Carbon compounds electronegativity

As a direct consequence of Bent s rule,56 carbon compounds with a significant amount of s-character in their bonds to an electronegative element, e.g., fluoro-alkynes, are unstable. Thus, reactions which involve change in hybridization at a carbon atom bearing such an acceptor can be promoted when the amount of s-character at the reactive atom decreases. The role of rehybridization in a variety of chemical and supramolecular processes has been extensively analyzed and reviewed recently.55,58... 

Having taken into account the change in electronegativity and size of the central atoms, it appears that the couplings are intrinsically larger for the carbon compounds. This helps clarify the anomalous behaviour which existed for coupling to a-CH groups which was discussed earlier (Section III.B.2.a). 

The hypothesized delocalization of lone pair electrons in the above silicon compounds is supported by the lowered basicity of the silyl compounds as compared to the corresponding carbon compounds. This reduced basicity is contrary to that expected on the basis of electronegativity effects operating through the a system since silicon is less electronegative than carbon. It is consistent with an internal Lewis acid-base interaction between the nitrogen and oxygen lone pairs and empty acceptor d orbitals on the silicon. Experimentally this reduced basicity is shown by the absence of disiioxane adducts with BF3 and BO ... 

Electronic effect Electronegativity of atom bonded to carbon Compound 6(CH3) 6(CH3) - 8.4... 

In general it is more difficult with these inorganic compounds to make statements on the constitution with any degree of certainty. In the first place the possibility of comparison with a number of similarly constituted compounds, which is the case with carbon compounds, is lacking. The values for atomic radii, etc., have, therefore, also a much smaller reliability. The R.E. cannot be calculated at all on account of the lack of values for the contributions of the separate bonds. Furthermore polar effects and contributions from ionic configurations play a much more important part since much greater differences in electronegativity occur in this case. 

Table III gives a summary of the results of using Equation 14 as a representation of the energies of atomization for the 62 test molecules. Results are quoted for both polarity functions, fp and f°. When the entire set of molecules is tested, fc seems to be the preferred function however, fp is definitely superior for the compounds without carbon, and f° and the alternate electronegativities are superior for the carbon compounds. For extrapolations to other molecules it would seem desirable to use fp for compounds without carbon and fc and the alternate electronegativities...

In each group consider the compounds from left to right. Again, chemical shifts are very rough estimates based on data in Table 10-6 and closeness of carbons to electronegative atoms. 

Organic Chemistry is the study of carbon compounds. Carbon can form a wide array of compounds, because of its size and ability to form covalent bonds with other carbon atoms. In addition, carbon can form bonds with many other elements. This property of carbon increases the facility of forming multitudes of different compounds. The particular electronegativity of carbon also plays a key role in its versatility. In this chapter, we will review some of the fundamental aspects of carbon atom and the main types of hybridizations involving carbon compounds. 

In this book we are concerned with the properties of compounds which contain metal—carbon bonds. Traditionally organometallic chemistry includes the carbon compounds of the metalloids boron, silicon and arsenic, but excludes those of phosphorus and of other more electronegative elements. Metal carbonyls are discussed, but not cyanides or carbides, which are more usefully considered in conjunction with inorganic rather than organometallic compounds. 

FIGURE 5.27. (a) When X differs little from carbon in electronegativity, the compound C2H2X is best represented by a classical structure (b) when X is far more electronegative than carbon, C2H4X is best represented by a tt-complex structure. 

The electron configuration of carbon ([He]2s 2p ) effectively prohibits ion foimation. This and carbon s electronegativity, which is intermediate between those of metals and nonmetals, cause carbon to complete its octet by sharing electrons. In nearly all its compounds, carbon forms four covalent bonds, which can be oriented in as many as four different directions ... 

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