Nitrosyl complexes of chromium

A. DICARBONYL(t -CYCLOPENTADIENYL)NITROSYL complexes of CHROMIUM, MOLYBDENUM, AND TUNGSTEN... 

Nitrosyl Complexes of Chromium(III) with Dipy and Phen 183... 

J. R. Dethlefsen, A. Dossing, and E. D. Hedegard, Electron paramagnetic resonance studies of nitrosyl and thionitrosyl and density functional theory studies of nitride, nitrosyl, thionitrosyl, and selenoni-trosyl complexes of chromium, Inorg. Chem., 49 (2010) 8769-8778. 

The chemistry of the dicarbonyl(7 -cyclopentadienyl)nitrosyl and the chloro-(i7 -cyclopentadienyl)dinitrosyl complexes of chromium, molybdenum, and tungsten [i.e., fT -CsHs)M(CO)j(NO)] and [(i7 -CsHs)M(NO)2Cl] has not been studied extensively, partly because of the various difficulties associated with their preparation. The procedures described below are of general applicability to all three metals and lead to the desired compounds in high yields. The carbonyl nitrosyl complexes are the synthetic precursors of the chloro nitrosyl complexes and so their preparation is described first. 

Several other nitroso compounds have been investigated by PES. The nitrosyl halides, Hal-NO, are basic inorganic compounds. Of particular inteest for organic chemists are nitrosamines, R2N—NO, and nitrites, RO—NO. The NO group occurs as a ligand in transition metal complexes and PE spectra of complexes of chromium, manganese, iron, cobalt and nickel have been measured. ... 

The NO complexes of chromium that have been reported to date exist in the nitrosyl forms. In coordination complexes in particular, several compounds of configuration Cr(NO) have been isolated these have been reviewed recently (80,81). In a 2005 review. Ford and coworkers noted that photolysis of some Fe, Mn, and Cr nitrosyl complexes often leads to the dissociation of the nitrosyl ligands (82). For example, photolysis of the [(H20)5Cr(N0)] complex under anaerobic conditions, and in the... 

Chromium, Molybdenum, and Tungsten. Neutron diffraction studies on [Crj-(CO)io(a -D)] at 17 K provide evidence for a four-fold site distribution of the deuterium. A more simple preparation of homo- and hetero-dinuclear complexes from the combination of 17-e species [M(CO)3Cp, (M=Cr, Mo, W) Mn(CO)s Fe(CO)2Cp Co(CO)4 Ni(CO)Cp] has been described. Heating [Cr(CO)2( -C6He)(NCMe)] results in the formation of the Cr Cr complex, [Cr2( -C6H6)2(/M-CO)3], and the antiferromagnetic complexes, [CraCpgCw-S)-(jM-EPh)2], (E = S, Se), have been reported. The preparation of a variety of nitrosyl dimers of chromium, molybdenum, and tungsten has been reported ... 

Chromatography cyclophosphazenes, 21 46, 59 technetium, 11 48-49 Chromites, as spinel structures, 2 30 Chromium, see Tetranuclear d-block metal complexes, chromium acetylene complexes of, 4 104 alkoxides, 26 276-283 bimetallics, 26 328 dimeric cyclopentdienyl, 26 282-283 divalent complexes, 26 282 nitrosyls, 26 280-281 trivalent complexes, 26 276-280 adamantoxides, 26 320 di(/ >rt-butyl)methoxides, 26 321-325 electronic spectra, 26 277-279 isocyanate insertion, 26 280 substitution reactions, 26 278-279 [9]aneS, complexes, 35 11 atom... 

Several chromium nitrosyls, and complexes of quinones which are members of redox series, can be considered to contain chromium(O) or chromium(I) (see Sections 35.4.2.6 and 35.4.4.8). 

Nitrosyl derivatives of the homologues of chromium may be made directly as insoluble precipitates by decomposing the complex anions [CbH5Mo(CO)3] and [CsHsW (CO) 3] with nitric oxide in aqueous media 85). After high-vacuum sublimation at 55-60° the orange-red... 

Table 64 Some Properties of Macrocyclic-chromium Nitrosyl Complexes ...

A direct, quantitative, and convenient method for the preparation of [Cr(H20)5N0] has been achieved by the slow, dropwise addition of an aqueous solution of Cr° (10 ml, 0.5 mol 1" ) to a stirred solution of HCIO4 (200 ml, 0.1 mol 1" ) which was continuously saturated with NO. This reaction is rapid and produces only [Cr(H20)5N0] , provided that NO is in excess. This study also confirmedthe previously reported d-d spectrum of this ion. Several e.s.r. studies of chromium nitrosyl complexes containing a variety of other ligands have been reported. The i.r.-polarized spectra of K3[Cr(CN)5N0],2H20 have been determined and the results strongly support the suggestion that the orientation of the anions is disordered. The salts K4[M(CN)5N0] (M = Cr or Mo) appear to be isomorphous and the assignment of the vibrational modes in these ° and related compounds has been discussed. ... 

Figures 7,8 shows plots of data for chromium and molybdenum nitrosyl species the slope with El(L) is essentially the same as for non-NO species. Thus, in Figure 7,8 [data from 10,31,32], a value for El(NO) is used which will cause the nitrosyl complexes to fit the correlation line. This yields El(NO + ) = 2.55 - 2.57 for both metal ions. Values in the range 1.2 -1.8, for El(NO" "), have been described by Clarke [33] for some technetium nitrosyl derivatives. This area would benefit from a detailed analysis.

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