Nitrosyl complexes cobalt

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. 

Factors That Control the Reactivity of Cobalt(III)-Nitrosyl Complexes in Nitric Oxide Transfer and Dioxygenation Reactions... 

As has been deseribed, the parent monoearbollide-metal earbonyl piano-stool species [2-(CO) -c/oi o-2,l-MCBioHii] are now known for all of the metals M = Mo (12), W (13), Re (14), Fe (11), Ru (6), Os (8), and Ni (18). Evidence also exists for a diearbonyl-platinum analogue of eompound 18, ° and as mentioned earlier, the manganese analogue of 14 has also briefly been reported. A notable absenee from this list, however, is any representative of the Group 9 metals. The earbonyl nitrosyl-cobalt complex 21 is very elosely related to the hitherto unknown dicarbonyl-cobalt dianion [2,2-(CO)2-c/oi o-2,l-CoCBioHii] and this species remains an attractive synthetie target. 

Cobalt mono-nitrosyl complexes, [Co(NO)(S—S)2], can be obtained similarly by treating [Co(S—S)2]22 with NO. However, these species are significantly less stable than their iron analogues (118). 

Optically active organometallic complexes have been used to study stereochemical reactions. Substituted cobalt nitrosyl complexes are interesting chiral see Chiral) complexes because they exhibit tetrahedral structures, whereas most optically active organometallic complexes are half-sandwich structmes with octahedral geometries. Diastereomeric cobalt complexes of the type Co(CO)(NO)(L)( L) (L = phosphite or phosphane L = optically active phosphane or isocyanide) have been synthesized from (4) via substitution (Scheme 6). ... 

Still more problematic is the apparent migratory insertion of nitric oxide into transition metal-carbon bonds, an important reaction in metal nitrosyl complexes and one that may be relevant to biochemical reactions (7). On the evidence of isotopic labeling and kinetic experiments, the insertion of NO into the C0-CH3 bond of the (cyclopentadie-nyl)cobalt complex (i75-C5H5)Co(NO)(CH3), which occurs in Reaction (3),... 

Wang X, Andrews L (2001) Cobalt carbonyl nitrosyl complexes matrix infrared spectra and density functional calculations. J Phys Chem A 105 4403-4409... 

LCon02] + RH2— [LCo i02H]- + RH followed by reactions of the radicals and HOa. In the case of the suporoxocobalamin complex, the [LCo OaH] complex has been characterized spectroscopically. In the reactions of nitrosyl-Schiflf-base-cob dt(n) [L Co(NO)] complexes with oxygen in the presence of base, B (e.g. pyridine), the formation of nitro-complexes has been reported. Kinetic studies show the reaction to be first order in [Oa] and cobalt complex. Quantitative uptake of 0.5 mole of dioxygen per mole of complex observed is in accord with the scheme... 

Carbonyl Nitric Oxides. Another group of metal-carbonyl complexes, worthy of investigation as CVD precursors, consists of the carbonyl nitric oxides. In these complexes, one (or more) CO group is replaced by NO. An example is cobalt nitrosyl tricarbonyl, CoNO(CO)3, which is a preferred precursor for the CVD of cobalt. It is a liquid with a boiling point of 78.6°C which decomposes at 66°C. It is prepared by passing NO through an aqueous solution of cobalt nitrate and potassium cyanide and potassium hydroxide. ... 

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