Cobalt nitrosyl carbonyl

This potassium salt, K4Ni2(CN)6, may be further reduced by potassium in liquid ammonia to yield a yellow substance, K4Ni(CN)4. This has nickel in the zero-valent state and is thus comparable to the metal carbonyls, Fe(CO)5 and Ni(CO)4 (p. 157), to cobalt nitrosyl carbonyl Co(CO)4NO, and to the metal ammoniates Ca(NH3)6 and Pt(NH3)2. However, K4Ni(CN)4, and the closely related acetylene derivative, K4Ni(C=CH)4, are especially unusual, for in them, the zero-valent metal has been incorporated into an anion, whereas in the carbonyls and metal ammoniates, the zerovalent metals are present as uncharged species. 

In all these compounds, some or all of the CO can be replaced by nitric oxide, NO, which is believed to donate three electrons to the metal. On this basis, the formation of the volatile cobalt nitrosyl carbonyl, Co(CO)3NO, is easily understood. 

Of the organometallic nitrosyls which have been reported, the great majority are simple substitution products of cobalt nitrosyl carbonyl, Co(NO)(CO)3 and of iron nitrosyl carbonyl, Fe(NO)2(CO)2. Recently, however, there has been research activity on cyclopentadienyl nitrosyls, nitrosyl pentacyanides, and alkyl and allyl nitrosyls. 

A number of such complexes have been prepared (Table II), the usual method of preparation being the action of organic isocyanides on iron or cobalt nitrosyl carbonyls, or on other nitrosyl complexes. The dipole moments of a number of the products have been measured (Table VI). 

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. ... 

Formation of Ni(CO)4 or Co(CO)4- by the cyanide method depends upon the stepwise substitution of the anion of the cyano complex by the iso-electronic carbon monoxide molecule. By treating Co2(CO)8 with potassium cyanide we obtained cyanocarbonyls of cobalt of low oxidation number (83). In reactions of the nitrosyl carbonyls of iron and cobalt, Behrens (86) substituted all the CO groups with CN to give K3[Co(NO)(CN)3] or... 

A rational method of preparation for the nitrosyl carbonyls of iron and cobalt was discovered by my former co-worker F. Seel (101) by acidic decomposition of the appropriate carbonylmetallate solution in the presence of nitrite. 

The nitrosyl carbonyls result from the action of NO on the polynuclear carbonyls of iron and cobalt. Like the carbonyls the nitrosyl carbonyls react with neutral molecules such as organic nitrogen compounds and with halogens, and in such reactions CO, and not NO, is replaced. Thus Fe(CO)2(NO)2 with iodine gives... 

Most of the carbonyls can be prepared by the direct combination of the metal with carbon monoxide. It is necessary that the metal be in a very active state as when freshly reduced from the oxide or a salt of the metal. While finely divided, freshly reduced nickel combines readily with carbon monoxide at room temperature and atmospheric pressure (synthesis 75) other metals require more elevated temperatures (up to 400 ) and very high pressures (up to 700 atm.). Cobalt nitrosyl tricarbonyl is produced when specially prepared cobalt is treated with a mixture of carbon monoxide and nitric oxide. 

CoNO(CO)3 Cobalt nitrosyl tri-carbonyl, 2 238, 239 Cr(CN)6K3 Potassium hexacyano-ohromate(III), 2 203 Cr(C2H302)2 Chromium(II) acetate, 1 122... 

CONC304 COBALT NITROSYL TRI CARBONYL 76.352 8.9853E-02 -2.4575E-05 -2.8140E-08 1.4023E-11 100 1500 gas... 

Tetracarbonylcobaltate(l-) ion Carbonyl (t)5-cyclopentadienyl)nitrosyl-[(trimethylphosphoranylidenelacetyl-KC lchromatel 1 -) ion Bis[tris( 1,2-ethanediamine-K2 N, N )cobalt(IIl)] tris[difluoro(oxa ato)dioxoiungstate(VI)]... 

The dependence of the principal components of the nuclear magnetic resonance (NMR) chemical shift tensor of non-hydrogen nuclei in model dipeptides is investigated. It is observed that the principal axis system of the chemical shift tensors of the carbonyl carbon and the amide nitrogen are intimately linked to the amide plane. On the other hand, there is no clear relationship between the alpha carbon chemical shift tensor and the molecular framework. However, the projection of this tensor on the C-H vector reveals interesting trends that one may use in peptide secondary structure determination. Effects of hydrogen bonding on the chemical shift tensor will also be discussed. The dependence of the chemical shift on ionic distance has also been studied in Rb halides and mixed halides. Lastly, the presence of motion can have dramatic effects on the observed NMR chemical shift tensor as illustrated by a nitrosyl meso-tetraphenyl porphinato cobalt (III) complex. 

As has been described, the parent monocarbollide-metal carbonyl piano-stool species 2-(CO)n-closo-2,1 -MCB,0II n] 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 dicarbonyl-platinum analogue of compound 18,20 and as mentioned earlier, the manganese analogue of 14 has also briefly been reported.3a A notable absence from this list, however, is any representative of the Group 9 metals. The carbonyl nitrosyl-cobalt complex 21 is very closely related to the hitherto unknown dicarbonyl-cobalt dianion [2,2-(CO)2-< 7<9.v<9-2,1 -CoCB10H 11]2 and this species remains an attractive synthetic target. 

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