Modulating Carrier Transfer over Carbazolic Conjugated Microporous Polymers via Donor Structural Design for Functionalization of Thiophenols

Abstract

Developing photocatalysts to steer conversion of solar energy toward high-value-added fine chemicals represents a potentially viable approach to address the energy crisis and environmental issues. However, enablement of this conversion is usually impeded by the sluggish kinetic process for proton-coupled electron transfer and rapid recombination of photogenerated excitons. Herein, we report a simple and general structural expansion strategy to facilitate charge transfer in conjugated microporous polymers (CMPs) via engineering the donor surrounding the trifluoromethylphenyl core. The resulting CMPs combine high surface area, strong light-harvesting capabilities, and tunable optical properties endowed by extended π-conjugation; the optimized compound CbzCMP-5 generated from 9,9′,9″-(2-(trifluoromethyl)benzene-1,3,5-triyl)tris(9H-carbazole) remarkably enhanced the photogenerated carrier transfer efficiency, enabling the functionalization of thiophenols toward thiocarbamates and 3sulfenylindoles with high photocatalytic efficiency. Most importantly, the in-depth insights into the carrier-transfer processes open up new prospects on further optimization and rational design of photoactive polymers for efficient charge-transfer-mediated reactions.

The effects of the linker length on iodine adsorption and fluorescence sensing property of the N, O, P containing covalent organic frameworks

“…The solution gradually deepened from colorless to dark brown, which indicated that iodine was separated from the skeletons and pores of the COFs (Figure 7b, insets). 27,33,39 As can be seen in Figure 7b, the iodine release rates of both COFs increased almost linearly before 120 min, since the iodine release was affected by the subject and the object. With a later gradual flattening due to free diffusion.…”

“…These phenomena suggested that electron transfer from electron‐rich COFs to the electron‐deficient iodine molecules that form complexes of I 3 − and I 5 − after obtaining the electrons, thus leading to the COFs to exhibit to large iodine adsorption capacity (Scheme 2). Therefore, the large iodine adsorption amounts of the COFs are mainly due to the chemisorption mechanism for electrostatic interactions between polyiodide anions and cation skeletons 27,33,40 …”

“…By calculation it is obtained that HPDA and HDAT release iodine of 4.31 and 3.30 g g À1 , respectively. 27 The amounts calculated at 400 C were nearly 95% and 85% of the iodine adsorption amounts of the two COFs. From the pore volume data and iodine density data calculated by HPDA and HDAT under 350 K standard conditions, the theoretical iodine adsorption amounts of HPDA and HDAT were 1.23 and 0.62 g g À1 .…”

“…Therefore, the large iodine adsorption amounts of the COFs are mainly due to the chemisorption mechanism for electrostatic interactions between polyiodide anions and cation skeletons. 27,33,40 TGA experimental results showed that HPDA and HDAT have good thermal stability. So I 2 @COFs were heated at 398 K and tested by the thermal removal method.…”

“…We compared HPDA and HDAT with HBD (prepared by. NOP‐6‐CHO and biphenyl diamine [BD]) 27 and investigated the effects of different lengths of the linker length on iodine adsorption and fluorescence sensing.…”