Nitrosyl clusters metals

There is interest in the possible use of other metal nitrosyl complexes as vasodilators, but from the series KJM(CN)6NO] where M = V, Cr, Mn, and Co (n = 3) or M = Mo (n = 4) neither the Cr nor the Mn complexes exhibit any hypotensive action (504). Iron-sulfur-nitrosyl clusters such as [Fe4S4(NO)4] are active, and their effects can be potentiated by visible light (505). 

Reductive nitrosylation, transition metal nitrosyl complexes, 34 296-297 ReFejSj cluster, 38 41-43 self-assembly system, 38 41-42 Refining, of actinide metals, see Actinide, metals, purification Refractory compounds heat treatment of solids, 17 105-110 crystal growth, 17 105, 106 decomposition, 17 107,-110 spheroidization, 17 106, 107 preparation of, using radio-frequency plasma, 17 99-102... 

Few successful reactions are known by which an organometallic nitrosyl product has been formed from the condensation of mononuclear metal nitrosyl complexes. The unique cluster (Tj -C5H5)3Mn3(NO)4 (39), which contains the only i3-NO known (7) (40), is prepared using photochemical or thermal (41) decarbonylation of (Tj -C5H5)2Mn2(CO)2(NO)2 [Eq. (25)]. The use of the redox condensation of a nitrosyl carbonylmetallate with a neutral metal carbonyl cluster to produce a nitrosyl cluster has... 

In this section the reactivity of metal nitrosyl complexes is discussed and related to the NO coordination mode. A considerable difference between the chemistry of nitric oxide and carbon monoxide complexes has already been noted. The reactivity of nitric oxide coordinated to transition metal centers, and of nitrosyl clusters, were thoroughly reviewed in 1979 by McCleverty (7) and in 1985 by Gladfelter 11), respectively therefore only a summary is presented here. Nucleophilic reactions of linear nitrosyl groups will not be considered. 

Although a large number of transition metal nitrosyl compounds have been prepared 208), Mn3(77--Cp)3(NO)4 described in Section II, D is the only characterized nitrosyl cluster 130). King has isolated a compound for which he postulated the formula Fe2(NO)2[S2C2(CF3)2]2, but the mass spectra indicated the formulation Fe3(NO)4S[S2C2(CF3)2]2 240). 

Method (i) is a route commonly utilized in monometal nitrosyl complexes. The nitrosyl ligand may function as (formally) a three-electrop donor (NO+) with a linear bonding mode, or as (formally) a one-electron donor (NO ) with a bent (—120°) M-N-0 arrangement. Conversion of the M-NO system to a M-NO system has two effects. First, it increases the metal oxidation state by two second, it generates a vacant coordination site. The dinitrosyl cluster Os3(CO)8(NO)2, which has... 

N NMR spectroscopy, 32 364-365 heterometallic cluster synthesis by nitrosylation of performed heterometallic aggregates, 32 350-351 from sulfur-rich metal complexes, 32 352-353... 

Metal cluster compounds can be conveniently grouped into two classes (I) polynuclear carbonyls, nitrosyls. and related compounds and (II) halide and oxide complexes. The former group was included m Chapter 15. The second class will be discussed in this section.146... 

The recent upsurge of interest in iron-sulfur-nitrosyl complexes has been stimulated in part by the reported isolation of [Fe2(SMe)2(NO)4] from natural sources (12), by the obvious resemblances between these complexes and the naturally occurring [2Fe-2S] and [4Fe-4S] clusters of iron sulfur proteins (23, 14), and by the connections between tetrairon-sulfur-nitrosyls and cubane-type clusters (15). Most of the work in this area has been published in the past 5 years or so, and no review has previously been made. However, a number of excellent reviews of the wider aspects of metal-nitrosyl chemistry have appeared (16 19). 

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