Pallada‐ and platinacycle complexes of phosphorus ylides; synthesis, X‐ray characterization, theoretical and electrochemical studies and application of Pd(II) complexes as catalyst in Suzuki‐Miyaura coupling reaction

Abstract

The new unsymmetrical phosphonium salts [Ph 2 PCH 2 PPh 2 CH 2 C(O)C 6 H 4 R]Br (R= m-Br (S 1 ) and p-CN (S 2 )) were synthesized in the reaction of 1,1bis(diphenylphosphino)methane (dppm) and BrCH 2 C(O)C 6 H 4 R (R= m-Br and p-CN) ketones, respectively. Further treatment with NEt 3 gave the α-keto stabilized phosphorus ylides Ph 2 PCH 2 PPh 2 C(H)C(O)C 6 H 4 R (R= m-Br (Y 1 ) and p-CN (Y 2 )). These ligands were reacted with [MCl 2 (cod)] (M= Pd and Pt; cod= 1,5cyclooctadiene) to give the pallada-and platinacycle complexes [MCl 2 (Ph 2 PCH 2 PPh 2 C(H)C(O)C 6 H 4 R)] (M= Pd, R= m-Br (3); R= p-CN (4) and M= Pt, R= m-Br (5); R= p-CN (6)). Cyclic voltammetry, elemental analysis, IR and NMR ( 1 H, 13 C and 31 P) spectroscopic methods were used for characterization of the obtained compounds. Further, the structure of complexes 3 and 4 were characterized crystallographically. Palladacycles 3 and 4 were proved to be excellent catalysts for the Suzuki-Miyaura coupling reactions of various aryl chlorides and arylboronic acids in mixed DMF/H 2 O media. Also, the bonding situations between two interacted fragments [PtCl 2 ] and Y 1 and Y 2 ligands in platinacycles 5 and 6 were investigated based on DFT method by using NBO, EDA and ETS-NOCV analysis.

Groups 9 and 10 Complexes of C–Donor Ligands Derived from Pyridinium-Stabilized Phosphorus Ylides

“…Thus, 14 exhibits modest catalytic activity under the reaction conditions used in this study. The activity of 14 is comparable to that reported for other stabilized P-ylide palladium complexes, such as 27 and 28 (Table 3, entries 6−7), 30,31 but is inferior to other established phosphine and NHC palladium catalysts. 32 In addition, the relatively low CO stretching frequency of 1984 cm −1 observed in Rh(I) complex 20 offers further evidence of strong ligand donor ability.…”

“…Using the procedure given for the preparation of 12a, ligand 12b (0.15 g, 89%) was obtained from 0.20 g (0.37 mmol) of 10b. 31 Alkylidene Dihydropyridine 12c. Using the procedure given for the preparation of 12a, ligand 12c (0.16 g, 92%) was obtained from 0.20 g (0.30 mmol) of 10c.…”

“…Using the procedure given for the preparation of 12a, ligand 12d (0.16 g, 90%) was obtained from 0.20 g (0.29 mmol) of 10d. 31 [(12a)PdCl 2 ] 2 •2BF 4 15. Alkylidene dihydropyridine 12a (0.17 g, 0.36 mmol) was dissolved in CH 3 CN (36 mL, 0.01 M) and deoxygenated by bubbling Ar through the solution for 15 min.…”

“…> 230 °C. 31 Diphenyl(diphenylphosphinomethyl)phosphonium Salt 9c. Obtained as a white solid, 0.52 g (95%).…”

Spectral and crystallography studies of new palladacycle complexes with P,C‐ and C,C‐donor ligands; Application of (OAL16) to optimizing the yield of Mizoroki‐Heck reaction

“…Additionally, Pd (II) complexes bearing phosphine groups have been extensively applied as efficient catalysts in some cross‐coupling reactions, specifically, the Mizoroki‐Heck reaction. The Mizoroki‐Heck reaction, has emerged as the most important and reliable method for construction of functionalized olefins, and it can be catalyzed with the Pd (II) complexes of such phosphorus ylides . Palladium complexes ( 1 and 2 ) were employed as homogeneous catalysts in C‐C coupling reactions.…”