Carbon suboxide, structure

A review article on carbon suboxide appeared in Houben Weyl in 1968 and its chemistry was summarized by Kappe and Ziegler in 1974 The structure of carbon suboxide is mainly linear. Carbon suboxide structurally resembles a ketene, but its chemistry is rather different although the polarization of the molecule is similar to that of ketenes. According to theoretical calculations the center carbon atom has the highest negative charge, as indicated in its resonance structure 8. 

Self-Test 3.9A Describe the structure of the carbon suboxide molecule, C302, in terms of hybrid orbitals, bond angles, and tr- and -ir-bonds. The atoms lie in the order OCCCO. 

In carbon suboxide, for which the structure 6=C=C=C=o is most important, structures such as O—CsC—CsaO + contribute about... 

The dehydration of malonic acid, H02C-CH2-C02H, produces C302 (known as tricarbon dioxide or carbon suboxide). Draw the structure for C302 and describe the bonding in terms of resonance structures. 

This oxide (m.p. —111.3 and b.p. 7 °C), also known as carbon suboxide, C302, contains carbon in the formal oxidation state of +4/3. Because this is lower that its oxidation state in either CO or C02, the oxide is called carbon suboxide. The molecule is linear and has the structure... 

The carbon suboxide molecule is linear,10 as expected for the two double-bond structures A and B and also for structures C and D ... 

A preparation of the thiazine ring system which should be investigated for generality is that of Baranova et al.,2il who interacted the l-aroyl-2-thioureas 151 with carbon suboxide to give 152. Compounds of structure similar to 152 were also obtained starting with 1,1-disub-stituted thioureas.247 Treatment of other cumulenes 153, ketenes(X = O)... 

Carbon suboxide has a linear slructure. probably a resonance of four. structures of which the last two below probably make a smaller contribution to the normal state of the molecule than the first iwo. 

Carbon suboxide (C302),50 an evil-smelling gas, is formed by dehydrating mal-onic acid with P2Os in vacuum at 140 to 150°C, or better, by thermolysis of diacetyltar-taric anhydride. The molecule is linear and can be represented by the structural formula 0=C=C=C=0. It is stable at -78°C, but at 25°C it polymerizes, forming yellow to violet products. Photolysis of Q02 gives QO, which will react with olefins ... 

Ethylenedione. the dimer of carbon monoxide, has attracted chemists interest since at least 1913 when its synthesis by dechlorination of oxalyl chloride was unsuccessfully attempted 37). This substance, which lies between carbon dioxide and carbon suboxide in the series of oxycumulenes, is the simplest possible unsaturated diketone. It can be represented by a number of canonical structures as shown below ... 

Carbon suboxide, the third carbon oxide, is a linear molecule with the Lewis structure... 

Carbon suboxide C3O2 has been the subject of several papers. Earlier workers . disagreed as to whether the structure is linear or bent. A (9,5,I)->[4,3,1] basis set calculation concluded that it is essential to include f/-orbitals to determine the potential for CCC bending. Although the agreement with experiment was not satisfactory, the molecule is predicted to be non-linear but it was concluded that a more extensive basis set calculation is needed. Calculations including Cl are needed here. 

Jacox et al. (2) have observed three vibrational fundamentals in the infrared spectrum by matrix isolation, and suggested a linear structure with ground state for the CCO radical (g). They also estimated the bond distances C-C = 1.160 A and C-0 - 1.279 A based on the structural analogy between the carbon suboxide and the CCO radical. Bayes (3) has predicted that the and states lie respectively 0.5 and 0.8 eV above the ground state. Thfese two elctronic states have been Included in the tabulation. 

Carbon suboxide is a linear symmetric molecule in its ground state and is of considerable Interest from a variety of viewpoints. Its electronic structure, for example, has been subjected to considerable theoretical analysis because of the extensive delocalized IT network. Because its constituent atoms are doubly bonded C and 0, it is the source of intensely chemiluminescent flames with atomic oxygen which have been shown to result in inverted distributions in product CO. The molecule has also been proposed as (i) a product of photochemical reactions in the primitive earth atmosphere, (il) a constituent of the Venus atmosphere, and (iii) a possible explanation for the variety of colors associated with the Mars surface. 

Wavelengths longer than 220 nm. The absence (2) of fluorescenci or phosphorescence in carbon suboxide excited in the ultraviolet would suggest that it is efficiently photodecomposed in this region of the spectrum. From its structural similarity to ketene, it is expected that this will involve production of C2O in step 1. The work of Bayes has in fact shown that this is the most probable process in the absorption region with a maximum at 265 nm. Bayes (11) found that photolysis of 02/02 mixtures led to production of allene rather than the acetylene, which is known (12) to be formed by insertion of carbon atoms into C2H. ... 

Diels, Otto P. H. (1876-1954). A German chemist who won a Nobel Prize in chemistry with Alder in 1950. He was awarded the prize for diene synthesis work which led to improved methods of analyzing and synthesizing organic compounds. His research resulted in the discovery of carbon suboxide, methods of dehydrating cyclical hydrocarbons using selenium, and determination of the structure of steroids. A student of Fischer s, Diels graduated from the University of Berlin. 

Carbon forms two common oxides, CO and CO2. It also forms a third (very uncommon) oxide, carbon suboxide, C3O2, which is linear. The structure has terminal oxygen atoms on both ends. Write the Lewis formula for C3O2. 

Carbon suboxide, 0 OC=C=0, an unusually reactive bisketene, functions as an efficient double electrophile, in the synthesis of heterocyclic compounds (1). One would expect that the molecule, having four cumulative ir bonds, should be of considerable interest in the field of polymer chemistry and should have been investigated vigorously. On the contrary, not only has the structure of its polymer not been unequivocally established, but also the physical properties of the polymer and the kinetics and mechanism of the polymerization process have not been studied to any significant extent, even though its polymerization product... 

Carbon suboxide is related in structure and properties to ketene, CH2 = CO, since both compounds contain a CO group linked by a double bond to carbon. Ketene is formed when the vapor of bromoacetyl bromide is heated with zinc —... 

Reaction (7) proceeds at room temperature and at one atmosphere pressure of carbon dioxide, thus converting the bridging ketenylidene ligand into the bridging oxided The ketenylidene complex reacts with carbon dioxide even in the solid state the gas produced from the zirconium derivative, promptly evacuated into a mass-spectrometer, was shown to be carbon suboxide C302d The inorganic reaction product appears to catalyze the polymerization of carbon suboxide to red solid productsd The structure of the product resulting from reaction (7), R = Pr , is shown in Fig. 8b. 

The electron-diffraction investigation of the structure of molecules of methyl azide and carbon suboxide. Proc. Natl. Acad. Sci. 19 (1933) 860-867. (L. O. Brockway and Linus Pauhng). 

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