Supramolecular organization of dye molecules in zeolite L channels: synthesis, properties, and composite materials

Sequential insertion of different dyes into the 1D channels of zeolite L (ZL) leads to supramolecular sandwich structures and allows the formation of sophisticated antenna composites for light harvesting, transport, and trapping. The synthesis and properties of dye molecules, host materials, composites, and composites embedded in polymer matrices, including two- and three-color antenna systems, are described. Perylene diimide (PDI) dyes are an important class of chromophores and are of great interest for the synthesis of artificial antenna systems. They are especially well suited to advancing our understanding of the structure–transport relationship in ZL because their core fits tightly through the 12-ring channel opening. The substituents at both ends of the PDIs can be varied to a large extent without influencing their electronic absorption and fluorescence spectra. The intercalation/insertion of 17 PDIs, 2 terrylenes, and 1 quaterrylene into ZL are compared and their interactions with the inner surface of the ZL nanochannels discussed. ZL crystals of about 500 nm in size have been used because they meet the criteria that must be respected for the preparation of antenna composites for light harvesting, transport, and trapping. The photostability of dyes is considerably improved by inserting them into the ZL channels because the guests are protected by being confined. Plugging the channel entrances, so that the guests cannot escape into the environment is a prerequisite for achieving long-term stability of composites embedded in an organic matrix. Successful methods to achieve this goal are described. Finally, the embedding of dye–ZL composites in polymer matrices, while maintaining optical transparency, is reported. These results facilitate the rational design of advanced dye–zeolite composite materials and provide powerful tools for further developing and understanding artificial antenna systems, which are among the most fascinating subjects of current photochemistry and photophysics

Synthesis and Electrochemical and Photophysical Characterization of New 4,4′‐π‐Conjugated 2,2′‐Bipyridines that are End‐Capped with Cyanoacrylic Acid/Ester Groups

Two new functionalized 4,4′‐disubstituted 2,2′‐bipyridines that were end‐capped with cyanoacrylic acid or cyanoacrylic acid ester anchoring groups, which might allow their efficient functionalization on TiO2 or other metal‐oxide semiconductor surfaces, have been synthesized and characterized by electrochemical, photophysical, and spectroscopic measurements. The electrochemical and photophysical properties of these 4,4′‐disubstituted 2,2′‐bipyridines with extended π systems, in particular their LUMO energies, make them promising candidates to build up inorganic–organic hybrid photosensitizers for the sensitization of metal‐oxide semiconductors (e.g., TiO2 nanoparticles and/or nanotubes).The fantastic 4,4′: The electrochemical and photophysical properties of new 4,4′‐disubstituted 2,2′‐bipyridines with extended π systems and cyanoacrylic acid or cyanoacrylic acid ester anchoring groups make them promising candidates to build up inorganic–organic hybrid photosensitizers for the sensitization of metal‐oxide semiconductors (e.g., TiO2 nanoparticles and/or nanotubes).Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137440/1/asia201501324.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137440/2/asia201501324_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137440/3/asia201501324-sup-0001-misc_information.pd

Synthesis and Characterization of Tris(Heteroleptic) Ru(II) Complexes Bearing Styryl Subunits

We have developed and optimized a well-controlled and refined methodology for the synthesis of substituted π-conjugated 4,4′-styryl-2,2′-bipyridine ligands and also adapted the tris(heteroleptic) synthetic approach developed by Mann and co-workers to produce two new representative Ru(II)-based complexes bearing the metal oxide surface-anchoring precursor 4,4′-bis[E-(p-methylcarboxy-styryl)]-2,2′-bipyridine. The two targeted Ru(II) complexes, (4,4′-dimethyl-2,2′-bipyridine)(4,4′-di-tert-butyl-2,2′-bipyridine)(4,4′-bis[E-(p-methylcarboxy-styryl)]-2,2′-bipyridine) ruthenium(II) hexafluorophosphate, [Ru(dmbpy)(dtbbpy)(p-COOMe-styryl-bpy)](PF6)2 (1) and (4,4′-dimethyl-2,2′-bipyridine)(4,4′-dinonyl-2,2′-bipyridine)(4,4′-bis[E-(p-methylcarboxy-styryl)]-2,2′-bipyridine) ruthenium(II) hexafluorophosphate, [Ru(dmbpy)(dnbpy)(p-COOMe-styryl-bpy)](PF6)2 (2) were obtained as analytically pure compounds in high overall yields (>50% after 5 steps) and were isolated without significant purification effort. In these tris(heteroleptic) molecules, NMR-based structural characterization became nontrivial as the coordinated ligand sets each sense profoundly distinct magnetic environments greatly complicating traditional 1D spectra. However, rational two-dimensional approaches based on both homo- and heteronuclear couplings were readily applied to these structures producing quite definitive analytical characterization and the associated methodology is described in detail. Preliminary photoluminescence and photochemical characterization of 1 and 2 strongly suggests that both molecules are energetically and kinetically suitable to serve as sensitizers in energy-relevant applications