Synthesis and Catalytic Activity of (η6-p-Cymene)(phosphane)ruthenium(II) Complexes Supported on Poly(biphenoxyphosphazene) or Chiral Poly(binaphthoxyphosphazene) Copolymers
✍ Scribed by Gabino A. Carriedo; Pascale Crochet; Francisco J. García Alonso; José Gimeno; Alejandro Presa-Soto
- Publisher
- John Wiley and Sons
- Year
- 2004
- Tongue
- English
- Weight
- 173 KB
- Volume
- 2004
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
Abstract
The polyphosphazene random copolymer containing diphenylphosphane ligands {[NP(OC~6~H~4~PPh~2~)~2~]~0.4~[NP(O~2~C~12~H~8~)]~0.6~}~n~ (1a) (O~2~C~12~H~8~ = 2,2′‐dioxy‐1,1′‐biphenyl), and the chiral binaphthoxy analogues {[NP(OC~6~H~4~PPh~2~)~2~]~0.1~[NP(O~2~C~20~H~12~)]~0.9~}~n~ [O~2~C~20~H~12~ = (R)‐2,2′‐dioxy‐1,1′‐binaphthyl] (1b) and {[NP(OC~6~H~4~PPh~2~)~2~]~0.2~[NP(O~2~C~20~H~10~Br~2~)]~0.8~}~n~ [O~2~C~20~H~10~Br~2~ = (R)‐2,2′‐dioxy‐6,6′‐dibromo‐1,1′‐binaphthyl] (1c), reacted in dichloromethane at room temperature with appropriate amounts of the dimeric complex [Ru(η^6^‐p‐cymene)Cl(μ‐Cl)]~2~ to give the corresponding polymeric (phosphane)Ru^II^ complexes {[NP(OC~6~H~4~PPh~2~[RuCl~2~(η^6^‐p‐cymene)]~x~)~2~]~0.4~[NP(O~2~C~12~H~8~)]~0.6~}~n~ [x = 0.5 (2a), 1 (2b)], {[NP(OC~6~H~4~PPh~2~[RuCl~2~(η^6^‐p‐cymene)])~2~]~0.1~[NP(O~2~C~20~H~12~)]~0.9~}~n~ (3) and {[NP(OC~6~H~4~PPh~2~[RuCl~2~(η^6^‐p‐cymene)])~2~]~0.2~[NP(O~2~C~20~H~10~Br~2~)]~0.8~}~n~ (4). The isolated products are soluble reddish solids, and are thermally very stable with very high glass transition temperatures. The reaction of 1b or 1c with the cationic precursor [RuCl(PPh~3~)~2~(η^6^‐p‐cymene)][PF~6~] in refluxing THF gave the crosslinked insoluble cationic polymeric complexes {[NP(OC~6~H~4~PPh~2~)~2~]~0.1~[NP(O~2~C~20~H~12~)]~0.9~[RuCl(η^6^‐p‐cymene)(PF~6~)]~0.05~}~n~ (5) and {[NP(OC~6~H~4~PPh~2~)~2~]~0.2~[NP(O~2~C~20~H~10~Br~2~)]~0.8~[RuCl(η^6^‐p‐cymene)(PF~6~)]~0.08~}~n~ (6). All the complexes were active catalysts in transfer hydrogenation of acetophenone by propan‐2‐ol, but the C~2~‐pockets containing the catalytic centers gave no enantioselectivity because of the conformational behavior of the chiral derivatives. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)