Molecular springs, muscles, rheostats, and precessing gyroscopes: from review to preview.

The concepts of molecular springs and gyroscopes have existed for some time, and there have been numerous reports published about these fascinating topics. Here we describe our interest in this topic, reviewing our initial progress. This is not a complete story, rather an offering of synthetic strategies, interesting molecular structures, observations, and possibilities. In many cases, the "properties" component of the structure-property relationship for a given compound is the result of a computational prediction. Given the present state of theoretical chemistry, a computer's predictive power can far exceed that which can be presently accomplished by existing experimental analytical means. The theoretical results reported here allude to intriguing possibilities. Hopefully, this intrigue will help catalyze the development of definitive, albeit rather esoteric, single-molecule analytical experiments. The intentionally speculative nature of this review is intended to stimulate new challenges for and perspectives from those in related fields of interest; hopefully presenting a preview of what is to come.