Nuclear energy side-chain

In the context of the direct mechanism, several perplexing features concerning nuclear and side-chain substitution of aromatic compounds have been highlighted [124-126], and in the search for explanations attempts have been made to estimate, by thermo-chemically based calculations, free energies of activation for reactions between radical cations and nucleophiles. Long-standing puzzles in this area include the dependence of the ratio of side chain/nuclear substituted products on the nucleophile for alkylbenzenes, side-chain acetoxylation predominates in acetic acid (AcOH) unless AcO is present, when nuclear substitution becomes important. 

The ring of ABA can theoretically have at least two minimum-energy conformers one is an envelope (or half-chair) with the axial side-chain, 1-i, and the other is an inverted envelope (or half-chair) with the equatorial side-chain, 1-ii [Fig. (3)] [42]. The crystal structure that has been reported for ABA [43,44] reveals that its ring is 1-i, and the nuclear Overhauser effect (NOE) experiments have suggested that the ring of... 

The two nuclei on the right side are just two of the many possible products of the fission process. Since more than one neutron is released in each process, the fission reaction is a self-propagating, or chain reaction. Neutrons released by one fission event may induce other fissions. When fission reactions are run under controlled conditions in a nuclear reactor, the energy released by... 

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