Rod shaped MoO3 nanocrystals were prepared from ammonium heptamolybdate tetra - hydrate (AHM) and ethylene diamine (en) as template agent in water via a hydrothermal process at 180 graduate C. The prepared nanocrystals were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The range size of nanorods are from a few nanometers (nm) to micrometers in length and 50 to 200 nm in diameter. It was also found that nanostructures of varied dimensionality such as plates and helical plates are formed using citric acid (CA), and starch as template respectively.
Macrocycles can be synthesized under kinetic or thermodynamic control, the latter leading to mixtures in equilibrium. Their composition can be controlled by addition of templates. Alkaline earth metal ions have been used to synthesize imine macrocycles of different sizes from dialdehydes and diamines specifically. In addition, the competition between the formation of a macrocycle or a bimacrocyclic cage compound can be controlled by a proper template ion. Also organic templates such as polyols can be used to stabilize a resulting macrocycle. As recognition reaction, the formation of boronic esters is presented, the macrocyclization was achieved by ring-closing metathesis. Due to the templates, endo-functionalized macrocycles are achieved, such as concave acids or bases, metal ion complexes and even N-heterocyclic carbenes. All of these can be part of a concave structure which determines their reactivity and selectivity in reactions such as acid/base catalysis, metallo-or-organocatalysis.
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