Heptanuclear Mixed-Valence Co4IIICo3II Molecular Wheel─A Molecular Analogue of Layered Double Hydroxides with Single-Molecule Magnet Behavior and Electrocatalytic Activity for Hydrogen Evolution Reactions.

We present a bifunctional heptanuclear cobalt(II)/cobalt(III) molecular complex formulated as [Co7(µ3-OH)4(H2L1)2(HL2)2](NO3)6·6H2O (1) (where H5L1 is 2,2'-(((1E,1'E)-((2-hydroxy-5-methyl-1,3-phenylene)bis(methanylylidene))bis(azanylylidene))bis(propane-1,3-diol)) and H2L2 is 2-amino-1,3-propanediol). Compound 1 has been characterized by single-crystal X-ray diffraction analysis along with other spectral and magnetic measurements. Structural analysis indicates that 1 contains a mixed-valence Co7 cluster where a central Co(II) ion is connected to six different Co centers (four CoIII and two CoII ions) by four µ3-OH groups, giving rise to a planar heptanuclear cluster that resembles a molecular fragment of a layered double hydroxide (LDH). Two triply deprotonated (H2L1)3- ligands form the outer side of the cluster while two singly deprotonated (HL2)- ligands are located at the top and bottom of the central heptanuclear core. Variable temperature magnetic measurements indicate the presence of weak ferromagnetic CoII···CoII interactions (J = 3.53(6) cm-1) within the linear trinuclear CoII cluster. AC susceptibility measurements show that 1 is a field-induced single-molecule magnet (SMM) with τ0 = 8.2(7) × 10-7 s and Ueff = 11.3(4) K. The electrocatalytic hydrogen evolution reaction (HER) activity of 1 in homogeneous phase shows an overpotential of 455 mV, with a Faradaic efficiency of 81% and a TOF of 8.97 × 104 µmol H2 h-1 mol-1.

ExPert ConsEnsus on the management of Advanced clear-cell RenaL celL carcinoma: INDIAn Perspective (PEARL-INDIA).

In advanced Renal Cell Carcinoma (aRCC), systemic therapy is the mainstay of treatment, with no or little role for surgery in these patients. Tyrosine kinase inhibitors (TKIs) and immune-oncological (IOs) therapies, either alone or in combination, are recommended in these patients depending on patient and tumour factors. The sequencing of therapies is critical in RCC because the choice of subsequent line therapy is heavily dependent on the response and duration of the previous treatment. There are additional barriers to RCC treatment in India. Immunotherapy is the cornerstone of treatment in ccRCC, but it is prohibitively expensive and not always reimbursed, effectively putting it out of reach for the vast majority of eligible patients in India. Furthermore, in advanced RCC (particularly the clear cell variety), Indian oncologists consider the disease burden of the patients, which is particularly dependent on the quantum of the disease load, clinical symptoms, and performance status of the patient, before deciding on treatment. There are no India-specific guidelines for clear cell RCC (ccRCC) treatment or the positioning and sequencing of molecules in the management of advanced ccRCC that take these country-specific issues into account. The current consensus article provides expert recommendations and treatment algorithms based on existing clinical evidence, which will be useful to specialists managing advanced ccRCC.

Strategic Synthesis of Heptacoordinated FeIII Bifunctional Complexes for Efficient Water Electrolysis.

In this research, highly efficient heterogeneous bifunctional (BF) electrocatalysts (ECs) have been strategically designed by Fe coordination (CR ) complexes, [Fe2 L2 (H2 O)2 Cl2 ] (C1) and [Fe2 L2 (H2 O)2 (SO4 )].2(CH4 O) (C2) where the high seven CR number synergistically modifies the electronic environment of the Fe centre for facilitation of H2 O electrolysis. The electronic status of Fe and its adjacent atomic sites have been further modified by the replacement of -Cl- in C1 by -SO4 2- in C2. Interestingly, compared to C1, the O-S-O bridged C2 reveals superior BF activity with extremely low overpotential (η) at 10 mA cm-2 (140 mVOER , 62 mVHER ) and small Tafel slope (120.9 mV dec-1 OER , 45.8 mV dec-1 HER ). Additionally, C2 also facilitates a high-performance alkaline H2 O electrolyzer with cell voltage of 1.54 V at 10 mA cm-2 and exhibits remarkable long-term stability. Thus, exploration of the intrinsic properties of metal-organic framework (MOF)-based ECs opens up a new approach to the rational design of a wide range of molecular catalysts.

