Bond Nature of Peroxides and Related Compounds

Abstract

Summary:Extended Huckel molecular orbital calculations were performed on various peroxides (hydroperoxides, peracids, and peresters), nitrites, nitrates, esters, ethers, and alcohols with particular reference to the bond nature of their O-O, O-N, C-O, and O-H linkages. We made several findings. Firstly, the order of the bond strengths of the above linkages in the compounds considered was: alcohol>ester>ether>>nitrate>nitrite>>hydroperoxide>peroxide>perester> peracid. Secondly, peroxide families or nitrite and nitrate families were characterized by the lowest unoccupied (or the LU+1), antibonding O-O or O-N linkages. Thirdly, a parallel between the overlap population of the above linkages (O-O or O-N) and their bond dissociation energies could be recognized, with certain irregularities. Fourthly, the monomer structures of alkyl hydroperoxides were more energetically stable and reactive to nucleophiles than dimer ones. Finally, the characteristic bond nature of the above linkages was discussed in connection with the wave function contours.

Advances in the Chemistry of Verdazyl Radicals

“…Experiments using BP labelled with l8 O in the carbonyl group have shown that attack by trialkylstannyl and triphenylmethyl radicals also takes place at the peroxy-oxygen 120 . Quantum-chemical calculations, indicating a deficiency of electron density in the peroxylinkage, are consistent with this finding 175 . The weak influence of the polarity of the medium and the low reaction constants p in the Hammett and Taft equations may indicate the formation of a weakly polar transition state in this reaction, i.e.…”