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Hexaazamacrocyclic Schiff bases have been extensively combined with lanthanoid (Ln) ions to obtain complexes with a highly axial geometry. However, the use of flexible hexaazatetraamine macrocycles containing two pyridines and acyclic spacers is rather uncommon. Accordingly, we obtained [DyL(OAc)2]OAc·7H2O·EtOH and [DyLMe2(Cl)2]Cl·2H2O, where L and LMe2 are the 18-membered macrocycles 3,6,10,13-tetraaza-1,8(2,6)-dipyridinacyclotetradecaphane and 3,10-dimethyl-3,6,10,13-tetraaza-1,8(2,6)-dipyridinacyclotetradecaphane, respectively, which contain ethylene and methylethylene spacers between their N3 moieties. [DyL(OAc)2]OAc·7H2O·EtOH represents the first crystallographically characterized lanthanoid complex of L, while [DyLMe2(Cl)2]Cl·2H2O contributes to increasing the scarce number of LnIII compounds containing LMe2. Furthermore, the crystal structure of L·12H2O was solved, and it was compared with those of other related macrocycles previously published. Likewise, the crystal structures of the DyIII complexes were compared with those of the lanthanoid and d-metal complexes of other 18-membered N6 donor macrocycles. This comparison showed some effect of the spacers employed, as well as the influence of the size of the ancillary ligands and the metal ion. Additionally, the distinct folding behaviors of these macrocycles influenced their coordination geometries. Moreover, the luminescent properties of [DyL(OAc)2]OAc·7H2O·EtOH and [DyLMe2(Cl)2]Cl·2H2O were also investigated, showing that both complexes are fluorescent, with the emission being sensitized by the ligands. [ABSTRACT FROM AUTHOR]

The preparation of dizirconium complexes based on a novel bis(indenyl)-(E/Z)-stilbene platform was explored. Negishi coupling between the in situ-generated diorganozincates obtained from the respective o/m/p-(E/Z)-dibromostilbenes and the bromo-functionalized zirconocene (η5-Cp*)(η5-2-methyl-4-bromoindenyl)ZrCl2, or, alternatively, the preparation of bis(indene)stilbene pro-ligands {o/m/p-(E/Z)-BisIndSB}H2 through Negishi coupling of the corresponding dibromostilbenes with 4-bromoindene and subsequent metallation/transmetallation with Cp*ZrCl3 or Zr(NMe2)4, allowed the preparation of a series of dinuclear complexes. These were analyzed by NMR spectroscopy and some of them by iASAP-mass spectrometry and by X-ray diffraction studies. Experimental results were compared with DFT modelling of the targeted dinuclear complexes evidencing that the (E)-complexes are more stable by 7–11 kcal mol−1 than their (Z)-analogues. Thermal, uncontrolled isomerization of (Z)- to (E)-stilbene platform was observed experimentally for some systems, in the course of their synthesis, either from the (Z)-dibromostilbene reagent or on the dinuclear complexes resulting from the Negishi coupling. Photoisomerization of the (E)- and (Z)-{BisIndSB}H2 proligands and of complexes {o-(E)-BisIndSB}(Zr(NMe2)3)2 and {m-(E)-BisIndSB}(ZrCl2Cp*)2 was investigated under a variety of conditions. It proved effective for the proligands but induced decomposition of the dizirconium complexes. Time-dependent DFT (TD-DFT) computations were performed to identify unambiguously the nature of the observed absorption bands and account for decomposition of the complexes. Preliminary ethylene/1-hexene homo- and copolymerization investigations did not evidence putative cooperativity phenomena within these dinuclear systems nor significantly differentiated behavior between the (Z)- and (E)-isomers of a given type of complex under the reaction conditions investigated. [ABSTRACT FROM AUTHOR]

C−H metalation is the most efficient method to prepare aryl–zinc and –aluminium complexes that are ubiquitous nucleophiles. Virtually all C−H metalation routes to form Al/Zn organometallics require stoichiometric, strong Brønsted bases with no base‐catalyzed reactions reported. Herein we present a catalytic in amine/ammonium salt (Et3N/[(Et3N)H]+) C−H metalation process to form aryl‐zinc and aryl‐aluminium complexes. Key to this approach is coupling an endergonic C−H metalation step with a sufficiently exergonic dehydrocoupling step between the ammonium salt by‐product of C−H metalation ([(Et3N)H]+) and a Zn−H or Al−Me containing complex. This step, forming H2/MeH, makes the overall cycle exergonic while generating more of the reactive metal electrophile. Mechanistic studies supported by DFT calculations revealed metal‐specific dehydrocoupling pathways, with the divergent reactivity due to the different metal valency (which impacts the accessibility of amine‐free cationic metal complexes) and steric environment. Notably, dehydrocoupling in the zinc system proceeds through a ligand‐mediated pathway involving protonation of the β‐diketiminate Cγ position. Given this process is applicable to two disparate metals (Zn and Al), other main group metals and ligand sets are expected to be amenable to this transition metal‐free, catalytic C−H metalation. [ABSTRACT FROM AUTHOR]

In this article we analyze the thermal processes in magnetically anisotropic metal complexes under the action of non-adiabatic switching of magnetic field. Using the non-stationary perturbation theory for the case of sudden perturbation, we show that this field can cause not only heat release, but also heat absorption, interconnected with the axial zero field splitting (parameter D) in a paramagnetic metal complex. As an illustrative example we consider the simplest S = 1-complexes having "easy axis" and "easy plane" types of anisotropy influenced by the magnetic field that is suddenly turned off. We demonstrate that the character of the thermal processes (heat dissipation or absorption) depends on the sign of D and direction of applied field and so the analysis of these processes can be in principle used as a complementary tool (in addition to SQIUD magnetometry, EPR spectroscopy and INS) for studying magnetic anisotropy. The conditions under which the non-adiabatic switching of the magnetic field gives rise to the heat absorption are revealed. This unusual phenomenon, which can be called "nonadiabatic field switching cooling", may have practical applications. [ABSTRACT FROM AUTHOR]