Reduction of Sulfur Dioxide to Sulfur Monoxide by Ferrous Porphyrin.

The reduction of SO2 to fixed forms of sulfur can address the growing concerns regarding its detrimental effect on health and the environment as well as enable its valorization into valuable chemicals. The naturally occurring heme enzyme sulfite reductase (SiR) is known to reduce SO2 to H2 S and is an integral part of the global sulfur cycle. However, its action has not yet been mimicked in artificial systems outside of the protein matrix even after several decades of structural elucidation of the enzyme. While the coordination of SO2 to transition metals is documented, its reduction using molecular catalysts has remained elusive. Herein reduction of SO2 by iron(II) tetraphenylporphyrin is demonstrated. A combination of spectroscopic data backed up by theoretical calculations indicate that FeII TPP reduces SO2 by 2e- /2H+ to form an intermediate [FeIII -SO]+ species, also proposed for SiR, which releases SO. The SO obtained from the chemical reduction of SO2 could be evidenced in the form of a cheletropic adduct of butadiene resulting in an organic sulfoxide.

Solvent- and Substrate-Induced Chiroptical Inversion in Amphiphilic, Biocompatible Glycoconjugate Supramolecules: Shape-Persistent Gelation, Self-Healing, and Antibacterial Activity.

We have shown solvent- and substrate-dependent chiral inversion of a few glycoconjugate supramolecules. (Z)-F-Gluco, in which d-glucosamine has been attached chemically to Cbz-protected l-phenylalanine at the C terminus, forms a self-healing hydrogel through intertwining of the nanofibers wherein the gelators undergo lamellar packing in the ß-sheet secondary structures with a single chiral handedness. Dihybrid (Z)-F-gluco nanocomposite gel was prepared by in-situ formation of silver nanoparticles AgNPs in the gel; this enhances the mechanical properties of the composite gel through physical crosslinking without altering the packing pattern. In contrast, (Z)-L-gluco bearing an l-leucine moiety does not form a hydrogel but an organogel. Interestingly, the chiral handedness of the aggregates of (Z)-L-gluco can be reversed by choosing suitable solvents. In addition to self-healing behavior, (Z)-L-gluco gel revealed shape persistency. Further, (Z)-F-gluco hydrogel is benign, nontoxic, non-immunogenic, and non-allergenic in animal cells. AgNP-loaded (Z)-F-gluco hydrogel showed antibacterial activity against both Gram-positive and Gram-negative bacteria.

Homogeneous Electrochemical Reduction of CO2 to CO by a Cobalt Pyridine Thiolate Complex.

The chemical and electrochemical reduction of CO2 to value added chemicals entails the development of efficient and selective catalysts. Synthesis, characterization and electrochemical CO2 reduction activity of a air-stable cobalt(III) diphenylphosphenethano-bis(2-pyridinethiolate)chloride [{Co(dppe)(2-PyS)2}Cl, 1-Cl] complex is divulged. The complex reduces CO2 under homogeneous electrocatalytic conditions to produce CO with high Faradaic efficiency (FE > 92%) and selectivity in the presence of water. Through detailed electrochemical investigations, product analysis, and mechanistic investigations supported by theoretical calculations, it is established that complex 1-Cl reduces CO2 in its Co(I) state. A reductive cleavage leads to a dangling protonated pyridine arm which enables facile CO2 binding through a H-bond donation and facilitates the C-O bond cleavage via a directed protonation. A systematic benchmarking of this catalyst indicates that it has a modest overpotential (∼180 mV) and a TOF of ∼20 s-1 for selective reduction of CO2 to CO with H2O as a proton source.

Selective Metal-Ligand Bond-Breaking Driven by Weak Intermolecular Interactions: From Metamagnetic Mn(III)-Monomer to Hexacyanoferrate(II)-Bridged Metamagnetic Mn2Fe Trimer.

