BODIPY-Based Polymers of Intrinsic Microporosity for the Photocatalytic Detoxification of a Chemical Threat
BODIPY-Based Polymers of Intrinsic Microporosity for the Photocatalytic Detoxification of a Chemical Threat
复制标题
DOI：
10.1021/acsami.1c21750
复制
发表时间：
2022-03-16
影响因子：
9.5
通讯作者：
Hupp, Joseph T.
中科院分区：
文献类型：
--
作者：
Atilgan, Ahmet;Beldjoudi, Yassine;Hupp, Joseph T.
能够在实际环境中消除化学威胁的有效异质光催化剂必须表现出出色的设备完整性。我们报告了一种共聚反应，可产生坚固、多孔、可加工、发色的 BODIPY（BDP；硼-二吡咯亚甲基），其含有固有微孔聚合物（BDP-PIM）。在 BDP 的中位位置安装五氟苯基会产生反应性单体，该单体与 5,5,6,6-四羟基-3,3,3,3-四甲基-1,1-螺二茚满 (TTSBI) 和四氟对苯二甲腈 (TFTPN) 结合产生 PIM 1。这些聚合物的合成后改性产生 Br BDPPIM-1a 和 1b-含溴聚合物2,6位。值得注意的是，溴化聚合物表现出与 H-BDP-PIM 相似的孔隙率和加工性能特征。气体吸附揭示了分子级孔隙度和高达 680 m(2) g(-1) 的 Brunette-Emmet-Teller 表面积。电子吸收光谱显示电荷转移 (CT) 谱带以 660 nm 为中心，而 BDP 和 TFTPN 单元的局部激发 LE 产生的谱带分别位于 530 和 430 nm。当 TFTPN 单元在 430 nm 处激发时，聚合物的荧光光谱揭示了到 BDP 单元的福斯特共振能量转移 (FRET) 途径；室温下的弱磷光表明单线态到三线态的系间窜越。低位三重态在能量上处于有利位置，可以敏化基态（三重态）分子氧向电子激发的单线态氧的转化。这些聚合物对硫芥模拟物 2-氯乙基乙基硫醚 (LEES) 的单线态氧驱动解毒的光敏能力已得到检验。虽然 CT 和 LEBDP 谱带的激发会产生较弱的催化活性（t 112 > 15 分钟），但对 TFTPN 较高能态的激发会导致光活性显着增加（t(1/2) 等于 5 分钟）。这种增加归因于（i）增强的光收集，（ii）TFTPN和BDP之间的FRET，（iii）具有大自旋轨道耦合能的重原子（溴）的存在，可以促进从供体-受体CT-、FRET-或LE生成的BDP单重态到BDP相关三重态的系间跨越，以及（iv）CEES反应性单线态氧形成的聚合物三重激发态敏化。
Effective heterogeneous photocatalysts capable of detoxi fying chemical threats in practical settings must exhibit outstanding device integrity. We report a copolymerization that yields robust, porous, processible, chromophoric BODIPY (BDP; boron-dipyrromethene)-containing polymers of intrinsic microporosity (BDP-PIMs). Installation of a pentafluorophenyl at the meso position of a BDP produced reactive monomer that when combined with 5,5,6,6-tetrahydroxy-3,3,3,3-tetramethyl-1,1-spirobisindane (TTSBI) and tetrafluoroterephthalonitrile (TFTPN) yields PIM 1. Postsynthetic modification of these polymers yields Br BDPPIM-1a and 1b-polymers containing bromine at the 2,6-positions. Remarkably, the brominated polymers display porosity and processability features similar to those of H-BDP-PIMs. Gas adsorption reveals molecular-scale porosity and Brunette-Emmet-Teller surface areas as high as 680 m(2) g(-1). Electronic absorption spectra reveal charge-transfer (CT) bands centered at 660 nm, while bands arising from local excitations, LE, of BDP and TFTPN units are at 530 and 430 nm, respectively. Fluorescence spectra of the polymers reveal a Forster resonance energy-transfer (FRET) pathway to BDP units when TFTPN units are excited at 430 nm; weak phosphorescence at room temperature indicates a singlet-to-triplet intersystem crossing. The low-lying triplet state is well positioned energetically to sensitize the conversion of ground-state (triplet) molecular oxygen to electronically excited singlet oxygen. Photosensitization capabilities of these polymers toward singlet-oxygen-driven detoxification of a sulfur-mustard simulant 2-chloroethyl ethyl sulfide (LEES) have been examined. While excitation of CT and LEBDP bands yields weak catalytic activity (t 112 > 15 min), excitation to higher energy states of TFTPN induces significant increases in photoactivity (t(1/2) congruent to 5 min). The increase is attributable to (i) enhanced light collection, (ii) FRET between TFTPN and BDP, (iii) the presence of heavy atoms (bromine) having large spin-orbit coupling energies that can facilitate intersystem crossing from donor-acceptor CT-, FRET-, or LE-generated BDP singlet states to BDP-related triplet states, and (iv) polymer triplet excited-state sensitization of the formation of CEES-reactive, singlet oxygen.