Electron spin resonance of Langmuir-Blodgett films fabricated with metal derivatives of polyazamacrocycles

This review analyses the results obtained through the Electron Spin Resonance (ESR) spectroscopy on multilayer Langmuir-Blodgett films fabricated with metal derivatives (mainly Cu2+, VO2+ and low-spin Co2+) of polyazamacrocycles (porphyrins, tetraazaannulenes, phthalocyanines). These metal ions are particularly suitable for an ESR analysis because of their relatively long electron spin relaxation times that render possible their observation even at room temperature and in all co-ordination symmetry. This allows us to obtain valuable data on both mobility and orientation of the metal-macrocycle systems adsorbed onto a solid support. The preliminary characterisation of the spreading monolayer obtained from the systems considered, as it is typically done by surface pressure/area isotherms, optical (UV-Vis) and ESR spectroscopies, is also reviewed.