Synthesis, Structures, and Norbornene Polymerization Behavior of Aryloxide-N-Heterocyclic Carbene Ligated Palladacycles
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- 作者：Yong Kong ; Lifang Wen ; Haibin Song ; Shansheng Xu ; Min Yang ; Binyuan Liu ; Baiquan Wang
- 刊名：Organometallics
- 出版年：2011
- 出版时间：January 10, 2011
- 年：2011
- 卷：30
- 期：1
- 页码：153-159
- 全文大小：897K
- 年卷期：v.30,no.1(January 10, 2011)
- ISSN：1520-6041
文摘
Treatment of the o-hydroxyaryl imidazolinium pro-ligands (2-OH-3,5-tBu2C6H2)(R)(C3H3N2)+Br鈭?/sup> [R = Me (3a), iPr (3b), tBu (3c), Ph (3d), Mes (3e)] with the palladacycle [Pd(dmba)(渭-Cl)]2 (dmba = Me2NCH2C6H5) (2) afforded the corresponding aryloxide-NHC (NHC = N-heterocyclic carbene)-ligated palladacycles (2-O-3,5-tBu2C6H2)(R)(NHC)Pd(dmba) [R = Me (4), iPr (5), Ph (6), Mes (7), tBu (8)]. Notably, without isolating 2, complexes 4鈭?b>8 could also be obtained by one-pot, three-component, sequential reaction of N,N-dimethylbenzylamine, PdCl2, and the pro-ligands in refluxing acetonitrile in the presence of K2CO3. When the N-functional group on the NHCs is tert-butyl, the NHC in 8 adopts an abnormal binding (C4-bonding). All these complexes were fully characterized by 1H and 13C NMR, high-resolution mass spectrometry (HRMS), and elemental analysis. Single-crystal X-ray diffraction analysis results further confirmed the molecular structures of 4鈭?b>8 and the abnormal binding of NHC in 8. With methylaluminoxane (MAO) as cocatalyst these palladacycles showed excellent catalytic activities up to 107 g of PNB (mol of Pd) 鈭? h鈭? in the addition polymerization of norbornene.