Synthesis, structures and optical power limiting of some transition metal and lanthanide monoporphyrinate complexes containing electron-rich diphenylamino substituents

Transition metal and lanthanide monoporphyrinate complexes based on 5,10,15,20-tetrakis[p-(diphenylamino)-phenyl]-21H,23H-porphine (H ₂tdpapp) have been synthesized and characterized and the X-ray crystal structures of the palladium and platinum analogues [M(tdpapp)] (M = Pd, Pt) determined. Experimental investigations of the nonlinear optical transmittance characteristics at 532 nm show that most of these new metalated porphyrinate complexes are excellent optical limiters with performances comparable or superior to those of the benchmark reverse saturable absorption dyes such as fullerene C₆₀ and (phthalocyanine)metal complexes. The nonlinear optical measurements reveal that the optical-limiting effects of porphyrins can be enhanced greatly by incorporation of lanthanide ions and covalent attachment of the electron-donating diphenylamino moieties to the parent porphyrinate ring. The optical-limiting thresholds for these lanthanide monoporphyrinate complexes range from 0.09 to 0.30 Jem^-2 at 82% linear transmittance, which makes them attractive candidates as optical-limiting materials for the protection of various optical devices.