This study investigates quercetin complexes as potential synergistic agents against the important respiratory pathogen Streptococcus pneumoniae. Six quercetin complexes (QCX1–6) were synthesized by reacting quercetin with various metal salts and boronic acids and characterized using FTIR spectroscopy. Their antibacterial activity alone and in synergism with antibiotics was evaluated against S. pneumoniae ATCC 49619 using disc diffusion screening, broth microdilution MIC determination, and checkerboard assays. Complexes QCX-3 and QCX-4 demonstrated synergy when combined with levofloxacin via fractional inhibitory concentration indices ≤ 0.5 as confirmed by time-kill kinetics. Molecular docking elucidated interactions of these combinations with virulence enzymes sortase A and sialidase. A biofilm inhibition assay found the synergistic combinations more potently reduced biofilm formation versus monotherapy. Additionally, gene–gene interaction networks, biological activity predictions and in-silico toxicity profiling provided insights into potential mechanisms of action and safety. [ABSTRACT FROM AUTHOR]

The present study of phytomitigation potential and adaptive physiological and biochemical responses of helophyte Typha latifolia L. growing in water bodies at different distances from the century-old copper smelter (JSC "Karabashmed" Chelyabinsk Region, Russia) was conducted for the first time. This enterprise is one of the most dominant sources of multi-metal contamination for water and land ecosystems. The aim of the research was to assess the heavy metal (Cu, Ni, Zn, Pb, Cd, Mn, and Fe) accumulation, the photosynthetic pigment complex, and some redox reactions in T. latifolia from six differently technogenic impacted sites. In addition, the quantity of mesophilic aerobic and facultative anaerobic microorganisms (QMAFAnM) in rhizosphere sediments, as well as some plant growth-promoting (PGP) attributes of 50 isolates from each site, were determined. The water and sediment metal concentrations in highly contaminated sites exceeded the permissible/critical limits and were found much higher than that previously reported by other researchers while studying this helophyte. Both the degree of contamination and geoaccumulation indexes further elucidated extremely high contamination due to prolonged activity of copper smelter. T. latifolia accumulated significantly higher concentrations of the most of studied metals in its roost and rhizome with meager transfer to leaves (the translocation factors were less than one). Spearman's rank correlation coefficient showed a strong positive correlation between the metal concentration in sediments and its content in T. latifolia leaves (rs = 0.786 at p < 0.001 on average) and roots/rhizome (rs = 0.847 at p < 0.001 on average). In highly contaminated sites, the folia content of chlorophyll a and carotenoids decreased (by 30 and 38%, respectively), while lipid peroxidation enhanced (by 42%) on average compared to S1–S3 sites. These responses were accompanied by increasing non-enzymatic antioxidant content (soluble phenolic compounds, free proline, and soluble thiols) that allow plants to resist under significant anthropogenic loads. QMAFAnM in the five studied rhizosphere substrates varied insignificantly (2.5 × 106 − 3.8 × 107 cfu g−1 DW) and was decreased only in the most contaminated site (4.5 × 105). The proportion of rhizobacteria capable of fixing atmospheric nitrogen decreased by 1.7 times, solubilizing phosphates by 1.5 times, and synthesizing indol-3-acetic acid by 1.4 times in highly contaminated sites, while the amount of siderophore, 1-aminocyclopropane-1-carboxylate deaminase, and HCN producing bacteria did not considerably change. The results indicate high resistance of T. latifolia to prolonged technogenic impact, probably due to compensatory adaptive changes in the nonenzymatic antioxidant level and presence of beneficial microorganisms. Thus, T. latifolia was found to be a promising metal-tolerant helophyte that could help in mitigation of metal toxicity due to their phytostabilization even in heavily contaminated environment. [ABSTRACT FROM AUTHOR]

Metal complexes with multidentate ligands are frequently used as model compounds to shed light on the (bio)‐inorganic chemistry of H2S. Zinc complexes bearing salen‐type ONNO ligands with different bridging groups are particularly relevant in this respect. Here, we describe the use of zinc complexes with the sulfur‐analogues of the ONNO ligands with the S‐donors replacing either the neutral nitrogen donors or the anionic oxygen atoms of the classical salen ligands. In addition, we studied a hexadentate cyclic ligand, with four neutral sulfur atoms and two anionic oxygens. Having two coordinative pockets this ligand is able to form a bimetallic zinc complex. We report how the different coordinative environments of the explored ligands influence the stability of the zinc complexes and their abilities to form the related hydrosulfide species. [ABSTRACT FROM AUTHOR]

Alkaline earth (AE) metal complexes have garnered significant interest in various functional fields due to their nontoxicity, low density, and low cost. However, there is a lack of systematic investigation into the structural characteristics and physical properties of AE‐metal‐organic frameworks (MOFs). In this research, we synthesized isostructural MOFs consisting of AE4(μ4‐Cl) clusters bridged by benzo‐(1,2;3,4;5,6)‐tris(thiophene‐2′‐carboxylic acid) (BTTC3−) ligands. The resulting structure forms a truncated octahedral cage denoted as [AE4(m4‐Cl)]6(BTTC)8, which further linked to a porous three‐dimensional framework. Among the investigated AE ions (Ca, Sr, and Ba), the Ca4‐MOF demonstrated good chemical stability in water compared to Sr4‐MOF and Ba4‐MOF. The N2 adsorption and solid‐state UV‐vis‐NIR absorption behaviors were evaluated for all AE4‐MOFs, showing similar trends among the different metal ions. Additionally, the proton conduction study revealed that the Ca4‐MOF exhibited ultra‐high proton conductivity, reaching 3.52×10−2 S cm−1 at 343 K and 98 % RH. Notably, the introduction of LiCl via guest exchange resulted in an improved proton conduction of up to 6.36×10−2 S cm−1 under similar conditions in the modified LiCl@Ca4‐MOF. The findings shed light on the regulation of physical properties and proton conductivity of AE‐MOFs, providing valuable insights for their potential applications in various fields. [ABSTRACT FROM AUTHOR]

We present complexes of alkali metal ions and the ammonium ion with the large cyclodimethylsiloxanes D7 and D8 (D=Me2SiO). The formation of such complexes is accompanied by rearrangements of the ligands to form complexes with a suitable ring size for the metal used. These rearrangements could be suppressed by suitable reaction conditions and rapid work‐up of the reaction mixtures. This enabled the isolation of [Li(D7)][GaI4] (1), [Li(D8)][GaI4] (2), [Na(D8)][GaI4] (3), [K(D8)][GaI4] (4) and [NH4(D8)][GaI4] (5). All of the prepared compounds were analysed using single‐crystal X‐ray diffraction as well as multinuclear NMR spectroscopy. This reveals very different coordination modes in the compounds obtained. [ABSTRACT FROM AUTHOR]