Metal-ligand coordination interactions are usually much stronger than weak intermolecular interactions. Nevertheless, here, we show experimental evidence and theoretical confirmation of a very rare example where metal-ligand bonds dissociate in an irreversible way, helped by a large number of weak intermolecular interactions that surpass the energy of the metal-ligand bond. Thus, we describe the design and synthesis of trinuclear Mn2Fe complex {[Mn(L)(H2O)]2Fe(CN)6},2- starting from a mononuclear Mn(III)-Schiff base complex: [Mn(L)(H2O)Cl] (1) and [Fe(CN)6]4- anions. This reaction implies the dissociation of Mn(III)-Cl coordination bonds and the formation of Mn(III)-NC bonds with the help of several intermolecular interactions. Here, we present the synthesis, crystal structure, and magnetic characterization of the monomeric Mn(III) complex [Mn(L)(H2O)Cl] (1) and of compound (H3O)[Mn(L)(H2O)2]{[Mn(L)(H2O)]2Fe(CN)6}·4H2O (2) (H2L = 2,2'-((1E,1'E)-(ethane-1,2-diylbis(azaneylylidene))bis(methaneylylidene))bis(4-methoxyphenol)). Complex 1 is a monomer where the Schiff base ligand (L) is coordinated to the four equatorial positions of the Mn(III) center with a H2O molecule and a Cl- ion at the axial sites and the monomeric units are assembled by π-π and hydrogen-bonding interactions to build supramolecular dimers. The combination of [Fe(CN)6]4- with complex 1 leads to the formation of linear Mn-NC-Fe-CN-Mn trimers where two trans cyano groups of the [Fe(CN)6]4- anion replace the labile chloride from the coordination sphere of two [Mn(L)(H2O)Cl] complexes, giving rise to the linear anionic {[Mn(L)(H2O)]2Fe(CN)6}2- trimer. This Mn2Fe trimer crystallizes with an oxonium cation and a mononuclear [Mn(L)(H2O)2]+ cation, closely related to the precursor neutral complex [Mn(L)(H2O)Cl]. In compound 2, the Mn2Fe trimers are assembled by several hydrogen-bonding and π-π interactions to frame an extended structure similar to that of complex 1. Density functional theoretical (DFT) calculations at the PBE1PBE-D3/def2-TZVP level show that the bond dissociation energy (-29.3 kcal/mol) for the Mn(III)-Cl bond is smaller than the summation of all the weak intermolecular interactions (-30.1 kcal/mol). Variable-temperature magnetic studies imply the existence of weak intermolecular antiferromagnetic couplings in both compounds, which can be can cancelled with a critical field of ca. 2.0 and 2.5 T at 2 K for compounds 1 and 2, respectively. The magnetic properties of compound 1 have been fit with a simple S = 2 monomer with g = 1.959, a weak zero-field splitting (|D| = 1.23 cm-1), and a very weak intermolecular interaction (zJ = -0.03 cm-1). For compound 2, we have used a model with an S = 2 monomer with ZFS plus an S = 2 antiferromagnetically coupled dimer with g = 2.009, |D| = 1.21 cm-1, and J = -0.42 cm-1. The metamagnetic behavior of both compounds is attributed to the weak intermolecular π-π and hydrogen-bonding interactions.

Synthetic Iron Porphyrins for Probing the Differences in the Electronic Structures of Heme a3, Heme d, and Heme d1.

A variety of heme derivatives are pervasive in nature, having different architectures that are complementary to their function. Herein, we report the synthesis of a series of iron porphyrinoids, which bear electron-withdrawing groups and/or are saturated at the ß-pyrrolic position, mimicking the structural variation of naturally occurring hemes. The effects of the aforementioned factors were systematically studied using a combination of electrochemistry, spectroscopy, and theoretical calculations with the carbon monoxide (CO) and nitric oxide (NO) adducts of these iron porphyinoids. The reduction potentials of iron porphyrinoids vary over several hundreds of millivolts, and the X-O (X = C, N) vibrations of the adducts vary over 10-15 cm-1. Density functional theory calculations indicate that the presence of electron-withdrawing groups and saturation of the pyrrole ring lowers the π*-acceptor orbital energies of the macrocycle, which, in turn, attenuates the bonding of iron to CO and NO. A hypothesis has been presented as to why cytochrome c containing nitrite reductases and cytochrome cd1 containing nitrite reductases follow different mechanistic pathways of nitrite reduction. This study also helps to rationalize the choice of heme a3 and not the most abundant heme b cofactor in cytochrome c oxidase.

