A facile means for the improvement of sensing properties of metal-organic frameworks through control on the key synthesis variables

Kukkar, Preeti,Kukkar, Deepak,Sammi, Heena,Singh, Karanveer,Rawat, Mohit,Singh, Pritpal,Basu, Soumen,Kim, Ki-Hyun Elsevier 2018 Sensors and actuators. B Chemical Vol.271 No.-

<P><B>Abstract</B></P> <P>In this study, we investigated the optimal conditions for solvothermal-assisted synthesis of Eu-BDC-NH<SUB>2</SUB> metal organic frameworks (MOFs) to improve their sensing capacity toward some selected target metal species. To this end, we focused on the interactive relationships between key synthesis variables (e.g., the relative molar ratios (and absolute amounts) of the reactants [EuCl<SUB>3</SUB>·6H<SUB>2</SUB>O vs. amino terephthalic acid (BDC-NH<SUB>2</SUB>)], temperature, and reaction duration). It was observed that different types of MOFs synthesized under diverse conditions consistently exhibited emission profiles of Eu<SUP>3+</SUP>. However, their luminescence properties were distinguished systematically by the synthesis conditions set for each sample group. The sensing potential of luminescent MOFs was explored for detection of toxic metal ions through two approaches, i.e., direct chemosensing and indirect biomolecule mediated sensing approach. In the former, the MOFs exhibited noticeable turn-off fluorescence behavior, especially with Hg<SUP>2+</SUP> ions (i.e., a high Stern-Volmer quenching constant (K<SUB>sv</SUB>) of 6.42 × 10<SUP>5</SUP> M<SUP>−1</SUP> and limit of detection (LOD) of 0.007 M). In the latter, nanocomposites of MOFs-cyanocobalamin were characterized by a highly selective turn on fluorescence response towards Co<SUP>2+</SUP> ions (K<SUB>sv</SUB> = −6.25 × 10<SUP>3</SUP> M<SUP>−1</SUP>; LOD = 0.7 M). As such, the sensing capacity of these MOFs was distinguished efficiently by control of synthesis variables.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Optimized synthesis of Eu-BDC-NH<SUB>2</SUB>-MOFs by solvothermal approach. </LI> <LI> Effect of three variables i.e. molar ratio of reactants, temperature and time period reported has been investigated. </LI> <LI> Enhanced luminescence intensity, high reproducibility, and high stability of the MOFs upto 1 year. </LI> <LI> Significant turn off fluorescence in presence of 1 ppm Hg<SUP>2+</SUP> metal ions. </LI> <LI> Distinct turn on fluorescence of MOF-CNCbl nanocomposites in presence of 1 ppm Co<SUP>2+</SUP> ions. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Recent progress in biological and chemical sensing by luminescent metal-organic frameworks

Kukkar, Deepak,Vellingiri, Kowsalya,Kim, Ki-Hyun,Deep, Akash Elsevier 2018 Sensors and actuators. B Chemical Vol.273 No.-

<P><B>Abstract</B></P> <P>Luminescent metal organic frameworks (LMOFs), formed by coordinated bridging between metal ions and multidentate organic ligands with relevant fluorescent structures, have been the subject of intense research due to their tunable photoluminescent properties. The numerous permutations and combinations of available metal ions and organic linkers can yield novel LMOFs for countless applications. The luminescent characteristics of LMOFs depend upon many factors, including their structural components, coordination milieu of the metal ions, chemical structure/volume of the pore surfaces, and host-guest interactions between the LMOFs and reacting species (e.g., non-covalent interactions, coordination bonds, and π-π interactions). The combined effects of these parameters justify the expansion of their application in various fields. In addition, they are recognized as ideal candidates for biological applications due to their high loading capacity of functional molecules, facile surface modification and conjugation with biocompatible ligands (such as antibodies and proteins), tunable structural geometry, and intrinsic biocompatibility. By elaborating on these points, this article provides up-to-date information on the developments in the scientific/technological application of LMOFs, with special emphasis on the types, properties, and potential in sensing and biological applications. The discussion is further expanded to describe the major challenges and constraints of this research field.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Cyclodextrin-metal–organic framework (CD-MOF): From synthesis to applications

T. Rajkumar,Deepak Kukkar,김기현,손종렬,Akash Deep 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.72 No.-

Porous coordination compounds, commonly known as metal–organic frameworks (MOFs), exhibit manyunique characteristics (e.g., high surface area, high porosity, and tunability). The corresponding naturallyoccurring counterparts, CD-MOFs have opened a new avenue of research in light of its non-toxic, edible,and renewable nature. These characteristics have led to their applications into numerous directionsincluding drug delivery, CO2 capture, separation/purification, adsorption, sensors, food packaging,electrical conductors, memristors, photocatalysis, and polymerization. In this review, we provide a briefdiscussion about the available technologies for the synthesis of CD-MOFs and their applications in manyprospective areas.

