordinated to Fe. However, 2 did not react with L under similar conditions.
Journal of Organometallic Chemistry, 1995
Bimetallic phosphido-bridged complexes CpW(CO)3(/z-PPh2)W(CO) 5 (1) and CpW(CO)2(/x-PPh2)W(CO) 5 ... more Bimetallic phosphido-bridged complexes CpW(CO)3(/z-PPh2)W(CO) 5 (1) and CpW(CO)2(/x-PPh2)W(CO) 5 (2) were prepared by the reaction of CpW(CO)3PPh 2 with W(CO)sTHF. The structures of 1 and 2 were determined by single X-ra.y diffraction. Crystal data for 1: CgsHa5OsPW2, space group, P21/n with a = 9.6234 (18) .&, b = 12.4514 (20) A, c = 20.750 (4) A,/3 = 98.445 (14) °, V= 2459.4 (7) A 3, Z = 4. The structure was refined to R = 0.031 and Rs, = 0.035. Crystal data for 2: C24H15OTPW2, space o 3 group, P21/n with a = 14.4801 (11) A, b = 11.6628 (12) A, c = 14.732 (3) A, /3 = 97.893 (11), F= 2464.3 (6) A, Z = 4. The structure was refined to R = 0.054 and R w = 0.050. The long distance between W and W (4.5096 (11) ,&) in 1 indicates that no metal-metal bond exists in the complex. The W-W distance was 3.1942 (12) ,~ in 2, indicative of a W-W bond. Substitution reactions between 2 and Lewis bases L (L = PPh3, PEt3, P(OMe) 3) produced CpW(CO)2(Iz-PPh2)W(CO)a(L) (3) with L regiospecifically and stereospecifically coordinating to the W(CO) 4 moiety trans to the phosphido bridge. The structure of CpW(CO)2(/z-PPh2)W(CO)a{P(OMe) 3} (3a) was determined by single-crystal X-ray diffraction. Crystal data for 3a: C26H2409P2W2, space group, P2~ with a = 9.2231 (16) ,&, b = 15.868 (3) A, c = 10.745 (3) ,&, /3 = 110.282 (18) °, V= 1475.1 (5) o 3
ChemInform, 2000
Rh(PPh 3 ) 3 Cl was immobilized on a (OEt) 3 Si(CH 2 ) 3 PPh 2 modified MCM-41 to form a stable h... more Rh(PPh 3 ) 3 Cl was immobilized on a (OEt) 3 Si(CH 2 ) 3 PPh 2 modified MCM-41 to form a stable hydrogenation catalyst. The morphology of the catalyst was characterized by X-ray absorption spectroscopy. The EXAFS results indicates that the immobilized Rh catalyst has an average Rh-O s (O s is a surface oxygen) and Rh-Si bond distances of 2.01 Å and 3.15 Å, respectively, suggesting that monomeric Rh complex bonds to the MCM-41 surface. However, the structure of the immobilized Rh complex is not retained after hydrogenation of cyclohexene at 75 • C under 150 psi of H 2 . After the reaction, the presence of Rh-Rh contribution with average bond distance of 2.68 Å and coordination number of 1.3 and the missing contribution with bond distance of 3.85 Å suggest that the reaction induces the coalescence of Rh complex to form dimeric Rh species. However, formation of trace amount of Rh metal clusters cannot be ruled out because rather small characteristic peak for the missing Rh-Rh shell may be covered by noise.
