71763-25-2Relevant academic research and scientific papers
Synthesis, structure, and reactivity of the thioformaldehyde complex [(η5-C5H5)Re(NO)(PPh 3)(η2-H2C=S)]+PF 6-
Buhro, William E.,Etter, Margaret C.,Georgiou, Savas,Gladysz,McCormick, Fred B.
, p. 1150 - 1156 (2008/10/08)
Reaction of [(η5-C5H5)Re(NO)(PPh3)(=CH 2)]+PF6- (2) and S=PPh3 gives a 1:1 mixture of thioformaldehyde complex [(η5-C5H5)Re(NO)(PPh 3)(η2-H2C=S)]+PF 6- (1) and ylide complex [(η5-C5H5)Re-(NO)(PPh3)(CH 2PPh3)]+PF6- (3). However, reaction of 2 and cyclohexene sulfide gives 1 (85-95% after recrystallization). An X-ray structure of 1 (crystal data: monoclinic, P21/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 Hu?ckel MO calculations on the model compound [(η5-C5H5)Re(NO)-(PH 3)(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)(SCH 3) (5, 85% after recrystallization). The reactivity of 1 is compared to that of formaldehyde complex [(η5-C5H5)Re(NO)(PPh 3)(η2-H2C=O)]+ PF6-, and the mechanisms of the above reactions are discussed.
Metal complexes of sulfur-containing ligands. Synthesis and properties of a series of rhenium-substituted sulfonium salts [(η5-C5H5)Re(NO)(PPh3)(CH 2-)]nS+(CH3)3-n (n = 1-3)
McCormick, Fred B.,Gleason, William B.,Zhao, Xiande,Heah, Poh Choo,Gladysz
, p. 1778 - 1785 (2008/10/08)
Reaction of [(η5-C5H5)Re(NO)(PPh3)(=CH 2)]+PF6- (1, -78°C) with CH3SCH3 gives sulfonium salt [(η5-C5H5)Re(NO)(PPh3)(CH 2S(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)(CH 2PPh3)]+PF6- (4, 76%) and [(η5-C5H5)Re(NO)(PPh3)(CH 2N(CH)4CH)]+PF6- (5), respectively. Reaction of 2 with RS- gives (η5-C5H5)Re(NO)(PPh3)(CH 2SR) (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)(CH 2-)]2S+CH3PF6- (7+PF6-, 89-92%) as a 2:1:1 mixture of diastereomers. 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) A?, b = 20.767 (2) A?, c = 13.944 (2) A?; 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)(CH 3) (8, 84%) and [(η5-C5H5)Re(NO)(PPh 3)(=CHSCH3)]+PF6- (9, 82%). Reaction of 1 with Na2S gives trinuclear sulfonium salt [(η5-C5H5)Re(NO)(PPh3)(CH 2-)]3S+PF6- (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.
MECHANISM OF COUPLING OF equals CH2 TO H2C equals CH2 AT A HOMOGENEOUS ( eta -C5H5)Re(NO)(PPH3) + CENTER. REMARKABLE ENANTIOMER SELF-RECOGNITION.
Merrifield,Lin,Kiel,Gladysz
, p. 5811 - 5819 (2007/10/02)
The methylidene complex couples to the ethylene complex at 273-308 K in CH//2Cl//2. The rate of coupling is second order in 1 and not affected by the presence of 5-10 equiv of RCN. Data collected from 273 to 308 K give numerical results. Crossover experiments show that no PPh//3 dissociation or intermolecular methylidene scrambling occurs prior to the rate-determining coupling step, and that the RR and SS transition states are greatly preferred over the RS transition state (enantiomer self-recognition). 84 refs.
EXPLORATORY ORGANOMETAL-SULFUR CHEMISTRY; SYNTHESES AND UNUSUAL PROPERTIES OF RHENIUM CH2SR, CHSRR', AND =CHSR>+ COMPLEXES
McCormick, Fred B.,Gladysz, J.A.
, p. C57 - C61 (2007/10/02)
The methylidene complex +PF6- (I) yields kinetically labile sulfonium salts when treated with CH3SCH3, CH3SCH2C6H5, and (η-C5H5)Re(NO)(PPh3)(CH2SCH3) (V); the binuclear addict formed in the latter case, (η
