Hazardous waste management is a major global issue, with ongoing efforts to reduce it hindered by continuous production from rapid population growth and industrialization. Inadequate technology has hindered the simultaneous collection of hazardous waste from water and vapor phases for sustainable energy applications in the material sector. Here, we present a novel, affordable method for developing a robust MOF (Cu-TPA-BPE IP-MOF) for the sequestration of iodine from the environment. The substantial free void space and 1D-porous channels in its crystal lattice enable the selective absorption of nearly 90% of trace amounts of I3- from water. An exceptional distribution coefficient (Kd∼103 mL/g) indicates a strong affinity for iodine. The accompanying mechanistic insights stem from the ultrahigh iodine selectivity found through extensive experimentally driven computational studies. Iodine absorption as a dopant enhances the conductivity of the hybrid material. Notably, when tested against aluminum metal, the I2 and I3--captured MOF exhibited a moderately high optical-dependent conductivity of 2.89 × 10-3 S/m with a significant rectification ratio of 20.56, making it a viable candidate for diode fabrication. Additionally, the I3--loaded MOF demonstrates high ionic conductivity of 1.14 × 10-3 S/cm. Conductivity analysis, dependent on concentration, positions the hybrid material to function as a sensor for detecting the iodine concentration in water.
We report herein an unusual occurrence of solvent-induced di- and hexanuclear lanthanide (Ln 2 and Ln 6 ) complexes using an unorthodox N-rich pyridyl-pyrazole-based ligand. The crystal structures of Ln 2 and Ln 6 complexes are isostructural and show a common feature: a nonpolar periphery and a polar core where the paramagnetic lanthanide centers are exclusively bridged by oxygen atoms. Such favorable magnetic exchange coupling leads to interesting magnetic behaviors with befitting single-molecule magnet (SMM) and magnetocaloric effect (MCE) features. The Dy 2 complex exhibits SMM behavior with befitting frequency and temperature-dependent out-of-phase signals along with an U eff value of similar to 49.3 K and a relaxation time of 4.82 x 10-9 s. Both Gd 2 and Gd 6 complexes exhibit cryogenic magnetic cooling with a -Delta S M value of 15.2 and 40.6 J kg-1 K-1, respectively, under an applied magnetic field of 5 T at 4 K and 8 T at 2.3 K. Detail theoretical investigations were also performed, which demonstrate gratifying synergism between theoretically derived and the experimentally obtained magnetic properties. The ionic conductivity measurements show excellent ionic conductivity values in the range of 4.32 x 10-4 to 7.92 x 10-4 S/cm at 80 degrees C and 95% relative humidity.
The current work aims to generate multifunctional MOFs by incorporating a well-known inorganic motif, a trinuclear Cu-pyrazolate [Cu3(μ3-OH)(μ-Pyz)3] (T-CuP) unit, as a node of the network. Accordingly, we report herein the synthesis and properties of five new compounds using five V-shaped dicarboxylic acids as auxiliary ligands. The structural features are consistent with the theme of grafting T-CuP units as nodal points of architectures whose chassis are primarily made of bent acids. V-shaped acids also induce a helical nature inside resulting frameworks. Beside their structural and physical features, T-CuP unit-based MOFs also vindicate our thematic approach of the trinuclear Cu-pyrazolate unit imparting specific physicochemical properties, such as magnetic, electrical, and catalytic properties, to resultant MOFs. The MOFs show excellent catalytic properties in reducing 4-nitrophenol, which could be attributed to the porous nature of the network along with the presence of metal centres with unsaturated coordination within the T-CuP unit. Furthermore, efficient photocatalytic degradation of harmful organic dyes confirms their importance for environmental remediation. The presence of a T-CuP unit and various functional groups also make some of the MOFs suitable candidates for electrical applications, which is indeed manifested in encouraging proton conductivity. Finally, the potential of current MOFs, fitted with a magnetically important trinuclear Cu-pyrazolate motif, as magnetic materials has also been thoroughly investigated.
