Synthesis, structure, and reactivity of the thioformaldehyde complex [(.eta.5-C5H5)Re(NO)(PPh3)(.eta.2-H2C:S)]+ PF6-
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Reaction of [(η75-C5H5)Re(NO)(PPh3)(=CH2)]+PF6“ (2) and S=PPh3gives a 1:1 mixture of thioformaldehyde complex [(η-C5H5)Re(NO)(PPh3)(η2-H2C=S)]+PF6“ (1) and ylide complex [η5-C5H5)Re-(NO)(PPh3)(CH2PPh3)]+PF6~ (3). However, reaction of 2 and cyclohexene sulfide gives 1 (85-95% after recrystallization). An X-ray structure of 1 (crystal data: monoclinic, P2i/c; a = 9.688 (2) A, b = 18.536 (4) A, c = 14.895 (s) A; β = 103.53 (2)°; Z = 4) shows that the η2-H2C=S ligand adopts a conformation that has significant overlap of its π* orbital with the rhenium fragment HOMO and its sulfur terminus syn to the PPh3. Extended Huckel MO calculations on the model compound [η5-C5H5)Re(NO)-(PH3)(η2-H2C=S)]+predict a similar conformational energy minimum. Complex 1 is stable in CD3CN (41 h, 51 °C) but rapidly reacts with PPh3(2 equiv) to give 3 (95%) and S—PPh3(88%). Reaction of 1 and NaBH3CN gives thiomethyl complex (η5-C5H5)Re(NO)(PPh3)(SCH3) (5, 85% after recrystallization). The reactivity of 1 is compared to that of formaldehyde complex [(η5-C5H5)Re(N0)(PPh3)(η2-H2C=0)]+PF6~, and the mechanisms of the above reactions are discussed. © 1987, American Chemical Society. All rights reserved.
author list (cited authors)
Buhro, W. E., Etter, M. C., Georgiou, S., Gladysz, J. A., & McCormick, F. B.