Carbonyls' 2p orbital populations, [2p], in W(CO) 5 L {L = PPh 3 , PPh 2 Me, PPhMe 2 } have been ... more Carbonyls' 2p orbital populations, [2p], in W(CO) 5 L {L = PPh 3 , PPh 2 Me, PPhMe 2 } have been determined by NMR spin-lattice relaxation techniques. Experimental values of axial [2p], compared with those reported for PMe 3 and P(OMe) 3 , reveal that PMe 3 is a slightly better p-acid than PPh 3 . Through space interactions between carbonyl and phenyl groups are insignificant since values of [2p] do not vary significantly in the series of phosphines, going from PMe 3 to PPh 3 . Natural bond orbital (NBO) studies indicate that p-accepting capabilities for these phosphines are primarily governed by the nature of P-C anti-bonding, s * P-C . Compared with PPh 3 , the better p-accepting s * P-C , as well as the better s-donating lone-pair LP(P), in PMe 3 can both be explained by the higher extents of rehybridization of the coordinated phosphorus atom. Based on this rehybridization argument, the NBO predicted order of increasing p-acidic strengths PPh 3 < PPh 2 Me < PPhMe 2 < PMe 3 , which cannot be clearly distinguished by NMR experiments, is ascribed to the same NBO trend of s-donating capabilities in a synergistic manner. Effects of coordination on P-Y (Y = C, O, F) bonding strengths in phosphines (or phosphites) are depending on two conflicting effects: rehybridization of LP(P) and the hyperconjugative-like d p ® s* P-Y back-donation.
Inorganica Chimica Acta, 2002
Fe2(CO)6(μ-S2) was used as a single source precursor in an attempt to produce FeS film via MOCVD.... more Fe2(CO)6(μ-S2) was used as a single source precursor in an attempt to produce FeS film via MOCVD. Pyrolysis of Fe2(CO)6(μ-S2) at temperature below 500°C produced Fe1−xS or Fe7S8 powder as indicated by its powder X-ray spectra. At 750°C, polycrystalline FeS powder was obtained. In film deposition, polycrystalline Fe1−xS or Fe7S8 films were obtained on Si(100) and Ag–Si(100) substrates below 500°C.
Chemistry of Materials, 1998
... (23) Fogg, AM; Dunn, JS; O'Hare, D. Chem. Mater.1998, 10, 354. (24) Evans, JSO; Barlow, ... more ... (23) Fogg, AM; Dunn, JS; O'Hare, D. Chem. Mater.1998, 10, 354. (24) Evans, JSO; Barlow, S.; Wong, H.-V.; O'Hare, D. Adv. Mater.1995, 7, 163. ... Leslie Poudret, Timothy J. Prior, Laura J. McIntyre and Andrew M. Fogg. Chemistry of Materials 2008 20 (24), 7447-7453. ...
Organometallics, 1994
T h e heterobimetallic phosphido-bridged complex CpW(C0)2(p-PPh2)Mo(C0)5 (1) was prepared by the ... more T h e heterobimetallic phosphido-bridged complex CpW(C0)2(p-PPh2)Mo(C0)5 (1) was prepared by the reaction of CpW(C0)3PPh2 with M o ( C~)~( C~H~) .
Organometallics, 2007
ABSTRACT
Organometallics, 2006
Reactions of CpW(CO) 2 (µ-PPh 2 )Mo(CO) 5 (1) with alkyl disulfides RSSR (R ) Me, Et, Pr, Bu n ) ... more Reactions of CpW(CO) 2 (µ-PPh 2 )Mo(CO) 5 (1) with alkyl disulfides RSSR (R ) Me, Et, Pr, Bu n ) in refluxing dichloromethane yielded the series of new mixed-metal and mixed-ligand bridged compounds CpW(CO)(µ-SR) 2 (µ-PPh 2 )Mo(CO) 3 (R ) Me (4a), Et (4b), Pr (4c), Bu n (4d)), CpW(CO)(µ-SR) 2 (µ-PPh 2 )Mo(CO)(SR) 2 (R ) Me (5a), Et (5b), Pr (5c), Bu n (5d)), and CpW(CO)(µ-SR) 2 (µ-PPh 2 )Mo(CO) 2 -(PPh 2 SR) (R ) Me (6a), Et (6b), Pr (6c), Bu n (6d)). All except 6c were characterized by single-crystal X-ray diffraction analysis. Formation of compounds 4-6 indicates a general procedure for cleavage of the S-S bonds of alkyl disulfides under mild conditions. Molecular structures of compounds 6a,b,d reveal the first transformation of the bridging PPh 2 ligand of 1 to give the hybrid ligands Ph 2 PSR (R ) Me, Et, Bu n ) via P-S bond formation. The average Mo-W bond distance (2.8255 Å) in the 34e dimers (4a-d, 6a,b,d) is shorter than that in the 32e dimers (5a-d), 2.8494 Å. This appears quite unusual, according to the 18e rule. DFT calculations have been performed to investigate this unusual observation.
