Nitrosyls bridging

Nitrosyl complexes are of considerable structural and chemical interest. Direct syntheses from the corresponding carbonyls are reported here for two nitrosyl-carbonyl clusters containing double nitrosyl bridges. ( Caution. Considerable amounts of toxic nitric oxide are used in these reactions, which should therefore be carried out in an efficient hood.)... 

Bonding of NO to transition metals usually occurs via the nitrogen atom. Other types of bonding occur in some rare cases and include twofold and threefold nitrosyl bridges o/jr-dihaptonitrosyls (so-called side-on nitrosyls) and isonitrosyls (M-O-N bound), as reviewed in [6]. 

Calderon JL, Cotton FA et al (1971) Molecular structure of an unusual binuclear manganese complex with highly unsymmetiical nitrosyl bridges. J Chem Soc D 1476-1477... 

Norton JR, Colhnan JP et al (1972) Preparation and structure of ruthenium and osmium nitrosyl carbonyl clusters containing double-nitrosyl bridges. Inorg Chem 11 382-388... 

Figure 11.13 Structures of polynuclear nitrosyl complexes (a) ((Cr( j -C5H5)(NO))2(M2-NH2)(M2-NO) showing linear-terminal and doubly bridging NO and (b) (Mn3( j -C5H5)3( 3-NO)3( 3-NO)] showing double-and triply-bridging NO the molecule has virtual symmetry and the average Mn-Mn distance is 250 pm (range 247-257 pm).

The hexamine cobalt (II) complex is used as a coordinative catalyst, which can coordinate NO to form a nitrosyl ammine cobalt complex, and O2 to form a u -peroxo binuclear bridge complex with an oxidability equal to hydrogen peroxide, thus catalyze oxidation of NO by O2 in ammoniac aqueous solution. Experimental results under typical coal combusted flue gas treatment conditions on a laboratory packed absorber- regenerator setup show a NO removal of more than 85% can be maitained constant. 

Osterloh, F., Saak, W, Haase, D. and Pohl, S. (1997) Synthesis, X-ray structure and electrochemical characterization of a binuclear thiolate bridged Ni-Fe-nitrosyl complex, related to the active site of NiFe hydrogenase. Chem. Commun. (Cambridge), 1997, 979-80. 

Cluster Compounds.—The green nitrosyl cluster Os3(CO)jo(NO)2 has been reported in 13% yield from the reaction of NO with Os3(CO) 2 benzene. Its i.r. spectrum suggests bridging nitrosyl groups, which was confirmed from an X-ray analysis of the Ru analogue. I.r. studies show that the structure (23)... 

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