Tetrakis-benzimidazoles draw attention with their structural similarities to ethylenediaminetetraacetic acid (EDTA) which is a medication used in the management and treatment of heavy metal toxicity, as well as having many different derivatives. In addition to the tetradentate feature due to the donor characteristic of the C=N nitrogen atom in each benzimidazole unit, there are also tetrakis-benzimidazole derivatives that show ligand properties up to octadentate through donor atoms such as N and O in the bridge units. The applications of tetrakis-benzimidazole derivatives and various metal complexes in many fields such as corrosion inhibitor, catalyst, enzyme inhibitor, superoxide dismutase, catalase activity, superoxide oxidase, DNA affinity, determination of H2O2, were investigated. In this study, a comprehensive review was conducted on N,N,N',N'-tetrakis(1H-benzimidazol-2-ylmethyl)ethane-1,2-diamine (EDTB), a hexadentate tetrakis-benzimidazole derivative. Synthesis routes, properties, various complexes of EDTB and its derivatives, their structural features and application areas have been reviewed and compiled in order to be useful for researchers who will work in this field. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance threatens the effective prevention and treatment of an increasingly broad spectrum of infections caused by pathogenic microorganisms. This pressing challenge has intensified the search for alternative antibiotics with new pharmacological properties. Due to the chemical synergy between the biological activity of antimicrobial peptides (AMPs) and the different modes of action, catalytic properties, and redox chemistry of metal complexes, metallopeptides have emerged in recent years as an alternative to conventional antibiotics. In the present investigation, peptide ligands conjugated with 5-carboxy-1,10-phenanthroline (Phen) were prepared by solid-phase peptide synthesis (SPPS), and the corresponding copper(II) metallopeptides, Cu-PhenKG and Cu-PhenRG (where K = lysine, R = arginine, and G = glycine), were synthesized and characterized. The antimicrobial activities of these compounds toward Gram-positive and Gram-negative bacteria, evaluated by the broth microdilution technique, indicate that the metal center in the metallopeptides increases the antimicrobial activity of the complexes against the conjugated peptide ligands. Minimum inhibitory concentration (MIC) values of 0.5 μg/mL for S. aureus with the Cu-PhenKG complex and 0.63 μg/mL for S. typhimurium with the Cu-PhenRG complex were obtained. The MIC values found for the conjugated peptides in all microorganisms tested were greater than 1.5 μg/mL. The interactions of the conjugated peptides and their metallopeptides with plasmid DNA were evaluated by agarose gel electrophoresis. Alterations on the replication machinery were also studied by polymerase chain reaction (PCR). The results indicate that the complexes interact efficiently with pBR322 DNA from E. coli, delaying the band shift. Furthermore, the resulting DNA–metallopeptide complex is not a useful template DNA because it inhibits PCR, since no PCR product was detected. Finally, molecular dynamics and molecular docking simulations were performed to better understand the interactions of the obtained compounds with DNA. The Cu-PhenRG complex shows a significantly higher number of polar interactions with DNA, suggesting a higher binding affinity with the biopolymer. [ABSTRACT FROM AUTHOR]

Novel platinum(II) complexes of 4′-substituted terpyridine ligands were synthesized and characterized. Each complex had a different biomolecule (amine, glucose, biotin and hyaluronic acid) as a targeting motif, potentially improving therapeutic outcomes. We demonstrated that complexes can self-assemble in water into about 150 nm nanoparticles. Moreover, the complexes were assayed in vitro toward a panel of human cancer cell lines (ovarian adenocarcinoma A2780, lung cancer A549, breast adenocarcinoma MDA-MB-231, neuroblastoma SHSY5Y) to explore the impact of the pendant moiety on the terpyridine toxicity. The platinum complex of terpyridine amine derivative, [Pt(TpyNH2)Cl]Cl, showed the best antiproliferative effect, which was higher than cisplatin and [Pt(Tpy)Cl]Cl. Selective in vitro antiproliferative activity was achieved in A549 cancer cells with the Pt–HAtpy complex. These findings underline the potential of these novel platinum(II) complexes in cancer therapy and highlight the importance of tailored molecular design for achieving enhanced therapeutic effects. [ABSTRACT FROM AUTHOR]

Cooperative effects have attracted considerable attention in recent years. These effects are ubiquitous in chemistry and biology and can govern interactions of proteins with other biomolecules, mechanisms of supramolecular recognition and polymerization, catalysis, assembly of compounds on surfaces, and physical properties such as magnetic, electronic or optical properties, e. g. Consequently, the understanding of cooperative effects can lead to a structure‐property relation that can pave the way to future applications in various research areas; however, with regard to cooperative effects in homo‐ and heterometallic complexes, we still are at the beginning of understanding. Nevertheless, concepts to describe cooperativity of metal centers as well as methodologies to investigate and model these effects have emerged over the last years. This concept article gives an overview of these existing concepts, approaches, and strategies to understand cooperative effects in homo‐ and heterometallic complexes. Special emphasis is put on concepts to define cooperative effects, their quantification, as well as methods to investigate cooperative effects. [ABSTRACT FROM AUTHOR]

[Display omitted] Metal nanoparticles (MNPs) with complex structure and uniform distribution demonstrate interesting physicochemical properties and thus are widely applied. The traditional wet chemistry methods are commonly applied to construct MNPs structure, yet they still exhibit limitations in the liquid-phase environment, particularly, for synthesis of supported MNPs in one-step process. Diverse synthesis strategies have been investigated to design complex MNPs in a more efficient manner, among which the thermal treatment atmosphere induced solid-phase ion diffusion (TASID) synthesis strategy serves as an attractive strategy. This review summaries recent progresses of complex MNPs construction via TASID synthesis strategy, which realize the structure design through thermally treating the precursors under various gas atmosphere, such as oxidative, reductive, carbonaceous, and inert gas. This TASID strategy can both achieve the MNPs structure design and uniform dispersion simultaneously, demonstrating its unique properties. MNPs with diverse composition and structure, such as hollow, core@shell, yolk@shell, Janus, and multi-chamber structure, are successfully synthesized. The TASID synthesis mechanisms of galvanic replacement, Kirkendall effect, Ostwald ripening, carburization, and exsolution are elaborated in detail. The synthesis-mechanism-structure correlation of TASID is identified and the applications of these constructed MNPs are presented. This strategy could be developed into a class of synthetic methods by applying various thermal gas. [ABSTRACT FROM AUTHOR]