Potential use of polymers and their complexes as media for storage and delivery of fragrances

Kaur, Rajnish,Kukkar, Deepak,Bhardwaj, Sanjeev K.,Kim, Ki-Hyun,Deep, Akash Elsevier 2018 Journal of controlled release Vol.285 No.-

<P><B>Abstract</B></P> <P>The use of fragrances is often essential to create an elegant, welcoming, or exhilarating environment. Through encapsulation, the release and delivery of fragrances are customized in many consumer products. For such purposes, cost-effective techniques have been developed and employed with the use of various polymers and porous organic materials to efficiently impart fragrances to foods and various other consumer products. After entrapment or uptake/storage of fragrant molecules within a polymeric complex, the properties can be investigated by automated thermal desorption (ATD) analysis. For efficient delivery, fragrances are adsorbed (or entrapped) in some media (e.g., fabric or paper). The release of such entrapped fragrances usually is achieved by spraying. Fragrances can be also loaded in a media by purging aroma gases or by adding fragrance essence directly into a liquid medium. Porous materials, such as zeolites, have been traditionally used for air purification as well as in cosmetics and similar applications. Similarly, other polymeric porous complexes have also been used in fragrance delivery as a templating agent for aromatherapy textiles. Such polymeric materials offer an advantage in terms of development of new hybrid blends via homogenous mixing of two or more matrices. Such blends may possess different desirable physical properties as encapsulants. This review article is aimed at presenting an overview of polymers and their complexes as the main media of fragrance encapsulation. This study also discusses the expansion and future application of porous materials as host matrices for fragrances.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Serendipity in solution–GQDs zeolitic imidazole frameworks nanocomposites for highly sensitive detection of sulfide ions

Sammi, Heena,Kukkar, Deepak,Singh, Jaskaran,Kukkar, Preeti,Kaur, Rajwinder,Kaur, Harmanpreet,Rawat, Mohit,Singh, Gurjinder,Kim, Ki-Hyun Elsevier 2018 Sensors and actuators. B, Chemical Vol.255 No.3

<P><B>Abstract</B></P> <P>An innovative and facile sensing approach for common inorganic anions present in aqueous media has been developed using nanocomposites of europium doped graphene quantum dots (GQDs:Eu) with zeolitic imidazole frameworks (ZIF-8). GQDs:Eu, prepared initially by solvothermal approach (at <10nm in diameter), exhibited a strong and intense blue emission at 430nm when dispersed in ethanol. ZIF-8 nanocubes, synthesized on a parallel basis, were in a fairly uniform size distribution (e.g., 185nm in diameter). The formation of nanocomposites by surface adsorption (between GQDs:Eu and ZIF-8) led to significant increase in fluorescence intensity as observed through photo-luminescence spectroscopy. Their interactions with anions (e.g., in terms of variations in the fluorescence intensity) were initially checked against sulfide and other anionic species (e.g., Br<SUP>−</SUP>, Cl<SUP>−</SUP>, F<SUP>−</SUP>, and NO<SUB>3</SUB> <SUP>−</SUP>). Among the tested ions, GQDs:Eu-ZIF-8 were found to effectively and sensitively detect sulfide (S<SUP>2−</SUP>) with significantly high turn on fluorescence. The feasibility of this nanosensing system was explored further toward the detection of S<SUP>2−</SUP> ions. These nanocomposites were thus demonstrated to be feasible for solution-based sensing of S<SUP>2−</SUP> ions with high reproducibility and sensitivity at limit of detection (LOD) of 0.12ppm.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An innovative approach for detection of pollutant sulfide ions is proposed. </LI> <LI> The method is built based upon turn on fluorescence intensity of GQDs:Eu in the matrix structure of Zeolitic Imidazole Framework Nanoparticles. </LI> <LI> Among the tested ions (e.g. S<SUP>2−</SUP>, Br<SUP>−</SUP>, Cl<SUP>−</SUP>, F<SUP>−</SUP>, and NO<SUB>3</SUB> <SUP>−</SUP>), the nanocomposites sensitively detect sulfide (S<SUP>2−</SUP>) with significantly high turn on fluorescence. </LI> <LI> This nanocomposite-based sensing method exhibit high reproducibility and sensitivity at limit of detection (LOD) of 0.12ppm. </LI> <LI> This approach can be extended further to the detection of sulfide ions from environmental samples. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>An innovative and facile sensing approach for solution-based sensing of sulfide (S<SUP>2−</SUP>) anions using nanocomposites of europium doped Graphene Quantum Dots (GQDs:Eu) with Zeolitic Imidazole Frameworks (ZIF-8) has been reported. These nanocomposites are thus demonstrated as an efficient platform for solution-based sensing of S<SUP>2−</SUP> ions with high reproducibility and selectivity.</P> <P>[DISPLAY OMISSION]</P>

