Luminescence properties of mixed-ligand MOFs containing fluorene scaffolds functionalized with isonicotinoyl arms. Issue 14 (16th March 2023)

• Record Type: Journal Article
• Authors: Delledonne, Andrea; Orlandini, Martina; Terenziani, Francesca; Mazzeo, Paolo Pio; Bacchi, Alessia; Carlucci, Lucia; Comotti, Angiolina; Perego, Jacopo; Pelagatti, Paolo
• Is Part Of: CrystEngComm. Volume 25:Issue 14(2023)
• Page Start: 2085
• Page End: 2095
• Publication Date: 2023-03-16
• Subjects: Crystals -- Periodicals; Crystal growth -- Periodicals; Crystallography -- Periodicals; Cristaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Cristallographie -- Périodiques; 548
• DOI: 10.1039/d3ce00087g
• Languages: English
• ISSNs: 1466-8033

Abstract

Abstract : Three new polycatenated mixed-ligand MOFs containing fluorene and naphthalene scaffolds have been solvothermally synthesized. Their solid-state luminescence has been investigated showing a Förster resonance energy transfer involving the two linkers. Abstract : Solvothermal reactions between three bis-pyridine-bis-amide ligands containing a fluorene scaffold bearing different substituents on the C9 position (CH2, 1 ; CMe2, 2 ; CO, 3 ) with 2, 6-naphthalenedicarboxylic acid (H2 ndca) and Zn(NO3 )2 ·6H2 O led to the isolation of three new microporous mixed-ligand MOFs (PUM310, containing 1 ; PUM310Me 2, containing 2 ; PUM310CO, containing 3 ). The structural characterization conducted with X-ray quality single crystals revealed parallel polycatenated frameworks of thick layers in all cases, corresponding to the topological type 5, 6L18. The entangled nets contain complete and truncated Zn-paddle wheels. In the truncated paddle wheel, a pyridine of the bis-amide linker has been replaced by a DMF molecule. Solvent removal leads to framework rearrangement, as evidenced by XRPD analysis performed on desolvated PUM310, with consequent framework shrinkage as also evidenced by volumetric adsorption analyses. The three MOFs are fluorescent in the solid state. The optical spectra are indicative of a Förster resonance energy transfer (FRET) involving ndca 2− as an excitation energy donor and the bis-pyridine linkers as acceptors, with a FRET efficiency close to 100% in the case of PUM310CO .