Designing supramolecular architectures with uncommon geometries embedded with functional building units is of immense importance in contemporary research. In this report, we present a new water-soluble Pd 12 L 6 supramolecular coordination nanocage (1) that was synthesized via selfassembly of a tetradentate donor (L) with ditopic acceptor cis-[(en)Pd-(NO 3 ) 2 ] [en = ethylenediamine]. Self-assembly of a tetratopic donor with a cis-blocked 90°acceptor commonly produces tri/tetra-or hexagonal barreltype structures. However, the resulting cage 1 has an uncommon geometry consisting of two triangular cupolas conjoined through an irregular common hexagonal base. Incorporation of the benzothiadiazole unit in the structure helped in the photogeneration of reactive oxygen species (ROS) in water. Many nanomaterials have shown to have the ability to mimic the catalytic activity of natural enzymes (nanozymes). Majority of such nanozymes are water insoluble metal/metal-oxide nanoparticles or extended metal organic frameworks (MOFs)/metal−carbon composites, etc. The present water-soluble Pd 12 nanocage 1 has shown excellent oxidase-like activity upon irradiation with white light. The enzymatic activity of 1 is photoregulated which offers other obvious advantages, such as external control of enzymatic activity and noninvasiveness. The oxidase-like activity and exogenous ROS generation have been further exploited in photocatalytic antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) bacterial strain.

Despite the remarkable improvement in modern medicine, the ever-increasing abundance of antibiotic-resistant microorganisms remains a catastrophic threat to global health care. β-Lactamase is playing one of the major roles in antibiotic resistance by making the conventional antibacterial agents abortive by destroying their lactam ring. The combination therapy of traditional antibiotics along with β-lactamase inhibitors is a potential solution to this problem. In this work, we have screened various functionalized two-dimensional molybdenum disulfide (2D-MoS2) nanomaterials as enzyme inhibitors that effectively bind with β-lactamase enzyme and reveal competitive inhibition. Among these, carboxylate-functionalized negatively charged 2D-MoS2 is the most potent inhibitor, and in vitro combinatorial application of this with conventional antibiotics has been able to remarkably suppress relevant drug-resistant bacterial growth rate. This study will help to further explore different surface-functionalized 2D nanomaterials with improved β-lactamase inhibition to fight against multidrug-resistant bacterial infections.

The peroxidase-like catalytic activity of various nanozymes was extensively applied in various fields. In this study, we have demonstrated the preparation of Fe-doped MoS2 (Fe@MoS2) nanomaterials with enhanced peroxidase-like activity of MoS2 in a co-catalytic pathway. In view of Fenton reaction, the peroxidase-like Fe@MoS2 nanozyme prompted the decomposition of hydrogen peroxide (H2O2) to a reactive hydroxyl radical (·OH). The efficient decomposition of H2O2 in the presence of Fe@MoS2 has been employed toward the antibacterial activity and detoxification of mustard gas simulant. The combined effect of Fe@MoS2 and H2O2 showed remarkable antibacterial activity against the drug-resistant bacterial strain methicillin-resistant Staphylococcus aureus and Escherichia coli with the use of minimal concentration of H2O2. Fe@MoS2 was further applied for the detoxification of the chemical warfare agent sulfur mustard simulant, 2-chloroethyl ethyl sulfide, by selective conversion to the nontoxic sulfoxide. This work demonstrates the development of a hybrid nanozyme and its environmental remediation from harmful chemicals to microbes.

Nanozymes, a class of nanomaterials that mimic the catalytic activity of natural enzymes, could be used to control the rapid spread of infectious diseases. Here, we have demonstrated that the intrinsic peroxidase-like activity of two-dimensional molybdenum disulfide (2D-MoS 2 ) nanosheets can be amplified through surface functionalization. Traditionally, hydrogen peroxide (H 2 O 2 ) has been widely used as a universal disinfectant agent but requires a high concentration. This can be taken care by the presence of any peroxidase-like catalyst to reduce the concentration of H 2 O 2 . Herein, we have explored the effect of surface functionality on peroxidase-like nanozyme activity of 2D-MoS 2 nanosheets. We observed that functionalization of 2D-MoS 2 nanosheets not only enhances the aqueous stability but also exhibits remarkably high peroxidase-like activity. Subsequently, we have extended this effect toward antibacterial activity in the presence of H 2 O 2 . The combination of the specific functionalized 2D-MoS 2 nanomaterial of a concentration of 5.6 μg/mL and H 2 O 2 of a concentration of only 0.5 mM (17642 times dilution of the commercially available 30% H 2 O 2 solution) showed an excellent antibacterial activity compared to H 2 O 2 alone. This work established that proper surface modification of various nanomaterials with intrinsic nanozyme properties can enhance the activity, which can be applied for many other related applications such as disinfectants, biosensors, drug delivery, and so forth.

Reaction of ethylidenepyridyl-functionalized bisphosphonates with vanadium containing oxo compounds has afforded three different bisphosphonate-polyoxovanadate derivatives, viz. 3), obtained in aqueous ammonium acetate buffer solutions (pH 4.7). Polyanions 1 and 2 were synthesized by the reaction of V2O5 with 1-hydroxy-2-(2-pyridyl) ethylidene-1,1-bisphosphonic acid (L1) and 1-hydroxy-2-(3-pyridyl) ethylidene-1,1-bisphosphonic acid (L2), respectively. Polyanion 3 was obtained by the reaction of VOSO4 with 1-hydroxy-2-(4-pyridyl) ethylidene-1,1-bisphosphonic acid (L3), in the presence of pyrazine. Single crystal X-ray diffraction and elemental analysis reveal that all the polyanions are crystallized as ammonium salts,Polyanions 1 and 2 crystallize in the non-centrosymmetric space group P21212 and have an Sshaped assembly containing two different sets of vanadium atoms, based upon their oxidationstate and different coordination environments. Polyanion 3 crystallizes in the centrosymmetric trigonal space group R𝟑 ̅ c and is observed to have a highly symmetric trinuclear structure. The polyanions have been characterized in solution with 1 H and 31 P NMR, and optical spectroscopy, and in the solid state with detailed magnetic analysis. The magnetic studies under an external dc field showed paramagnetic behavior in agreement with the presence of V(IV) ions for 1a-3a.Furthermore, in vitro studies of the synthesized bisphosphonate-polyoxovanadate compounds were observed to exhibit peroxidase like activity, and hence were employed to enhance the antibacterial activity of H2O2 solution at very low concentrations thereby minimizing the 3 possibilities of other side effects. Isostructural derivatives of compounds 1a and 2a with L3, viz. 4a), has been identified using infrared spectroscopy, and characterized with NMR spectroscopy and elemental analysis.Similarly, an isostructural derivative of 3a with L2, viz. (NH4)2[H6(V IV O)3(O){O3P-C(OH)(CH2-3-C5NH4)-PO3}3]•21H2O (5a), has also been identified using infrared spectroscopy, and characterized with elemental analysis.