Group 4 metal complexes bearing the aminoborane motif: origin of tandem ring-opening metathesis/vinyl-insertion polymerization
Group 4 metal complexes bearing the aminoborane motif: origin of tandem ring-opening metathesis/vinyl-insertion polymerization
复制标题
带有氨基硼烷基序的第 4 族金属配合物:串联开环复分解/乙烯基插入聚合的起源
DOI:
10.1039/c5py00303b
复制
发表时间:
2015
影响因子:
4.6
通讯作者:
Buchmeiser
中科院分区:
文献类型:
--
作者:
Buchmeiser
Three tailored ansa-type Zr(IV)- and Hf(IV)-complexes, Zr-1, Hf-1 and Zr-2, all bridged by a dimethylsilylene group and bearing both a 6-[2-(BR2)phenyl]pyrid-2-yl motif (R = ethyl, mesityl) and an η1/η5-bound ligand with different Lewis base character and steric demand, have been synthesized. Their structures have been determined by single-crystal X-ray diffraction analysis. Upon activation with methylalumoxane (MAO), Zr-1, Hf-1 and Zr-2 are capable of polymerizing norborn-2-ene (NBE) via ring-opening metathesis polymerization (ROMP). In the MAO-activated copolymerization of ethylene (E) with NBE; however, pure vinyl insertion polymerization (VIP)-derived poly(NBE)-co-poly(E) is obtained by Zr-1, Hf-1 and the model pre-catalyst (Zr-3), which does not contain the borylamino motif. In contrast, Zr-2 yields copolymers containing both ROMP- and VIP-derived poly(NBE)ROMP-co-poly(NBE)VIP-co-poly(E) units via an α-H elimination process. Variable-temperature 11B NMR measurements allow for identifying tri- and tetracoordinated borane species. The propensity of catalysts Zr-1, Hf-1, Zr-2 and Zr-3 to switch from VIP to ROMP is discussed on the basis of their structural differences. A detailed NMR study of the reaction of Zr-1, Zr-2, Hf-1 and in particular of dimethylsilylene-bis(6-[2-(diethylboryl)phenyl]pyrid-2-ylamido)ZrCl2 (Zr-4) with MAO and with MAO/NBE clarifies the reaction cascade from VIP to ROMP and allows for establishing a general concept for a tailored switch from VIP to ROMP within the same polymer chain, allowing for tandem VIP–ROMP copolymerization of E with NBE.
登录
查看更多内容
DOI:
--
发表时间:
1993
期刊:
影响因子:
--
作者:
M. D. Fryzuk;S. Mao;M. Zaworotko;L. MacGillivray
通讯作者:
L. MacGillivray
DOI:
--
发表时间:
2005
期刊:
影响因子:
--
作者:
Levi J. Irwin;J. Reibenspies;Stephen A. Miller
通讯作者:
Stephen A. Miller
DOI:
--
发表时间:
1995
期刊:
影响因子:
--
作者:
M. Schmid;H. Alt;W. Milius
通讯作者:
W. Milius
影响因子:
15
作者:
M. D. Fryzuk;Paul B. Duval;S. Mao;M. Zaworotko;L. MacGillivray
通讯作者:
L. MacGillivray
影响因子:
5.5
作者:
Ciftci, Mustafa;Batat, Pinar;Yagci, Yusuf
通讯作者:
Yagci, Yusuf