Inorganica Chimica Acta最新文献

The regioselectivity of the ligand substitution reaction of square-planar Pt(II) complexes with chelating ligands pyridyl-NHC (Py-NHC), phenyl-NHC (Ph-NHC), and phenyl-pyridine (ppy, Ph-Py) was studied. The reaction of the dichlorido Pt(II) complex bearing these chelating ligands in the presence of pyrazole (pz) ligands afforded mono-pyrazole adducts [PtCl(ChL)(pz)]ⁿ⁺ (n = 0 and 1; ChL=chelating ligand (Py-NHC, Ph-NHC, Ph-py)). The structures of the PtCl(pz) complexes with the Py-NHC, Ph-NHC, and Ph-Py chelating ligands were confirmed by X-ray crystallographic analysis. The regioselectivity of the ligand substitution reaction between the pyrazole moieties and chloride ions can be controlled by the strength of the trans effect of the chelating ligands. Based on the structures of the products, a clear trend of Py < NHC < Ph was observed in the trans effect of the chelating ligands. This finding provides a rational synthetic procedure for asymmetric Pt(II) complexes with chelating ligands in a stepwise manner.

This study concerns the synthesis of zinc isoporphyrin (2), from zinc porphyrin [Zn(4-Cl)TPP], (1), where TPP- tetraphenylporphyrin ligand. Because of the prospective applications such as an infrared dye and catalyst in photomedicine, isoporphyrin has been in high demand. However, there is limited documentation of metalloisoporphyrins. Here, we have discussed the synthesis, characterization, coordination chemistry and theoretical studies of zinc isoporphyrin, 2. Compound 2 was characterized using UV–visible, ¹H NMR, ¹³C NMR and ESI Mass analysis. Electrochemical studies were carried out using cyclic voltammetry. Theoretical studies including structure optimization, analysis of electronic transition, and natural bond analysis (NBO) were performed for both 1 and 2. Besides that, the global reactivity indices of 1 were compared with 2. The lower HOMO-LUMO energy gap in 2 (1.95 eV) supports the shifting of Q bands to a lower energy region. The molecular docking studies of 1 and 2 were performed for the first time and found that isoporphyrins can act as a potential inhibitor of G-quartet DNA associated with cancer disease. These results may be useful in designing effective therapeutics for the treatment of cancer.

A 6-(thiophen-2-yl)benzo[4,5]thieno[3,2-c]quinoline (QTP), with thiophene and quinoline based moieties as binding sites, has been synthesized and characterized with spectroscopic methods, and DFT. The synthesized probe QTP showed highly sensitive and highly specific fluorescent ‘turn-on’ effect (λem = 280 nm) for the 1:1 binding with Fe³⁺ ions to form probe QTP.Fe³⁺ complex in semi-aqueous medium (acetonitrile:water (50:50; v/v)) and live cells. The 1:1 binding stoichiometry of probe QTP and Fe³⁺ ions were proposed by DFT calculations and confirmed by the NMR spectroscopy, and mass spectrum of probe QTP.Fe³⁺ complex. Importantly, with the LOD 6.37 µM for the detection of Fe³⁺ ions, receptor QTP did not show any interference from potentially competing ions, indicates its biocompatibility. The micromolar limit of detection (6.37 µM), cell permeability, and low cytotoxicity allows the probe QTP to be an outstanding tool for the live-cell imaging and detection of ferric ions in live cells.

The reaction of monooxidized thioyl (4-CH₃)C₆H₃N-2-NH(P(S)Ph₂) (1) ligand with MCl₂(COD)(M = Pd, Pt) in equimolar ratio resulted in cis-[MCl₂{1-κ²S,N^py}] (M = Pd (2), Pt(3)) complexes. Also, The reaction of 1 with HgX₂ (X = Cl, I) produced cis-[HgX₂{1-κ²S,N^py }] (X = Cl(4), I(5)). Complexes 2–5 have been isolated and characterized by multinuclear NMR (¹H, ¹³C, and ³¹P) and IR spectroscopy. The molecular structures of 2, 4, and 5 were determined using single X-ray crystallography. 4 and 5 are the first structurally defined instances of this type of κ²S,N^py -bidentate ligand with Hg(II) metal complexes. The new palladium(II) complex 2 as a pre-catalyst in the Suzuki cross-coupling process was also investigated.

A copper(II)/potassium(I) Schiff base polymeric complex has been synthesized and characterized. Salen-type N₂O₂O₂′ donor compartmental Schiff base ligand has been used where copper(II) resides in the inner N₂O₂ core and potassium (I) sits in the outer O₂O₂′ core. Single crystal X-ray analysis revealed that the unintended formation of a disordered bromine atom led to Cu⋯Br π-hole coinage bond (CiB) interaction. The energetics regarding the CiB interactions have been rationalized using DFT calculations, QTAIM, and ELF study.

