Supramolecular chemistry representing “chemistry beyond molecule” include any chemical species where the interaction energy between subunits is small compared to other relevant parameters. This chemistry has developed into a coherent and lively body of concepts and objects, incorporating novel areas of investigation. However, the discussions are limited to the author's present research activities and interests.
An important area of activity is the interaction of light with matter where the degree of organization of the receiving “matter” plays a crucial role. It is possible to design structurally organized and functionally integrated systems capable of elaborating the energy and information input of photons to perform complex functions such as molecular scale arithmetic, sensing, information storage, charge separation, light harvesting, and so on. In the area of molecular scale arithmetic, the “bottom-up” approach utilizing the principles of supramolecular chemistry, virtually opens up unlimited possibilities to circumvent the problems associated with the “top-down” techniques.
The development of supramolecular approach towards the construction of nanodevices and nanomachines could be possible by the large amount of knowledge in other fields of chemistry, particularly organic chemistry. However, clear advantage of using metal complexes are due to high damage threshold, fast response time as well as tailorability of molecular structure through the coordinated metal center. For this, an important research topic of supramolecular chemistry is generation of large metal-organic framework structures with void spaces for catalysis, supramolecular storage of molecules, optical nonlinearity and associated phenomena, molecular machines, etc. For metal-ligand ensembles, nature of metal ions, multidentate ligands and dative bonding drive and direct self-assembly processes. Here, use of identical sub-units in the self-assembly process reduces the lexicon of interactions to a minimum thus economizing on the amount of information necessary to describe a giant structure. Besides, this provides a way to put metal ions at strategic positions for potential applications. In short, supramolecular chemistry offers great possibilities in a number of contemporary research areas.
Prof. Parimal K. Bharadwaj
Department of Chemistry
Indian Institute of Technology Kanpur