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Dimethyl)(phenylethynyl)silyl-substituted cyclopentadiene [C.sub.5][H.sub.5]Si[Me.sub.2][C.sub.2]Ph (1) was synthesized by the reaction of in situ generated [C.sub.5][H.sub.5]Si[Me.sub.2]Cl with Li[C.sub.2]Ph. Metallation of 1 with [sup.n]BuLi or KN[(Si[Me.sub.3]).sub.2] gave the corresponding Li (2) and K (3) salts. Transmetallation of 2 with transition metal halides MCl2 (M = Ti[Cl.sub.2], Fe, and Co) generated the corresponding early and late transition metal metallocenes (4, 5, and 6) with pendant alkynyl substituents. Compounds 4 and 6 are the first examples of bis alkyne appended Ti and Co metallocenes. Complexes 5 and 6 undergo alkyne dimerization in the presence of CpCo[(CO).sub.2] generating metallocenophanes 7 and 8 incorporating two metal atoms. Compounds 3, 4[Cl.sub.2], 6, and [8][OTf] have been characterized by single crystal X-ray structure analysis. Key words: cyclopentadiene, alkyne, titanium, cobalt, heterometallic, metallocenophane. Resume : On a realise la synthase du (dimethyl)(phenylethynyl)silylcyclopentadie;ne, [C.sub.5][H.sub.5]Si[Me.sub.2][C.sub.2]Ph (1) par reaction du chlorure de (dime;thyl)(phe;nyle;thynyl)silyle, [C.sub.5][H.sub.5]Si[Me.sub.2]Cl avec le Li[C.sub.2]Ph. La metallation du produit 1 avec [sup.n]BuLi ou le KN[(Si[Me.sub.3]).sub.3] conduit aux sels correspondants du lithium (2) ou du potassium (3). La transmetallation du produit 2 avec des halogeenures de metaux de transitions, M[Cl.sub.2] (M = Ti[Cl.sub.2], Fe et Co) conduit aux metallocenes correspondants (4, 5 et 6)de metaux de transition du debut et de la fin de cette serie portant des substituants alcynyles. Les composes 4 et 6 sont les premiers exemples de metallocenes du titane et du cobalt portant deux appendices bisalcyne. Les complexes 5 et 6, mis en presence de CpCo[(CO).sub.3], donnent lieu a une dimeerisation de l'alcyne qui conduit aux metallocenophanes 7 et 8 incorporant deux atomes metalliques. On a caracterise les composes 3, 4[Cl.sub.2,] 6 et [8][OTf] par diffraction des rayons-X par un cristal unique. Mots-cles: cyclopentadiene, alcyne, titane, cobalt, heteeromeetallique, metallocenophane. [Traduit par la Redaction], Introduction Cyclopentadienyl (Cp) ligands are one of the most common ligands used in organometallic chemistry as they form complexes with most of the transition metals. Various functional groups have been [...]

The solid-state structures and the physical, solution magnetic, solid-state magnetic, and spectroscopic (NMR and UV/vis) properties of a range of oxygen- and nitrogen-free dialkylmanganese(II) complexes are reported, and the solution reactivity of these complexes toward H2 and ZnEt2 is described. The compounds investigated are [{Mn(μ-CH2SiMe3)2}∞] (1), [{Mn(CH2CMe3)(μ-CH2CMe3)2}2{Mn(μ-CH2CMe3)2Mn}] (2), [Mn(CH2SiMe3)2(dmpe)] (3; dmpe = 1,2-bis(dimethylphosphino)ethane), [{Mn(CH2CMe3)2(μ-dmpe)}2] (4), [{Mn(CH2SiMe3)(μ-CH2SiMe3)}2(μ-dmpe)] (5), [{Mn(CH2CMe3)(μ-CH2CMe3)}2(μ-dmpe)] (6), [{Mn(CH2SiMe3)(μ-CH2SiMe3)}2(μ-dmpm)] (7; dmpm = bis(dimethylphosphino)methane), and [{Mn(CH2CMe3)(μ-CH2CMe3)}2(μ-dmpm)] (8). Syntheses for 1-4 have previously been reported, but the solid-state structures and most properties of 2-4 had not been described. Compounds 5 and 6, with a 1:2 dmpe/Mn ratio, were prepared by reaction of 3 and 4 with base-free 1 and 2, respectively. Compounds 7 and 8 were accessed by reaction of 1 and 2 with 0.5 equiv or more of dmpm per manganese atom. An X-ray structure of 2 revealed a tetrametallic structure with two terminal and six bridging alkyl groups. In the solid state, bisphosphine-coordinated 3-8 adopted three distinct structural types: (a) monometallic [LMnR2], (b) dimetallic [R2Mn(μ-L)2MnR2], and (c) dimetallic [{RMn(μ-R)}2(μ-L)] (L = dmpe, dmpm). Compound 3 exhibited particularly desirable properties for an ALD or CVD precursor, melting at 62-63 °C, subliming at 60 °C (5 mTorr), and showing negligible decomposition after 24 h at 120 °C. Comparison of variable-temperature solution and solid-state magnetic data provided insight into the solution structures of 2-8. Solution reactions of 1-8 with H2 yielded manganese metal, demonstrating the thermodynamic feasibility of the key reaction steps required for manganese(II) dialkyl complexes to serve, in combination with H2, as precursors for metal ALD or pulsed CVD. In contrast, the solution reactions of 1-8 with ZnEt2 yielded a zinc-manganese alloy with an approximate 1:1 Zn/Mn ratio. [ABSTRACT FROM AUTHOR]

