767-59-9Relevant academic research and scientific papers
Indenyl zirconium dinitrogen chemistry: N2 coordination to an isolated zirconium sandwich and synthesis of side-on, end-on dinitrogen compounds
Pun, Doris,Lobkovsky, Emil,Chirik, Paul J.
, p. 6047 - 6054 (2008)
Exposure of the isolable zirconocene sandwich compounds, (η5-C5Me5)(η5-C 9H5-1-R1-3-R2)Zr (R1 = Me, iPr, tBu; R2 = Me) to one atmosphere of dinitrogen resulted in N2 coordination. X-ray diffraction and NMR spectroscopy establish that the resulting dimeric dinitrogen compounds contain an unusual μ2,η2-bridging indenyl ring and a weakly activated N2 ligand. N2 coordination from the isolable zirconium sandwich compounds is extremely sensitive to the number and size of the indenyl subsituents. Compounds bearing two [iPr] or three methyl substituents are stable as η9 sandwich compounds for weeks under dinitrogen likely due to the inability to dimerize through a two-atom N 2 bridge. Performing the reduction of (η5-C 5Me5)(η5-C9H5-1- R1-3-R2)ZrCl2 (R1 = iPr, tBu; R2 = Me; R1 = R2 = SiMe 3) under an N2 atmosphere produced a different outcome; rare examples of side-on, end-on zirconium dinitrogen compounds were isolated and in one case, crystallographically characterized. Protonolysis studies with weak Bronsted acids were used to evaluate the relative activation of the bridging dinitrogen ligands.
Upper excited state photochemistry: Solution and gas phase photochemistry and photophysics of 2- and 3-cyclopropylindene
Waugh, Tim,Morrison, Harry
, p. 3083 - 3092 (1999)
The cyclopropylcarbinyl radical rearrangement has been used to probe the photochemistry and photophysics of S2 and S1 in 2-cyclopropylindene (2CPI) and 3-cyclopropylindene (3CPI). Studies in solution and the gas phase are described. Population of S2 with 254 nm light excitation in the gas phase produces the anticipated ring expansion products 2,3,3a,8- tetrahydrocyclopenta[a]indene (1, Φ1 = 0.1) and 1,3,3a,8- tetrahydrocyclopenta[a]indene (2, Φ2 = 0.06) from 2CPI and 3CPI, respectively (Scheme 3). Direct excitation into the S2 state (254 nm) of 2CPI in solution also produces compound 1. The efficiency of the solution phase chemistry is a function of excitation wavelength (Φ1 = 0.022 and 0.006 for 254 and 280 nm, respectively). The solution phase excitation spectrum of 2CPI shows an anomalous dependency on monitoring wavelength which is attributed to a conformational equilibrium. The S1 singlet lifetimes of the cyclopropylindenes are quite short (0.39 and 1.0 ns for 2CPI and 3CPI, respectively) relative to the previously measured values for the corresponding methylindenes (2.3 and 13.9 ns). These shortened lifetimes are attributed to cyclopropyl ring opening in S1 with rates of 2.1 x 109 and 9.2 x 108 s-1 for 2CPI and 3CPI, respectively. Semiempirical excited state calculations support descriptions of the S2 and S1 states of alkylindenes as biradicals.
Catalysts that produce polyethylene with broad, bimodal molecular weight distribution
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, (2021/01/19)
The present disclosure relates to ansa-metallocene catalyst compounds that include (1) a first indenyl ligand substituted at the 3-position with a substituted or unsubstituted C4-C40 hydrocarbyl group, wherein the hydrocarbyl group is branched at the β-position, and (2) a second indenyl ligand substituted at its 3-position with a substituted or unsubstituted alkyl group or a β-branched alkyl group. Catalyst systems prepared with the catalyst compounds, polymerization methods using such catalyst systems, and polyolefins made using the polymerization methods are also described.
Unbridged indacenyl metallocenes
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Page/Page column 62; 69, (2021/05/12)
The present disclosure provides novel unbridged group 4 indacenyl-containing metallocene compounds. The catalyst system may be used for olefin polymerization processes.
Carbocation catalysed ring closing aldehyde-olefin metathesis
Ni, Shengjun,Franzén, Johan
, p. 12982 - 12985 (2018/11/23)
A highly efficient aldehyde-olefin metathesis catalysed by the carbocation, 4-phenylphenyl-diphenylmethylium ion, has been developed. This protocol is characterized by high yields, low catalyst loading (down to 2 mol%), good functional group compatibility and mild reaction conditions.
Cyclopropenylgold(I) Complexes as Aurated Carbenoids or Quasi-Carbenes
Mulks, Florian F.,Antoni, Patrick W.,Rominger, Frank,Hashmi, A. Stephen K.
, p. 1810 - 1821 (2018/03/21)
Highly strained hydrocarbons have always been a research target of high interest. Due to their untypical electronic structure, they show interesting reactivity patterns and can easily be activated by π-coordination to or insertion reactions with metal complexes. Herein we report the synthesis of a range of 3,3-disubstituted cyclopropenylgold(I) complexes. The synthesis of such compounds with a metal, which usually easily activate cyclopropenes is a double-edged sword. We found σ-bound vinylic gold to generally have a strong stabilizing effect in terms of ring strain. The complexes show a strong distortion, preactivating the cyclopropenyls towards the ring-opening mode which thermally generates 1-aurated vinylcarbenes which is reflected by a much faster conversion (Ea of 10 kcal/mol instead of 40 kcal/mol, the reaction proceeds at temperatures as low as ?20 °C instead of 200 °C reported in the literature). In 3-phenyl-cyclopropenyl complexes, these could be trapped intramolecularly to give indenylgold(I) complexes. The properties of these highly strained complexes were investigated, utilizing a range of analytical and experimental procedures and Kohn-Sham density functional theoretic methods. (Figure presented.).
