The chemistry of the mechanical bond.

The use of templation in the synthesis of unnatural products where two or more components are mechanically interlocked has not only raised the efficiency of their production to near quantitative levels in some instances, but the molecular recognition that aids and abets the templation is also part and parcel of the molecules after they have been prepared, purified and presented for investigation. The fact that the molecular recognition 'lives on' in mechanically interlocked molecules, following their templated formation, makes them prime candidates for applications that straddle the scientific and technical worlds from devices that could spawn new information technologies to integrated systems that could have fundamental applications in the health-care industries. The challenge to make more and more sophisticated compounds is predicated upon our fundamental understanding of the nature of the mechanical bond and how this associated knowledge base can be employed to do complex systems chemistry in very different environments where emergent phenomena become the order of the day (critical review, 104 references).