TY - JOUR

T1 - Inside/outside

T2 - Post-synthetic modification of the Zr-benzophenonedicarboxylate metal–organic framework

AU - Mohmeyer, Alexander

AU - Schäfer, Malte

AU - Schaate, Andreas

AU - Locmelis, Sonja

AU - Schneider, Andreas M.

AU - Behrens, Peter

N1 - Funding information: This work was in part funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy within the Cluster of Excellence PhoenixD (EXC 2122, Project ID 390833453). We thank T. Heinemeyer for preparing the electron microscopic images. M.S. is grateful for a fellowship from the Ph.D. programme “Hannover school of nanotechnology?sensors” of the LNQE, funded by the State of Lower Saxony. In addition, we thank the Institut für Organische Chemie at the Leibniz University Hannover for performing NMR spectroscopy measurements.

PY - 2020/2/4

Y1 - 2020/2/4

N2 - The Zr-based metal–organic framework, Zr-bzpdc-MOF, contains the photoreactive linker molecule benzophenone-4,4′-dicarboxylate (bzpdc) which imparts the possibility for photochemical post-synthetic modification. Upon irradiation with UV light, the keto group of the benzophenone moiety will react with nearly every C−H bond-containing molecule. Within this paper, we further explore the photochemical reactivity of the Zr-bzpdc-MOF, especially with regard to which restrictions govern internal versus external reactions. We show that apart from reactions with C−H bond-containing molecules, the MOF reacts also with water. By studying the reactivity versus linear alcohols we find a clear delineation in that shorter alcohol molecules (up to butanol as a borderline case) react with photoexcited keto groups throughout the whole crystals whereas longer ones react only with surface-standing keto groups. In addition, we show that with the alkanes n-butane to n-octane, the reaction is restricted to the outer surface. We hypothesize that the reactivity of the Zr-bzpdc-MOF versus different reagents depends on the accessibility of the pore system which in turn depends mainly on the size of the reagents and on their polarity. The possibility to direct the post-synthetic modification of the Zr-bzpdc-MOF (selective modification of the whole pore system versus surface modification) gives additional degrees of freedom in the design of this metal–organic framework for shaping and for applications.

AB - The Zr-based metal–organic framework, Zr-bzpdc-MOF, contains the photoreactive linker molecule benzophenone-4,4′-dicarboxylate (bzpdc) which imparts the possibility for photochemical post-synthetic modification. Upon irradiation with UV light, the keto group of the benzophenone moiety will react with nearly every C−H bond-containing molecule. Within this paper, we further explore the photochemical reactivity of the Zr-bzpdc-MOF, especially with regard to which restrictions govern internal versus external reactions. We show that apart from reactions with C−H bond-containing molecules, the MOF reacts also with water. By studying the reactivity versus linear alcohols we find a clear delineation in that shorter alcohol molecules (up to butanol as a borderline case) react with photoexcited keto groups throughout the whole crystals whereas longer ones react only with surface-standing keto groups. In addition, we show that with the alkanes n-butane to n-octane, the reaction is restricted to the outer surface. We hypothesize that the reactivity of the Zr-bzpdc-MOF versus different reagents depends on the accessibility of the pore system which in turn depends mainly on the size of the reagents and on their polarity. The possibility to direct the post-synthetic modification of the Zr-bzpdc-MOF (selective modification of the whole pore system versus surface modification) gives additional degrees of freedom in the design of this metal–organic framework for shaping and for applications.

KW - benzophenone

KW - modulation

KW - photochemistry

KW - post-synthetic modification

KW - zirconium

UR - http://www.scopus.com/inward/record.url?scp=85078975634&partnerID=8YFLogxK

U2 - 10.1002/chem.201903630

DO - 10.1002/chem.201903630

M3 - Article

C2 - 32017252

AN - SCOPUS:85078975634

VL - 26

SP - 2222

EP - 2232

JO - Chemistry - a European journal

JF - Chemistry - a European journal

SN - 0947-6539

IS - 10

ER -