The state of p‐phenylphenol molecules in dioxane/water mixture, a commonly used reaction system for enzymatic polymerization of phenols and aromatic amines, was investigated by difference UV absorption spectroscopy and Fourier transform (FT) Raman spectroscopy. The aggregate of p‐phenylphenols is found on the basis of the exciton peaks observed in difference UV absorption spectra. FT Raman spectroscopy demonstrates further that p‐phenylphenol molecules aggregate together in “face to face” fashion. A simplified model is proposed for aggregation of p‐phenylphenol molecules in dioxane/water mixture, which can elucidate the variation of the molecular weight of poly (p‐phenylphenol) coupled in the reaction system. © 1995 John Wiley & Sons, Inc.

Efficient synthesis of cyclic polymers has received much attention in polymer chemistry field. Although photochemical cycloaddition of terminal p-bonded units provides a plausible way toward cyclic polymerization, it remains challenging to avoid side reactions by manipulating the reaction selectivity. Herein supramolecular confinement has been developed as a promising strategy to address this issue, by introducing highly directional hydrogen bonds to the photoreactive cyanostilbenes. The cyanostilbenes units on both ends of a telechelic macromonomer are orientationally aligned with high local concentrations, yielding [2+2] photo-cycloaddition products upon 430 nm light irradiation. It leads to the formation of cyclic polymers in the self-assembled state, in stark contrast to Z-E isomerization of cyanostilbenes in the monomeric state. Overall, supramolecular confinement effect exemplified in the current study provides new avenues toward cyclic topological polymers with high synthetic efficiency.

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Phosphorescent host–guest systems have attracted considerable attention because of their intriguing properties and diverse applications. In this study, a polyhedral oligomeric silsesquioxane-functionalized gold­(III) tweezer receptor has been designed and synthesized. It is capable of sandwiching platinum­(II) terpyridine compounds into its cavity with a high noncovalent binding affinity (association constants: ∼105 M–1 in chloroform). The resulting heterometallic host–guest complexes exhibit enhanced phosphorescent emission compared with those of the individual species in chloroform, thanks to the prevention of vibration and rotation upon noncovalent complexation. They can further assemble into nanospheres in chloroform/diethyl ether (1:9, v/v) owing to phase segregation between the metallotweezer/guest motif and the peripheral polyhedral oligomeric silsesquioxane unit. When terpyridine platinum­(II) chloride serves as the complementary guest, the resulting noncovalent system displays an intraligand emission at the individual host–guest complexed state yet excimeric emission at the supramolecular assembled state, yielding the phosphorescent solvatochromic behaviors. Overall, the polyhedral oligomeric silsesquioxane-functionalized metallotweezer combines guest encapsulation and supramolecular assembly capabilities, which provides new avenues for color-tunable phosphorescent materials.