206366-34-9Relevant academic research and scientific papers
Synthesis of neutral group 4 metal-carboryne complexes and their reactivity toward unsaturated molecules
Ren, Shikuo,Qiu, Zaozao,Xie, Zuowei
supporting information, p. 4292 - 4300 (2013/09/02)
A series of neutral group 4 metal-carboryne complexes of the general type [η2-R2C(NR1)2] 2M(η2-C2B10H10) were prepared via a salt metathesis reaction of [η2-R 2C(NR1)2]2MCl2 with Li2C2B10H10 (M = Ti, Zr, Hf; R 1 = iPr, cyclohexyl, R2 = Me, nBu, Ph) in high yields. Their structures were confirmed by single-crystal X-ray analyses. They reacted with ketone, nitrile, and heterocumulenes such as carbodiimide, isocyanate, thioisocyanate, carbon disulfide, and phenyl azide to give various monoinsertion products, in which the unsaturated bond inserted into one of the M-Ccage bonds, resulting in the formation of heterocycles. However, these metal-carboryne complexes did not show any reactivity toward pyridines, alkynes, and alkenes. The results clearly indicated that [η2-R2C(NR1)2] 2M(η2-C2B10H10) shared some common properties with Cp2Zr(η2-C 2B10H10) in reaction with heterocumulenes; on the other hand, they showed significant differences in reaction with pyridines, alkynes, and alkenes. These may be mainly ascribed to ligand steric effects.
Metallocene analogues containing bulky heteroallylic ligands and their use as new olefin polymerization catalysts
Richter, Joachim,Edelmann, Frank T.,Noltemeyer, Mathias,Schmidt, Hans-Georg,Shmulinson, Michal,Eisen, Moris S.
, p. 149 - 162 (2008/10/09)
A series of Ti and Zr metallocene analogues containing bulky benzamidinate ligands has been prepared and fully characterized. Treatment of TiCl4(THF)2 or ZrCl4(THF)2 with two equivalents of the appropriate benzamidinate anions affords the bis(benzamidinato) complexes [C6H5C(NC3H7)2]2MCl2 (M=Ti (1), Zr (2)) and [C6H5C(NC6H11)2]2MCl2 (M = Ti (3), Zr (4)). The zirconium complex 2 was structurally characterized by X-ray diffraction. In a similar manner the nonafluoromesityl derivative [(CF3)3C6H2C(NC6H11)2]2ZrCl2 (5) was synthesized from ZrCl4(THF)2 and Li[(CF3)3C6H2C(NC6H11)2]. Methylation of 4 with methyllithium yields the dimethyl complex [C6H5C(NC6H11)2]2ZrMe2 (6). The mixed-ligand metallocene analogues [C6H5C(NC3HT7)2](C5Me5)MCl2 (M = Ti (7), Zr (8)) and [C6H5C(NC6H11)2](C5Me5)TiCl2 (9) have been prepared by reacting (C5Me5)TiCl3 or (Cs5Me5)ZrCl3 with one equivalent of a lithium N,N'-dialkytbenzamidinate. The polymerization of ethylene and propylene has been studied by the catalytic precatalyst complexes I and 2 upon reaction of an excess of methylalumoxane to obtain the active cationic complexes. The polymerization activity of the complexes is comparable to other benzamidinate ancillary containing ligands although toward shorter amounts of time due to a competitive inhibition presumably obtained by a β-hydrogen elimination from the ligand. Polymerization activity is strongly dependent on catalyst and cocatalyst concentrations and on temperature.
