What goes on in sub-critical solvothermal synthesis of metal ion complexes?

The remarkable success of solvothermal methods in providing an extraordinary range of new materials has somewhat obscured the fact that much of the underlying chemistry remains ill-understood. This is true, particularly in sub-critical solvothermal syntheses yielding coordination polymers and frameworks, making product selection and optimisation of yields a matter of empirical variations in reactant mixtures and reaction conditions. There are, however, many indications within known observations of the operation of factors that could be better understood by their independent direct study under solvothermal conditions. This article provides some suggestions to identify such factors.