Evidence of Photoinduced Charge Separation in the Metal–Organic Framework MIL‐125(Ti)‐NH2 |
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| Authors: | Dr Maykel de Miguel Mrs Florence Ragon Prof Thomas Devic Prof Christian Serre Prof Patricia Horcajada Prof Hermenegildo García |
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| Institution: | 1. Instituto de Tecnología Química CSIC‐UPV and Departamento de Química, Universidad Politécnica de Valencia, Av. De los Naranjos S/N, 46022 Valencia (Spain);2. Institut Lavoisier CNRS UMR 8180, Université de Versailles Saint‐Quentin‐en‐Yvelines, 45 Avenue des Etats Unis, 78035 Versailles cedex (France) |
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| Abstract: | Herein, we describe the photochemical behavior of the porous metal–organic framework MIL‐125(Ti)‐NH2, built up from cyclic Ti8O8(OH)4 oxoclusters and 2‐aminoterephthalate ligands. While MIL‐125(Ti)‐NH2 does not emit upon excitation at 420 nm, laser flash photolyses of dry samples (diffuse reflectance) or aqueous suspensions (transmission) of the solid have allowed detecting a transient characterized by a continuous absorption from 390 to 820 nm decaying in the sub‐millisecond timescale, which is quenched by oxygen. This transient has been attributed to the charge‐separation state. Firm evidence for this assignment was obtained by lamp irradiation of aqueous suspensions of MIL‐125(Ti)‐NH2 in the presence of electron‐donor (N,N,N′N′‐tetramethyl‐p‐phenylenediamine) or electron‐acceptor (methylviologen) probe molecules, which has allowed the visual detection of the corresponding radical ions, in agreement with the occurrence of photoinduced charge separation in MIL‐125(Ti)‐NH2. |
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| Keywords: | charge separation clusters materials science metal– organic frameworks photochemistry |
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