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Living crystallization-driven self-assembly (CDSA) has emerged as an efficient strategy to generate nanofibers of π-conjugated polymers (CPNFs) in a controlled fashion. However, reports of donor–acceptor (D–A) heterojunction CPNFs are extremely rare. The preparation of these materials remains a challenge due to the lack of rational design guidelines for the D–A π-conjugated units. Herein, we report a versatile CDSA strategy based upon carefully designed D–A-co-oligomers in which electron-deficient benzothiadiazole (BT) or dibenzo[b,d]thiophene 5,5-dioxide (FSO) units are attached to the two ends of an oligo(p-phenylene ethynylene) heptamer [BT-OPE7-BT, FSO-OPE7-FSO]. This arrangement with the electron-deficient groups at the two ends of the oligomer enhances the stacking interaction of the A–D–A π-conjugated structure. In contrast, D–A–D structures with a single BT in the middle of a string of OPE units disrupt the packing. We employed oligomers with a terminal alkyne to synthesize diblock copolymers BT-OPE7-BT-b-P2VP and BT-OPE7-BT-b-PNIPAM (P2VP = poly(2-vinylpyridine), PNIPAM = poly(N-isopropylacrylamide)) and FSO-OPE7-FSO-b-P2VP and FSO-OPE7-FSO-b-PNIPAM. CDSA experiments with these copolymers in ethanol were able to generate CPNFs of controlled length by both self-seeding and seeded growth as well as block comicelles with precisely tunable length and composition. Furthermore, the D–A CPNFs with a BT-OPE7-BT-based core demonstrate photocatalytic activity for the photooxidation of sulfide to sulfoxide and benzylamine to N-benzylidenebenzylamine. Given the scope of the oligomer compositions examined and the range of structures formed, we believe that the living CDSA strategy with D–A-based co-oligomers opens future opportunities for the creation of D–A CPNFs with programmable architectures as well as diverse functionalities and applications.

3,3-Difluoro-1,2-diphenylcyclopropene (CpFluor), a bench-stable fluorination reagent, has been developed in the deoxyfluorination of carboxylic acids to afford various acyl fluorides. This all-carbon-based fluorination reagent enabled the efficient transformation of (hetero)aryl, alkyl, alkenyl, and alkynyl carboxylic acids to the corresponding acyl fluorides under the neutral conditions. This deoxyfluorination method was featured by the synthesis of acyl fluorides with in-situformed CpFluor, as well as the one-pot amidation reaction of carboxylic acids via in-situformed acyl fluorides.

Although living crystallization-driven self-assembly (CDSA) has emerged as a facile approach to generate uniform π-conjugated-polymer-based fiber-like micelles, the extension of living CDSA to prepare uniform donor–acceptor (D–A) fiber-like micelles of controlled length with attractive near-infrared (NIR) absorption/emission, photodynamic (PD), and photothermal (PT) properties is virtually unexplored. Herein, three block copolymers composed of the same corona-forming P2VP44(P2VP = poly(2-vinylpyridine), the subscript is the degree of polymerization) but different D–A π-conjugated core-forming co-oligomers of OPE4-DPP-OPE4(OPE4= oligo(p-phenylene ethynylene), DPP = diketopyrrolopyrrole) are designed and synthesized to probe the steric and electronic effect of co-oligomers of OPE4-DPP-OPE4on their CDSA behaviors and photophysical properties. One co-oligomer contains a DPP with two 2-ethylhexyl side chains flanked by two thiophene-OPE4segments (b-T-OPE4-DPP-OPE4). The variation of the second one is the replacement of 2-ethylhexyl side chains with linear octyls (l-T-OPE4-DPP-OPE4). The last one is composed of a DPP with two linear octyl side chains flanked by two phenylene-OPE4segments (l-P-OPE4-DPP-OPE4). Uniform fiber-like micelles can be generated by a self-seeding approach for b-T-OPE4-DPP-OPE4-b-P2VP44and l-P-OPE4-DPP-OPE4-b-P2VP44, whereas polydisperse fiber-like micelles only can be obtained for l-T-OPE4-DPP-OPE4-b-P2VP44likely due to the multiple packing modes of l-T-OPE4-DPP-OPE4. Intriguingly, the aging of micelles of l-T-OPE4-DPP-OPE4-b-P2VP44can promote the conversion of the packing mode of l-T-OPE4-DPP-OPE4units to their most thermodynamically stable packing mode, and thus, self-seeding of aged seed micelles of l-T-OPE4-DPP-OPE4-b-P2VP44gave uniform fiber-like micelles of controlled length. More interestingly, micellar solution of b-T-OPE4-DPP-OPE4-b-P2VP44exhibits NIR absorption/emission, PT, and PD activities upon the light irradiation at 660 nm. Although micellar solution of l-T-OPE4-DPP-OPE4-b-P2VP44also shows NIR absorption/emission and PT activity, its PD activity is much lower relative to that of b-T-OPE4-DPPa-OPE4-b-P2VP44. The micellar solution of l-P-OPE4-DPP-OPE4-b-P2VP44exhibits neither NIR absorption/emission nor PT/PD activities upon the light irradiation at 660 nm. All these results showed that a small variation of structure of OPE4-DPP-OPE4can lead to distinct CDSA behaviors and absorption/emission/PD/PT properties.