In situ fabricated MOF–cellulose composite as an advanced ROS deactivator-convertor: fluoroswitchable bi-phasic tweezers for free chlorine detoxification and size-exclusive catalytic insertion of aqueous H2O2. Issue 8 (31st January 2022)

• Record Type: Journal Article
• Authors: Goswami, Ranadip; Bankar, Balasaheb D.; Rajput, Sonal; Seal, Nilanjan; Pillai, Renjith S.; Biradar, Ankush V.; Neogi, Subhadip
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 8(2022)
• Page Start: 4316
• Page End: 4332
• Publication Date: 2022-01-31
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d1ta10504c
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Hydrogen-bonded 2D MOF as fluoroswitchable bi-phasic tweezer for free chlorine and size-selective alkene epoxidation catalyst via H2 O2 insertion: a smart and greener approach for ROS deactivator-convertor through reconfigurable composite design. Abstract : Combining the merits of structural diversity, and purposeful implantation of task-specific functionalities, metal–organic frameworks (MOFs) instigate targeted reactive oxygen species (ROS) scavenging and concurrent detoxification via self-calibrated emission modulation. Then again, grafting of catalytically active sites in MOFs can benefit developing a greener protocol to convert ROS generators to technologically important building blocks, wherein tailorable MOF-composite fabrication is highly sought for practical applications, yet unexplored. The chemo-robust and hydrogen-bonded framework encompassing free –NH2 moiety affixed pores serves as an ultra-fast and highly regenerable fluoro-probe for selective detection of toxic ROS producers hypochlorite ion (ClO − ) and H2 O2 with record-level nanomolar sensitivity. While the bio-relevant antioxidant l -ascorbic acid (AA) imparts notable quenching to the MOF, a significant 3.5 fold emission enhancement with bi-phasic colorimetric variation ensues when it selectively scavenges ClO − from uni-directional porous channels through an unprecedented molecular tweezer approach. Apart from a battery of experimental evidence, density functional theory (DFT) results validate " on – off – on " fluoroswitching from redistribution of MOF orbital energy levels, and show guest-mediated exclusive transition from " Tight state" to " Loose state". The coordination frustrated metal site engineered pore-wall benefits the dual-functionalized MOF in converting the potential ROS generator H2 O2 via selective alkene epoxidation under mild-conditions. Importantly, sterically encumbered substrates exhibit poor conversion and demonstrate first-ever pore-fitting-induced size selectivity for this benign oxidation. Judiciously planned control experiments in combination with DFT-optimized intermediates provide proof-of-concept to the ionic route of ROS conversion. Considering an effective way to broaden the advanced applications of this crystalline material, reconfigurable MOF@cotton fiber (CF) is fabricated via in situ growth, which scavenges free chlorine and concomitantly squeezes it upon exposure to AA with obvious colorimetric changes over multiple real-life platforms. Furthermore, multi-cyclic alkene epoxidation by MOF@CF paves the way to futuristic continuous flow reactors that truly serves this smart composite as a bimodal ROS deactivator-convertor and explicitly denotes it as an advanced promising analogue from contemporary state-of-the-art materials.