Molecular components nanotechnology

These analytical nanosystems are built with atomic precision using nanotechnology elements. These materials and devices can, in fact, be obtained from molecular components that assemble themselves chemically by principles of molecular recognition or from larger entities without atomic-level control (Rios et al., 2009). 

The concept of device can be extended to the molecular level [1-3]. A molecular-level device can be defined as an assembly of a discrete number of molecular components (that is, a supramolecular structure) designed to achieve a specific function. Each molecular component performs a single act, while the entire supramolecular structure performs a more complex function, which results from the cooperation of the various molecular components. The extension of the concept of device to the molecular level is of interest not only for basic research, but also for the growth of nanoscience and the development of nanotechnology [4]. Looking at supramolecular chemistry from the viewpoint of functions with references to devices of the macroscopic world is a very interesting exercise that helps the development of chemistry by introducing new concepts. 

Two main approaches are used in nanotechnology that is, the bottom up approach and the top-down approach. In case of the bottom-up approach, the different type of materials and the instruments are made up from different types of molecular components, which combine themselves by chemical ways basing on the mechanism of molecular recognition. In case of the top-down approaches, various nano-objects are made from various types of components without atomic-level control. Materials reduced to the nanoscale can show different properties compared to what they exhibit on a macro scale, enabling unique applications. The basic premise is that properties can dramatically change when a substance s size is reduced to the nanometer range. For instance, ceramics, which are normally brittle, can be deformable when their size is reduced, opaque substances become transparent (copper) stable materials turn combustible (aliuninum) insoluble materials become soluble (gold) [61, 62],... 

Molecular electronics was bom in the 1990s as a branch of nanotechnology dealing with the study and application of molecular building blocks for the fabrication of electronic components [1-3]. Today, after more than 15 years of intense... 

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