Date on Master's Thesis/Doctoral Dissertation

5-2007

Document Type

Master's Thesis

Degree Name

M.S.

Department

Chemistry

Committee Chair

Grapperhaus, Craig

Subject

Alkenes--Oxidation; Alkenes--Reactivity; Reactivity (Chemistry)

Abstract

This thesis reports the reactivity of the trithiolato Ru complex PPN[Ru(DPPBT)3] (DPPBT = 2-diphenylphosphinobenzenethiolate) (1a) with alkenes upon oxidation. Complex 1a in acetonitrile shows two redox events at -345 mV and +455 mV in the square wave voltammogram. Bulk oxidation at a holding potential of +100 mV yields [tris(2-(diphenylphosphino)thiaphenolato)ruthenium(III)], (1b). During oxidation, the absorption bands at 540 nm, 797 nm and 1041 nm grow in intensity while there is a decrease in the absorption band at 435 nm. A plot of charge versus time during bulk electrolysis shows a total coulometric charge of 1.14 electron equivalent. The square wave voltammogram is not effected by this oxidation. Further oxidation by one electron in the presence of ethylene at a holding potential of +620 mV yields [(ethane-1,2-diylbis(thio-2,1-phenylene)diphenylphosphine)ruthenium(II)] hexafluorophosphate, (2a). During oxidation the absorption bands at 540 nm, 797 nm and 1041 nm decrease in intensity. Complex 2a displays a single redox couple at +804 mV. The +ESI-MS of 2a shows a parent ion peak at m/z = 1009.1013 amu. The 31P NMR spectrum of 2a shows chemical shift values of ð1 = 61.0 ppm, ð2 = 40.3 ppm, ð3 = 37.5 ppm with coupling constants of J12 ˜ J13 ˜ 30 Hz and J23 = 304 Hz. Complex 2a can be oxidized at a holding potential of +1000 mV to yield [(ethane-1,2-diylbis(thio-2,1-phenylene)diphenyl phosphine)ruthenium(III)] hexaflurophosphate, (2b). The EPR of 2b displays a rhombic signal with g1 = 2.09, g2 = 2.03, g3 = 2.04. Oxidation of 1b in the presence of alkenes including 1-hexene, styrene, cyclohexene, and norbornene yield products similar to 2a. Each of these products can be oxidized to an analogue of 2b. Complex 2a can also be prepared, as the bromide salt, from 1a and 1,2-dibromoethane. The complex [(ethane-1,2-diylbis(thio-2,1-phenylene)diphenylphosphine)ruthenium(II)] bromide crystals as thin yellow plates in the monoclinic space group P21/c with unit cell dimensions of a = 10.2565(9) ?, b = 13.2338(12) ?, c = 38.325(3) ?, and ß = 93.3960(10)°.

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