How the Substitution Faraway from NHCs Affects the Structural Features and Catalytic Activity of Dicarbene Dipalladium Complexes |
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| Authors: | Kaiqi Ge Changsheng Cao Gang Liu Yuling Li Juan Zhang Guangsheng Pang Yanhui Shi |
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| Affiliation: | 1. College of Chemistry and Chemical Engineering and Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials, Jiangsu Normal University, Xuzhou, Jiangsu, 221116, P. R. China;2. State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun, Jilin, 130012, P. R. China |
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| Abstract: | A series of [PdPyCl2]2(di‐NHC) complexes were prepared (di‐NHC are two 1‐(2,6‐dimethylphenyl)imidazolidene molecules bridged by an aliphatic –(CH2)n– linker (n = 3, 4, 5, 6, and 10)). All complexes were fully characterized by NMR spectroscopy and elemental analyses. The crystal structures of four complexes (n = 3, 4, 5 and 6) were determined by X‐ray diffraction. The influence of the distant methyl group on the structural features and catalytic activity with increasing of length of linker was investigated by comparing the results of these 2,6‐dimethylphenyl palladium complexes with those of their known mesityl analogues. X‐ray studies show the distant methyl substitution has big impact on the structure feature of the complexes with the shorter linker between two NHC (ethylene and propylene), but has a little or no effect on that of the complexes with longer linker (butylene and hexylene). Catalytic results of the arylation of styrene show that the remote substitute has big effect on the regioselectivity of the product in all complexes with shorter and longer linkers, but has a limited effect on the yield. |
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| Keywords: | Dinuclear Palladium N‐heterocyclic carbene Crystal structure Heck reaction |
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