  Recent years have seen a large increase in the number of reported framework
materials, including the nowadays-ubiquitous metal-organic frameworks (MOFs).
Many of these materials show flexibility and stimuli-responsiveness, i.e. their
structure can undergo changes of large amplitude in response to physical or
chemical stimulation. We describe here a toolbox of theoretical approaches,
developed in our group and others, to shed light into these materials'
properties. We focus on their behavior under mechanical constraints,
temperature changes, adsorption of guest molecules, and exposure to light. By
means of molecular simulation at varying scale, we can now probe, rationalize
and predict the behavior of stimuli-responsive materials, producing a coherent
description of soft porous crystals from the unit cell scale all the way to the
behavior of the whole crystal. In particular, we have studied the impact of
defects in soft porous crystals, and developed a methodology for the study of
their disordered phases (presence of correlated disorder, MOF glasses, and
liquid MOFs).