Hydrophobic Shielding of Outer Surface: Enhancing the Chemical Stability of Metal-Organic Polyhedra.

Metal-organic polyhedra (MOP) are a promising class of crystalline porous materials with multifarious potential applications. Although MOPs and metal-organic frameworks (MOFs) have similar potential in terms of their intrinsic porosities and physicochemical properties, the exploitation of carboxylate MOPs is still rudimentary because of the lack of systematic development addressing their chemical stability. Herein we describe the fabrication of chemically robust carboxylate MOPs via outer-surface functionalization as an a priori methodology, to stabilize those MOPs system where metal-ligand bond is not so strong. Fine-tuning of hydrophobic shielding is key to attaining chemical inertness with retention of the framework integrity over a wide range of pH values, in strong acidic conditions, and in oxidizing and reducing media. These results are further corroborated by molecular modelling studies. Owing to the unprecedented transition from instability to a chemically ultra-stable regime using a rapid ambient-temperature gram-scale synthesis (within seconds), a prototype strategy towards chemically stable MOPs is reported.

Mediastinal Gray Zone Lymphoma.

A 50-year-old male presented with cough and breathlessness. A positron emissoin tomography scan revealed FDG (Fluorodeoxyglucose) avid mediastinal mass. Tru-cut biopsy showed fibrotic stromal tissue with cellular infiltrate consisting of abnormal lymphoid cells and few large cells with smudged nucleus. Immunohistochemistry revealed diffuse positivity with CD20, focal positivity for CD30 and rare CD15 positive cells. Histological picture and immune profile showed overlaping features of non-Hodgkin's as well as Hodgkin's lymphoma. A diagnosis of mediastinal gray zone lymphoma was made. The patient showed a complete metabolic response to six cycles of chemotherapy.

Strategies to Improve Electrical Conductivity in Metal-Organic Frameworks: A Comparative Study.

Metal-organic frameworks (MOFs), formed by the combination of both inorganic and organic components, have attracted special attention for their tunable porous structures, chemical and functional diversities, and enormous applications in gas storage, catalysis, sensing, etc. Recently, electronic applications of MOFs like electrocatalysis, supercapacitors, batteries, electrochemical sensing, etc., have become a major research topic in MOF chemistry. However, the low electrical conductivity of most MOFs represents a major handicap in the development of these emerging applications. To overcome these limitations, different strategies have been developed to enhance electrical conductivity of MOFs for their implementation in electronic devices. In this review, we outline all these strategies employed to increase the electronic conduction in both intrinsically (framework-modulated) and extrinsically (guests-modulated) conducting MOFs.

New Cyanostyrylcopillar[5]arene Derivative: Synthesis, Photophysical Study, Chromogenic Detection of Aliphatic Amines, and Biofilm-Antibiofilm Activity.

The synthesis, characterization, and application of a new cyanostyrylcopillar[5]arene 1 is reported. Single-crystal X-ray diffraction and other spectroscopic techniques confirm the identity of the new copillar 1. The X-ray diffraction study reveals that the copillar 1 exhibits a 1D supramolecular chain in the solid state involving π···π interactions along the crystallographic c-axis and 1D chains are further connected by interchain C-H···π interactions to establish 2D supramolecular layers within the crystallographic bc-plane. 2D supramolecular chains on further packing introduce a 3D structure with void spaces filled with hexane molecules. Through minimal deviation in the dihedral angle, the cyano-substituted ethylenic group in 1 shows a conjugation with the phenolic -OH, favoring intramolecular bond conjugation (ITBC) and colorimetrically detects the aliphatic amines over aromatic amines in CH3CN. Among the aliphatic amines, tertiary amines are differentiated from primary and secondary amines by the naked eye through color change. Both in solution and solid states, 1 displays vapor phase detection of volatile aliphatic amines. Antibacterial activity analysis shows that while 1 exhibits the antibiofilm action against Gram-positive pathogenic bacteria, Staphylococcus aureus, it promotes biofilm formation by Gram-negative pathogenic bacteria, Pseudomonas aeruginosa.

