Syntheses, Reactivities and Catalytic Properties of Ruthenium and Osmium Complexes

Catalytic H/D exchange reactions of olefins with D2O were developed. Heating a mixture of olefins and D2O at 100 °C in the presence of 3 mol % of RuHCl(CO)(PPh3)3 leads to the isolation of deuterated olefins. The incorporation of deuterium is found at vinyl carbons and the carbons of alkyl chain directly attached to the vinyl group. The catalytic reaction is applicable for both terminal and internal olefins.;In the presence of MHCl(CO)(PPh3)3 (M = Ru, Os), the methyl group of alpha-methyl styrene and the methylene group of 1,3-diphenylpropene undergo H/D exchange reactions with D2O at a rate slower than that for the vinyl moiety. Detailed mechanistic studies of the H/D exchange reactions were carried out both experimentally and theoretically. It was found that the different rates of the H/D exchange reactions are related to bond rotations about M-Calpha and Calpha-Cbeta bonds.;Catalytic H/D exchange reactions of alcohols with D2O were also developed. With the ruthenium hydrogen transfer catalyst [[( p-cymene)RuCl(NH2CH2CH2O)] 2(mu-H)]Cl (3 mol %), reactions of a variety of alcohols with D2O at 80 °C in the presence of KOH lead to the isolation of deuterated alcohols with deuterium regioselectively incorporated at the beta-carbon position of alcohols.;An efficient and convenient synthetic method for the preparation of monosubstituted cyclopentadienyl ruthenium complexes was developed. Treatment of RuHCl(PPh 3)3 with fulvenes without sp3-CH protons at the carbon alpha to the exocyclic carbon of fulvene produces cleanly mono-substituted cyclopentadienyl ruthenium complexes (eta5-C 5H4R)RuCl(PPh3)2 via hydride transfer to the electrophilic exocyclic carbon of fulvenes. When fulvenes containing sp3-CH protons at the carbon alpha to the exocyclic carbon were used, the reactions produce the expected (eta 5-C5H4R)RuCl(PPh3)2 complexes along with minor amounts of vinylcyclopentadienyl ruthenium complexes due to dehydrogenation.;Two synthetic methodologies were developed for the preparation of half-sandwich osmium complexes with the general formula (eta5 -cyclopentadienyl)OsCl(PPh3)2. The first approach involves the reactions of OsH3Cl(PPh3)3 with cyclopentadienes. Treatment of OsH3Cl(PPh3)3 with CpH (CpH, Cp*H, indene, and C5Me4RH (R=H, Et, n-Pr), gives (eta5-cyclopentadienyl)OsCl(PPh 3)2 via C-H bond oxidative addition of cyclopentadienes followed by reductive elimination of hydrogen. Another method involves the insertion reactions of OsH3Cl(PPh3)3 with fulvenes. Treatment of OsH3Cl(PPh3)3 with fulvene or tetramethylfulvene gives (eta5-C 5R4R')OsCl(PPh3)2 (R = H; R' = -CH2(p-C6H4CH3), -CH2(p-C6H4OCH3), -CH2CMe3, -CHPh2 and R = Me; R' = -CH 2(p-C6H4CH3), -CH 2(p-C6H4OCH3), -CH 2(pyrenyl)).;The reactions of Cp*OsCl(PPh3)2 with alkynes were studied. Treatment of Cp*OsCl(PPh3)2 with terminal alkynes HC≡CR (R = Ph, TMS) produced Cp*OsCl(PPh3)(=C=CHR) (R = Ph, H). Treatment of Cp*OsCl(PPh3)2 with internal alkyne CH3O2CC≡CCO2CH3 gave Cp*OsCl(PPh 3)(CH3O2CC≡CCO2CH3). Reaction of Cp*OsCl(PPh3)2 with diphenyl propargylic alcohols gave the osmium allenylidene complex Cp*OsCl(PPh3)(=C=C=CPh 2). Treatment of Cp*OsCl(PPh3)2 with alkynols produced expected vinylidene complexes as well as oxacycliccarbene complexes depending on the length of alkyl chain. Treatment of Cp*OsCl(PPh3) 2 with HC≡CPh and HC≡CC(OH)Ph2 in the presence of TlOTf gave cationic osmium vinylidene and allenylidene complexes respectively. Treatment of Cp*OsCl(PPh3)2 with alkynols in the presence of TlOTf only gave cationic osmium vinylidene complexes [Cp*Os(PPh3) 2(=C=CH(CH2)n-OH)]+ (n = 1 - 4).;Reaction of fulvene C5Me4CH(C6H 4PPh2) with [(p-cymene)RuCl2] 2 produced ruthenium fulvene complex (eta 1:eta6-C5Me4CH(C 6H4PPh2))RuCl2. The iodide analog ( eta1:eta6-C 5Me4CH(C6H4PPh2))RuI 2 could be prepared from the reaction of (eta 1:eta6-C5Me4CH(C 6H4PPh2))RuCl2 with NaI. The cationic species [(eta1:eta 6-C5Me4CH(C6H4PPh 2))RuCl(PPh3)]PF6 and [(eta 1:eta6-C5Me4CH(C 6H4PPh2))RuCl(MeCN)]PF6 could be obtained by treatment of (eta1:eta 6-C5Me4CH(C6H4PPh 2))RuCl2 with PPh3 and MeCN respectively in the presence of TlPF6. The catalytic properties of these fulvene complexes for isomerization of allylic alcohols were also studied.