Liquid crystal phase crossover (columnar↔calamitic) in polycatenar CuII 5-(3,4-dialkoxybenzylidine)aminotropololonates

The new tetracatenars bis[5-(3,4-dialkoxybenzylidine)aminotropolonato] copper(II) are mesogenic. As the 3,4-dialkoxy chains on the phenyl rings increase in length, the phase behavior shifts from calamitic to discotic (columnar), the first case of a metallomesogen series to exhibit both calamitic and columnar phases. When n⩽12 the complexes melt to calamitic liquid crystals (specifically the smectic C phase), while for n⩾13 the liquid crystal phases are columnar (specifically the phase columnar hexagonal phase)