The development of phosphinoamine–Pd(II)–imidazole complexes: implications in room‐temperature Suzuki–Miyauracross‐coupling reaction

Abstract

The reaction of N‐methylimidazole (N‐MeIm) and N‐butylimidazole (N‐BuIm) with the complexes [PdCl2(PPh2py–P,N)] and [PdCl2(PPh2Etpy–P,N)] in the presence of NH4PF6 under N2 at room temperature afforded four new cationic Pd(II) complexes [PdCl(PPh2py–P,N)(N‐MeIm)](PF6) (1), [PdCl(PPh2py–P,N)(N‐BuIm)](PF6) (2), [PdCl(PPh2Etpy–P,N)(N‐MeIm)](PF6) (4) and [PdCl(PPh2Etpy‐P,N)(N‐BuIm)](PF6) (5) in good yields, where PPh2py is 2‐(diphenylphosphino)pyridine and PPh2Etpy is 2‐{2‐(diphenylphosphino)ethyl}pyridine). The complexes were fully characterized. The catalytic activities of these complexes were investigated for Suzuki–Miyaura cross‐coupling reactions at room temperature. Complex 2 exhibited excellent activity compared to other analogs. Copyright © 2013 John Wiley & Sons, Ltd.

Ni(II), Cu(II) and Pd(II) Complexes of Anisaldehyde-4-phenyl-thiosemicarbazone: Synthesis, Spectral Characterization and Biological Study

“…The complex 3 in its cyclic voltammogram demonstrated one irreversible reductive response at -0.89 V [∆Ep = 440 mV]. This feature could be assigned to the Pd(II)/Pd(0) redox couple [36], since palladium complexes of π-acceptor ligands undergo two-electron reduction with the stabilization of Pd(0) [37]. Another couple at +0.85V could be tentatively ascribed for irreversible Pd(II)/Pd(IV) couple [∆Ep = 770 mV].…”

Synthesis and Characterization of Cobalt(II) Complexes with Hemilabile P^N Donor Ligands

“…1 FT-IR study: The ν(C-N) stretching frequency for the complex, C1 was observed at 1436 cm -1 which was almost equal to the ν(C-N) stretching frequency value of the free ligand, indicating that the -NMe2 did not take part in the complexation. A weak band at 432 cm -1 and a moderate intensity band at 343 cm -1 could be assigned to Co-P and Co-Cl stretching vibrations, respectively [5]. In the IR spectrum of C2 a sharp band at 1431 cm -1 was attributed to the νpy(C=N) vibration.…”

“…Transition metal complexes containing hemilabile ligand have received considerable attention because of their unusual structural features, versatile binding modes and biological implications [1][2][3][4][5][6][7]. Different types of hemilabile ligands such as P-O, P-S, P-N etc.…”

Transition metal complexes of the pyridylphosphine ligand o-C6H4(CH2PPy2)2

“…This indicated that the fluxional behaviour occurring in solution converted one phosphorus The upfield signal at −47.36 ppm in the 31 P NMR spectrum is diagnostic of a four-membered chelate complex. 75,76 This indicated that in solution pyridyl nitrogens were coordinating reversibly to the iridium centre, forming a four-membered ring. This is consistent with the two different environments for the pyridyl protons of the ligand 1 observed in the 1 H NMR spectrum of this complex at room temperature, as an average of the two pyridyl rings that coordinate to the iridium would be observed as well as the two pyridyl rings that did not interact with the metal centre.…”