Novel Octahedral Nickel†(II) Complex with Flexible Piperazinyl Moiety Exhibits Potent Cytotoxic Effect Along with Anti-Migratory and Anti-Metastatic Effect on Human Cancer Cells.

Synthesis of non-platinum transition metal complexes with N,O donor chelating ligand for application against pathogenesis of cancer with higher efficacy and selectivity is currently an important field of research. We assessed the anti-cancer effect of a mixed ligand Ni(II) complex on human breast and lung cancer cell lines in this investigation. Mononuclear mixed ligand octahedral Ni(II) complex [NiIIL(NO3)(MeOH)] complex (1), with tri-dentate phenol-based ligand 2,4-dichloro-6-((4-methylpiperazin-1-yl) methyl) phenol (HL) along with methanol and nitrate as ancillary ligand was prepared. Piperazine moiety of the ligand exists as boat conformation in this complex as revealed from single crystal X-ray study. UV-visible spectrum of complex (1) exhibits three distinct d-d bands due to spin-allowed 3 A2 g→3T1 g (P), 3 A2 g→3T1 g(F) and 3 A2 g→3T2 g(F) transitions as expected in an octahedral d8 system. Our study revealed that Complex (1) induces apoptotic cell death in mouse and human cancer cells such as mcf-7, A549 and MDA-MB-231 through transactivation of p53 and its pro-apoptotic downstream targets in a dose dependent manner. Furthermore, complex (1) was able to slow the migratory rate of MDA-MB-231 cells' in vitro as well as epithelia -mesenchymal transition (EMT), the key step for metastatic transition and malignancy. Over all our results suggest complex (1) as a potential agent in anti-tumor treatment regimen showing both cytotoxic and anti-metastatic activity against malignant neoplasia.

Simultaneous presence of both open metal sites and free functional organic sites in a noncentrosymmetric dynamic metal-organic framework with bimodal catalytic and sensing activities.

Assimilation of open metal sites (OMSs) and free functional organic sites (FOSs) with a framework strut has opened up a new route for the fabrication of novel metal-organic materials, thereby providing a unique opportunity to explore their multiple functionalities. A new metal-organic framework (MOF), {[Cu(ina)2(H2O)][Cu(ina)2(bipy)]·2H2O}n (1) (ina=isonicotinate, bipy=4,4'-bipyridine), has been synthesized and characterized. Complex 1 is crystallized in the orthorhombic noncentrosymmetric space group Aba2 and consists of two different 2D coordination polymers, [Cu(ina)2(H2O)]n and [Cu(ina)2(bipy)]n, with entrapped solvent water molecules. Hydrogen-bonding interactions assemble these two different 2D coordination layers in a single-crystal structure with interdigitation of pendant 4,4'-bipy from one layer into the groove of another. Upon removal of guest molecules, 1 undergoes a structural transformation in single-crystal-to-single-crystal fashion with expansion of the effective void space. Each metal center is five-coordinated and thus can potentially behave as an OMS, and the free pyridyl groups of pendant 4,4'-bipy moieties and free -C=O groups can act as free FOSs. Thus, owing to presence of both OMSs and free FOSs, the framework exhibits multifunctional properties. Owing to the presence of OMSs, the framework can act as a Lewis acid catalyst as well as a small-molecule sensor material, and in a similar way, owing to the presence of free FOSs, it performs as a Lewis base catalyst and a cation sensor material. Furthermore, owing to noncentrosymmetry with large polarity along a particular direction, it shows strong second-harmonic generation/nonlinear optical (SHG-NLO) activity.

Transmembrane fluoride anion transport by meso-3,5-bis(trifluoromethyl)phenyl picket calix[4]pyrrole.

Meso-3,5-bis(trifluoromethyl)phenyl picket calix[4]pyrrole 1 displays excellent fluoride anion transport activity across artificial lipid bilayers showing EC50 = 2.15 µM (at 450 s in EYPC vesicle) with high fluoride over chloride ion selectivity. The high fluoride selectivity of 1 was ascribed to the formation of a sandwich type π-anion-π interaction complex.