In situ green synthesis of Au/Ag nanostructures on a metal-organic framework surface for photocatalytic reduction of p-nitrophenol

Karanveer Singh,Deepak Kukkar,Ravinder Singh,Preeti Kukkar,Nardev Bajaj,Jagpreet Singh,Mohit Rawat,Akshay Kumar,Ki-Hyun Kim 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.81 No.-

In this manuscript, we report the insitu growth of gold nanoparticles (GNPs) and silver nanoparticles(SNPs) over Ce/Tb-doped Y-benzene tricaroboxylate metal organic frameworks (MOF-76). Thephotocatalytic potential of these nanocomposites (NCs) was then assessed for the photocatalyticreduction of p-nitrophenol (p-NP) in aqueous medium. The NCs had large surface area to favorablyshowcase the efficient absorption of light energy. Correspondingly, it facilitated the electron transferbetween the valance and conduction bands to promote the reductive removal of p-NP. Among the testedcatalysts, GNPs@MOF-76 (Ce) (MOF-76(1a)) (dosage: 10 ml of 5 mg.ml 1) recorded the maximumcatalytic efficiency (96.3%) with an apparent rate constant (K0app: 0.33 min 1). Further, MOF-76 (1a) NCsexhibited good recyclability (e.g., a catalytic efficiency of 77.45% over 3 cycles). Moreover, the proposedNCs exhibited superior performance over commercial photocatalysts (e.g., p25 TiO2 nanopowder)towards p-NP reduction. As such, the results of this experimental study successfully demonstrated thesuperiority of the MOF immobilized nanoparticles (NPs) as an efficient platform for the removal ofindustrial grade pollutants.

Exceptionally stable green-synthesized gold nanoparticles for highly sensitive and selective colorimetric detection of trace metal ions and volatile aromatic compounds

Karanveer Singh,Deepak Kukkar,Ravinder Singh,Preeti Kukkar,김기현 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.68 No.-

The manuscript reports synthesis of exceptionally stable gold nanoparticles (GNPs) using Momordica charantia fruit extract. The synthesis approach was optimized by refining three experimental variables including source of the fruit extract (peel, seed, and seed coat), pH of the solution, and temperature of the reaction medium. As synthesized GNPs showed excellent stability against various thiolated compounds (e.g., thioglycolic acid, thiourea, l-cystine, 1-dodecanethiol, and cysteamine hydrochloride). Moreover, these nanoparticles showed distinctive colorimetric responses against Cd2+ and thiophenol (TP) from their potential interferences. The limit of detection (LOD) values for Cd2+ and TP were determined as 0.186 and 0.154 μM, respectively.

Biogenic synthesis of silver nanoparticles and its photocatalytic applications for removal of organic pollutants in water

Jagpreet Singh,Vanish Kumar,Sukhwinder Singh Jolly,김기현,Mohit Rawat,Deepak Kukkar,Yiu Fai Tsang 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-

A facile/clean/sustainable route for the preparation of silver nanoparticles (Ag NPs) was investigatedusing Trigonella foenum-graecum (TF) leaf extract. The bio-reduced Ag NPs showed photocatalyticdegradation potential of 88% and 86% for reactive blue 19 (RB19) and reactive yellow 186 (RY186),respectively (at 180 min). The complete mineralization of degraded medium was monitored by decline inchemical oxygen demand (COD). The role of activation energy in photocatalytic degradation process wasinvestigated across different temperatures. In light of their photocatalytic efficiency, reusability, andenvironment friendly synthesis approach, biogenic Ag NPs were demonstrated as effective system forefficient water purification.