Engineering the Optical Response of the Titanium-MIL-125 Metal-Organic Framework through Ligand Functionalization

作者：Hendon, Christopher H.; Tiana, Davide; Fontecave, Marc; Sanchez, Clement; D'arras, Loic; Sassoye, Capucine; Rozes, Laurence^*; Mellot-Draznieks, Caroline; Walsh, Aron

来源：Journal of the American Chemical Society, 2013, 135(30): 10942-10945.

DOI：10.1021/ja405350u

• BAND-GAPS
• CO2
• MOFS
• PHOTOCATALYST
• TUNABILITY
• SEPARATION
• AMINO
• ZN

Herein we discuss band gap modification of MIL-125, a TiO2/1,4-benzenedicarboxylate (bdc) metal-organic framework (MOF). Through a combination of synthesis and computation, we elucidated the electronic structure of MIL-125 with aminated linkers. The band gap decrease observed when the monoaminated bdc-NH2 linker was used arises from donation of the N 2p electrons to the aromatic linking unit, resulting in a red-shifted band above the valence-band edge of MIL-125. We further explored in silico MIL-125 with the diaminated linker bdc(NH2)(2) and other functional groups (-OH, -CH3, -Cl) as alternative substitutions to control the optical response. The bdc-(NH2)2 linking unit was predicted to lower the band gap of MIL-125 to 1.28 eV, and this was confirmed through the targeted synthesis of the bdc-(NH2)(2)-based MIL,-125. This study illustrates the possibility of tuning the optical response of MOFs through rational functionalization of the linking unit, and the strength of combined synthetic/computational approaches for targeting functionalized hybrid materials.