Synthesis and reactivity of bridging bis(alkyl) and bis(alkylidene) complexes derived from the chiral rhenium fragment [η5-C5H5)Re(NO)(PPh3)]+ Academic Article uri icon

abstract

  • Reactions of Li+ [(η5-C5H5) Re(NO)(PPh3)]- and TfO(CH2nOTf(0.5 equiv.; a, n = 3; b, n = 4; c, n = 5; d, n = 8) give the bridging bis(alkyl) complexes (η5-C5H5)Re(NO)(PPh3(CH2)n(PPh3) (NO)Re (η5-C5H5) (7a-d, 80-89%) as 50-75:50-25 mixtures of configurational diastercomers (meso, dl). Reactions of 7 and Ph3C+PF6- (2 equiv.) give the bridging bis(alkylidene) complexes [(η5-C5H5) Re(NO)(PPh3(=CH(CH2)n-2HC=)(PPh3)(NO)Re(η5-C5H5)]2+2PF6-(3a-d, 76-93%). When heated in chlorobenzene, 3c and 3d rearrange (kobs = 3.9 × 10-5 s-1, 3c, 72°C; 6.3 × 10-5 s-1, 3d, 66°C) to the bridging bis(alkene) complexes [(η5-C5H5)Re(NO)(PPh3(H2CCH(CH2) n-4HCCH2)-(PPh3)(NO)Re(η5-C5H5)]2+2PF6- (5c,d2+ 2PF6-, 90-97%). No cycloalkene complexes derived from ReCHR/ReCHR coupling are detected. Complexes 5c2+ 2BF4- and 5d2+ 2BF4- are independently prepared by reactions of (η5-C5H5)Re(NO)(PPh3)(CH3), HBF4·OEt2and α,ω-dienes in chlorobenzene. © 1992.

author list (cited authors)

  • Roger, C., Peng, T., & Gladysz, J. A.

citation count

  • 11

publication date

  • November 1992