title: Engineering the optical response of the titanium-MIL-125 metal-organic framework through ligand functionalization.
abstract: 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.
authors.affiliation: Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Hendon
authors.forename: Davide
authors.initials: D
authors.lastname: Tiana
authors.forename: Marc
authors.initials: M
authors.lastname: Fontecave
authors.forename: Clément
authors.initials: C
authors.lastname: Sanchez
authors.forename: Loïc
authors.initials: L
authors.lastname: D'arras
authors.forename: Capucine
authors.initials: C
authors.lastname: Sassoye
authors.forename: Laurence
authors.initials: L
authors.lastname: Rozes
authors.forename: Caroline
authors.initials: C
authors.lastname: Mellot-Draznieks
authors.forename: Aron
authors.initials: A
authors.lastname: Walsh
mesh_terms: D004738:Engineering; D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D055620:Optical Phenomena; D009942:Organometallic Compounds / Q000737:chemistry*; D010795:Phthalic Acids / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: C547494:1,4-benzenedicarboxylate; D008024:Ligands; D009942:Organometallic Compounds; D010795:Phthalic Acids; D014025:Titanium