The present work evaluates the water oxidation catalytic activity of a Mn-based metal-organic framework (MOF), which we envisioned to reduce the oxygen evolution reaction (OER) overpotential because of its high electrical conductivity, facilitated by solvent-encapsulated structural features. The presence of Mn centers induces interesting magnetic features in the MOF, which exhibits impressive cryogenic magnetic refrigeration with a ΔSM value of 29.94 J kg-1 K-1 for a field change of ΔH = 5T at 2.3 K. To the best of our knowledge, the ΔSM value of the current system ranked the highest position among the published examples. The crystal structure aligns perfectly with the thematic expectations and features as many as ten metal-coordinated water molecules, forming an extensive web of a hydrogen-bonded network while facing toward the porous channel filled with another set of much-anticipated entrapped lattice water molecules. Such structural features are expected to manifest high proton conductivity, and detailed investigation indeed yields the best value for the system at 1.57 × 10-4 S/cm at 95% humidity and 85 °C. In order to evaluate the thematic notion of a one-to-one relationship between OER and improved electrical conductivity, extensive electrocatalytic water splitting (WS) investigations were carried out. The final results show highly encouraging WS ability of the Mn-MOF, showing the electrocatalytic surface area value of the active species as 0.0686 F/g with a turnover frequency value of 0.043 [(mol. O2) (mol. Mn-MOF)-1 s-1]. Another fascinating aspect of the current communication is the excellent synergy observed between the experimental WS outcomes and the corresponding theoretical data calculated using density functional theory (DFT). Consequently, a plausible mechanism of the overall OER and the role of the Mn-MOF as a water oxidation catalyst, along with the importance of water molecules, have also been derived from the theoretical calculations using DFT.
Clusters of galaxies, being the largest collapsed structures in the universe, offer valuable insights into the nature of cosmic evolution. Precise calibration of the mass of clusters can be obtained by extracting their gravitational lensing signal on the Cosmic Microwave Background (CMB) fluctuations. We extend and test here the performance achieved on cluster scales by the parameter-free, maximum a posteriori (MAP) CMB lensing reconstruction method, which has been shown to be optimal in the broader context of CMB lensing mass map and power spectrum estimation. In the context of cluster lensing, the lensing signal of other large-scale structures acts as an additional source of noise. We show here that by delensing the CMB fluctuations around each and every cluster, this noise variance is reduced according to expectations. We also demonstrate that the well-known bias in the temperature quadratic estimator in this regime, sourced by the strong non-Gaussianity of the signal, is almost entirely mitigated without any scale cuts. Being statistically speaking an optimal and blind lensing mass map reconstruction, the MAP estimator is a promising tool for the calibration of the masses of clusters.
Alarmingly increasing population and industrial growth has immensely affected water bodies and potable water sources by elution of many heavy toxic metal ions, including cadmium (II). The rising threat has demanded easy and cost-effective detection of this heavy metal ion so as to spread widely across the masses and eliminate the poisoning of water. With this aim, we have synthesized a zinc -based fluorescent probe (rBDZn) having reduced Schiff base backbone with N- and Odonor atoms derived from 5-bromosalicaldehyde and 2,2-dimethylpropane-1,3-diamine, characterized with the aid of single crystal X-ray analysis, revealing a trimeric structure linearly bridged by azide ion. The complex has been found to exhibit a cyan blue fluorescence getting 'turned -off' in the presence of cadmium ion selectively along with many other cations in the aqueous solution together with a naked -eye visible color change from pale yellow to colorless. Steady-state and timeresolved fluorescence titration, and absorption titration experiments were performed. During the investigation of the sensing pathway it is observed that the detection of Cd2+ is being associated with the formation of the cadmium complex rBDCd from the probe rBDZn and this has been explained though a probable mechanism. In support of the fact a single crystal of Cd-substituted complex have been isolated and verified with single crystal XRD and computational calculations. Proper justification of the selectivity of the probe towards cadmium ion with a very low detection limit of 1.72 nM enables its genuine impact in the pollution management.
