Search

Currently, there are many uses of metal complexes, especially in the fields of medicinal chemistry and catalysis. Thus, fabrication of new complexes which perform as a catalyst and chemotherapeutic drug is always a beneficial addition to the literature. Herein, we report three heterocyclic thiosemicarbazone-based Pd(II) complexes [Pd(HL1)Cl] (C1), [Pd(L2)(PPh3)] (C2) and [Pd(L3)(PPh3)]Cl (C3) having coligands Cl and PPh3. Thiosemicarbazone ligands (H2L1, H2L2 and HL3) and the complexes (C1–C3) were characterized methodically using several spectroscopic techniques. Single-crystal X-ray diffraction methods reveal that the structural environment around the metal center of C2 is square planar, while for C1 and C3 it is a slighty distorted square plane. The supramolecular network of compounds was built via hydrogen bonds, C–H⋯π and π⋯π interactions. Density functional theory (DFT) study of the structure of the complexes supports experimental findings. The application of these complexes as catalysts toward Suzuki–Miyaura coupling reactions has been examined with various aryl halides and phenyl boronic acid in PEG 400 solvent. The complexes displayed good biomolecular interactions with DNA/protein, with a binding constant value of the order of 105 M−1. C3 showed greater binding efficacy toward these biomolecules than the other complexes, which might be due to the cationic nature of C3. Furthermore, antitumor activity of the complexes was studied against the human triple-negative breast cancer (TNBC) cell line MDA-MB-231. It was found that C3 was more toxic (IC50 = 10 ± 2.90 μM) toward MDA-MB-231 cells than the other complexes. A known chemotherapeutic drug, 5-fluorouracil, was included as positive control. The programmed cell death mechanism of C3 was confirmed. Additionally, complex-induced apoptosis was confirmed and occurred via a mitochondria-dependent (intrinsic) pathway. [ABSTRACT FROM AUTHOR]

As a contribution to the development of new ruthenium complexes with pharmacologically interesting properties, two new cyclometallated ruthenium(II) carbonyl complexes of the general formula [Ru(L1/L2)(CO)(PPh3)2] (1/2) were synthesized and characterized using analytical and spectral techniques (IR, UV/visible, 1H NMR and ESI-MS). The crystal structures of complexes (1 and 2) were confirmed by X-ray crystallography, which indicated CNO tridentate coordination of the ligands through C(aryl)–S bond activation. The electronic structures and spectral properties of complexes 1 and 2 were interpreted by DFT and TDDFT calculations. The binding ability of the Ru(II) complexes with calf thymus DNA (CT DNA) and bovine serum albumin (BSA) has been explored by absorption and emission titration methods. A good binding affinity with DNA was observed with an intercalative binding mode, which was further confirmed by EB displacement and viscosity measurement studies. The BSA protein binding studies have been monitored by quenching of tryptophan and tyrosine residues in the presence of complexes and the quenching mechanism was found to be static. Synchronous and 3D fluorescence spectroscopy studies were carried out to validate the micro environmental changes in BSA. In addition, the in vitro cytotoxicity of the ligands and complexes against the human breast cancer cell line (MCF-7), human lung cancer cell line (A549), triple negative breast cancer cell line (MDA-MB-231) and gastric adenocarcinoma cell line (AGS) was investigated by using the MTT assay and the IC50 values of the complexes towards MCF-7 cell lines were found to be even less compared to cisplatin. [ABSTRACT FROM AUTHOR]

Considering the pervasive and multifarious impact of copper ions in different biological processes, this research effort covers the one-pot easy synthesis, characterization details (spectroscopic, X-ray structure and quantum calculation including DFT and TD DFT), Hirshfeld surface computation, and bio, catalytic and anticancer activities of a benzoate bridging NNO tethered homo-binuclear copper complex of the formulation [(CuL)2(PhCOO)](ClO4) (1). The bio-catalytic activities of 1 have been evaluated spectrophotometrically during the aerial oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) and 2-aminophenol (OAPH) in acetonitrile. Using spectro-photo and fluorometric titration, it has been found that complex 1 binds avidly to CT DNA and BSA protein (binding propensities of ∼105 M−1). The data from circular dichroism (CD) and viscosity testing indicate that it binds to DNA intercalatively. The static quenching of BSA's endogenous fluorescence is demonstrated by fluorescence life time titration using 1, which is further verified by a temperature-dependent quenching analysis. Synchronous spectroscopic tests combined with CD and 3D fluorescence spectra of BSA in the presence of 1 support the protein's structural modifications around the Trp-residue. Relevant thermodynamic parameters (ΔH, ΔS and ΔG) and FRET distances between the pair (BSA and 1) were also estimated. Finally, the MTT colorimetric technique was used to measure 1's cytotoxic activities against a range of malignant and non-cancerous cell lines. 1 exhibits specific cytotoxicity against MCF-7 (human breast cancer) exclusively (IC50 = 9.53 ± 2.5 μM at 24 h) with an apoptotic mechanism of cell death, as validated by Hoechst and AO/EB staining. [ABSTRACT FROM AUTHOR]

