Rigid photoluminescence

Recently, a very interesting example of solvatochromism was reported by Fujiki and co-workers.206 Poly(methyl-3,3,3-trifluoropropylsilylene), 87, synthesized via Wurtz coupling, showed solvatochromism as a result of weak, non-covalent intramolecular Si- -F-G interactions which rendered the conformation of the polysilane uniquely controllable by solvent choice and molecular weight. UV, shown in Figure 18, photoluminescence, NMR, and viscosity studies on the polymer indicated a 73 helical rod-like conformation at room temperature in non-coordinating solvents (e.g., toluene and decane), since the intramolecular interaction resulted in constraining the chain in a rigid helix. 

As a result of the relatively rigid layers, strong forces are exterted on the interlayer guests in LDHs. From the magnitude of the red shift in the photoluminescence observed on intercalation of [SmWio036] in LDHs, it has been estimated that the layers exert a uniaxial stress of about 14 GPa on the guest anion [96,97]. 

This rigid core compound displayed a PLQY value in the microciystalline powder of q = 48% (Barbarella et al., 2001). DTTOMe4 belongs to a class of oligothiophene-S,S-dioxides characterized by high photoluminescence efficiency both in solution and in the solid state, contrary to conventional thiophene oligomers and conformationally flexible oligothiophene-... 

Ti(OH)2(OSi)2, while Ti-oxides incorporated within the zeolite framework have a closed structure of Ti(OSi)4, as suggested by Coluccia et al. [15] Moreover, it is likely that the molecular environment of the Ti-oxides such as the rigidity or flexibility of the zeolite framework causes a significant and pronounced effect on the chemical properties of the Xi04 unit. Taking these results into consideration, the different band positions of the observed photoluminescence of the various Ti-oxide catalysts may be attributed to the differences in the molecular environment of the Ti-oxides such as the rigidity or flexibility of the zeolite framework and the local stmctures of the Ti04 unit, /. e., Ti(OSi)4,... 

The Raman spectrum of NbSej single crystals exhibit three first order lines at 29.6, 230.9 and 238.3 cm. The low frequency line at 29.6 cm is due to the rigid layer vibration mode (Ej ) which accounts for the weak interlayer bonding. The high-frequency lines at 230.9 and 238.3 cm are due to the A,g and Ejg modes, respectively. The high frequency Raman modes in the NbScj nanostructures were found to be identical to those of the bulk crystal. Bulk NbSc2 shows a photoluminescence band of very weak intensity band at around 825 nm possibly due to trapped states. The band is shifted to 820 nm in the nanostructures. 

The rigid spirobifluorene linkage significantly increases in the glass transition temperatures, which are in the range of 246-280°C. The luminophores show the characteristic absorptions and photoluminescence of ordinary mono-p Tazoloquinoline derivatives, in the blue region. ... 

Tedesco, E., F. Della Sala, L. Favaretto, G. Barbarella, D. Albesa-Jove, D. Pisignano, G. Gigli, R. Cingolani, and K.D.M. Harris. 2003. Solid-state supramolecular organization, established directly from powder diffraction data, and photoluminescence efficiency of rigid-core oligothiophene-S,S-dioxides. J Am Chem Soc 125 12277-12283. 

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