Peptides, both natural and synthetic, are well suited for a wide range of purposes and offer versatile applications in different fields such as biocatalysts, injectable hydrogels, tumor treatment, and drug delivery. The research of the better part of the cited papers was conducted using various database platforms such as MetalPDB. The rising prominence of therapeutic peptides encompasses anticancer, antiviral, antimicrobial, and anti-neurodegenerative properties. The metals Na, K, Mg, Ca, Fe, Mn, Co, Cu, Zn, and Mo are ten of the twenty elements that are considered essential for life. Crucial for understanding the biological role of metals is the exploration of metal-bound proteins and peptides. Aside from essential metals, there are other non-essential metals that also interact biologically, exhibiting either therapeutic or toxic effects. Irregularities in metal binding contribute to diseases like Alzheimer's, neurodegenerative disorders, Wilson's, and Menkes disease. Certain metal complexes have potential applications as radiopharmaceuticals. The examination of these complexes was achieved by preforming UV–Vis, IR, EPR, NMR spectroscopy, and X-ray analysis. This summary, although unable to cover all of the studies in the field, offers a review of the ongoing experimentation and is a basis for new ideas, as well as strategies to explore and gain knowledge from the extensive realm of peptide-chelated metals and biotechnologies. [ABSTRACT FROM AUTHOR]

Due to their structural arrangements, coordination complexes have shown potential to combat various human diseases. Nitrogen heteroatoms are a fascinating class of coordination compounds with many applications in synthesis and medicine. Herein, four Co(II), Zn(II), Cu(II), and Ni(II) complexes (I–IV) such as [CoC10H14Cl2N6O2] (I), [ZnC6H10Cl2N6O2] (II), [Cu2C16H34N2O12] (III), and [Ni4C80H100N16O22] (IV) bearing aza-heterocyclic ligands have been synthesized under one-pot self-assembly conditions. The reaction of 2-amino-4-hydroxy-6-methylpyrimidine and 3-amino-5-hydroxypyrazole with CoCl2·6H2O and ZnCl2, respectively, produced two mononuclear complexes (I)–(II) while two binuclear complexes (III)–(IV) (complex IV are in two halves) were synthesized using Cu (OAC)2·H2O and NiCl2·6H2O, respectively, with salicylidene salicylhydrazide. Then, the complexes were characterized using NMR, FTIR UV–Vis, X-ray diffraction, TGA, and elemental analysis techniques to confirm their structures. The synthesis complexes were employed against different human tumour cell lines (SMMC-7721, A549, MDA-MB-231, and SW480). The best activity was demonstrated by complex (II) against human tumour cell lines SMMC-7721 (liver cancer cell) with an IC50 value of (6.356 µM). [ABSTRACT FROM AUTHOR]

Cancer has become the second leading reason for death in the world. Cell biology states that the bulk of anti‐cancer medications focuses on DNA. A study of how complexes of metals interact with DNA is crucial in creation of the effective chemotherapy drugs. The interactions of DNA with Schiff base and their metal complexes are a thrust area for many researchers, and many papers have reported on them. An amino molecule reacts with carbonyl group to form a variety of chemicals called Schiff bases. Many studies have shown that Schiff bases have compounds that affect biological processes. Due to their potential use as novel reagents for biotechnology and medicine, the research of interactions between transition metal complexes and nucleic acids has grown significantly during the past few decades. It was shown that several metal Schiff base complexes may intercalate DNA. Small molecules can attach themselves to DNA through different ways, such as intercalation and groove binding. The main method to measure nuclease activity was gel electrophoresis, and the ligand alone had much lower activity than the complex. To set the stage for this analysis, a brief overview of Schiff bases and their complexes is provided. Further, this review provides an overview of the DNA interactions brought forth by Schiff base metal complexes. It also draws attention to new developments in the study of Schiff bases and their metal complexes and their prospective use as a bioactive core for DNA cleavage and binding. [ABSTRACT FROM AUTHOR]

Novel divalent chelates of Co (II), Cu (II), Zn (II) and Ni (II) were prepared and described of the form [M (NTM)(CH3COO)2] where NTM = [1‐(4‐nitrophenyl)‐1H‐1,2,3‐triazol‐4‐yl)methanol ligand. Elemental analyses, infrared red, 1H and 13CNMR, electronic, magnetic susceptibility, conductivity measurements and X‐ray diffraction studies were used to assess our divalent metal complexes. Moreover, the stability and stoichiometry of the novel metal chelates were examined through the job's method in solutions. Correlation of all spectroscopic techniques states that NTM acts as a bi‐dentate NO ligand to afford octahedral complex geometry for all the investigated metal chelates. Thermodynamic and kinetics factors for various thermal degradation phases were calculated. Moreover, B3LYP/LANL2DZ/6‐311 g(d,p) theoretical study has been applied for estimating the MEP and quantum chemical reactivity descriptors of studied molecules. Moreover, the UV–Vis absorption spectra for the investigated molecules are predicted via the time‐dependent DFT (TD‐DFT) calculations. In addition, MOE‐ docking was tested on two different proteins, the receptor of (3HB5) breast cancer mutant oxidoreductase as well as the receptor of Glucosamine‐6‐phosphate synthase in complex with glucosamine‐6‐ phosphate of (2VF5) E.coli and COVID‐19 protease. The results recommended that the (NTMCo), (NTMNi), (NTMCu) and (NTMZn) complexes showed the highest inhibitory activity compared to the other NTM ligands as antimicrobial and breast cancer candidates. Furthermore, in‐vitro anti‐bacterial, anti‐fungal, cytotoxic and anti‐oxidant performances for the selected ligand as well as its chelates were studied. All metal chelates presented superiority, proceeding free organic ligand ineffective management, definitely NTMCu complex. [ABSTRACT FROM AUTHOR]

