Monolayer and multilayer films of differently substituted metal tetraazaannulene complexes

The properties of monolayers and multilayers of nickel(II) compounds with the dinaphtho derivative of the macrocycle ligand dinaphtho{b,i}5,7,12,14-tetramethyltetraaza[14]annulene with one and two hexadecanoyl chains on the water surface and onto a solid support have been studied from a thermodynamic and spectroscopic point of view and the results were compared with those from the dibenzo analogues. The molecular plane showed a tilted edge-on orientation at the air-water interface. The spreading monolayers were stable with time and their stability was almost independent of the compound used. The presence of hysteresis in the compression-expansion-compression cycles indicated an incomplete reversibility. Films prepared with the monohexadecanoyl macrocycle metal derivatives were regular and homogeneous whereas the occurrence of two alkyl chains on the ring resulted in a monolayer too viscous to be transferred.