Isolation of New Disilanylene-bridged Bis（cyclopentadienyl）tetracarbonyldiiron Complexes and Molecular Structure of [η^5, η^5-C5H4SiMe（SiMePh2）C5H4]Fe2（CO）2（μ-CO）2

1,2-Diphenyl-1,2-dimethyldisilanylene-bridged bis-cyclopentadienyl complex[η~5,η~5-C_5H_4PhMeSiSiMePh-C_5H_4]Fe_2(CO)_2(μ-CO)_2(1)was synthesized by a modified procedure,from which the trans-isomer 1b that was pre-viously difficult to obtain has been isolated for the first time.More interestingly,two new regio-isomers[η~5,η~5C_5H_4SiMe(SiMePh_2)C_5H_4]Fe_2(CO)_2(μ-CO)_2(2)and [η~5,η~5-C_5H_4Me_2SiSiPh_2C_5H_4]Fe_2(CO)_2(μ-CO)_2(3)were occa-sionally obtained during above process,the novel structures of which opened up new options for further study ofthis type of Si—Si bond-containing transition metal complexes.The molecular structure of 2 has been determinedby the X-ray diffraction method.     

Gold(I) as an Artificial Cyclase: Short Stereodivergent Syntheses of (−)‐Epiglobulol and (−)‐4β,7α‐ and (−)‐4α,7α‐Aromadendranediols

Three natural aromadendrane sesquiterpenes, (?)‐epiglobulol, (?)‐4β,7α‐aromadendranediol, and (?)‐4α,7α‐aromadendranediol, have been synthesized in only seven steps in 12, 15, and 17 % overall yields, respectively, from (E,E)‐farnesol by a stereodivergent gold(I)‐catalyzed cascade reaction which forms the tricyclic aromadendrane core in a single step. These are the shortest total syntheses of these natural compounds.     

[(η5‐C5R5)TiCl2(η5‐C5H4SiMe2)]2O·nCH2Cl2

The first title metallocene, 1,3‐bis(dichlorotitanocene)‐1,1,3,3‐tetramethyldisiloxane dichloromethane solvate, [(η⁵‐C₅H₅)­TiCl₂­(η⁵‐C₅H₄­Si­Me₂)]₂O·­CH₂Cl₂, (I), crystallizes in space group P2₁/c. Compound (I) represents the first crystal structure of a bimetallic siloxy‐bridged titanocene. The geometric parameters of (I) are similar to those of the parent titanocene; however, the disiloxane substituents adopt an unexpected eclipsed conformation. The second title metallocene, 1,3‐bis­[(penta­methyl­cyclo­penta­dienyl)­(cyclo­penta­dien­yl)­titanium dichloride]‐1,1,3,3‐tetra­methyl­disiloxane, [(η⁵‐C₅‐Me₅)­TiCl₂­(η⁵‐C₅H₄­Si­Me₂)]₂O, (II), represents the second crystal structure of a bimetallic siloxy‐bridged titanocene and crystallizes in the space group P2₁/n. Compound (I) possesses non‐crystallographic twofold molecular symmetry and both metal centers adopt pseudo‐tetrahedral geometries. The geometric parameters of (II) are similar to those of the mixed titanocene Cp*CpTiCl₂ (Cp* = C₅Me₅) and the disiloxane substituents adopt a staggered conformation.     

Reaction of (η5‐C5H5)Fe(CO)2I with Anionic Bidentate Phosphine Ligands PPh2(o‐C6H4NHLi) or PPh2(o‐C6H4OLi)

The o‐substituted hybrid phenylphosphines, PPh₂(o‐C₆H₄NH₂) and PPh₂(o‐C₆H₄OH), could be deprotonated with LDA or n‐BuLi to yield PPh₂(o‐C₆H₄NHLi) and PPh₂(o‐C₆H₄OLi), respectively. When added to a solution of (η⁵‐C₅H₅)Fe(CO)₂I at room temperature, these two lithiated reagents produce a chelated neutral complex 1 (η⁵‐C₅H₅)Fe(CO)[C(O)NH(o‐C₆H₄)PPh₂‐C,P‐η²] for the former and mainly a zwitterionic complex 2 , (η⁵‐C₅H₅)Fe⁺(CO)₂[PPh₂(o‐C₆H₄O^?)] for the latter. Complex 1 could easily be protonated and then decarbonylated to give 4 [(η⁵‐C₅H₅)Fe(CO){NH₂(o‐C₆H₄)PPh₂‐N,P‐η²}⁺]. Complexes 1 and 4‐I have been crystallographically characterized with X‐ray diffraction.     

