17961-83-0Relevant articles and documents
Protodesilylation of Arylsilanes by Visible-Light Photocatalysis
García Manche?o, Olga,Kuhlmann, Jan H.,Uygur, Mustafa
supporting information, p. 1689 - 1694 (2022/03/14)
The first visible-light-mediated photocatalytic, metal- and base-free protodesilylation of arylsilanes is presented. The C(sp2)-Si bond cleavage process is catalyzed by a 5 mol % loading of a commercially available acridinium salt upon blue-light irradiation. Two simple approaches have been identified employing either aerobic or hydrogen atom transfer cocatalytic conditions, which enable the efficient and selective desilylation of a broad variety of simple and complex arylsilanes under mild conditions.
Organic metal compounds and organic light emitting diodes comprising the same
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Paragraph 0154; 0173; 0176-0178, (2018/12/01)
PURPOSE: An organic metal compound is provided to have excellent thermal properties and light emitting efficiency, thereby being useful for a display and lighting device. CONSTITUTION: An organic metal compound is represented by chemical formula 1. In chemical formula 1, each of R and Z is hydrogen, deuterium, cyano, halogen hydroxy, nitro, C1-40 alkyl, C1-40 alkoxy, C1-40 alkylamino, C6-40 arylamino, C3-40 heteroarylamino, C1-40 alkoxy group, C1-40 alkylamino, C6-40 aryl group, C3-40 aryloxy group, germanium, phosphorous, and boron; each of A, B, C, D, and E is a substituted or unsubstituted aromatic cycle, or substituted or unsubstituted hydrocycle, X is carbon or nitrogen, G is chemical bond or C1-4 alkylene which can be substituted by (R-Zi)n.
Arylcalcium hydrides as precursors to alkoxides and aryloxides of calcium
Dunne, John P.,Tacke, Matthias,Selinka, Carola,Stalke, Dietmar
, p. 1416 - 1425 (2007/10/03)
Calcium atoms react with +I-substituted benzene derivatives under cocondensation conditions to yield arylcalcium hydrides. With toluene, tert-butylbenzene, and trimethyl(phenyl)silane the reaction showed no selectivity for C-H activation, resulting in the formation of each of the three possible isomers, while with m-xylene the reaction resulted in selective activation of the bond meta to the CH3 groups. Treatment of (tert-butylphenyl)calcium hydride with di- and trisubstituted phenols such as 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, and 2,4,6-tri-tert-butylphenol resulted in the formation of calcium aryloxides in yields > 95%. [Ca(2,4,6-tBu3C6H2O)2 (THF)3] crystallises from a THF solution as a distorted trigonal bipyramid, with two THF ligands in the trans-axial positions and the third THF ligand and both aryloxide groups in equatorial positions. The Ca-OAryl bond length was found to average at 2.181(3). A. The Ca-O-CAryl angles are almost linear, with Cal-O1-C1 and Ca1-O2-C19 being 173.9(3)° and 178.8(3)°, respectively, while the O1-Cal-O2 angle was determined as 157.04(12)°. A reaction between (tert-butylphenyl)calcium hydride and triphenylmethanol resulted in the formation of the corresponding monomeric calcium bis(alkoxide) Ca(OCPh3)2(THF)4 in 95% yield. The structure was determined as a distorted octahedron with the alkoxide ligands in a cis-equatorial arrangement. The Ca-O bond length was determined at 2.1609(17) A. The Ca-O-CAryl angle of 177.46(16)° is almost linear, while the O1-Cal-O1A angle was determined at 110.12(19)°. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).
Highly electrophilic olefin polymerization catalysts. Quantitative reaction coordinates for fluoroarylborane/alumoxane methide abstraction and ion-pair reorganization in group 4 metallocene and 'constrained geometry' catalysts
Deck, Paul A.,Beswick, Colin L.,Marks, Tobin J.
, p. 1772 - 1784 (2007/10/03)
Reaction enthalpies of group 4 metallocenes having the general formula L2M(CH3)2 (L = Cp, 1,2-Me2Cp, Me5Cp; L2 = Me2Si(Me4Cp)((t)BuN); M = Ti, Zr, and Hf) with the strong organo-Lewis acid B(C6F5)3 were measured using batch titration calorimetry in toluene. Methide abstraction to form the corresponding L2MCH3+CH3B(C6F5)3- contact ion pairs is highly exothermic in all cases. Exothermicity increases with increasing Cp methyl substitution: for M = Zr, ΔH = -23.1(3), -24.3(4), and -36.7(5) kcal mol-1 for L = Cp, Me2Cp, and Me5Cp, respectively for M = Hf and L = 1,2-Me2Cp, ΔH = -20.8(5) kcal mol-1. 'Constrained geometry' complexes (L2 = Me2Si(Me4Cp)((t)BuN)) exhibit similar exothermicities, with ΔH = -22.6(2), -23.9(4), and -19.3(6) kcal mol-1 for M = Ti, Zr, and Hf, respectively. In contrast, analogous reactions with methylalumoxane (M:Al = 1:50) are less exothermic, with ΔH = -10.9(3) and -8.9(4) kcal mol-1 for L = 1,2-Me2Cp and M = Zr and Hf, respectively. Under identical conditions, (1,2-Me2Cp)2M-(CH3)2 (M = Zr, Hf) complexes also undergo methide abstraction with the less Lewis-acidic triarylboranes (C6F5)2BAr (AT = 3,5-C6H3F2, Ph, and 3,5-C6H3Me2); however, conversions to the corresponding (Me2-Cp)2MCH3+ CH3B(C6F5)2Ar- ion pairs, are incomplete. Variable-temperature NMR measurements yield thermodynamic parameters for partial methide abstraction by these less Lewis-acidic boranes. For Ar = 3,5-C6H3F2, ΔH = -18.7(7) and -15.2(8) kcal mol-1 with ΔS = -42(2) and -35(3) e.u:; for Ar = Ph, ΔH = -14.8(8) and -13.3(6) kcal mol-1 with ΔS = -31(2) and -39(2) e.u.; for Ar = 3,5-C6H3Me2, ΔH = -10.8(6) and -12.7(5) with ΔS = -19(2) and -36(4) e.u., in each case for M = Zr and Hf, respectively. Dynamic NMR analyses reveal that the activation barriers for methide abstraction from the neutral metallocene dialkyls are small and relatively insensitive to the borane identity (AH = 2-6 kcal mol-1) while ion-pair separation/recombination processes are greatly facilitated by polar solvents. Ethylene polymerization activities for eight (Me2Cp)2MCH3+CH3B(C6F5)2Ar- complexes measured in toluene solution (25°C, 1 atm) follow a trend in metal (Zr > Hf)as well as a substantial trend in triarylborane (Ar = C6F5 > 3,5-C6H3F2 > Ph ~3,5-C6H3-Me2). Polymerization activities correlate roughly with MCH3+ 13C NMR chemical shifts and enthalpies of methide abstraction.
Process for preparing silylated aromatic acids
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, (2008/06/13)
An improved process is disclosed for preparation of silicon-containing aromatic polyacids by liquid phase oxidation of a silyl compound in the presence of oxygen and a catalyst comprising cobalt-manganese-bromine. 2-Trimethylsilyl-p-xylene is oxidized to