Redox‐switchable catalysis is an efficient process to modulate the activity and/or selectivity in the polymerization with greater polymerization control and precision. In this work, the ferrocenyl‐functionalized diarylamines 4‐Fc‐C6H4NHC6H5 (HL1), 4‐Fc‐C6H4NH(2,6‐Me2C6H3) (HL2), and 2,6‐iPr2–4‐Fc‐C6H2NHC6H5 (HL3) were prepared and used as pro‐ligands to obtain the arylamido‐ligated rare‐earth metal complexes. Treatment of RE (CH2C6H4NMe2‐o)3 with 1 equiv. of HL1–3 in toluene afforded the ferrocenyl‐functionalized‐arylamido rare‐earth metal bis(o‐dimethylaminobenzyl) complexes L1Sc(CH2C6H4NMe2‐o)2 (1), L2RE(CH2C6H4NMe2‐o)2 (RE = Sc (2), Y (3)), and L3Y(CH2C6H4NMe2‐o)2 (4) in good yields. The compositions of these complexes were verified by NMR spectroscopy and elemental analysis. HL1 and HL3 were subjected to single‐crystal X‐ray diffraction. Electrochemical and NMR studies indicated that 4 could be oxidized with AgBF4 to generate the corresponding oxidized species 4ox, which could be facilely reduced back to 4 by use of CoCp2 as the reductant. The redox‐reversible ability between 4 and 4ox gave the chance to modulate the reactivity by switching the oxidized and reduced forms of one complex. For a controlled polymerization of ε‐caprolactone, 4 was active, and the polymerization process could be easily "on/off" switched by the redox reaction occurred on the ferrocenyl moiety. [ABSTRACT FROM AUTHOR]

In the recent past the molecular engineering of coordination metal complexes has attracted new interest in the field of nonlinear optics (NLO), which find their applications in optoelectronics and optical data storage technology it is the transition metal along with the organic moieties that induce the control over the optical nonlinearity these properties of the materials not only enhance the intensity but also have a drastic effect on the polarization of incident laser light. This is an important criterion for all-optical switching applications. Coordination metal complexes are a very good target to aim at because of their robustness, physical and chemical stability, and other variable degrees that lead to an increment in NLO responses, most importantly all these properties can be either manipulated or tailored or tunable according to the requirement. Apart from the metal center, these molecules acting as legend must be chromophoric with donor-acceptor nature. In these molecules, the NLO response is intrinsically based on the 'push-pull' mechanism of the electrons. Obviously to these molecules, when a metal is in contact, the electronic push-pull mechanism alters rendering the molecule non-symmetric. This review article mainly concentrates on small mononuclear metal complexes for NLO application. [ABSTRACT FROM AUTHOR]

Octahedral iodide clusters of molybdenum and tungsten [M6I8L6] are considered as promising components of new classes of luminescent materials. When excited with the light at a wavelength of ≤450 nm, the clusters form long-lived triplet states emitting red phosphorescence. This phosphorescence is deactivated in the presence of molecular oxygen to form singlet oxygen in a high yield. Due to the capability of photogenerating singlet oxygen, the [M6I8L6] clusters and related materials exhibit photoinduced cytotoxicity and bactericidal action. Universal methods developed to date make it possible to prepare cluster compounds with specified compositions and properties depending on ligand L. This review considers the prospects for developing drugs for antimicrobial photodynamic inactivation and photodynamic cancer therapy based on the [M6I8L6] clusters. [ABSTRACT FROM AUTHOR]

Precious metal complexes, which act as excellent photoredox catalysts, have now being replaced by earth‐abundant metal complexes. This review focused on redox reactivity of ligand‐to‐metal charge transfer (LMCT) and metal‐to‐ligand charge transfer (MLCT) excited states of earth‐abundant metal complexes. Iron complexes with strongly σ‐donating NHC‐ligands (NHC = N‐heterocyclic carbene) has emerged, featuring long lived LMCT excited states due to a significantly increased barrier for deactivation via metal centered states. A Fe(III)‐NHC complex acts as an effective photoredox catalyst for various photocatalytic redox reactions. Although manganese(IV)‐oxo complexes have no long‐lived excited states (τ < < 1 ns). Once acids such as Sc(OTf)3 and HOTf are bound to the oxo moiety of Mn(IV)‐oxo complexes, the photoexcitation of acid‐bound Mn(IV)‐oxo complexes resulted in formation of the excited states with microseconds lifetimes, which are capable of oxidation of substrates including benzene to phenol. Photoexcited states of Mn(III), Mn(II) and Mn(I) complexes act as photoreductants to reduce substrates including O2. On the other hand, photoexcited states of Co(IV) and Co(III) complexes act as photooxidants, whereas those of Co(II) and Co(I) complexes act as photoreductants. With regard to the excited state lifetime, [Cr(tpe)2]3+ (tpe = 1,1,1‐tris(pyrid‐2‐yl)ethane) exhibited the longest luminescence lifetime (τ = 4500 μs), acting as an effective photoredox catalyst for photocatalytic redox reactions. The LMCT state of a Cr(0) complex acts as a super photoreductant. Thus, LMCT and MLCT excited states of earth‐abundant metal complexes are utilized as strong photooxidants and photoreductants, respectively. [ABSTRACT FROM AUTHOR]

This article describes the synthesis of a new metal complex using 6-methyl-2-thioxo-2,3-dihydropyrimidin-4(1H)-one. The compound was analyzed using several methods, including determining its melting point and employing UV-Vis, IR, ATR, 1H NMR, HSQC, and Raman spectroscopy for the free ligand. The metal complex was formed by combining aqueous solutions of metal salts with the ligand dissolved in DMSO and water, along with NaOH in a metal-to-ligand-to-base ratio of 1:4:2. The NMR signals of the ligand were assigned using 1H-1H COSY, DEPT-135, HMBC, and HMQC spectra. Furthermore, the compound's antimicrobial activity against Gram-positive and Gram-negative bacteria, as well as yeasts, was assessed. [ABSTRACT FROM AUTHOR]

The development of OLED materials by molecular design is important for high performance organic light emitting diode because tailoring the molecular structures can dramatically tune the properties such as efficiency, color, stability of device. Near‐infrared organic light‐emitting diodes (NIR OLEDs) with heavy metals or TADF materials are regularly reported due to the advantages of their various applications in healthcare services, veil authentication, and night vision displays. In this paper, we are summarized the collection of innovative organic near‐infrared (NIR) emitters which is crucial factor to design specific NIR emitter for NIR OLEDs [ABSTRACT FROM AUTHOR]

The aim of the presented research was to synthesize and characterize via elemental analysis, HRMS, thermogravimetric analysis, FTIR and EPR a novel series of transition metal complexes of Cu(II), Co(II), Ni(II) and Mn(II) with β-L-aspartyl-cyclohexyl amide as ligand. The HRMS recorded spectra confirm the obtaining of new compounds. The changes in the FTIR spectra of the metal complexes, compared to the ligand, support the complexation process. The thermal stability of the ligand and its metal complexes was discussed in the 20-8000C temperature range, in air atmosphere. In all of the studied complexes, the aspartyl amide acts as a bidentate ligand, its coordination involving the carboxylate oxygen and the nitrogen atom belonging to the free amino group of the amino acid. Metal complexes are formed in the 1:2 (Metal:Ligand) ratio as found by the elemental analysis. Except the free ligand, all the metal complexes are hydrating with water molecules, and the thermal stability of these suggested whether the water molecules are inside or outside the coordination sphere. The shape of EPR spectrum for copper complex at room temperature suggests the presence of CuN2O2 monomeric species with a rhombic distortion around the metallic ion. The results indicate that their stability range obeys the Irving-Williams series. [ABSTRACT FROM AUTHOR]