Synthesen und Charakteristika von Heterobimetallorganika des Siliciums mit dem 2‐(Dimethylaminomethyl)ferrocenyl‐Liganden FcN (η5‐C5H5)Fe[η5‐C5H3(CH2NMe2)]—

Syntheses and characteristics of the heterobimetalorganics of the silicon with the 2‐(dimethylaminomethyl)ferrocenyl ligand FcN (η⁵‐C₅H₅)Fe[η⁵‐C₅H₃(CH₂NMe₂)]^— The heterobimetallic lithiumorganyl [2‐(dimethylaminomethyl)ferrocenyl] lithium, LiFcN, reacts with silicon(IV)‐chlorid, SiCl₄, under the formation of heterobimetallic silicon(IV) organyl [(FcN)₃SiCl] ( 1 ). The heterobimetallic organosilanol [(FcN)₃SiOH] ( 2 ) is formed at hydrolysis of 1 . A detailed characterization of the defined compounds 1 and 2 was carried out by NMR‐ rsp. mass‐spectrometry and by crystal X‐ray analysis of 2 .     

On the Reactivity of (−)‐(R)‐Carvone and (−)‐4aα,7α,7aβ‐Nepetalactone: Synthesis of New Heterocycles

The 1,3‐dipolar cycloaddition of 4‐chlorobenzonitrile oxide to the unsaturated system of (?)‐(R)‐carvone occurred exclusively at C(8) to give a new isoxazoline derivative. This derivative reacts with NH₂OH to yield a new heterocycle, observed for the first time. On the other hand, the addition of 4‐chlorobenzonitrile oxide to the unsaturated lactone (?)‐4aα,7α,7aβ‐nepetalactone gave, in a good yield, also a new heterocycle, again obtained for the first time. The terpenoid (?)‐(R)‐carvone and iridoid (?)‐4aα,7α,7aβ‐nepetalactone were isolated from Moroccan species Mentha viridis (L.) and Nepeta tuberosa (L.), respectively. The new heterocycles obtained were identified by combination of chromatographic and spectroscopic methods.     

Reactions of Cyclohexyl Isocyanide with η5‐Substituted Cyclo‐pentadienyl MoMo Triply Bonded Complexes. Crystal Structure of [Mo(CO)2(η5‐C5H4CO2CH3)]2(μ‐η2‐CNC6H11)

Reactions of one or two equiv. of cyclohexyl isocyanide in THF at room temperature with Mo?Mo triply bonded complexes [Mo(CO)₂(η⁵‐C₅H₄R)]₂ (R=COCH₃, CO₂CH₃) gave the isocyanide coordinated Mo? Mo singly bonded complexes with functionally substituted cyclopentadienyl ligands, [Mo(CO)₂(η⁵‐C₅H₄R)]₂(μ‐η²‐CNC₆H₁₁) ( 1a , R=COCH₃; 1b , R=CO₂CH₃) and [Mo(CO)₂(η⁵‐C₅H₄R)(CNC₆H₁₁)]₂ ( 2a , R=COCH₃; 2b , R=CO₂CH₃), respectively. Complexes 1a , 1b and 2a , 2b could be more conveniently prepared by thermal decarbonylation of Mo? Mo singly bonded complexes [Mo(CO)₃(η⁵‐C₅H₄R)]₂ (R=COCH₃, CO₂CH₃) in toluene at reflux, followed by treatment of the resulting Mo?Mo triply bonded complexes [Mo(CO)₂(η⁵‐C₅H₄R)]₂ (R=COCH₃, CO₂CH₃) in situ with cyclohexyl isocyanide. While 1a , 1b and 2a , 2b were characterized by elemental analysis and spectroscopy, 1b was further characterized by X‐ray crystallography.     

Modeling η5‐C5Me4SiMe3 with η3‐C3H5 for DFT study of a tetranuclear yttrium polyhydrido complex [(η5‐C5Me4SiMe3)YH2]4

π‐Allyl (η³‐C₃H₅), a four‐electron donor, was used as a ligand model to replace η⁵‐C₅Me₄SiMe₃ in DFT calculations on the tetranuclear yttrium polyhydrido complex (η⁵‐C₅Me₄SiMe₃)₄Y₄H₈ containing a Y₄H₈ tetrahedral core structure, which may separate the four π‐allyl groups and hence suppress the allyl ligand coupling during the computation. In terms of the calculated core geometry, isomerization energy barrier, charge population, and frontier orbital features of the complex, the η³‐C₃H₅ ligand model is comparable to η⁵‐C₅H₅. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

Syntheses and Anti—inflammatory Actiobn of （η—C5H5）2Ti （Cin）2 and （η—C5H5）2Ti（Tzea）2

Two new Complexes(Cp)2Ti(Cin)2and (CP2)Ti(Tzea)2(CP=Cyclopentadienyl η^5-C5H5)have been synthesized in THF by the reaction of HCin(Cincofen,2-phenylquinoline-4-carboxylic acid)or HTzea(5-phenyltetrazolyl-2-ethanoic acid)with(Cp)2TiCl2,and characterized by elemental analyses,IR,1H NMR and 13C NMR,UV spectra,molar conductivity,TGDTA.In the complexes the carboxyl groups are coordinated to Ti(IV)in a monodentate manner,The inhibitory actions of the complexes on mice ear tumefaction caused by croton oil and the rat foot granulation growth produced by cotton wool are higher than those of the corresponding ligands HCin,HTzea and [(Cp)2TiCl2],while their toxicities are lower than those of the free ligands.ηη