Structural response to desolvation in a pyridyl-phenanthrene diarylethene-based metal–organic framework

A phenanthrene-based diarylethene linker with linear pyridyl connectivity, 4,4′-(9,10-bis(2,5-dimethylthiophen-3-yl)phenanthrene-2,7-diyl)dipyridine linker (TPDPy) was prepared and subsequently used to synthesize an air-stable metal–organic framework, UBMOF-3 (Zn3(BDC)3(TPDPy)1(DMF)1.5, BDC = 1,4-benzenedicarboxylate, DMF = N,N-dimethylformamide). Upon irradiation with ultraviolet light, this photo-responsive framework, composed of terephthalate, TPDPy, and zinc pinwheels, exhibits strong linear dichroism consistent with the crystal structure. Activation (desolvation) of the crystal leads to a significant change in the crystal structure that improves the ability to crystallographically resolve the photochromic linker.