Inflammation and thrombosis are implicated in several chronic disorders. Recent studies have outlined the way in which several compounds can offer protection against inflammation. Within this comprehensive review the so-far reported anti-inflammatory health-promoting effects of several metal-based complexes, both in vitro and in vivo, are thoroughly presented. These metal-based compounds usually interfere with various biochemical processes associated with the inflammatory response and thrombus formation and become capable of inhibiting these biochemical pathways with proposed health benefits. Emphasis is given to the multifaceted actions of metal-based complexes that have exhibited potent anti-inflammatory and antithrombotic activities against the inflammatory mediator, platelet-activating factor (PAF), and its thrombo-inflammatory signaling, as well as on their anti-platelet and antitumor health promoting properties. Furthermore, the enhancement of the anti-inflammatory potency of well-established bioactive compounds by their incorporation as ligands in several metal-based complexes is discussed. Metal-based complexes bearing natural anti-inflammatory bioactives are also outlined. Characteristic examples of both free and metal-based porphyrins are explored. These compounds are recognized to have anti-inflammatory and antithrombotic assets, in addition to other pleiotropic advantages including antibacterial or anticancer actions. Additionally, applications of metal complexes in various models of inflammatory and thrombotic complications are demonstrated. The combined results of this study show that further research is required towards the preparation of several metal-based complexes with improved pharmacological profiles. Finally, restrictions on the application of these metal-based compounds are also covered, along with their prospects for the future and the need for additional study in order to improve their efficacy and safety. [ABSTRACT FROM AUTHOR]

A range of metal complexes derived from the HBTADH ligand (4-{[(6-chloro-1,3-benzothiazol-2-yl)imino]methyl}benzene-1,4-diol) have been synthesized, and their structural characterization has been conducted, yielding compounds of the type [M(BTADH)2]. Electron spin resonance (ESR), electronic absorption, mass, electromagnetic moments, NMR, infrared, and C, H, N, and S analysis spectroscopy were some of the methods used for characterization. A tetrahedral geometry has been projected for the complexes containing Hg(II), Zn(II), and Cd(II), but a high spin octahedral geometry is anticipated for the other complexes. In contrast, the spectra suggest that the Pd(II) complex will have a square planar shape. Metal complexes in nitrobenzene do not behave like electrolytes because of the compound's low molar conductance values. In addition, this study examined and evaluated the antibacterial activity of all compounds that were synthesised. [ABSTRACT FROM AUTHOR]

In this work, we have synthesized various zinc metal complexes with different acylhydrazoneoxime derivatives. The synthesis process involved condensation of para-substituted isonitrosoacetophenones (4-R-INAP) and terephthalohydrazide (TPHD). To produce these complexes, we reacted zinc chloride with various 4-substituted isonitrosoacetophenone terephthalohydrazide ligands (4-R-INAP-TPHD), where R= -H, -CH3, -OCH3 and -Cl. We employed different physicochemical and spectroscopic methods like elemental analysis, TG-DTA, UV-Visible, FTIR, and NMR spectroscopy, electrical conductance, and magnetic susceptibility to analyze the Schiffs base and zinc metal complexes. In addition, we tested the antibacterial activities of these compounds against selected bacteria strains. [ABSTRACT FROM AUTHOR]

The pyrazole derivatives and its metal complexes are considered to be pharmacologically significant with a variety of pharmacological applications. The present investigation highlights the synthesis of pyrazole based novel ligand, 4-[(E)-(3-hydroxypyridin-2-yl)diazenyl]-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one (PDP) and its Co(II), Ni(II), Cu(II) complexes. The structure of the synthesized compounds has been evaluated using various physicochemical and spectroscopic techniques. Cyclic Voltammetry (CV) results are used to confirm the electrocatalytic ability of the modified electrode, [Co(PDP)2]Cl2.2H2O/GCE for the detection of Folic acid (FA) at different concentrations. The CV results displayed good electro-catalytic activity with 10-120 µML-1 with limits of detection (LOD) of 0.0666 µML-1. This electrode has a sensitivity of 2.8784 µAµM-1cm-2 for FA. The bio-efficacy of the synthesized ligand and its complexes have been evaluated against the bacteria (S.aures and E.coli) and fungal (A.flavus and P.anomala) strains using standard method. Antidiabetic study on two different enzymes, a-amylase and a-Glucosidase indicating excellent inhibition by the metal complexes having the maximum IC50 Value of 105.34 for a-amylase and 107.15 mg/mL for a-Glucosidase. [ABSTRACT FROM AUTHOR]

We are now moving into the antimicrobial resistance (AMR) era where more antibiotic resistant bacteria are now the majority, a problem brought on by both misuse and over use of antibiotics. Unfortunately, the antibiotic development pipeline dwindled away over the past decades as they are not very profitable compounds for companies to develop. Regardless researchers over the past decade have made strides to explore alternative options and out of this we see revisiting historical infection control agents such as toxic metals. From this we now see a field of research exploring the efficacy of metal ions and metal complexes as antimicrobials. Such antimicrobials are delivered in a variety of forms from metal salts, alloys, metal complexes, organometallic compounds, and metal based nanomaterials and gives us the broad term metalloantimicrobials. We now see many effective formulations applied for various applications using metals as antimicrobials that are effective against drug resistant strains. The purpose of the document here is to step aside and begin a conversation on the issues of use of such toxic metal compounds against microbes. This critical opinion mini-review in no way aims to be comprehensive. The goal here is to understand the benefits of metalloantimicrobials, but also to consider strongly the disadvantages of using metals, and what are the potential consequences of misuse and overuse. We need to be conscious of the issues, to see the entire system and affect through a OneHealth vision. [ABSTRACT FROM AUTHOR]

