Pradhumn Singh, D. Das, O. Prakash
2013
Citations
0
Influential Citations
20
Citations
Journal
Inorganica Chimica Acta
Abstract
Abstract The reactions of in-situ generated PhS − , PyS − and PhSe − with 4-(2-chloroethyl)morpholine hydrochloride and 1-(2-chloroethyl)piperidine hydrochloride in N 2 atmosphere have resulted in N -{2-(arylchalcogeno)ethyl}morpholine/piperidine ligands ( L1 − L6 ), which on reaction with Na 2 PdCl 4 at room temperature result in complexes of composition [PdCl 2 ( L )] ( 1 – 6 ; L = L1 − L6 ). All the complexes except 2 have been characterized by X-ray crystallography. The geometry around Pd is nearly square planar in all the cases. The Pd−S and Pd−Se bond lengths are in the ranges 2.2598(10)−2.2795(14) and 2.3541(6)−2.3632(15) A, respectively. In 77 Se{ 1 H} NMR spectra of Pd(II)-complexes with L5 and L6 (Se ligands), the signals appear at higher frequency (up to 187 ppm) with respect to those of corresponding free ligands. Pd(II)-complexes ( 2 , 4 and 6 ) have been found promising for Heck reaction of aryl bromides with methyl acrylate. The TON values are up to 18 200 and TOF up to 758 h −1 (with complex 6 as catalyst). The Pd-complexes of piperidene derivatives show little higher catalytic efficiency than those of morpholine ones. The positive Hg-test has implied that nano-sized Pd(0) species probably catalyze Heck reactions.