Iridium(III)-Based Metal–Organic Frameworks as Multiresponsive Luminescent Sensors for Fe³⁺, Cr₂O₇^2–, and ATP^2– in Aqueous Media

Abstract

Three iridium(III)-based metal-organic frameworks (MOFs), namely [Cd{Ir(ppy-COO)}(DMF)(HO)]·6HO·2DMF (1), [Cd{Ir(ppy-COO)}(DMA)(HO)]·0.5HO·2DMA (2), and [Cd{Ir(ppy-COO)}(DEF)(HO)]·8HO·2DEF (3) (ppy-COOH = methyl-3-(pyridin-2-yl)benzoic acid, DMF = N,N-dimethylformamide, DMA = N,N-dimethylacetamide, DEF = N,N-diethylformamide), have been synthesized and characterized. Single-crystal structural determinations reveal that compounds 1-3 are isostructural, showing a three-dimensional framework structure with (3,6) connected rtl topologyin whose trimers of {Cd(COO)} are cross-linked by Ir(ppy-COO). The structures are completely different from those of other Ir(III)-based MOFs. Compound 1 was selected for a detailed study on sensing properties. The excellent luminescence as well as good water stability of 1 makes it a highly selective and sensitive multiresponsive luminescent sensor for Fe and CrO. The detection limits are 67.8 and 145.1 ppb, respectively. Compound 1 can also be used as an optical sensor for selective sensing of adenosine triphosphate (ATP) over adenosine diphosphate (ADP) and adenosine monophosphate (AMP) in aqueous solution. This is the first example of iridium(III)-based MOFs for the optical detection of Fe, CrO, and ATP. More interestingly, the luminescent composite film doped with 1% (w/w) of compound 1, 1@PMMA (PMMA = poly(methyl methacrylate)), can be successfully prepared, which endows efficient sensitivity for Fe and CrO detection and thus provides great potential for future applications.

Supramolecular iridium(III) assemblies

“…dimethylacetamide and DEF is N,N-diethylformamide) were recently reported by Zheng and co-workers [143]. X-ray single-crystal structure analyses revealed that MOF11, MOF12 and MOF13 are isostructural and crystallized in the monoclinic space group P2 1 /n, showing a three dimensional framework where complex L1 bridges three Cd 2+ ions through its six carboxylate oxygen atoms…”

Two-dimensional Cd(ii) coordination polymer encapsulated by Tb3+ as a reversible luminescent probe for Fe3+

“…S17 †), a linear presented at lower and higher experimental concentration range (0-20 mM; 36-90 mM), and the K SV and LOD values were 1.31 AE 0.01 Â 10 4 M À1 , 1.09 AE 0.02 Â 10 5 M À1 , respectively, displaying the high quenching efficiency of the Fe 3+ ions. [48][49][50] In addition, the LODs based on Tb 3+ @Cd-P were also obtained and 0.66 AE 0.02 mM for Fe 3+ ions.…”

Free Standing Large Area Metal-Organic Nanosheets Encapsulating Periodically Spaced Single-Ion Magnets

“…The organometallic iridium centres adopt distorted-octahedral geometries [Ir-C: 1.998, Ir-N: 2.118 Å] (Table S2), similar to those reported in other heterometallic Ir-M coordination polymers. 30 The [Ir(ppy-COO) 3 ] 3organometallic ligands are arranged on opposite sides of the anionic layer where one enantiomer with one polarity takes one face the other enantiomer with the opposite polarity on the other face ( Figure 1). The resulting layer is neither chiral nor polar and a centrosymmetric cell is formed.…”