The rapid release of gas by a chemical reaction to generate momentum is one of the most fundamental ways to elicit motion that could be used to sustain and control the motility of objects. We report that hollow crystals of a three‐dimensional supramolecular metal complex that releases gas by photolysis can propel themselves or other objects and advance in space when suspended in mother solution. In needle‐like regular crystals, the reaction occurs mainly on the surface and results in the formation of cracks that evolve due to internal pressure; the expansion on the cracked surface of the crystal results in bending, twisting, or coiling of the crystal. In hollow crystals, gas accumulates inside their cavities and emanates preferentially from the recess at the crystal terminus, propelling the crystals to undergo directional photomechanical motion through the mother solution. The motility of the object which can be controlled externally to perform work delineates the concept of "crystal microbots", realized by photoreactive organic crystals capable of prolonged directional motion for actuation or delivery. Within the prospects, we envisage the development of a plethora of light‐weight, efficient, autonomously operating robots based on organic crystals with high work capacity where motion over large distances can be attained due to the large volume of latent gas generated from a small volume of the crystalline solid. [ABSTRACT FROM AUTHOR]

Organoalkali compounds have undergone a far‐reaching transformation being a coupling partner to a mediator in unusual organic conversions which finds its spot in the field of sustainable synthesis. Transition‐metal catalysis has always been the priority in C(sp3)−H bond functionalization, however alternatively, in recent times this has been seriously challenged by earth‐abundant alkali metals and their complexes arriving at new sustainable organometallic reagents. In this line, the importance of MN(SiMe3)2 (M=Li, Na, K & Cs) reagent revived in C(sp3)−H bond functionalization over recent years in organic synthesis is showcased in this minireview. MN(SiMe3)2 reagent with higher reactivity, enhanced stability, and bespoke cation‐π interaction have shown eye‐opening mediated processes such as C(sp3)−C(sp3) cross‐coupling, radical‐radical cross‐coupling, aminobenzylation, annulation, aroylation, and other transformations to utilize readily available petrochemical feedstocks. This article also emphasizes the unusual reactivity of MN(SiMe3)2 reagent in unreactive and robust C−X (X=O, N, F, C) bond cleavage reactions that occurred alongside the C(sp3)−H bond functionalization. Overall, this review encourages the community to exploit the untapped potential of MN(SiMe3)2 reagent and also inspires them to take up this subject to even greater heights. [ABSTRACT FROM AUTHOR]

We report here a formal insertion of a metal carbene complex in a single carbon‐carbon bond. This behavior occurs with the participation of an α‐imino gold carbene complex, generated from benzofused triazapentalenes or, in a one‐pot procedure, from their 1‐propargyl‐1H‐benzotriazole precursors, and gold‐catalytically activated ynamides. As the result, 3H‐indole derivatives were obtained, with formation of a quaternary center. A computational analysis carried out on the reaction mechanism indicates that the bulkiness of the gold ligand plays a key role forcing a conformation, which includes aromatic interactions, that favors the approximation of the carbenic carbon to the reactive site. In addition, a negative crossover experiment rules out a cationic arene migration pathway. [ABSTRACT FROM AUTHOR]

The reaction kinetics of photocatalytic CO2 reduction is highly dependent on the transfer rate of electrons and protons to the CO2 molecules adsorbed on catalytic centers. Studies on uncovering the proton effect in catalysts on photocatalytic activity of CO2 reduction are significant but rarely reported. In this paper, we, from the molecular level, revealed that the photocatalytic activity of CO2 reduction is closely related to the proton availability in catalysts. Specifically, four dinuclear Co(II) complexes based on Robson-type ligands with different number of carboxylic groups (-nCOOH; n = 0, 2, 4, 6) were designed and synthesized. All these complexes show photocatalytic activity for CO2 reduction to CO in a water-containing system upon visible-light illumination. Interestingly, the CO yields increase positively with the increase of the carboxylic-group number in dinuclear Co(II) complexes. The one containing -6COOH shows the best photocatalytic activity for CO2 reduction to CO, with the TON value reaching as high as 10,294. The value is 1.8, 3.4, and 7.8 times higher than those containing -4COOH, -2COOH, and -0COOH, respectively. The high TON value also makes the dinuclear Co(II) complex with -6COOH outstanding among reported homogeneous molecular catalysts for photocatalytic CO2 reduction. Control experiments and density functional theory calculation indicated that more carboxylic groups in the catalyst endow the catalyst with more proton relays, thus accelerating the proton transfer and boosting the photocatalytic CO2 reduction. This study, at a molecular level, elucidates that more carboxylic groups in catalysts are beneficial for boosting the reaction kinetics of photocatalytic CO2 reduction. [ABSTRACT FROM AUTHOR]

The discovery that cyclic (ArO)2PF can support Rh-catalysts for hydroformylation with significant advantages in tuning regioselectivity transformed the study of metal complexes of monofluorophos ligands from one of primarily academic interest to one with potentially important applications in catalysis. In this review, the syntheses of monofluorophosphites, (RO)2PF, and monofluorophosphines, R2PF, are discussed and the factors that control the kinetic stability of these ligands to hydrolysis and disproportionation are set out. A survey of the coordination chemistry of these two classes of monofluorophos ligands with d-block metals is presented, emphasising the bonding of the fluorophos to d-block metals, predominantly in low oxidation states. The application of monofluorophos ligands in homogeneous catalysis (especially hydroformylation and hydrocyanation) is discussed, and it is argued that there is great potential for monofluorophos complexes in future catalytic applications. [ABSTRACT FROM AUTHOR]

In anticipation of the correlations between catalyst structures and their properties, the catalytic activities of 2-imino-1,10-phenanthrolyl iron and cobalt metal complexes are quantitatively investigated via linear machine learning (ML) algorithms. Comparatively, the Ridge Regression (RR) model has captured more robust predictive performance compared with other linear algorithms, with a correlation coefficient value of R2 = 0.952 and a cross-validation value of Q2 = 0.871. It shows that different algorithms select distinct types of descriptors, depending on the importance of descriptors. Through the interpretation of the RR model, the catalytic activity is potentially related to the steric effect of substituents and negative charged groups. This study refines descriptor selection for accurate modeling, providing insights into the variation principle of catalytic activity. [ABSTRACT FROM AUTHOR]

