The Therien research group has a longstanding interest in materials featuring extended pi-conjugation. We have found that linking chromophores with acetylene bridges provides strong coupling, evidenced by dramatic redshifting and intensification of long-wavelength absorptions. For porphyrins linked in this way at their meso positions, the result is a very interesting class of conjugated materials featuring globally delocalized ground and excited states, intense near-infrared absorptions and emissions, and unparalleled aptitudes for charge delocalization.
Arrays combining porphyrins with ruthenium terpyridyl complexes are nonlinear optical materials that boast extremely high hyperpolarizabilities at telecommunication-relevant wavelengths. Such supermolecular materials are also excellent candidates for optical limiting as these compounds exhibit intense NIR absorption from long-lived excited states with large excited-state molar extinction coefficient. Current efforts in our group aim to optimize the control of the band gaps and energy levels within chromophore arrays for application to photovoltaic devices and to extend nonlinear optical properties of macromolecules to the bulk phase using noncentrosymmetric architectures.