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Rapid geometrical equilibrium of palladium(II) complexes with tris[2-(diphenylphosphino)ethyl]phosphine disulfide and diselenide and their catalytic activity for Suzuki coupling reaction by Sen-ichi Aizawa; Takashi Hase; Tsuyoshi Wada is a Chemistry article available to read on EtoBox.

What is Rapid geometrical equilibrium of palladium(II) complexes with tris[2-(diphenylphosphino)ethyl]phosphine disulfide and diselenide and their catalytic activity for Suzuki coupling reaction about?

Palladium(II) complexes with a tetradentate pseudo-tripodal ligand having two phosphino groups and two phosphine sulfide or selenide groups, pp 3 X 2 (pp 3 = tris[2-(diphenylphosphino)ethyl]phosphine, X = S (1) or Se (2)), were prepared from [PdCl(pp 3 )]Cl. Both of these phosphine chalcogenide complexes 1 and 2 showed rapid equilibrium between the five-coordinate [PdCl(pp 3 X 2 )]Cl with two bound phosphine chalcogenide groups and four-coordinate [PdCl 2 (pp 3 X 2 )] with two dissociated pendant ones in chloroform. The thermodynamic parameters for the reaction, [PdCl(pp 3 X 2 )] + + Cl À ¢[PdCl 2 (pp 3 X 2 )], were obtained by low-temperature 31 P NMR as follows: K 298 = 3.7 • 10 3 and 5.4 • 10 2 mol À1 , DH = 11.3 ± 0.3 and 13.4 ± 0.4 kJ mol À1 , and DS = 106 ± 2 and 97 ± 2 J mol À1 K À1 for 1 and 2, respectively. The rate for the geometrical change at 246.7 K for 1 was appreciably faster than that for 2. These thermodynamic and kinetic results indicate that the phosphine selenide Se atoms can stabilize the five-coordinate structure by effective p-back donation from Pd(II) compared with the phosphine sulfide S atoms. Difference in retention of the catalytic activity for Suzuki co

Who reads Rapid geometrical equilibrium of palladium(II) complexes with tris[2-(diphenylphosphino)ethyl]phosphine disulfide and diselenide and their catalytic activity for Suzuki coupling reaction?

Author

Sen-ichi Aizawa; Takashi Hase; Tsuyoshi Wada

Publisher

Elsevier Science; Elsevier ; Elsevier BV (ISSN 0022-328X)

Published

2007

Language

EN

Field

Chemistry (Physical Sciences)