70780-90-4Relevant articles and documents
Highly Recoverable Pd(II) Catalysts for the Mizoroki-Heck Reaction Based on N-Heterocyclic Carbenes and Poly(benzyl ether) Dendrons
Ortiz, Alba,Gómez-Sal, Pilar,Flores, Juan C.,De Jesús, Ernesto
supporting information, p. 3598 - 3610 (2018/10/31)
Two series of bis(imidazolylidene)palladium complexes of general formula [PdBr2(NHC)2] have been prepared. The molecular weight of the complexes was enlarged by bonding poly(benzyl ether) dendrons of increasing size (G0 to G3) at the nitrogen atom of the NHC ligands. Complexes 1-4 contain monodentate NHC ligands coordinated in a trans mode, whereas complexes 9-12 contain a chelating ethylene-bridged bis(NHC) ligand. The complexes were recovered from the product stream of a Mizoroki-Heck reaction by nanofiltration through thermally and chemically stable ceramic membranes. The recoverability is better for larger complexes and chelate ligands. In particular, chelate G3 complex 12 maintained a constant activity during the 13 recovery cycles performed, affording an accumulated turnover number (TON) of 13a€000. On average, around 99.5% of the metal is recovered in each recovery cycle, and contamination by palladium is only 3 mg per kg of product. Several models to explain the efficiency of the recovery are discussed.
Synthesis and Physicochemical Studies on 1,2-Bisazolylethanes
Torres, J.,Lavandera, J. L.,Cabildo, P.,Claramunt, R. M.,Elguero, J.
, p. 771 - 782 (2007/10/02)
Twenty symmetrical and asymmetrical 1,2-bisazolylethanes have been obtained from azoles and 1,2-dibromoethane or 1-chloro-2-(pyrazol-1-yl)ethane by phase transfer catalysis (PTC).The 1H and 13C nmr properties are reported and the chemical shifts of the ethylene carbon atoms discussed using an additive model.