Acid catalyzed 1, 2 Michael addition reaction: a viable synthetic route in designing fullerene core starlike macromolecule

Abstract

AbstractThe paper describes a comprehensive investigation to establish the heterophase acid‐catalyzed 1, 2 Michael addition reaction between fullerenol (nucleophile) and substituted acrylates (R = H, CH3, Ph)/vinyl acrylates (electron deficient olefins). The main emphasis is to evaluate structure–property relationship and establish a mechanism for tuning the structure in different operating conditions, which could be useful while adapting this reaction in designing of fullerene core starlike macromolecules. The effect of substituents on the rate of formation of the product is another important aspect covered in the present paper. The most significant outcome of the present investigation are (i) the nature of the product formed has direct bearing with operating process, whereas, (ii) rate of reaction and the properties of the end‐products depends on the nature and position of substituents attached to olefins. Adopting heterogeneous phase reaction scheme, the reaction can be easily controlled at 1, 2 Michael addition stage which otherwise proceeds further to provide cyclic product in single‐phase reaction. The nature of the substituent at β‐carbon of the olefins have the inverse effect on the rate of the reaction. The steric rather than electronic effect of substituents governs the rate of reaction. However, the significant influence of β‐substituents on the properties of the Michael addition products are observed in a more classical manner. The phenyl substituent at the β‐position measured the slowest rate of reaction but imparts highest thermal stability. In such systems, the vinyl substitution on esteric carbon further reduces both the reaction rate and the thermal stability. Copyright © 2008 John Wiley & Sons, Ltd.