Autocatalysis and surface catalysis in the reduction of imines by SmI 2

Chintada Nageswara Rao, Shmaryahu Hoz

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

The reduction of the three imines, N-benzylidene aniline (BAI), N-benzylidenemethylamine (BMI), and benzophenone imine (BPI), with SmI 2 gives the reduced as well as coupled products. The reactions were found to be autocatalytic due to the formation of the trivalent samarium in the course of the reaction. When preprepared SmI3 was added to the reaction mixture, the reaction rate increased significantly. However, the kinetics were found to be of zero order in SmI2. This type of behavior is typical of surface catalysis with saturation of the catalytic sites. Although no solids are visible to the naked eye, the existence of microcrystals was proven by light microscopy as well as by dynamic light scattering analysis. Although HRTEM shows the existence of quantum dots in the solid, we were unable to make a direct connection between the existence of the quantum dots and the catalytic phenomenon. In the uncatalyzed reaction, the order of reactivity is BPI > BMI > BAI. This order does not conform to the electron affinity order of the substrates but rather to the nitrogen lone pair accessibility for complexation. This conclusion was further supported by using HMPA as a diagnostic probe for the existence of an inner sphere electron transfer reaction.

Original languageEnglish
Pages (from-to)14795-14803
Number of pages9
JournalJournal of the American Chemical Society
Volume133
Issue number37
DOIs
StatePublished - 21 Sep 2011

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