Sulfur-bonded sulfoxide complexes of rhodium(III) and rhodium(I)

Abstract

Aqueous 2-propanol solutions of RhCl3•3H2O on treatment with sulfoxides yield mer-RhCl3L3 complexes, the sulfoxide L being dimethyl (DMSO), tetramethylene (TMSO), methyl phenyl (MPSO), or (R)-methyl-p-tolyl (MPTSO); with diphenyl sulfoxide (DPSO), a [RhCl(DPSO)2]2 complex with S-bonded sulfoxide is obtained via the propanol reduction of a Rh(III) intermediate. The mer-rhodium(III) complexes in solution contain two sulfur-bonded sulfoxides (R2SO), and one oxygen-bonded sulfoxide (R2SO) that is trans to a (R2SO) ligand. The DMSO ligand in mer-RhCl3(DMSO)2(DMSO) is displaced by amides, amine oxides, and phosphine oxides; the DMSO cis to the oxygen-bonded ligands is identified in nmr by using the ring current shielding effects of OPPh2Me. Salts of [RhCl4(R2SO)2]− have been obtained with n-propyl sulfoxide and DMSO using several cations, including the symmetrically hydrogen-bridged species, [R2SO—H—OSR2]+. The cyclooctene precursor [RhCl(C8H14)2]2 has been used to synthesize [RhCl(DPSO)(C8H14)]2, [RhCl(DMSO)2]2, and [RhCl(DIOS)2]2, where DIOS is (2R,3R)-2,3-isopropylidene-2,3-dihydroxy-1,4-bis(methylsulfinyl)butane. The nature of rhodium–sulfur bonding is discussed, especially in terms of a contribution of metal–sulfur π-backbonding.

Effects of halide (X) and sulfoxide (R2SO) replacement within the ruthenium(II) nitroimidazole complexes, RuX2(R2SO)m, (nitroimidazole)n, m = 1-3, n = 1 or 2: their characterization, solution chemistry, radiosensitizing activity, and related properties

“…Bonding through the S of a sulfoxide increases the vso with respect to the free ligand value, this being 1050 and 950 cm-' for dmso and tmso, respectively (16)(17)(18). The ir data for all the new complexes 2 and 4-14 (see Experimental section) show bands consistent with S-bonded sulfoxides.…”

Selective catalytic oxidation using hydrogen/oxygen mixtures with solutions of iridium and rhodium complexes

“…Using DMSO as solvent with olefinic substrates gave only sulphone formation according to reaction [4], presumably because the olefin is unable to compete with DMSO for a coordination site. The DMSO appears to stabilize the rhodium(I11) hydride, rather than the rhodiuni(1) state (reaction [3]), as observed in synthetic studies (23). The oxygen atom transfer to the sulfoxide is again considered to involve a hydroperoxide intermediate rather than free hydrogen peroxide; coordination of the sulfoxide may not be essential, since the mechanism outlined in equation [21], which is exactly analogous to that suggested for the metal-catalyzed alkylhydroperoxide oxidation of sulfides to sulfoxides (52) For personal use only.…”

“…Rh) were prepared according to literature proccdurcs (17,(19)(20)(21). The complexes IrHC12(DMSO)3 (22) and RhCI,(DMSO), (23) with meridional dimethylsulfoxide ligands wcre also synthesized via published methods. 1.5-Cyclooctadiene.…”

“…Use of the RhC1,(DMSO)3 complex in DMA, which readily generates RhCl,(DMSO)? (DMA) containing two S-bonded DMSO ligands (23), yielded also some sulfone (DMSO?) and sulfide (DMS) by oxygenation and hydrogenation, respectively.…”

Spectroscopic Evidence for Steric Enhancement of Resonance in Rhodium (Iii) Chloride Complexes

“…[8] These complexes are of mer-RhCl 3 L 3 . The nature of Rh-S bonding is discussed in terms of a contribution of metal-sulphur π-back bonding.…”