Understanding the chemical reactivity of phenylhalocarbene systems: an analysis based on the spin-polarized density functional theory

摘要

Global and local indices based on the spin-polarized density functional theory (SP-DFT) have been used to rationalize the philicity power and spin polarization pattern of a family of singlet substituted phenylhalocarbenes, (pYPhXC, Y = –NO2 , –CN, –CHO, –F, –H, –CH3 , –OH, –OCH3 , –NH2 ; X = –F, –Cl, –Br). The local reactivity may be traced out by the simple condensed-to-atoms model for the SP-DFT Fukui functions, namely ${f^{+}_{rm{NS},k}}$ and ${f^{+}_{rm{SS},k}}$ . For the addition of some singlet phenylhalocarbenes on tetramethylethylene a linear correlation among the global ${(omega _{rm{N}})}$ and local electrophilicity index ${(omega _{rm{N,C}})}$ , and the observed rate constants were found. This result supports a mechanistic model where the carbene adds to the olefin in a single step that is controlled by the carbene electrophilicity. These results emphasize the usefulness of general SP-DFT philicities in the rationalization of chemical reactivity at initial stages of reactions that could involve both charge transfer and spin polarization processes.