New Pd (II) and Pt (II) complexes (C1/C2) with a O,N,N donor pincer ligand, 4‐hydroxy‐3‐((E)‐1‐(((Z)‐phenyl (pyridin‐2‐yl)methylene)hydrazono)ethyl)‐2H‐chromen‐2‐one (HL) were synthesized and methodically characterized by several spectroscopic and XRD techniques. Absorption and fluorescence techniques were used to assess the mechanism of interaction of the complexes with bovine serum albumin protein. MTT assay was executed to investigate the antiproliferative activity of the complexes with several cancer cell lines (MCF‐7, HCT116, A549, and HepG2) along with a normal cell line (PBMC). Both C1 and C2 showed better antiproliferative activity with HepG2 cell line (IC50 value of 15.3 and 5.1 μM, respectively). A cytotoxicity study was performed, and complex C2 exhibited a better antiproliferative activity as compared to C1. The morphological changes were also examined by staining methods, and fragmented DNA unveiled that the cell death took place through apoptosis. [ABSTRACT FROM AUTHOR]

Agricultural production in India is highly vulnerable to climate change. Transformational change to farming systems is required to cope with this changing climate to maintain food security, and ensure farming to remain economically viable. The south Asian rice-fallow systems occupying 22.3 million ha with about 88% in India, mostly (82%) concentrated in the eastern states, are under threat. These systems currently provide economic and food security for about 11 million people, but only achieve 50% of their yield potential. Improvement in productivity is possible through efficient utilization of these fallow lands. The relatively low production occurs because of sub-optimal water and nutrient management strategies. Historically, the Agro-met advisory service has assisted farmers and disseminated information at a district-level for all the states. In some instances, Agro-met delivers advice at the block level also, but in general, farmers use to follow the district level advice and develop an appropriate management plan like land preparation, sowing, irrigation timing, harvesting etc. The advisories are generated through the District Agrometeorology Unit (DAMU) and Krishi Vigyan Kendra (KVK) network, that consider medium-range weather forecast. Unfortunately, these forecasts advisories are general and broad in nature for a given district and do not scale down to the individual field or farm. Farmers must make complex crop management decisions with limited or generalised information. The lack of fine scale information creates uncertainty for farmers, who then develop risk-averse management strategies that reduce productivity. It is unrealistic to expect the Agro-met advisory service to deliver bespoke information to every farmer and to every field simply with the help of Kilometre-scale weather forecast. New technologies must be embraced to address the emerging crises in food security and economic prosperity. Despite these problems, Agro-met has been successful. New digital technologies have emerged though, and these digital technologies should become part of the Agro-met arsenal to deliver valuable information directly to the farmers at the field scale. The Agro-met service is poised to embrace and deliver new interventions through technology cross-sections such as satellite remote sensing, drone-based survey, mobile based data collection systems, IoT based sensors, using insights derived from a hybridisation of crop and AIML (Artificial Intelligence and Machine Learning) models. These technological advancements will generate fine-scale static and dynamic Agro-met information on cultivated lands, that can be delivered through Application Programming Interface (APIs) and farmers facing applications. We believe investment in this technology, that delivers information directly to the farmers, can reverse the yield gap, and address the negative impacts of a changing climate. [ABSTRACT FROM AUTHOR]

Rhenium(I) complexes of type [Re(CO)3(NN)Cl] (NN = α-diimine) with MLCT absorption in the orange-red region of the visible spectrum have been synthesized and fully characterized, including single crystal X-ray diffraction on two complexes. The strong bathochromic shift of MLCT absorption was achieved through extension of the π-system of the electron-poor bidiazine ligand 4,4′-bipyrimidine by the addition of fused phenyl rings, resulting in 4,4′-biquinazoline. Furthermore, upon anionic cyclization of the twisted bidiazine, a new 4N-doped perylene ligand, namely, 1,3,10,12-tetraazaperylene, was obtained. Electrochemical characterization revealed a significant stabilization of the LUMO in this series, with the first reduction of the azaperylene found at E 1 / 2 (0 / −) = −1.131 V vs. Fc+/Fc, which is the most anodic half-wave potential observed for N-doped perylene derivatives so far. The low LUMO energies were directly correlated to the photophysical properties of the respective complexes, resulting in a strongly red-shifted MLCT absorption band in chloroform with a λmax = 586 nm and high extinction coefficients (ε586nm > 5000 M−1 cm−1) ranging above 700 nm in the case of the tetraazaperylene complex. Such low-energy MLCT absorption is highly unusual for Re(I) α-diimine complexes, for which these bands are typically found in the near UV. The reported 1,3,10,12-tetraazaperylene complex displayed the [Re(CO)3(α-diimine)Cl] complex with the strongest MLCT red shift ever reported. UV–Vis NIR spectroelectrochemical investigations gave further insights into the nature and stability of the reduced states. The electron-poor ligands explored herein open up a new path for designing metal complexes with strongly red-shifted absorption, thus enabling photocatalysis and photomedical applications with low-energy, tissue-penetrating red light in future. [ABSTRACT FROM AUTHOR]

A new chromone-based fluorescent probe (HMPM) is introduced for the selective detection of Pd2+. The designed probe exhibits a ratiometric fluorescence enhancement, which can be attributed to the ESIPT and/or chelation enhancement fluorescence (CHEF) processes. HMPM is efficient enough to detect Pd2+ solely in the presence of other metal ions in DMSO/H2O solution (1 : 1, v/v, pH = 7.2) with a limit of detection as low as 2.9 nM. Furthermore, the complex formation of HMPM with Pd2+ is confirmed by the single crystal X-ray diffraction method. The changes in electronic structure and absorption spectrum of HMPM upon complexation with Pd2+ are supported by DFT and TDDFT calculations. Moreover, the probe (HMPM) could be effectively used for the detection of Pd2+ by a dip-stick method. [ABSTRACT FROM AUTHOR]

Sympathetic ophthalmia following parsplana vitrectomy is a known complication. We describe here a case of recurrent disc neovascularization in a patient of sympathetic ophthalmia. It promptly responded to steroids initially but later recurred with inflammation.