NOVEL PRECATALYST SCAFFOLDS FOR CROSS-COUPLING REACTIONS, AND METHODS OF MAKING AND USING SAME
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Page/Page column 36, (2016/05/02)
The present invention provides novel transition-metal precatalysts that are useful in preparing active coupling catalysts. In certain embodiments, the precatalysts of the invention are air-stable and moisture-stable. The present invention further provides methods of making and using the precatalysts of the invention.
Synthesis and structural characterization of novel three carbon atom bridged ansa-bis(indenyl)zirconocene complexes: Applications in ethylene polymerization
Polo-Cerón, Dorian,Gómez-Ruiz, Santiago,Ceballos-Torres, Jesús,Prashar, Sanjiv,Fajardo, Mariano,Reyes, Manuel L.
, p. 129 - 133 (2014/08/18)
The ansa indenyl ligand precursors CH2CH2CH 2(C9H6R)2 (R = Me (7), Et (8), Pr (9)) have been prepared by the reaction of the corresponding lithium indene, Li(C9H6R-1)
Neutral dimethylzirconocene complexes as initiators for the ring-opening polymerization of ε-caprolactone
Villasenor, Elena,Gutierrez-Gonzalez, Ruben,Carrillo-Hermosilla, Fernando,Fernandez-Galan, Rafael,Lopez-Solera, Isabel,Fernandez-Pacheco, Ana Rodriguez,Antinolo, Antonio
, p. 1184 - 1196 (2013/04/10)
The synthesis, structures, and ring-opening polymerization (ROP) activity of new dimethyl-ansa- and -non-ansa-zirconocene complexes are reported. The substituted indene precursors 1-C9H7R [R = CH3 (1), CH2Ph (2) and C2H4(C4H 7O2) (3)] were synthesised by treating RBr [R = CH 2Ph and C2H4(C4H7O 2)] or MeI with indenyllithium. Likewise, bridged indenyl/cyclopentadiene compounds [Me2Si(3-C9H 6R)(C5Me4H)] [R = H (4), CH3 (5), CH2Ph (6) and C2H4(C4H 7O2) (7)] were obtained by treating the lithium salt of the appropriately substituted indene with ClSiMe2(C 5Me4H). ansa-Indenyl-cyclopentadienylmetallocenes [Zr{Me2Si(3-η5-C9H5R) (η5-C5Me4)}Cl2] [R = H (8), CH3 (9), CH2Ph (10), C2H4(C 4H7O2) (11)] were subsequently obtained by treating the dilithium salts of the corresponding ligands with ZrCl4 in toluene. The dimethyl derivatives [Zr{Me2Si(3-η5- C9H5R)(η5-C5Me 4)}Me2] [R = H (12), CH3 (13), CH2Ph (14), C2H4(C4H7O2) (15)] were prepared by treating the corresponding ansa-zirconocene dichloride complex with MgMeBr. Dialkyl derivative [Zr{Me2Si{3-η5-C 9H5(CH2Ph)}(η5-C 5Me4)}(CH2SiMe3)2] (16) was prepared by adding 2 equiv. of LiCH2SiMe3 to complex 10. Mixed indenyl/cyclopentadienylzirconocene complexes [Zr(η5- C9H6R)(η5-C5H 5)Cl2] [R = H (17), C2H4(C 4H7O2) (18)] were prepared by treating the lithium salt of the appropriately substituted indene with [Zr(η5- C5H5)Cl3]. Likewise, dimethyl derivatives [Zr(η5-C9H6R)(η5-C 5H5)Me2] [R = H (19), C2H 4(C4H7O2) (20)] were prepared by treating the corresponding mixed indenyl/cyclopentadienyl dichloride complex with 2 equiv. of MgMeBr. The X-ray crystal structures of 7, 12, and 13 were also established. Finally, comparative catalytic studies of zirconium complexes 12-16, 19 and 20 in ROP reactions of ε-caprolactone are described. Synthesis, characterization, and catalytic studies of new dimethyl-ansa- and -non-ansa-zirconocene complexes for ring-opening polymerization of ε-caprolactone are described. Copyright
1,2,3-trisubstituted indanes by highly diastereoselective palladium-catalyzed oxyarylation of indenes with arylboronic acids and nitroxides
Kirchberg, Sylvia,Froehlich, Roland,Studer, Armido
supporting information; experimental part, p. 6877 - 6880 (2010/12/19)
Chemecal quation presented Excellent stereoselectivity is obtained in the synthesis of biologically interesting 1,2,3-trisubstituted indanes B by the reaction of readily prepared 3-substituted indenes A with commercially available arylboronic acids by using various TEMPO derivatives as external oxidants and Pd(OAc)2 as a catalyst. The anti,anti isomers are formed and reactions occur stereospecifically under mild conditions.