This work delivers a targeted synthesis of four isostructural O-substituted imidazole-based zinc(II) complexes, namely, [Zn2(L1)2(I)2](DMF) (1), [Zn2(L2)2(I)2](DMF) (2), [Zn2(L1)2(Br)2] (3), and [Zn2(L2)2(Br)2] (4), derived from homologous Schiff-base ligands HL1 and HL2 to explore their impact on free radicals, microbes, and dephosphorylation of phosphoesters. The antioxidant activity of all complexes was checked by various radical scavenging assays (ABTS+•, DPPH•, and H2O2 radical quenching). Among them, complex 2 showed superior radical quenching activity, as indicated by its lowest EC50 value and thus maximum antioxidative capability. Again, antibacterial assays against several Gram-positive and Gram-negative bacteria were conducted to evaluate the zone of inhibition. The minimum bactericidal concentration and minimum inhibitory concentration values from the microdilution method for all complexes revealed complex 3 to have maximum potency against Gram-positive bacteria. The P-O bond hydrolysis in the phospholipid chain caused by the hydrolytic phosphoesterase activity of the Zn(II)-complexes plays a crucial role in cell membrane rupture. A model substrate 4-PNPP was used to explain the potency of monomeric Zn(II) complex (3) for cell penetration over dimeric one (2) with a proper mechanism. Furthermore, a heme model substrate, Fe(TPP)Cl, has been introduced with the most potent complex 3 and has spectrophotometric evidence for covalent interaction with imidazole and Fe(III) that can disrupt the nitric oxide dioxygenase function of flavohemoglobin, leading to bacterial cell death. To our knowledge, this is the first case to report a novel mechanism of antimicrobial action where both the metal and the ligand are cooperatively involved in bacterial cell death. The main goal of this work is to invent multifunctional therapeutics as well as the proper chemical rationalization of biological processes using mechanistic approaches, which includes investigating the roles of halides, imidazoles, and solution-phase structural variations of complexes..
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
The present communication deals with the synthesis, characterization of a Cr-based metallogel and explores its electrical-magnetic properties. The proton conductivity and toxic dye sequestrations have also been investigated.
A reaction between CoCl2 and L3-(CO2-)2 (2 : 1 stoichiometry) in CH3OH affords a discrete complex [CoII4-{L3-(CO2-)2}2(μ3-OCH3)2(CH3OH)2(H2O)2Cl2] (1) [L3-(CO2-)2 = 3-[N-{2-(pyridin-2-yl)methyl}amino]-bis(propionate)]. The structure of 1 reveals two terminal mononuclear CoII{L3-(CO2-)2}Cl units connected by a dimeric CoII2(μ3-OCH3)2(CH3OH)2(H2O) unit present in the centre through two methoxo (μ3-OCH3)- and two carboxylate (μ-1,1-OCO-) bridges affording a tetranuclear coordination cluster of Co(II) with a defective dicubane topology. In 1, Co1 (terminal) has distorted octahedral CoIIN2O3Cl and the central Co2 has CoIIO6 coordination. Such coordination arrangements afford the observed topology. Variable-temperature magnetic studies reveal anti-ferromagnetic coupling in 1. Three magnetic exchange interactions (one anti-ferromagnetic and two ferromagnetic: J1 = +3.3 cm-1 (Co⋯Co 3.176 Å; μ-1,1-OCO- and μ3-OCH3 bridges), J2 = -2.5 cm-1 (Co⋯Co 3.228 Å; μ-1-OCO- and μ3-OCH3 bridges) and J3 = +10.6 cm-1 (Co⋯Co 3.084 Å; two μ3-OCH3 bridges)) have been identified, with the inclusion of the orbital reduction parameter (α = Aκ = 1.38), spin-orbit coupling (λ = -158 cm-1) and axial distortion (energy gap Δ = -975 cm-1 between singlet and doublet levels), rationalized by density functional theory (DFT) calculations.
