| Substituent-dependent structures and catalysis of benzimidazole-tethered N-heterocyclic carbene complexes of Ag(I), Ni(II) and Pd(II) | |
| Department | 羰基合成与选择氧化国家重点实验室 |
Li FW(李福伟) ; Hu JJ(胡建金); Lip Lin Koh; T. S. Andy Hor
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| 2010 | |
| Source Publication | Dalton Trans.
 |
| ISSN | 1477-9226 |
| Volume | 39Pages:5231-5241 |
| Abstract | Homoleptic cationic benzimidazole-imidazolin-2-ylidene N-heterocyclic carbene (NHC = L) complexes of NiII and PdII have been prepared directly from the ligand precursor in salt form [H.L]Cl and from the transmetallation route via AgI. The N-tether of the imidazolinylidene ring imposes a significant influence on the nuclearity of the intermediate Ag(I)-NHC complexes and the geometric isomer outcome of the d8 products. Use of a benzyl-substituted NHC gives [Ag4(LBn)2Cl4], 2a (from [HLBn]Cl, 1a, andAg2O) (Bn = benzyl), which shows an alignment of four silver atoms bridged by the difunctional C–N ligands and chlorides. Its transmetallation with NiCl2(PPh3)4 and PdCl2(MeCN)2 results in double-metal salts 2[M(LBn)2]2+[Ag4Cl8]4- (M = Ni (3a) and Pd (4a)). The nuclearity of the Ag4 aggregate is maintained in the transmetallation process. Their Ag-free forms [M(LBn)2]Cl2 (M = Ni (5) and Pd (6)) were prepared by direct deprotonation of 1a with M(OAc)2. The two carbenic carbon donor are cis- to each other in both 3a and 4a, thus imposing the weaker s-benzimidazole nitrogen donor to be trans to them. A sterically demanding mesityl pendant however gives the dinuclear dissymmetic [Ag2(LMes)2Cl2], 2b (Mes = mesityl) that shows a 12-membered metallomacrocyclic ring with a 2-coordinated [AgI(NHC)2] and 4-coordinated [AgI(Imd)2Cl2] (Imd = imidazole). Transmetallation of the latter, or direct metallation from [HLMes]Cl, 1b, gives [M(LMes)2]Cl2 (M = Ni (3b) and Pd (4b)) with the two carbonic carbon trans to each other. The catalytic potential of 3b and 4b, which are more effective than 5 and 6, has been demonstrated by their high activities in Ni-catalyzed Kumada at room temperature and Pd-catalyzed Heck couplings of aryl and/or heteroaryl halides, respectively. |
| Subject Area | 物理化学 |
| Funding Organization | the Agency for Science, Technology and Research (R143-000-364-305);the Ministry of Education (R-143-000-361-112) |
| Indexed By | SCI |
| Language | 英语 |
| Funding Project | 均相催化研究组 |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.licp.cn/handle/362003/461 |
| Collection | 羰基合成与选择氧化国家重点实验室（OSSO） |
| Corresponding Author | T. S. Andy Hor |
| Recommended Citation GB/T 7714 | Li FW,Hu JJ,Lip Lin Koh,et al. Substituent-dependent structures and catalysis of benzimidazole-tethered N-heterocyclic carbene complexes of Ag(I), Ni(II) and Pd(II)[J]. Dalton Trans.,2010,39:5231-5241. |
| APA | 李福伟,胡建金,Lip Lin Koh,&T. S. Andy Hor.(2010).Substituent-dependent structures and catalysis of benzimidazole-tethered N-heterocyclic carbene complexes of Ag(I), Ni(II) and Pd(II).Dalton Trans.,39,5231-5241. |
| MLA | 李福伟,et al."Substituent-dependent structures and catalysis of benzimidazole-tethered N-heterocyclic carbene complexes of Ag(I), Ni(II) and Pd(II)".Dalton Trans. 39(2010):5231-5241. |
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