Organometallics, 2003
ABSTRACT
Organometallics, 1995
... Shin-Guang Shyu,*$+ Shu-Min Hsiao,+>f Kuan-Jiuh Lin,' and H.-M Gauf ... Synthesis, Sp... more ... Shin-Guang Shyu,*$+ Shu-Min Hsiao,+>f Kuan-Jiuh Lin,' and H.-M Gauf ... Synthesis, SpectroscopicCharacterization, and Molecular Structures of 4 and 5. Complex 4 was first prepared by the reaction between Li2[CpW(C0)2-PPhzI and Fe(C0hB1-2.~ We synthesized the W-Fe ...
Organometallics, 1995
The metal-metal bond in CpFe(CO)@-PPh2)@-CO)W(CO)4 (1) was cleaved by Lewis bases L (L = PMe3, PP... more The metal-metal bond in CpFe(CO)@-PPh2)@-CO)W(CO)4 (1) was cleaved by Lewis bases L (L = PMe3, PPh2H, CH3CN) to produce CpFe(CO)z@-PPhz)W(C0)4L (31, in which L regioselectively and stereospecifically coordinates to W cis to the phosphido bridge. When L was PPh3 or P(OMe)3, both cis and trans isomers were obtained. When CpFe(CO)z@-PPh2)W(C0)5 (2) reacted with PMe3, one CO ligand on Fe was replaced by PMe3 to produce CpFe(CO)(PMe3)@-PPh2)W(C0)5 (4). Structures of CpFe(C0)2@-PPhz)W(C0)4(PMe3) (3bcis), CpFe(CO)&-PPh2)W(CO)4(P(OMe)3) (3c-trans), and 4 were determined by single-crystal X-ray diffraction studies. Crystal data for 3b-cis: C26H#eO&W, space group P21/c, a = 9.832(4) A, b = 16.027(3) A, c = 18.264(4) A, p = 103.87(2)", V = 2794(1) Hi3, and 2 = 4. The structure was refined to R = 0.026 and R, = 0.031. Crystal data for 3c-trans: C26H24-FeOsPzW, space group Pna21, a = 22.779(4) A, b = 11.669(2) A, c = 10.580(1) A, V = 2812.7(7) Hi3, and 2 = 4. The structure was refined to R = 0.023 and R, = 0.026. Crystal data for 4: 114.10(1)', V = 2741.8(7) A3, and 2 = 4. The structure was refined to R = 0.021 and R, = C26&4FeO6P2W, space group P21/n, a = 15.768(2) A, b = 10.7111(2) A, C = 17.784(2) A, p = 0.024. W irradiation of 3 removed one CO to form CpFe(CO)@-PPh2)W(CO)qL (5). The structure of CpFe(CO)(p-PPh2)W(C0)4(PPh3) (5e-trans) was determined by a single-crystal X-ray diffraction study. Crystal data for Be-trans: C~O H~O F~O~P~W , space grou P21/c, a = 18.6696(8) A, b = 12.6178(6) A, c = 18.195(1) A, p = 118.220(5)', V = 3777.5(3) i3, and 2 = 4. The structure was refined to R = 0.028 and R, = 0.030.
Organometallics, 2004
ABSTRACT
Journal of the American Ceramic Society, 2004
Journal of Catalysis, 2009
Journal of Catalysis, 2004
Titanium oxide was grafted on the surface of MCM-41 to produce a mesoporous TiO2/MCM-41 composite... more Titanium oxide was grafted on the surface of MCM-41 to produce a mesoporous TiO2/MCM-41 composite to serve as a catalyst support. Vanadia was grafted on this titania support to produce V2O5/TiO2/MCM-41 and catalytic oxidation of ethanol by air was used as a probe reaction to study the influence of the support on the catalytic behavior of this catalyst. Catalyst V2O5/TiO2/MCM-41
European Journal of Inorganic Chemistry, 2002
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Papers by Shin-guang Shyu