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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
- Source :
-
Journal of Organometallic Chemistry . Dec2008, Vol. 693 Issue 25, p3729-3740. 12p. - Publication Year :
- 2008
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Abstract
- Abstract: Tetra-ether substituted imidazolium salts, LHX (where LH= N,N′-bis(2,2-diethoxyethyl)imidazolium cation and X=Br, BF4, PF6, BPh4, NO3 and NTf2 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 LBHBr. Reaction of LHBr with Ag2O afforded [L2Ag][AgBr2] (1). Mononuclear Pd-complex trans-[L2PdCl2] (2) and dinuclear Pd-complex [(LPdCl2)2] (3) were obtained by 1:1 and 1:2 reaction of in situ generated Ag-carbene with Pd(CH3CN)2Cl2. cis-[LPdPPh3Cl2] (4) was synthesized from reaction of PPh3 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 ·4H2O at 120°C under vacuum generated trans-[L2NiBr2] (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. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 0022328X
- Volume :
- 693
- Issue :
- 25
- Database :
- Academic Search Index
- Journal :
- Journal of Organometallic Chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 35206263
- Full Text :
- https://doi.org/10.1016/j.jorganchem.2008.09.017