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• 作者：Stephan Peitz ; Normen Peulecke ; Bernd H. Mu虉ller ; Anke Spannenberg ; Hans-Joachim Drexler ; Uwe Rosenthal ; Mohammed H. Al-Hazmi ; Khalid E. Al-Eidan ; Anina Wo虉hl ; Wolfgang Mu虉ller
• 刊名：Organometallics
• 出版年：2011
• 出版时间：April 25, 2011
• 年：2011
• 卷：30
• 期：8
• 页码：2364-2370
• 全文大小：880K
• 年卷期：v.30,no.8(April 25, 2011)
• ISSN：1520-6041

文摘

We report in this paper the isolation and characterization of novel heterobimetallic Cr/Al complexes based on the PNPN ligand along with an assessment about their relevance as intermediates in the ethane selective trimerization process consisting of CrCl₃(THF)₃, the aminophosphorus ligands Ph₂PN(R)P(Ph)N(R鈥?H (1a, R = R鈥?= i-Pr; 1b, R = R鈥?= c-Hex; 1c, R = n-Hex; R鈥?= i-Pr). Different reactions between these ligands or their aluminated products with different chromium salts and Et₃Al gave the binuclear P,P鈥?coordinated chromium(II)鈭抍hloro鈭抋luminum鈭抋midophosphane complexes [(渭(Cr,Cr)-Cl)(渭(Cr,Al)-Cl)Cr{魏²P,P-P(Ph₂)N(R)P(Ph)N(R)Al(Et₂)}]₂ (2a, R = R鈥?= i-Pr; 2b, R = R鈥?= c-Hex; 2c, R = n-Hex; R鈥?= i-Pr). By using Ph₂PN(i-Pr)P(Ph)N(i-Pr)H (1a) the corresponding complex [(渭(Cr,Cr)-Cl)(渭(Cr,Al)-Cl)Cr{魏²P,P-P(Ph₂)N(i-Pr)P(Ph)N(i-Pr)Al(Me₂)}]₂ (2d) was also obtained. Complexes 2a,c,d were characterized by X-ray analysis. The formation and role of these compounds are discussed and identified as an important step during the activation of the catalytic system. Studies reveal that the activity of the described trimerization reaction can be enhanced by an optimized Cr/Al/Cl ratio without affecting the high selectivity to 1-hexene, thus clarifying the importance of chlorine as part of the catalytic species.