Construction of covalent organic frameworks (COFs) with a hollow and uniform morphologyregardless of whether planar or nonplanar building blocks are employedis still challenging. Herein, we report a facile strategy for the self-assembly and template-free synthesis of hollow spherical COFs by increasing the percentage content of 2-(2-azidoethoxy)ethoxy groups in the pore skeleton of a COF. Moreover, the morphological diversity dependent on the percentage content of 2-(2-azidoethoxy)ethoxy groups in the COF structure is observed. COF-100%N3, which is formed by the polycondensation of the nonplanar 1,3,5-tris(4-aminophenyl)benzene monomer, having the highest percentage content of the 2-(2-azidoethoxy)ethoxy group (100%), is self-assembled into homogeneous hollow spheres. For the first time, our strategy effectively explores the self-assembly of the planar monomer into a hollow spherical COF. Hollow spherical TPP-COF-100%N3 is formed via the polycondensation of the planar 2,4,6-tris(4-aminophenyl)pyridine monomer and 2-(2-azidoethoxy)ethoxy group (100%). Due to the favorable characteristics of its specific surface area and hollow mesoporous nature, spherical COF-100%N3 functions as an enticing sensing platform for the fluorescence-selective and -sensitive detection of telomere DNA. Consequently, this research study documents a facile strategy for constructing a unique hollow spherical COF and expands the application of COFs as fluorescent platforms for DNA detection.

In this paper, we describe the construction of a new fluorescent hydroxyl- and hydrazone-based covalent organic framework (TFPB-DHTH COF) through the one-pot polycondensation of 1,3,5-tris(4-formylphenyl)benzene (TFPB) and 2,5-dihydroxyterephthalohydrazide (DHTH) under...

New porphyrin-functionalized benzoxazine (Por-BZ) in high purity and yield was synthesized in this study based on 1H and 13C NMR and FTIR spectroscopic analyses through the reduction of Schiff base formed from tetrakis(4-aminophenyl)porphyrin (TAPP) and salicylaldehyde and the subsequent reaction with CH2O. Thermal properties of the product formed through ring-opening polymerization (ROP) of Por-BZ were measured using DSC, TGA and FTIR spectroscopy. Because of the rigid structure of the porphyrin moiety appended to the benzoxazine unit, the temperature required for ROP (314 °C) was higher than the typical Pa-type benzoxazine monomer (ca. 260 °C); furthermore, poly(Por-BZ) possessed a high thermal decomposition temperature (Td10 = 478 °C) and char yield (66 wt%) after thermal polymerization at 240 °C. An investigation of the thermal and luminescence properties of metal–porphyrin complexes revealed that the insertion of Ni and Zn ions decreased the thermal ROP temperatures of the Por-BZ/Ni and Por-BZ/Zn complexes significantly, to 241 and 231 °C, respectively. The metal ions acted as the effective promoter and catalyst for the thermal polymerization of the Por-BZ monomer, and also improved the thermal stabilities after thermal polymerization.

The development of new interconnections and synthetic approaches for the formation of porous organic polymers (POPs) is a challenging endeavor. Herein, we report a facile gramscale approach for the synthesis of uracil-and pentaazaphenalenefunctionalized porous organic polymers (Ur-POPs), namely, Ur-TPA, Ur-TPB, Ur-TPP, and Ur-TPT POPs, through a one-pot quadruple Mannich polycondensation of 6-aminouracil with paraformaldehyde and triamine linkers having various degrees of planarity, without the need for any additives such as templates and catalysts. Interestingly, the obtained Ur-POPs exhibited a uniform rod-like morphology, and depending on the planarity of the triamine linkers, a diameter variety of the rod was observed. These Ur-POPs possessed high specific surface areas, as high as 360 m 2 g −1 , and high thermal stability. In addition, the presence of uracil units in the primary skeleton of Ur-POPs combined with their regular rod-like structures endowed them with superior capabilities for remarkable selective recognition toward adenine in an aqueous solution.