170151-48-1Relevant articles and documents
Utilizing the TEMPO Radical in Zirconocene Cation and Hydrido Zirconocene Chemistry
Liu, Yun-Lin,Kehr, Gerald,Daniliuc, Constantin G.,Erker, Gerhard
, p. 3407 - 3414 (2017)
Dimethylzirconocene reacts with 2 molar equiv of the persistent radical TEMPO to give the Cp2Zr(Me)OTMP complex 12 with formation of TEMPOMe. Methyl anion abstraction from 12 with B(C6F5)3 generates the [Cp2ZrOTMP+] cation 13 (with the [MeB(C6F5)3]- anion) that undergoes a typical intramolecular frustrated Zr+/N Lewis pair (FLP) reaction with phenylacetylene. With PtBu3 it reacts as an intermolecular Zr+/P FLP trapping carbon dioxide. Complex 12 reacts with HB(C6F5)2 also by methyl anion abstraction to form the μ-H bridged tight ion pair Cp2ZrOTMP(μ-H)BMe(C6F5)2 (19). It serves as a Cp2Zr(H)OTMP zirconocene hydride source in the reaction with CO2, giving the respective [Zr](μ-formate)[B] complex 23. With carbon monoxide it forms the Zr-(η2-acetaldehyde)[B] complex 30 by transfer of both the hydride and the methyl anion from the Zr/B pair to the carbon atom of the CO molecule.
Borane-functionalized oxide supports: Development of active supported metallocene catalysts at low aluminoxane loading
Tian, Jun,Wang, Shaotian,Feng, Yuding,Li, Jieming,Collins, Scott
, p. 137 - 150 (1999)
Treatment of hydroxylated silica or alumina with tris(perfluorophenyl)borane (1), bis(perfluorophenyl)borane (2) or bis(perfluorophenyl)boron chloride (3), provides borane-functionalized supports of variable composition, as revealed by in situ monitoring
Synthesis and characterization of neutral and cationic aluminum complexes supported by a furfuryl-containing aminophenolate ligand for ring-opening polymerization of ?-caprolactone
Kiriratnikom, Jiraya,Chotchatchawankul, Sucheewin,Haesuwannakij, Setsiri,Kiatisevi, Supavadee,Phomphrai, Khamphee
, p. 8374 - 8383 (2018)
The synthesis, structural characterization and reactivity of aluminum complexes supported by a novel tetradentate aminophenolate ligand containing furfuryl groups (LH), LAlMe2 (1), LAlMeCl (2) and LAlMeOtBu (3), are described. The molecular structures of ligand LH and complexes 1-3 are determined by X-ray structural analysis. Complexes 1-3 contain a four-coordinated mononuclear aluminum center. Activation of complex 1 with either B(C6F5)3 or [Ph3C][B(C6F5)4] afforded the corresponding cationic complex, [LAlMe][MeB(C6F5)3] or [LAlMe][B(C6F5)4], respectively. All cationic complexes were stable at room temperature in the absence of an external Lewis base over a week. The cationic complex [LAlMe][MeB(C6F5)3] decomposed upon heating at 70 °C, giving a neutral LAlMe(C6F5) complex. Complexes 1-3 were inactive for the ring-opening polymerization (ROP) of ?-caprolactone (CL) at room temperature. However, only the cationic aluminum complex [LAlMe][MeB(C6F5)3] in the presence of benzyl alcohol was found to be active in the ROP of CL at room temperature in a well-behaved manner, giving a first-order reaction with respect to [CL].
Zirconocene mediated acetylboron chemistry
Jian, Zhongbao,Daniliuc, Constantin G.,Kehr, Gerald,Erker, Gerhard
, p. 5724 - 5727 (2018)
The methyl zirconocene complex Cp?2Zr(Me)OMes reacts with H3C-B(C6F5)2 and CO to give the respective acetyl(methyl)borate Zr complex. Cp?2Zr(H)OMes reacts with H3C-B(C6F5)2 and CO to give the respective acetyl(hydrido)borate Zr product, admixed with a minor amount of the formyl(methyl)borate Zr complex isomer. Prolonged exposure to CO under close to ambient conditions results in the uptake of another CO equivalent to yield the corresponding borata-β-lactone zirconocene product.
CO-Reduction Chemistry: Reaction of a CO-Derived Formylhydridoborate with Carbon Monoxide, with Carbon Dioxide, and with Dihydrogen
Jian, Zhongbao,Kehr, Gerald,Daniliuc, Constantin G.,Wibbeling, Birgit,Wiegand, Thomas,Siedow, Melanie,Eckert, Hellmut,Bursch, Markus,Grimme, Stefan,Erker, Gerhard
, p. 6474 - 6483 (2017)
Treatment of the bulky metallocene hydride Cp?2Zr(H)OMes (Cp? = pentamethylcyclopentadienyl, Mes = mesityl) with Piers' borane [HB(C6F5)2] and carbon monoxide (CO) gave the formylhydridoborate complex [Zr]-O=CH-BH(C6F5)2 ([Zr] = Cp?2Zr-OMes). From the dynamic NMR behavior, its endergonic equilibration with the [Zr]-O-CH2-B(C6F5)2 isomer was deduced, which showed typical reactions of an oxygen/boron frustrated Lewis pair. It was trapped with CO to give an O-[Zr] bonded borata-β-lactone. Trapping with carbon dioxide (CO2) gave the respective O-[Zr] bonded cyclic boratacarbonate product. These reaction pathways were analyzed by density functional theory calculation. The formylhydridoborate complex was further reduced by dihydrogen via two steps; it reacted rapidly with H2 to give Cp?2Zr(OH)OMes and H3C-B(C6F5)2, which then slowly reacted further with H2 to eventually give [Zr]-O(H)-B(H)(C6F5)2 and methane (CH4). Most complexes were characterized by X-ray diffraction.
