Enhancing Selectivity and Kinetics in Oxidative Photocyclization by Supramolecular Control. Issue 41 (19th September 2018)

• Record Type: Journal Article
• Authors: Haldar, Ritesh; Diring, Stéphane; Samanta, Pralok K.; Muth, Marius; Clancy, William; Mazel, Antoine; Schlabach, Sabine; Kirschhöfer, Frank; Brenner‐Weiß, Gerald; Pati, Swapan K.; Odobel, Fabrice; Wöll, Christof
• Is Part Of: Angewandte Chemie international edition. Volume 57:Issue 41(2018)
• Page Start: 13662
• Page End: 13665
• Publication Date: 2018-09-19
• Subjects: aggregation -- cyclization -- photooxidation -- regioselectivity -- surface MOFs; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201806996
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Photochemical reactions typically proceed via multiple reaction pathways, yielding a variety of isomers and products. Enhancing the selectivity is challenging. Now, the potential of supramolecular control for oxidative photocyclization of a tetraarylethylene, containing a stereogenic −C=C− bond, is demonstrated. In solution, this photochemical reaction produces three constitutional isomers (substituted phenanthrenes), with slow kinetics. When the reactant is assembled into a crystalline framework, only one product forms with accelerated kinetics. Key to this selectivity enhancement is the integration into a surface grown metal–organic framework (SURMOF); the dramatic gain in selectivity is ascribed to the hindrance of the rotational freedom of the −C=C− double bond. The structure of the MOF is key; the corresponding reaction in the solid does not result in such a high increase in selectivity. A striking change of luminescence properties after photocyclization is observed. Abstract : Photomeditated oxidative cyclization of a suitably substituted stilbene, after integration in a surface anchored metal‐organic framework as a linker, yielded one phenanthrene isomer with about 96 % selectivity, and improved reaction kinetics.