The reaction of [Li(THF)4][(Mn{C(SiMe3)3})3(μ-Cl)4(THF)] (1) with K(allylTMS2) (allylTMS2= 1,3-C3H3(SiMe3)2) afforded [(η3-allylTMS2)Mn{C(SiMe3)3}{ClLi(THF)3}] (2). Attemptedsublimation of 2yielded [(η3-allylTMS2)Mn{C(SiMe3)3}(THF)] (3), indicating that 2extrudes LiCl at elevated temperatures.Additionally, LiClin 2was displaced by reaction with PMe3,quinuclidine, and dmap (dmap = 4-(dimethylamino)pyridine), providing[(η3-allylTMS2)Mn{C(SiMe3)3}(L)] (L = PMe3(4), quinuclidine(5), dmap (6)). Treatment of PMe3complex 4with BPh3yielded bright red [(allylTMS2)Mn{C(SiMe3)3}] (7)accompanied by a precipitate of Ph3B(PMe3).Mixed alkyl/π-allyl manganese(II) complexes 2–7are pyrophoric red solids with a high-spin d5configuration, and all were crystallographically characterized.In the solid-state structures, the allyl ligands in 2–6adopt a syn,synconfiguration, whereas in base-free 7, the allyl ligandhas a syn,anticonfiguration. Complexes 4, 5, and 7sublimed cleanly (5mTorr) at 70, 90, and 50 °C, respectively. Complex 4exhibited a particularly favorable combination of volatility andthermal stability, given that its appearance and powder X-ray diffractionpattern were unchanged after 24 h in a sealed flask at 100 °C.Compounds 2–7are the first high-spind5mixed alkyl/allyl complexes, and 7is thefirst room-temperature-stable example of a mononuclear transition-metalcomplex bearing only alkyl and allyl ligands. [ABSTRACT FROM AUTHOR]

The rearrangement of the acyloxy carbene, XCOOC:H, to the carbene XC:OCHO, via a shift of the carbonyl oxygen from one carbon to another, has been investigated by the DFT method using the B3LYP potential. Different substituents taken for the study are X=H (S0 and T1), CH3, B, F and Cl. It has been found that the reaction proceeds in two steps and the intermediate is a four-centered structure, which is the formally neutral equivalent of the 6π-electron cyclobutadienyl dianion. The activation energy for the first step is not affected very much with change in the substituent (X), but the second step is very sensitive to the nature of the substituent. This has been explained on the basis of the charge transfer effects. The thermodynamic and kinetic parameters for the reaction have also been discussed. [Copyright &y& Elsevier]

The molecular structures and stabilities of some of the lowest states of some C3H4 isomers have been calculated by two density functionals and the results compared with experimental data as well as our previous MNDO calculations. Results show that the B3LYP functional is the best suited for these studies. The MNDO results are also reasonably good in comparison with experiment. [Copyright &y& Elsevier]

The synthesis of novel Co(I) polymers featuring CpCo(C(4)R(4)) units are reported. The cyclopentadienyl ring on the CpCo(C(4)R(4)) unit has been functionalized with acrylate or methacrylate groups. Acrylate derivatives of these compounds were found to polymerize giving rise to the first example of polymers containing neutral, 18 e cobaltoarenocenes in the side chain., (© The Royal Society of Chemistry 2011)