A functionalized UiO-66 MOF for turn-on fluorescence sensing of superoxide in water and efficient catalysis for Knoevenagel condensation

Abstract

A MOF based sensor is reported for specific, rapid, and sensitive sensing of O2·− and effective and recyclable catalysis of Knoevenagel condensation.

What Lies beneath a Metal–Organic Framework Crystal Structure? New Design Principles from Unexpected Behaviors

“…MOFs that stabilize a fluorophore in a dark geometry can become luminescent when external stimuli induce a structural transition (non-obvious from the crystal structure), enhance interlinker π-overlap, , or enable bond-forming reactions with the linkers. These can be used to tune the selectivity of the turn-on response. − Such complex interrelationships point to the necessity for computational modeling to understand alignment between MOF bands and guest molecular orbitals and the effects on fluorophore rigidity and vibrational modes due to incorporation in the MOF crystal. However, with so few examples of novel turn-on and turn-off incongruities, there is also a need for further fundamental synthetic endeavors to guide theory.…”

Nanotechnologies for Reactive Oxygen Species“Turn-On” Detection

“…Furthermore, exposure to excess O 2 •− would oxidize organisms, biological membranes, and tissues and cause diseases such as hepatitis, cancer, and diabetes (Gorrini et al, 2013). Nanomaterials such as carbon dots (Liang et al, 2020;Yue et al, 2021), MOF (Das et al, 2019), and tobacco mosaic virus (TMV) nanoparticles (Dharmarwardana et al, 2018) have been fabricated as selective sensors for "turn-on" sensing of O 2…”

“…Furthermore, exposure to excess O 2 •− would oxidize organisms, biological membranes, and tissues and cause diseases such as hepatitis, cancer, and diabetes ( Gorrini et al, 2013 ). Nanomaterials such as carbon dots ( Liang et al, 2020 ; Yue et al, 2021 ), MOF ( Das et al, 2019 ), and tobacco mosaic virus (TMV) nanoparticles ( Dharmarwardana et al, 2018 ) have been fabricated as selective sensors for “turn-on” sensing of O 2 •− . Silver nanoparticle (Ag NP)-coated carbon quantum dot (CQD) core–shell-structured nanocomposites (CQD@Ag NCs) have been developed for fluorescent sensing of intracellular O 2 •− (LOD = 0.3 μM) ( Figure 2I ).…”

“…Enhancement of the fluorescence response of the MOF upon stepwise addition of O 2•− has been recorded. The mechanism of the fluorescence "turn-on" procedure is recognized as follows: the structural collapse of the MOF in the presence of O 2•− can result in the release of the linker (2-((pyridin-4-ylmethyl)amino)terephthalic acid) with the enhancement of the fluorescence intensity of the system(Das et al, 2019).…”

Preparation of a novel Fe3O4@SiO2@propyl@DBU magnetic core–shell nanocatalyst for Knoevenagel reaction in aqueous medium

“…Knoevenegal reaction is the condensation reaction of a reactive methylene compounds with aldehydes or ketones under weak base conditions, which resulting in α, βunsaturated carbonyl compounds (1). In recent years, to improve the Knoevenegal reaction, protic ionic liquids (2), mesoporous materials (3), amine-functionalized ionic liquid-based periodic mesoporous organosilica (4), carbamic acid ammonium salt (5), zeolite (6), MOFs (7)(8)(9)(10)(11)(12)(13), melamine-derived graphitic carbon nitride (14), molybdenum carbide (15), amines functionalized C 60 (16), quinine (17), polyoxometalate (POM) cluster organic frameworks (18)(19)(20), Pickering emulsion (21), Fe 3 O 4 @ZIF-8 (22) and nanohybrid material (23) have been reported as catalysts to catalyze this reaction. Although these catalysts have good catalytic effect, most of them suffer from harsh recovery conditions, low yield, long reaction time or poor reuse effect.…”