Novel Ag(I), Pd(II), Ni(II) complexes of N,N '-bis-(2,2-diethoxyethyl) imidazole-2-ylidene: Synthesis, structures, and their catalytic activity towards Heck reaction

作者：Yang Wei Hsuan; Lee Chen Shiang; Pal Sachindranath; Chen Yan Nian; Hwang Wen Shu^*; Lin Ivan J B; Wang Ju Chun

来源：Journal of Organometallic Chemistry, 2008, 693(25): 3729-3740.

DOI：10.1016/j.jorganchem.2008.09.017

• Ether substituted N-heterocyclic carbene
• Silver
• Palladium
• Nickel
• Heck reaction

Tetra-ether substituted imidazolium salts, LHX ( where LH = N,N'-bis(2,2-diethoxyethyl) imidazolium cation and X = Br, BF(4), PF(6), BPh(4), NO(3) and NTf(2) anions) were derived from imidazole. Attempts to produce aldehyde functionalized imidazolium salt through acid hydrolysis of LHBr resulted an unexpected tetra-hydroxy compound LAHBr and the dialdehyde compound L(B)HBr. Reaction of LHBr with Ag(2)O afforded [L(2)Ag][AgBr(2)] (1). Mononuclear Pd-complex trans-[L(2)PdCl(2)] (2) and dinuclear Pd- complex [(LPdCl(2))(2)] ( 3) were obtained by 1: 1 and 1: 2 reaction of in situ generated Ag-carbene with Pd(CH(3)CN)(2)Cl(2). cis-[LPdPPh(3)Cl(2)] (4) was synthesized from reaction of PPh(3) with dinuclear complex 3. Hydrolysis of 3 under acidic conditions also generates a hydroxy derivative 3A and the aldehyde derivative 3B. Direct heating of LHBr with Ni(OAc)(2)center dot 4H(2)O at 120 degrees C under vacuum generated trans-[L(2)NiBr(2)] (5). These complexes were characterized by NMR, mass, elemental analysis, and X-ray single crystal diffraction analysis. Pd- Pd interaction was observed in 3. All the Pd complexes exhibited excellent catalytic activity in Heck reaction.

• 出版日期2008-12-1
• 单位苏州大学; 东华大学