Post-Synthetically Elaborated BODIPY-Based Porous Organic Polymers (POPs) for the Photochemical Detoxification of a Sulfur Mustard Simulant

Designing
new materials for the effective detoxification of chemical
warfare agents (CWAs) is of current interest given the recent use
of CWAs. Although halogenated boron-dipyrromethene derivatives (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene
or BDP or BODIPY) at the 2 and 6 positions have been extensively explored
as efficient photosensitizers for generating singlet oxygen (1O2) in homogeneous media, their utilization in
the design of porous organic polymers (POPs) has remained elusive
due to the difficulty of controlling polymerization processes through
cross-coupling synthesis pathways. Our approach to overcome these
difficulties and prepare halogenated BODIPY-based porous organic polymers
(X-BDP-POP where X = Br or I) represents an attractive
alternative through post-synthesis modification (PSM) of the parent
hydrogenated polymer. Upon synthesis of both the parent polymer, H-BDP-POP, and its post-synthetically modified derivatives, Br-BDP-POP and I-BDP-POP, the BET surface areas
of all POPs have been measured and found to be 640, 430, and 400 m2·g–1, respectively. In
addition, the insertion of heavy halogen atoms at the 2 and 6 positions
of the BODIPY unit leads to the quenching of fluorescence (both polymer
and solution-phase monomer forms) and the enhancement of phosphorescence
(particularly for the iodo versions of the polymers and monomers),
as a result of efficient intersystem crossing. The heterogeneous photocatalytic
activities of both the parent POP and its derivatives for the detoxification
of the sulfur mustard simulant, 2-chloroethyl ethyl sulfide (CEES),
have been examined; the results show a significant enhancement in
the generation of singlet oxygen (1O2). Both
the bromination and iodination of H-BDP-POP served to
shorten by 5-fold of the time needed for the selective and catalytic
photo-oxidation of CEES to 2-chloroethyl ethyl sulfoxide (CEESO).

鉴于近期化学武器（CWAs）的使用，设计新型材料以有效脱除化学武器剂（CWAs）已成为当前研究热点。尽管在均相介质中，位于2和6位的卤素取代硼二吡咯甲烷衍生物（4,4-二氟-4-硼-3a,4a-二氮杂-苯并[1,2-d]吲哚，或称BDP或BODIPY）已被广泛研究作为高效的生成单线态氧（1O2）的光敏化剂，但它们在多孔有机聚合物（POPs）设计中的应用却因通过交叉偶联合成途径控制聚合反应过程的困难而难以实现。本研究旨在克服这些困难，通过后合成修饰（PSM）母体氢化聚合物，制备基于卤素取代BODIPY的多孔有机聚合物（X-BDP-POP，其中X代表Br或I），这为一种具有吸引力的替代方案。在合成母体聚合物H-BDP-POP及其后合成修饰的衍生物Br-BDP-POP和I-BDP-POP后，所有POPs的BET表面积分别为640、430和400 m2·g–1。此外，BODIPY单元2和6位引入重卤素原子导致荧光（聚合物和溶液相单体形式）淬灭，并增强磷光（尤其是聚合物和单体的碘化版本），这是由于有效的系间窜越所致。母体POPs及其衍生物对芥子气模拟物2-氯乙基乙基硫醚（CEES）的异相光催化解毒活性已得到检验；结果显示，单线态氧（1O2）的生成显著增强。对H-BDP-POP的溴化和碘化处理均缩短了CEES选择性光催化氧化为2-氯乙基乙基亚砜（CEESO）所需时间的5倍。