During the last 15 years our work has been devoted to the synthesis of porphyrins and metalloporphyrins substituted in the meso, pyrrolic and axial positions, with the aim to introduce significant perturbations to the highly polarizable electronic system of porphyrin ring, which is characterized by a variety of low lying excited states. This feature has attracted a widespread interest for these molecules in the optical materials area and, in particular, we have investigated the second-order nonlinear optical (NLO) properties, determining the quadratic hyperpolarizability in solution, by the EFISH technique, of asymmetrically substituted meso- and ?-pyrrolic tetraphenyl porphyrins, both with a push or pull substituent.1 Interestingly, the porphyrinc core has shown an ambivalent character as donor or acceptor, depending on the pull or push nature of the substituent respectively.1 Asymmetric arylethynyl push-pull porphyrinates were investigated, in order to evaluate the effect of different metals on the second-order NLO response, both theoretically2 and experimentally.3 Finally ZnII-porphyrinates substituted in the axial position have shown to be less perturbed by the presence of the push or pull substituent.1 Also, the third-order nonlinear optical response has been investigated on some porphyrinic systems by means of two-photon absorption (TPA) measurements, for its possible applications based on optical limiting devices.4 More recently porphyrinic systems have shown all the characteristics to be very interesting dyes for applications in DSSCs,3 as confirmed by theoretical calculations, performed by DFT and TDDFT methods, which have shown a well-defined localization, in the excited state, of the HOMO and the LUMO on the donor and acceptor moieties, respectively.4 Thus we have prepared some push-pull meso-substituted ZnII-porphyrinates,4,5 with a carboxylic group as acceptor/anchoring group, and a quite new series of ZnIItetraarylporphyrinates featured by sterically bulky tert-butyl groups, mono-substituted or push-pull di-substituted in ?-position by a straightforward and rapid method developed by our research group.5
Push-pull meso- and ?-substituted ZnII-porphyrinates: from second-order NLO to DSSCS
A Orbelli Biroli;
2013
Abstract
During the last 15 years our work has been devoted to the synthesis of porphyrins and metalloporphyrins substituted in the meso, pyrrolic and axial positions, with the aim to introduce significant perturbations to the highly polarizable electronic system of porphyrin ring, which is characterized by a variety of low lying excited states. This feature has attracted a widespread interest for these molecules in the optical materials area and, in particular, we have investigated the second-order nonlinear optical (NLO) properties, determining the quadratic hyperpolarizability in solution, by the EFISH technique, of asymmetrically substituted meso- and ?-pyrrolic tetraphenyl porphyrins, both with a push or pull substituent.1 Interestingly, the porphyrinc core has shown an ambivalent character as donor or acceptor, depending on the pull or push nature of the substituent respectively.1 Asymmetric arylethynyl push-pull porphyrinates were investigated, in order to evaluate the effect of different metals on the second-order NLO response, both theoretically2 and experimentally.3 Finally ZnII-porphyrinates substituted in the axial position have shown to be less perturbed by the presence of the push or pull substituent.1 Also, the third-order nonlinear optical response has been investigated on some porphyrinic systems by means of two-photon absorption (TPA) measurements, for its possible applications based on optical limiting devices.4 More recently porphyrinic systems have shown all the characteristics to be very interesting dyes for applications in DSSCs,3 as confirmed by theoretical calculations, performed by DFT and TDDFT methods, which have shown a well-defined localization, in the excited state, of the HOMO and the LUMO on the donor and acceptor moieties, respectively.4 Thus we have prepared some push-pull meso-substituted ZnII-porphyrinates,4,5 with a carboxylic group as acceptor/anchoring group, and a quite new series of ZnIItetraarylporphyrinates featured by sterically bulky tert-butyl groups, mono-substituted or push-pull di-substituted in ?-position by a straightforward and rapid method developed by our research group.5I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
