Metal complexes of sulfur-containing ligands. Synthesis and properties of a series of rhenium-substituted sulfonium salts [(.eta.5-C5H5)Re(NO)(PPh3)(CH2)]nS+(CH3)3-n(n = 1-3)
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Reaction of [(η5-C5H5)Re(NO)(PPh3)(=CH2)]+PF6- (1, -78 °C) with CH3SCH3 gives sulfonium salt [(η5-C5H5)Re(NO)(PPh3)(CH2S(CH3)2)]+PF6- (2, 90-95%). Variable-temperature NMR data show that CH3SCH3 reversibly gives from 2 with ΔG*262= 14.2 kcal/mol and ΔG*289 = 12.9 kcal/mol. Reaction of 2 with PPh3 and pyridine give [(η5-C5H5)Re(NO)(PPh3)(CH2PPh3)]+PF6- (4, 76%) and [(η5-C5H5)Re-(NO)(PPh3)(CH2N(CH)4CH)]+PF6- (5), respectively. Reaction of 2 with RS- gives (η5-C5H5)Re(NO)-(PPh3)(CH2SR) (6, 79-95%; R = CH3(a), C6H5 (b), CH2C6H5 (c)). Reaction of 1 or 2 with 6a gives binuclear sulfonium salt [(η5-C5H5)Re(NO)(PPh3)(CH2-)]2S+CH3PF6- (7+PF6-, 89-92%) as a 2:1:1 mixture of dia-stereomers. Treatment of 7+PF6- with NaI/CH3CN gives 7+I-, which crystallizes as one diastereomer as shown by X-ray crystallography. Crystal data: orthorhombic, Pnma; a = 18.348 (6) Å,b = 20.767 (2) Å, c = 13.944 (2) Å; Z = 4. Reaction of 7+PF6- with PPh3 gives 4 (90%) and 6a (71%). Pyrolysis of 7+PF6- (80 °C, 8 h) gives (η5-C5H5)Re(NO)(PPh3)(CH3) (8, 84%) and [(η5-C5H5)Re(NO)(PPh3)(=CHSCH3)]+PF6-(9, 82%). Reaction of 1 with Na2S gives trinuclear sulfonium salt [(η5-C5H5)Re(NO)(PPh3)(CH2-)]3S+PFe- (10, 84%). Complex 10 reacts only sluggishly with PPh3 (65 °C). These reactions show that the (η5-C5H5)Re(NO)(PPh3) moiety significantly enhances the basicity of sulfide sulfur atoms that are β to it. © 1986, American Chemical Society. All rights reserved.
author list (cited authors)
McCormick, F. B., Gleason, W. B., Zhao, X., Heah, P. C., & Gladysz, J. A.