Phenylene-bridged PMOs

Figure lb reports the UV-Visible spectrum of the liquid 1,4-bis(triethoxysilyl)benzene, the precursor of the phenylene-bridged PMO, into which traces of iodine have been dissolved. Only one band due to iodine is visible at 362 nm. We suggest this band to be due to I3" ion, which in aqueous solution absorbs at 355 nm [8], The presence of a band at the same wavelength in the case of I2 adsorbed onto AW-Ph-HMM reveals, also in... 

Iodine molecules adsorbed onto the structural aromatic rings provide information on the electron-donor strength, which appears to be higher in phenylene-bridged PMO than that reported for benzene and comparable with that reported for p-xilene. Traces of I3" species were also detected. From a comparison between two phenylene-bridged PMOs with different degree of order in the walls, aromatic rings in the material with amorphous walls appear more available for interaction with iodine. 

Keywords PMO, BTEB, Phenylene-Bridged, Iodine, UV-Visible. 

Of special significance in the development of PMO materials was the synthesis of porous materials with crystalline order of the bridged silsesquioxane inside the framework walls, initially achieved through the use of tt-tt interactions between 1,4-phenylene-bridged silsesquioxane precursors.33 Molecular scale periodicity in... 

Highly luminescent PMOs films could be fabricated using oligo(phenylene-vinylene) (OPV)-bridged precursors with different lateral substituents (Figure 4.12b) [78]. For all of the OPV-PMO films, the addition of TEOS at a ratio of 1 2 by weight of the precursor was necessary to recover periodic... 

As a general rule, PMOs were usually synthesized by short aliphatic chains like methane, ethane, and ethylene, as well as the aromatic groups phenylene and biphenylene as bridging organic moieties, mostly in the form of disilanes with rare reports of trisilanes and tetrasilanes. 

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