We report herein two multifunctional metal- organic frameworks (MOFs) that exhibit excellent mutually inclusive electrical and magnetic properties. Accordingly, two cobalt and nickel based MOFs (Co-MOF, Ni-MOF) were generated using a flexible bispyrazole based ligand and 2-sulphono terephthalic acid. The idea is to generate paramagnetic metal ion based magnetic MOFs, which can also be used to fabricate electrical devices by utilizing the immobilized free sulfonic groups and encapsulated H-bonded water clusters for active charge species generation and transportation. Further support comes from the intriguing structural features of the MOFs that include extensive H bonded water clusters, free sulfonic acid moiety, or syn-anti bridged carboxylates, which make them highly suitable candidates for generating electrical and magnetic materials. Further complementary support for their candidature comes from the high thermal, chemical, and physical stability of the MOFs. The impedance spectroscopy data and I-V results unequivocally support the suitability of the MOFs for electronic device fabrication showing a befitting conductivity value of 1.80 x 10-4 S/m with an ideality factor of 1.06 for Ni-MOF. Interestingly, the Co-MOF shows a light dependent behavior with conductivity values of 9.09 x 10-5 S/m (dark) and 6.31 x 10-4 S/m (light) and ideality factors of 0.78 (dark) and 0.92 (light). The MOFs, fitted with a free sulfonic acid moiety and extensive H-bonded water clusters, show high potential for proton exchange membrane fuel cells (PEMFCs) development with corroborating proton conductivity values of 1.95x 10-3 S/cm and 5.80 x 10-4 S/cm for Ni-MOF and Co-MOF, respectively, at 95% relative humidity and 85 degrees C. Moreover, the interesting structural aspects like syn-anti bridged carboxylates prompt us to explore the magnetic behavior of the MOFs. The NiMOF shows some interesting antiferromagnetic behavior. The Co-MOF reveals intriguing single molecule magnet behavior with a Ueff value of 34 K and moderate relaxation time of 3.5x 10-8 s.
Photoinduced electricity and proton conductivity led fuel cells have emerged, inter alia, as highly promising systems for unconventional energy harvesting. Notwithstanding their individual presence with widely acclaimed results, an integrating system with mutually inclusive manifestation of both features has hitherto not been reported in the literature. To achieve this objective, our approach was to design a ligand system incorporating prerequisite features of both systems, like extended conjugation instigating photophysical activity and functional groups facilitating ionic conduction. As such, we report herein the design, synthesis, and characterization of a pyridyl-pyrazole-based silver compound that exhibits an excellent photocurrent generation and very high proton conductivity. The X-ray single-crystal structure of the Ag complex fully supports our notion, showing extensive π-π conjugated aromatic rings with a protruding free sulfonic group, facing toward solvent-filled channels with numerous supramolecular interactions. The nanoscopic silver metallogel induces semiconductive features in the system which ultimately result in photoresponse behavior in terms of photocurrent generation with an whopping photocurrent gain (Ion/Ioff) of 21.2. To complete the idea of an integrated system, the proton conductivity values were also measured for both gel and crystalline states, while the former state yields a better result. The maximum proton conductivity value turns out to be 1.03 × 10-2 S cm-1 at 70 °C, which is higher than or comparable to those of well-known systems in the literature for proton conductivity.
The impetus for the present work was to design multifunctional inorganic materials that can be utilized in their original as-synthesized state of the matter. Accordingly, we have successfully designed a benzene-tricarboxylic acid based dual-purpose Fe-metallogel that can be used as an efficient material for cryogenic magnetic cooling as well as electronic device fabrication as Schottky barrier diode in their original gel state. The metallogel shows remarkable mechanical strength, self-sustainability and thixotropic behaviour. The gel sample has been thoroughly characterized using IR, UV-Vis spectroscopy, SEM, TEM, AFM techniques, XPS and Mossbauer spectroscopy. The porous nature, which forms the basis of the current gel based MCE study and SBD fabrication, was confirmed with gas sorption data. The porous metallogel network with by-default entrapped anion and protic solvents of the fabricated electrical device provides an excellent platform for charge transportation with a corroborating conductivity value of 4.53x10(-6) Sm-1. As if to complement the notion of multifunctional material, the magnetic studies on the Fe-gel show significant cryogenic magnetic cooling behaviour. The theoretical result calculated using DFT are found to be highly consistent with the experimental results of the metallogel. Furthermore, we have evaluated the potential of the compound as a fuel cell membrane with detailed proton conductivity measurements on the xerogel, showing an encouraging value of 4.58x10(-4) S/cmat 95 % relative humidity and 75 degrees C temperature.
The work presents herein the LMWG property of pyridine–pyrazole containing Schiff base ligand in presence of toxic heavy metals like Pb, Cd and Hg. These MOGs exhibited gel based remarkable toxic dye adsorption and multi-stimuli responsiveness.
