Rhenium nitrosyl complexes

The treatment of [ReOCl3(PPh3)2] with NO gas is a complex reaction and yields a number of paramagnetic rhenium(II) nitrosyl complexes depending on the conditions. This has been checked... 

Llamazares A, Schmalle HW, Berke H (2001) Ligand-assisted heterolytic activation of hydrogen and silanes mediated by nitrosyl rhenium complexes. Organometallies... 

Complexes containing rhenium in the oxidation state +IV are comparatively rare. There is no extended chemistry in aqueous media and many rhenium(IV) complexes tend to hydrolyze when exposed to water. The stabilization of rhenium(IV) centers requires a well-balanced donor-acceptor behavior of the ligands and, thus, none of the classical rr-donor ligands such as O or TT-acceptors such as carbonyls or nitrosyls are characteristic for this oxidation state... 

Acetylacetonato complexes of various composition have been reported as the products of reactions between acetylacetone (Hacac) and rhenium nitrosyl precursors. Compositions of [Re(NCpCl(acac)2(H20)] and [Re(N0)(acac)3(Hacac)(H20)2] have been assigned to the prod-... 

Most rhenium nitrosyl complexes have been prepared using NO, NOX or HN03 as the nitrosylat-ing agent. Recently, the reductive nitrosylation of [Re04] with NH2OH-HCl in the presence of NCS or Nf in an alkaline medium has been accomplished.556 The complexes formed in this way include [Re(NO)X3(H20)] (X = NCS or N3) and [Re(N0)X2(L)(H20)j (L = bipy or phen), containing the [ReNO]2+ moiety and existing in several isomeric forms. 

A thiolato-nitrosyl complex [Re2 (NO)2 (SPh)7] has been made in low yield by reacting [Re(NO)Cl2(PPh3)2] (later reformulated as [Re(NO)Cl2(OMe)(PPh3)2])560,561 with thiophenol in refluxing methanol in the presence of triethylamine. The crystal structure performed on the [Pl P] salt of the p-tolylthiol derivative shows the complex to consist of two pseudooctahedral rhenium units linked by three bridging thiolato ligands. The Re—Re distance of 2.783(1) A indicates significant metal-metal interaction.562... 

The NO + MF, (except NO -f WF,) reactions proceed spontaneously at 20°. The reactions were followed tensimetrically. Gaseous products were identified by infrared spectroscopy and the solid products were examined by. y-ray powder-photography. Both ReF, and OsF, formed NO+[MF,] (cub.) salts and neither salt could be induced to combine with more NO to yield the quadrivalent (NO),MF, compound. In their reactions with nitrosyl fluoride at 20°, however, the rhenium and osmium fluorides are clearly differentiated ReF, readily forms a thermally stable 2 1 adduct, which is isomorphous with (NOjjWFg, whereas the OsF, -i- ONF reaction is complex. The identification of small quantities of nitrogen oxide trifluoride, in the gaseous product of the reaction, indicate the existence of an... 

The most important nitrile compound of Re is ReCl3(NCMe)(PPh3)2, a complex which finds much use as a starting material for the synthesis of other Re complexes and some derivatives of Re. This complex and others of its kind are discussed in Section 43.5.1.6. Other complexes that contain a single nitrile ligand, e.g. [ReOBr4(NCMe)] and [ReBr4(NO)(NCMe)] , are most conveniently considered in other sections, i.e. Rhenium(V) Complexes (Section 43.7) and Nitrosyls (Section 43.10), respectively, for the two examples cited here. 

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