Photochemically driven molecular devices and machines

The development of civilization has always been strictly related to the design and construction of devices – from wheel to jet engine – capable of facilitating man movement and travelling. Nowadays the miniaturization race leads scientists to investigate the possibility of designing and constructing machines and motors at the nanometer scale, that is, at the molecular level. Research on supramolecular chemistry has shown that molecules are convenient nanometer-scale building blocks that can be used, in a bottom-up approach, to construct ultra-miniaturized devices and machines. Chemists are in an ideal position to develop such a molecular approach to functional nanostructures because they are able to design, synthesize, investigate and operate with molecules. Much of the inspiration to construct molecular devices and machines comes from the outstanding progress of molecular biology that has begun to reveal the secrets of the natural nanomachines which constitute the material base of life. Surely, the supramolecular architectures of the biological world are themselves the premier, proven examples of the feasibility and utility of nanotechnology, and constitute a sound rationale for attempting the realization of artificial molecular devices. The bottom-up construction of machines as complex as those present in Nature is a prohibitive task. Therefore chemists have tried (i) to construct much simpler systems, without mimicking the complexity of the biological structures, (ii) to understand the principles and processes at the basis of their operation, and (iii) to investigate the challenging problems posed by interfacing artificial molecular machines with the macroscopic world, particularly as far as energy supply and information exchange are concerned.