A multifunctional porous organic Schottky barrier diode.

Mesoporous materials: A multifunctional porous organic material (ANPPIT; see picture) has been synthesized and characterized. Multifunctionality of the compound has been determined from nitrogen adsorption, guest-dependent luminescence, and electrical conductivity measurements.

Hypercalcemia of Malignancy: Time to Pull the Brakes.

Hypercalcemia of malignancy (HOM) is usually seen in advanced stage and carries a poor prognosis. Survival outcomes are dismal and most of the patients are unable to receive subsequent definite anti-cancer therapy. There is lack of any retrospective or prospective data regarding hypercalcemia of malignancy in Indian population. We aim to describe survival outcomes in hypercalcemia associated with solid organ malignancies. Forty-five patients diagnosed with HOM associated with solid organ malignancies were included in the study. Patients were followed up till death. Clinical features and survival outcomes were noted. Squamous cell carcinoma of head and neck region and lung comprised most of the cases associated with HOM. Most of the patients presented with poor performance status. Median overall survival (OS) was 20 days (2-78 days). Median OS was 35 days (9-58 days) in those who received definite anti-cancer therapy. Four-week mortality rate was estimated as 59.5%, while this increased to 75.7% within 6 weeks from the diagnosis of hypercalcemia. Survival outcomes are poor after the diagnosis of hypercalcemia in cancer patients. Best supportive care including hospice care should be strongly considered at this point of time instead of definite systemic anti-cancer therapy.

Multifractal analysis of ZnO nanoparticles.

ZnO nanoparticles (NPs) have variety of applications in different fields due to its size, structure, as well as physical and chemical properties. One of its prominent characteristics is its antibacterial behavior. Nonlinear Dynamical Theory (NLD) has a vast scope in the field of material science, especially when subtle correlations are searched for to extract hidden information. Since nano-ZnO materials may be used in inhibiting pathogens, its nonlinear features can be quantified and calibrated with the help of NLD tools. Multi-fractal Analysis (MFA) is an important diagnostic tool of NLD for not only analyzing nonlinear signal or images, but also predicting any spurious events likely to occur in the system under study. Thus, the analysis of the surface texture of the ZnO nano particles formed, using the TEM images and relate it with the variations of the XRD signal using NLD tools, is our first attempt reported here. Further, tools of MFA are used, for the first time, to see if there exists any correlation between the texture of the nano particles formed and the Zone of Inhibition (ZoI) we obtain as an output after allowing certain pathogens inhibit in the presence of the same nano particles. Analysis of TEM images guide us to predict the texture and structure of crystallites of ZnO:Cu samples which are responsible for overall behavior of inhibiting pathogens. In this paper, MFA of ZoI images, TEM images, and signal of four different Cu-doped ZnO nanoparticles are carried out and their outcomes are calibrated for estimating the size and pattern of unknown NPs synthesized under similar physical and chemical condition. Moreover, that MFA can be used reliably to predict spurious or abnormal surface structure or bacterial inhibition is also established.

Evaluation of Iron Status in Patients of Solid Organ Malignancies: Study from a Cancer Research Centre.

Anemia associated with cancer is a major public health issue. The gravity of this problem is likely to be higher in India due to already existing malnutrition in the general population. Iron deficiency anemia (IDA) as a subset has not been evaluated in Indian population of cancer patients. This study was undertaken to evaluate iron status among newly diagnosed advanced-stage cancer patients with anemia at a cancer research institute in India. Sixty-four patients of anemia were identified who fulfilled the inclusion criteria. Iron status was noted. Absolute iron deficiency (AID) was identified in 8 (12.5%) patients. Functional iron deficiency (FID) was seen in 48 (75%) patients. Probable functional iron deficiency (PFID) was seen in 2 (3.1%) patients while no iron deficiency (NID) was seen in 6 (9.3%) patients. FID is seen in majority of advanced-stage solid organ cancer patients in India. Large sample studies are required to better define the exact prevalence of iron deficiency, chemotherapy-induced anemia, and anemia in cancer subtypes.