Chemical Patterning in Single Crystals of Metal–Organic Frameworks by [2+2] Cycloaddition Reaction. Issue 42 (28th August 2019)

• Record Type: Journal Article
• Authors: Park, In‐Hyeok; Lee, Eunji; Lee, Shim Sung; Vittal, Jagadese J.
• Is Part Of: Angewandte Chemie international edition. Volume 58:Issue 42(2019)
• Page Start: 14860
• Page End: 14864
• Publication Date: 2019-08-28
• Subjects: [2+2] cycloaddition -- crystal engineering -- metal–organic frameworks -- molecular patterning -- strained molecules; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201904834
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Conventional chemical patterning involves films of polymeric materials. Herein, we demonstrate that the presence or absence of guest solvents in the crystal voids modulates the patterning of the cyclobutane rings in highly strained metal–organic frameworks (MOFs) under UV light. The olefin pairs of the spacer ligands, which resemble a ladder‐like structure, in the MOF, undergo a [2+2] cycloaddition reaction in a single‐crystal‐to‐single‐crystal manner. For instance, a partial photoreaction in the MOFs in the absence of a guest solvent as well as with dimethylacetamide in the voids generated two different patterns of the cyclobutane rings. Surprisingly, the MOF with the lattice dimethylformamide undergoes 100 % photoreaction, but the photoproduct contains broken chains. Such chemical patterning at the molecular level represents a next step in crystal engineering. Abstract : Paint the town red : Upon irradiation of crystals of highly strained metal–organic frameworks (MOFs) with UV light, adjacent olefins in the spacer ligands undergo a [2+2] cycloaddition reaction to produce cyclobutane rings. The presence or absence of guest solvents in the crystal voids modulates this reaction and the final positioning of the cyclobutane rings, resulting in different patterns.