Rhenium nitrosyls

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. Messmer Rhenium-Nitrosyl-Hydride mit aktivierten Metall-WasserstofF-bindungen. Dissertation University of Zurich, 1999, Hartung-Gorre, Konstanz, 2000. 

Group 7 Rhenium Nitrosyl Complexes in Homogeneous Catalysis. 183... 

In these rhenium nitrosyl complexes the nitrosyl ligand takes different functions (1) as an ancillary NO ligand mimicking isoelectronic metal carbonyls (2) as a frans-influence ligand to activate donor ligands for atom or group transfer reaction. 

Ligand-metal bifunctional catalysis provides an efficient method for the hydrogenation of various unsaturated organic compounds. Shvo-type [83-85] Ru-H/OH and Noyori-type [3-7] Ru-H/NH catalysts have demonstrated bifimctionality with excellent chemo- and enantioselectivities in transfer hydrogenations and hydrogenations of alkenes, aldehydes, ketones, and imines. Based on the isoelectronic analogy of H-Ru-CO and H-Re-NO units, it was anticipated that rhenium nitrosyl-based bifunctional complexes could exhibit catalytic activities comparable to the ruthenium carbonyl ones (Scheme 29) [86]. 

Choualeb A, Maccaroni E, Blacque O, Schmalle HW, Berke H (2008) Rhenium nitrosyl complexes for hydrogenations and hydrosilylations. Organometallics 27 3474—3481... 

Cboualeb A, Lougb AJ, Gusev DG (2007) Hydridic rhenium nitrosyl complexes with pmcer-type PNP ligands. Organometallics 26 3509-3515... 

Freeh CM, et al. Unprecedented ROMP activity of low-valent rhenium-nitrosyl complexes mechanistic evaluation of an electrophilic olefin metathesis system. Chemistry 2006 12(12) 3325-38. 

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... 

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... 

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... 

Rhenium Carbonyl-( j5-cyclopenta-dienyl)-formyl-nitrosyl- XIII/9a, 157... 

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