Assemblies of salts of urea and thiourea derivatives and release of hosts from composites with calcium oxide

Abstract

The structural characterisation of self-assemblies and photoluminescence of the perchlorate and nitrate salts of 1-(naphthalen-1-yl)-3-[(pyridin-4-yl)methyl]urea (naphurea) and 1-(naphthalen-1-yl)-3-[(pyridin-4-yl)methyl]thiourea (naphthiourea) and their comparison with the parent urea or thiourea derivatives are presented. The naphthalene derivatives showed characteristic emissions, among which the nitrate salt of naphurea showed dual emissions at 386 and 509 nm upon excitation at 335 nm. We have taken the advantage of the emissive behaviour of these compounds to deliberate the comparative release of urea derivatives from composites of calcium oxide impregnated with them. The hydrolytic instability of the salt and modulation of the in situ acid–base properties of the salt from pellets of CaO@Hnaphurea.X (X = nitrate or perchlorate) are discussed.