Metal-promoted shift of equilibrium between the two fluorescent forms of a synthetic macrocycloureide in view of designing chemical sensors

Atypical Behavior of a New Dialkyl Macrocycloureide in Langmuir−Blodgett Film Formation

“…The development of a new family of receptors characterized by the presence of powerful ligating moieties such as urea, amide groups, and aromatic cycles have been performed in our group, and the first synthesized element of this family, a urea macrocyclophane (5,21-Bis(methoxycarbonyl)-1,9,17-trioxo-2,10,16,24-tetraaza[9.3]metaorthocyclophane), is a fluorescent molecule existing under monomer and dimer forms. , This compound is able to specifically bind Zn(II) ions, and its quantification is based on the linearity of the fluorescent signal increase vs the ion concentration. In a previous work, the immobilization of this macrocycloureide in a nanostructure was obtained through the Langmuir−Blodgett technique, and as the macrocycloureide alone cannot be transferred onto the substrate, it was compulsory to use a host molecule such as docosanoic acid to buildup Langmuir−Blodgett (LB) films.…”

Immobilization inside Langmuir−Blodgett Films of a Fluorescent Artificial Receptor for Zn(II) Recognition

“…Third, a stacking of molecules may take place during the compression. The interfacial behavior of the macrocycloureide has to be related to its characteristics in solution; the molecule is a strong base (p K a = 12.4). Then, in the conditions used here (subphase at pH 12) it should significantly be in the deprotonated state.…”