Palladium(II) complexes with sulphonium ylides

A new Pd(II) complex of a sulfur ylide; Synthesis, X-ray characterization, theoretical study and catalytic activity toward the Suzuki–Miyaura reaction

“…In the far-IR spectra of complexes 3a and 3b, two Pd-Cl stretching bands were observed at 333 and 255 cm -1 , which are in accord with both cis-and trans-dichlorobis(sulfur ylide) structures in the solid state [11]. Also, the ν(CO) and in the mid-IR spectrum of sulfur ylide 2 was observed at around 1596 cm -1 , occurring at a lower frequency than the related sulfonium salt 1 (1676 cm -1 ).…”

“…The higher field pair of SMe 2 and the methinic proton signals may be assigned to the trans isomer [48]. Since the methinic carbons are chiral, two (RR/SS or RS/SR) diastereoisomers are expected for these complexes [11]. The presence of two such dynamic diastereoisomers was observed in the 1 H NMR spectrum of complexes 3a and 3b.…”

“…Thus, a downfield shift for the signal of the SCH group and a decrease of the electron density in the S=C bond in the sulfur ylide was expected. Contrariwise, coordination of the sulfur ylide through the Cα atom causes an upfield shift in the 13 C NMR signal of methinic group [11], from 52 ppm in ylide 2 to 49 ppm in complexes 3a and 3b. This upfield shift of the SCH signal for these complexes is the most important aspect of the 13 C NMR spectra and this is due to the change in the hybridization of the ylidic carbon atom from sp 2 to sp 3 [49].…”

“…This upfield shift of the SCH signal for these complexes is the most important aspect of the 13 C NMR spectra and this is due to the change in the hybridization of the ylidic carbon atom from sp 2 to sp 3 [49]. Downfield shifts for the CO and OCH 3 signals were also observed for complex 3, indicating a much lower shielding of the carbon atoms of the CO and OCH 3 groups in this complex [11]. The presence of two nearby singlet peaks for SCH, OCH 3 and four CH 3 signals for two SMe 2 groups in the 13 C NMR spectra of complexes 3a and 3b…”

“…The complexation of sulfur ylides to various transition metals has been extensively studied [9,[11][12][13], however the synthesis, X-ray characterization, theoretical study and also application of a palladium complex of a sulfur ylide as a precursor in the Suzuki-Miyaura coupling reaction are the key advantages of this study. This paper includes the synthesis, spectroscopic and X-ray crystallographic characterization, theoretical study and application of new palladium(II) complex of an α-keto stabilized sulfur ylide in the Suzuki-Miyaura cross-coupling reaction.…”