Geometrical and Linkage Isomers of [OsCl₂(dmso)₄] − The Complete Picture

Abstract

The isomerisation between the three known isomers of the [OsCl 2 (dmso) (2), and cis-[OsCl 2 (dmso-S) 4 ] (3) -has been investigated by NMR spectroscopy, X-ray crystallographic analysis, and DFT calculations. We show that the two dmso-linkage isomers 2 and 3 equilibrate slowly at room temperature in solutions of both dimethyl sulfoxide (DMSO) and light-protected chloroform. Although crystals of 2 precipitate from DMSO solutions, crystals of 3 were obtained from chloroform solutions. Compound 2 isomerises to 1 after exposure to sunlight, while 1 transforms into 2 in hot DMSO solution. The molecular energies were calculated by DFT methods, which show that in the gas phase there are small differences in the total energies (E t ), with 1 exhibiting

The Complexes [OsCl2(azole)2(dmso)2] and [OsCl2(azole)(dmso)3]: Synthesis, Structure, Spectroscopic Properties and Catalytic Hydration of Chloronitriles

“…trans-[OsCl 2 (dmso) 4 ] and cis-[OsCl 2 (dmso) 4 ] were prepared according to literature protocols. [18] trans,cis,cis-[OsCl 2 (Hind) 2 …”

“…Note that the downfield shift of dmso protons when coordinated through oxygen is much less with respect to the metal-free dmso. [18] In cis-[OsCl 2 (dmso)(dmso) 3 ], for example, this signal is observed at δ = 2.76 ppm. In the 13 C NMR spectrum the dmso resonance is present at δ = 45.4 (1) and 45.6 ppm (3).…”

“…However, the third (linkage) isomer cis-[MCl 2 -(dmso) 4 ], with all dmso ligands coordinated via sulfur, has been isolated only for osmium (II). [18] In addition, it should be noted that despite the similarity between ruthenium(II) dmso and osmium(II) dmso complexes, the latter have, in general, rarely been used as precursors in inorganic synthesis. Examples reported in the literature have been confined to reactions of trans-[OsCl 2 (dmso) 4 ], trans-[OsBr 2 (dmso) 4 ] or cis,fac-[OsCl 2 (dmso)(dmso) 3 ] with chelating ligands containing Te, Sb or P as donor atoms.…”

Osmium(IV) Halide Complexes with Dimethyl Sulfoxide[H(dmso)2][OsX5(dmso‐κO)], X=Cl, Br: Synthesis, Structure, and Properties

“…Even among platinum metal complexes with DMSO, osmium compounds take a special place. First, osmium is multivalent and thus coordination compounds of osmium in the formal oxidation states of +2, +3, and +4 are known. Second, osmium coordination compounds demonstrate impressive structural flexibility and diverse types of structural isomerism.…”

Synthesis and Reactivity of Ru-, Os-, Rh-, and Ir-Halide−Sulfoxide Complexes

“…Both isomers cis,fac-OsCl 2 (dmso-S) 3 (dmso-O) (38) and cisOsCl 2 (dmso-S) 4 (39) have been isolated, depending on the solvent. 369,370,372 In conclusion, the preferred binding mode of dmso on ruthenium is through S, unless the steric demand of the other ligands is significant. Besides that for steric reasons, dmso coordination through oxygen is also favored by a net positive charge of the complex.…”