Molecular structures novel chromophores

Finally, Ziessel and coworkers have recently designed novel molecular structures incorporating both a Pt" and Ru" center [23], This work has shown the directionality of Pt—>Ru energy transfer upon excitation of the Pt" moiety, sensitizing the Ru-chromophore localized 3CT emission. Upon ligation of the Ru moiety, the typical Ptn-based luminescence near 513 nm is quantitatively quenched while the long lifetime Ru" emission appears around 610 nm. 

Using these novel LB films, systematic studies have been carried out to elucidate which features of the molecular structures of azo chromophores govern the photoinduced switching of the liquid-crystal alignment.165-169 The effects of spacer length (n) and tail length (m + 1) on the photoresponse of liquid-crystal... 

An important challenge in the design of novel conjugated polymers is the synthesis of materials with tailor-made solid-state electronic properties. This section outlines the synthesis of the most significant classes of poly(para-phenylenevinylene)s (PPVs), poly(para-phenylene)s (PPPs), and related structures. Furthermore, this review demonstrates that the chromophoric and electronic properties of conjugated rr-systems are sensitive to their molecular and supra-molecular architecture. 

Finally, in a novel application, some uniquely structured hexapyrrolidine derivatives of C60 with Th and D3 molecular symmetries have been synthesized and characterized by analytical methods and x-ray crystallography [260]. This work revealed strong luminescence, indicative of photophysical properties that are unusual in comparison with other fullerene derivatives. Therefore, the hexapyrrolidine adduct was utilized as a chromophore in the fabrication of a white light organic LED [261]. 

Our collaborators, Kim, Lee and coworkers have also synthesized a series of novel two-photon chromophores by utilizing dithienothiophene (DTT) as the n-center [15]. The experimental result has shown that the DTT moiety leads to an enhancement of molecular two-photon absorptivity. We hypothesized that the dramatic improvement of 03 values is due to this rigid, planar and polarizable fused-terthiophene structure, which provides a significant reduction of the band gap and extension of Tt-electron delocalization. The chemical structures and the measured 02 values of these chromophores are depicted in Fig. 5. 

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