10060-17-0Relevant articles and documents
Carbanion mechanisms XXI. Solution acidity of triphenylsilane
Buncel, Erwin,Venkatachalam
, p. 208 - 210 (2000)
Comparative acidity measurements have been performed between triphenylsilylpotassium and a series of arylmethanes by 1H-NMR in tetrahydrofuran: Ph3SiK + ArnCH4 - n ? Ph3SiH + ArnCH3 - nK Metalation of the arylmethane was complete in the case of Ph3CH (pKa 31.4) and Ph2CH2 (pKa 33.4) but with (p-CH3·C6H4)2CH2 (pKa 35.1) ~50% metalation of the di-p-tolymethane occurred, indicating that the two acids have equal pKa. No reaction occurred with 4-Ph·C6H4·CH3 (pKa 38.7). Thus pKa Ph3SiH ≈ 35.1 in THF. This represents the first solution measurement of the acidity of an organosilane.
METAL-STABILIZED CARBANIONS VI. FORMATION OF SOME ARYLMETHYL AND DIBENZOTROPENYL CARBANIONS COMPLEXED WITH TRICARBONYLCHROMIUM. A KINETIC AND A 13C NMR STUDY
Ceccon, Alberto,Gambaro, Alessandro,Venzo, Alfonso
, p. 209 - 222 (1984)
Rate constants have been measured for the α-metallation of some arylmethanes, of 5H-dibenzocycloheptene and its dihydro derivative, free and complexed with tricarbonylchromium, by potassium hydride in tetrahydrofuran in the presence of 18-crown-6 ether.The stable solutions of the complexed anions have been studied by 13C NMR spectroscopy.With the free ligands the kinetic acidity depends upon the structure to a great extent, but in the corresponding complexes the rates of metallation do not vary appreciably.On the basis of the 13C chemical shift data a close similarity is suggested between the electronic structures of the arylmethyl and dibenzotropenyl anions which would account for their very similar metallation rates.
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Yost,Hauser
, p. 2325,2327 (1947)
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Effect of isomeric pyridine moieties in ethynylstyrene derivatives on their anionic polymerization
Kang, Beom-Goo,Kang, Nam-Goo,Lee, Jae-Suk
experimental part, p. 5199 - 5209 (2012/07/27)
The anionic polymerization behaviors of ethynylstyrene derivatives containing isomeric pyridine moieties, 2-(2-(4-vinylphenyl)ethynyl)pyridine (A), 3-(2-(4-vinylphenyl)ethynyl)pyridine (B), and 4-(2-(4-vinylphenyl)ethynyl) pyridine (C), were investigated in the identical conditions. The anionic polymerization of A-C was performed with (diphenylmethyl)potassium (Ph 2CHK) in tetrahydrofuran (THF) at -78 °C. The polymerization of A proceeded quantitatively at -78 °C for 4 h, and the resulting poly(A) possessed predictable molecular weights (Mn = 3300-68,500) and narrow molecular weight distributions (MWDs) (Mw/Mn = 1.04-1.11). In contrast, the anionic polymerization of B was not performed at -78 °C for 4 h due to the occurrence of side reactions. The monomer B was quantitatively recovered after the reaction. In the polymerization of C performed at -78 °C for 6 h, observed Mn values of the resulting poly(C) were in good agreement with calculated molecular weights based on monomer to initiator ratios, but the MWDs were somewhat broad (M w/Mn = 1.23-1.31). To estimate the reactivity of A and to characterize its living nature, the block copolymerization of A with 2-vinylpyridine (2VP) and methyl methacrylate (MMA) was performed. The well-defined block copolymers, poly(2VP)-b-poly(A) and poly(A)-b-poly(MMA), were successfully synthesized without any additives.
Metal complexes containing partially delocalized II-bound groups and addition polymerization catalysts therefrom
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, (2008/06/13)
Novel Group 4 metal complexes wherein the metal is in the +2 or +4 formal oxidation state containing a cyclic or noncyclic, non-aromatic, anionic, dienyl ligand group bound to M and having a bridged ligand structure, catalytic derivatives of such complexe