The present work is part of our ongoing quest for developing functional inorganic complexes using unorthodox pyridyl-pyrazolyl-based ligands. Accordingly, we report herein the synthesis, characterization, and luminescence and magnetic properties of four 3d-4f mixed-metal complexes with a general core of Ln2Zn6 (Ln = Dy, Gd, Tb, and Eu). In stark contrast to the popular wisdom of using a compartmental ligand with separate islands of hard and soft coordinating sites for selective coordination, we have vindicated our approach of using a ligand with overcrowded N-coordinating sites that show equal efficiency with both 4f and 3d metals toward multinuclear cage-cluster formation. The encouraging red and green photolumiscent features of noncytotoxic Eu2Zn6 and Tb2Zn6 complexes along with their existence in nanoscale dimension have been exploited with live-cell confocal microscopy imaging of human breast adenocarcinoma (MCF7) cells. The magnetic features of the Dy2Zn6 complex confirm the single-molecule-magnet behavior with befitting frequency- and temperature-dependent out-of-phase signals along with an Ueff value of ∼5 K and a relaxation time of 8.52 × 10-6 s. The Gd2Zn6 complex, on the other hand, shows cryogenic magnetic refrigeration with an entropy change of 11.25 J kg-1 K-1 at a magnetic field of 7 T and at 2 K. Another important aspect of this work reflects the excellent agreement between the experimental results and theoretical calculations. The theoretical studies carried out using the broken-symmetry density functional theory, ORCA suite of programs, and MOLCAS calculations using the complete-active-space self-consistent-field method show an excellent synergism with the experimentally measured magnetic and spectroscopic data.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Besides iron, ironically neodymium (Nd) is the most ubiquitously used metal for magnetic purposes, even among the lanthanides, when it comes to the field of molecular magnetism, yet it ranks among the least studied metals. However, strong apathy towards this magnetic lanthanide means that vital information will be missed, which is required for the advancement of the subject. Herein, we have successfully demonstrated the usefulness of a hexanuclear neodymium complex as a magnetic material, and also in electronic device fabrication. A {NdIII6} cage with an aesthetically pleasing butterfly topology was synthesized using a rather non-conventional N-rich pyridyl-pyrazolyl based ligand. The cage shows single molecule magnet (SMM) properties, with an effective energy barrier, Ueff, value of 3.4 K and relaxation time, τ0, of 3.1 × 10-4 s, originating from an unusual occurrence of metal centres with different coordination environments. Furthermore, magnetic studies reveal significant cyrogenic magnetic cooling, with a magnetic entropy change of 8.28 J kg-1 K-1 at 5 T and 3 K. To the best of our knowledge, the titular compound is the only example of a Nd-complex that exhibits concomitant magnetocaloric effect (MCE) and SMM properties. Complete active space self-consistent field (CASSCF) calculations were carried out to shed light on the origin of the magnetic anisotropy and magnetic relaxation of the compound. The same uniqueness is also true for the first electronic investigation carried out on the Nd complex. The maiden electronic device fabricated using the Nd complex shows an interesting intertwining of electronic and optical features, which contribute towards its improved photosensitized optoelectronic data.
The largest fluctuation in the CMB sky is the CMB dipole, which is believed to be caused by the motion of our observation frame with respect to the CMB rest frame. This motion accounts for the known motion of the Solar System barycentre with a best-fit amplitude of 369 km/s, in the direction (ℓ= 264°, b=48°) in galactic coordinates. Along with the CMB dipole signal, this motion also causes an inevitable signature of statistical anisotropy in the higher multipoles due to the modulation and aberration of the CMB temperature and polarization fields. This leads to a correlation between adjacent CMB multipoles causing a non-zero value of the off-diagonal terms in the covariance matrix which can be captured in terms of the dipolar spectra of the bipolar spherical harmonics (BipoSH). In our work, we jointly infer the CMB power spectrum and the BipoSH spectrum in a Bayesian framework using the Planck-2018 SMICA temperature map. We detect amplitude and direction of the local motion consistent with the canonical value v=369 km/s inferred from CMB dipole with a statistical significance of 4.54σ, 4.97σ and 5.23σ respectively from the masked temperature map with the available sky fraction 40.1%, 59.1%, and 72.2%, confirming the common origin of both the signals. The Bayes factor in favor of the canonical value is between 7 to 8 depending on the choice of mask. But it strongly disagrees (by a value of the Bayes factor about 10-10–10-11) with a higher value of local motion which one can infer from the amplitude of the dipole signal obtained from the CatWISE2020 quasar catalog using the WISE and NEOWISE data set.