Single crystal to single crystal polymorphic phase transition of a silver nitrate 24-crown-8 complex and its pseudo-polymorphism

A silver nitrate 24-crown-8 complex [Ag sub(4)(24-crown-8)(NO sub(3)) sub(4)] (1) was synthesized, showing a single crystal to single crystal polymorphic phase transition induced by temperature and leading to polymorph [Ag sub(4)(24-crown-8)(NO sub(3)) sub(4)] 1'. When this complex (1) is exposed to humidity or directly crystallized from a water containing solvent, a pseudo polymorph [Ag sub(4)(24-crown-8)(NO sub(3)) sub(4)(H sub(2)O) sub(2)] (2) with two additional water molecules is obtained. When this pseudo polymorph is heated above 100 degree C, it may be transformed back into the first structure (1).