Herein, a homobimetallic azomethine-functionalized nickel(II) complex, [Ni₂L₂(van)(μ_1,1-NCS)] (AMR-1, where L = 2-[(2-Hydroxy-1,1-dimethyl-ethylimino)-methyl]-6-methoxyphenol, molecular weight = 788.20 (found)) has been judiciously synthesized with N-coordinated end-on thiocyanate. AMR-1 exhibited promising chromogenic variation from pale green to colourless with hypochromic shifting in the visible region in the presence of silver(I). Herein, the exposed sulfur site of the co-ligand acts as chemodosimetric recognition site for highly selective detection of a soft metal pollutant, silver ion (Ag⁺) with the limit of detection (LOD) of 0.37 ppm. Along with this, aqueous cyanide (CN⁻) recognition was accomplished in a mutually independent way with distinct chromogenic variation from pale green to yellowish color within ∼5 s. This led to the LOD of 0.46 ppm, which is much lower than the safe limit, set by the World Health Organization (WHO). The stability constant value for cyanide interaction with AMR-1 is obtained to be 1.49 × 10³ M⁻¹ as per 1:1 binding stoichiometry. Experimental findings, obtained from UV–Vis, HR-MS, FT-IR, and ¹H NMR spectroscopic studies in conjugation with the decreased HOMO-LUMO energy gap from 3.40 eV to 2.07 eV, obtained from density functional theory studies, support the mechanistic pathway of interaction. Implementing molecular logic platforms benefits from fabricating three-input-two-output logic circuits by imitating variable spectroscopic outcomes. Real-time multifarious applications of AMR-1 have been accomplished with paper strip-based solid-state assay and recognition of the target-specific analytes from targeted medicinal specimens and from both cyanogenic as well as non-cyanogenic food sources. To the best of our knowledge, this is probably the first nickel(II) complex derived sensory receptor that is effectually implemented towards recognition of another metal ion, silver (I) along with CN⁻ from aqueous as well as from real specimens.

Two new 2D Mn(II)-based coordination polymers (CPs), {[Mn(H₃L)(phen)]·H₂O}_n (1) and {[Mn(H₃L)(bpy)]·1.5H₂O}_n (2), were synthesized using one pot procedure. They were isolated from 2,4-bis(3,5-dicarboxylphenxoy)benzoic acid (H₅L) and two chelating N-donor ligands 1,10-Phenanthroline (phen) and 2,2′-bipyridine (bpy) for photocatalytic applications. The identification of the complexes was confirmed through elemental analysis, FTIR, PXRD, crystallography, and TG analysis, confirming distorted octahedral NNO4 coordination of Mn(II) with the carboxylate O atoms chelating and syn-syn bridging mode (1) and (2). Powder XRD confirmed phase-purity, while TG analysis indicated thermal stability of the complexes up to 400 °C. Both Mn(II)-based coordination polymers (1) and (2) showed optical semiconducting behavior, making them suitable candidates for photocatalysis. The Mn(II)-based coordination polymers (1) showed a 91.93 % degradation of nitrofurazone (NFZ) through photodecomposition. The trapping experiment established that the catalysis of NFZ photodecomposition is primarily attributed to O₂⁻ radicals.

Metal ions participate in numerous essential biological processes in our body. In the external environment, metal ions are present in food, soil, and water. However, the presence of metal ions concentration above the permissible limits may cause hazardous effect on environment and human beings. Therefore, detection of metal ions with high selectivity and sensitivity is important for biological system and in environmental monitoring. In literature, several examples employing Schiff base derivatives or MNPs as optical sensors for metal ions were investigated. However, studies on the development of Schiff base stabilized metal nanoparticles as optical sensors for hazardous metal ions are scanty in the literature. At present, it is essential to be able to construct controlled ultra-small, highly dispersed, stable, and functionalized metal nanoparticles (MNPs) to make them suitable for industrial applications. The production of Schiff base stabilized metal nanoparticles (MNPs) can be achieved easily without demanding experimental requirements. As a result, it provides a simple, quick, and effective approach to create highly efficient catalysts for the treatment of environmental pollutants. Herein, we report Schiff base and organic ligand stabilized metal nanoparticles as potential chemosensors for hazardous metal ions.

Three transition metal complexes of s-triazine ligand (^MorphBPT) were synthesized, characterized, and their supramolecular structures are explored. Their structures are confirmed to be [Co(^MorphBPT)₂](ClO₄)₂ (1), [Mn(^MorphBPT)₂](ClO₄)₂ (2), and [Ni(^MorphBPT)(H₂O)₃]Cl₂·2H₂O (3) using single crystal X-ray diffraction. In all cases, the ^MorphBPT is a tridentate N-chelator. Hence, the metal ions have hexa-coordination environment in all complexes. In the two homoleptic complexes 1 and 2, the O···H, C···H, and C···O contacts, in addition to some short N···O and H···H contacts detected only in 2, are the most important. For 3, the Cl···H, O···H, and C···H contacts are the most significant. Enrichment ratio was used to detect the atom pairs which have the highest probability to form non-covalent interactions. The nature of MN and MO coordination interactions is analyzed with the aid of AIM calculations. Also, the interactions with the ligand moieties lowers the charge of Co(II), Ni(II), and Mn(II) to 0.8411, 0.9332, and 0.8308 e, respectively. The three complexes 1, 2, and 3 exhibited antibacterial activity exceeds the reference drug gentamicin against P. vulgaris where the diameter of the inhibition zones (DIZs) are determined to be 28, 29, 27, and 25 mm, respectively. In addition, 1 and 2 have antifungal activity better (DIZ = 18 mm) and equal (DIZ = 17 mm) compared to ketoconazole against A. fumigatus, respectively. The Mn(II) complex 2 is the most active against MCF-7 (75.3 ± 3.1 μM) and A-549 (40.2 ± 2.7 μM) cancerous cell lines.

In the past decades, lanthanide(III) complexes from the Schiff base ligands have received attention for their marvelous luminescence properties. Accordingly, their complexes have been used in a variety of applications in optical, biological and environmental fields. In this review, the structural and sensitization aspects of the lanthanide(III) Schiff base complexes have been investigated. The factors that induce their luminescence properties through efficient energy transfer pathways have been discussed thoroughly, such as (1) metal’s geometry, (2) ligand’s design and the preferred binding modes, (3) temperature and (4) molecular aggregation. In addition, the nature of the low-lying excited triplet state initiated from (1) intra-ligand charge transfer, ILCT, (2) ligand to metal charge transfer, LMCT, (3) ligand–ligand interaction, LLI, or (4) mixed d-f or f-f excited states in a single molecule, have also been discussed in detail.