Transferability in aldehydes and ketones.: II.: Alkyl chains

An analysis of the transferability of hydrocarbon chains in aldehydes and ketones was carried out, considering the values obtained for the atomic and bond properties of these chains in a series of 42 compounds. Likewise, the differences between the n-alkane groups and the methylene and methyl groups of a chain containing a carbonyl group were established. All the properties were calculated using the theory of atoms in molecules on 6-31+ +G**//6-31G* wave functions. The values of the atomic properties and their evolution with L(Omega) and the size of the molecule allow the carbon atoms of an alkyl skeleton to be classified considering both their position with respect to the C=O group (alpha, beta, gamma, delta or further) and their position in relation to the end of the chain (terminal C, C previous to the terminal, and the rest). For some of the properties of the carbons in alpha or beta dispositions to the C=O group, it is also necessary to consider the nature of the other alkyl radical bonded to the carbonyl group (H,CH3,CH2CH3 or longer for C in alpha,H,CH3 or longer for C in beta). The bond properties (the bond length, the distance to the critical point of the bond, the ellipticity, the charge density at the critical point, the Laplacian of the charge density at the critical point) display lower dependency on the position in relation to both elements, and only bring about a difference between the bonds including C in alpha or beta to the C=O and/or C at the end of the chain, and a common behavior pattern for the other C-C bonds. (C) 2000 American Institute of Physics. [S0021-9606(00)00728-5].