Organic metal complexes (OMCs) transport trace metals (e.g. , Co, Ni, Cu) from surface soils, via the unsaturated zone, to sites of cave carbonate (speleothem) formation. OMCs clearly imprint on speleothem trace element chemistry, but the role of kinetic factors in the signal transfer process has yet to be elucidated. We investigated whether OMCs may viably link metal concentrations in stalagmites and local hydrology (i.e. , drip rate), via their time-sensitive dissociation (or 'decay') in the speleothem water thin-film. We performed competitive ligand exchange experiments using water and soil samples from eight geographically diverse Aotearoa New Zealand caves, providing a first comparative characterisation of speleothem-specific OMC kinetics. Critically, this approach corroborated that NOM ligands limit transition metal availability at the dripwater-speleothem interface, exhibiting stabilities on the order Cu ≈ Co > Ni, whereas organic complexation of the alkaline earth metals Mg and Sr was virtually absent. Systematic variations of OMC stability with natural organic matter characteristics were not observed amongst water samples, whilst enhanced complexation was clearly evident in the comparably organic-rich soil extracts. Our results imply that the supply of transition metals to speleothems is inversely related to drip rate, increasing with drip interval via the decay of OMCs. This process appears most sensitive on time-scales relevant to typical speleothem-forming settings (<0 to ca. 40 drips min−1, corresponding to ca. <5.6 mL min−1), and therefore provides a general, mechanistic link to a quantitative proxy of palaeoclimatic cave drip rates. [ABSTRACT FROM AUTHOR]

Single‐atom heterogeneous catalysts (SACs) hold promise as sustainable alternatives to metal complexes in organic transformations. However, their working structure and dynamics remain poorly understood, hindering advances in their design. Exploiting the unique features of droplet‐based microfluidics, we present the first in‐situ assessment of a palladium SAC based on exfoliated carbon nitride in Suzuki–Miyaura cross‐coupling using X‐ray absorption spectroscopy. Our results confirm a surface‐catalyzed mechanism, revealing the distinct electronic structure of active Pd centers compared to homogeneous systems, and providing insights into the stabilizing role of ligands and bases. This study establishes a valuable framework for advancing mechanistic understanding of organic syntheses catalyzed by SACs. [ABSTRACT FROM AUTHOR]

Nitrosyl ruthenium complexes have emerged as promising platforms for the controlled delivery of nitric oxide (NO) and nitroxyl (HNO), both of which possess significant therapeutic implications. Considering this scenario, we synthesized and characterized the metal complex cis‐[RuNO(phen)2(2MIM)]3+ and its precursors, where phen and 2MIM correspond to 1,10‐phenantroline and 2‐methylimidazole, respectively. Comprehensive structural elucidation was undertaken using a combination of spectroscopic and electrochemical methodologies, including XANES/EXAFS experiments. This structural data was further validated through DFT computational analyses. We demonstrated that such compound can release NO and HNO in the presence of thiol‐based substrates. Not only this, but the same metal complex can also delivery nitric oxide under irradiation with visible light (λ=460 nm). The nitrosyl complex and its derivatives displayed marked vasodilatory capabilities as evidenced in assays involving isolated rat aorta rings. They also exhibited commendable antioxidant activity in free radical scavenging assays. Collectively, based on these data, this nitrosyl ruthenium compound is a potential therapeutic candidate, especially in the field of cardiovascular pathology like atherosclerosis, thereby deserving further in‐depth investigations. [ABSTRACT FROM AUTHOR]

This article discusses the importance and versatility of metal complexes with N-donor ligands in various fields such as chemistry, biochemistry, material science, and the chemical industry. The reactivity and structural features of these complexes depend on factors such as the nature of the central atoms, the arrangement of N-donor ligands, and the presence of co-ligands. The article also highlights the applications of these complexes in the synthesis of industrially important materials and their use as catalysts in various reactions. The Special Issue of Inorganics focuses on the latest advances in the chemistry of complexes with N-donor ligands, covering a wide range of ligands and their synthesis, characterization, and properties. The articles include studies on the reactivity of chiral N-heterocyclic stannylene, iron(III) complexes with N-phenylpyrazole-based ligands, organosilicon pyridine-2-olates, lanthanide-containing coordination polymers, iridium(III) and rhodium(III) complexes, zinc(II) compounds with a pyrazole-type ligand, silver(I) perchlorate complexes, iron(II) complexes with tridentate Schiff bases, and the thermal decomposition of cobalt(III) permanganate. The Special Issue also features two important reviews on the chemistry of transition metal salts with ammonia-ligand complexes and XO4-type oxoanions, and the NMR and single-crystal data of [Extracted from the article]

Preconcentration of strontium and barium as complexes with 11 organic reagents by coprecipitation with organic co-precipitants for their subsequent determination by X-ray fluorescence spectrometry is studied. The most effective systems turned out to be those included reagents from bisazosubstituted chromotropic acids, nitchromazo and chlorophosphonazo III. Complexes of these metals are virtually quantitatively coprecipitated as pairs with cations of the brilliant green dye, of the collector is an associate of an excess of the analytical reagent with cations of this dye. It is shown that the additional use of polyvinyl butyral as an indifferent co-precipitant ensures not only the almost complete extraction of these elements from solutions, but also the preparation of emitter concentrates suitable for X-ray fluorescence measurements using the standard-background technique. High efficiency allows, under optimal conditions, the achievement of very low limits of detection (IUPAC): 0.03 μg/mL Sr and 0.19 μg/mL Ba, even in working with small samples (by volume). [ABSTRACT FROM AUTHOR]

Dipnictenes of the type RE=ER (E=P, As, Sb, Bi) are the isovalence electronic heavier analogs of alkenes. Although diphosphenes and dipnictenes in general show a variety of binding modes in metal complexes, little is known about haptotropic shift reactions involving these ligands. Herein, we report an unprecedented η2 to η1 rearrangement of the dipnictene ligands in titanocene complexes of the type Cp2Ti(Pn2Ar2) (Pn=P, As; Ar=2,4,6‐Me3‐C6H2, Mes; 2,6‐iPr2‐C6H3, Dip; 2,4,6‐iPr3‐C6H2, Tip), initiated by Lewis basic ligands (L=MeCN, PMe3, AdNC, CO). In the presence of L the dipnictene ligand changes its hapticity from η2 to η1 and complexes of the general form Cp2Ti(L)(Pn2Ar2) with a succinctly different electronic structure are obtained. Electronically, the new complexes are best described as biradicaloids with antiferromagnetically coupled (via a π‐bond) [Cp2TiIII]⋅+ and [Pn2Ar2]⋅− fragments. However, the biradical character of these systems is affected by the electronic features of the co‐ligand and significantly decreases moving from PMe3/MeCN (σ‐donors) to CNAd/CO (σ‐donors/π‐acceptors). [ABSTRACT FROM AUTHOR]

Transition metal complexes, such as the low‐spin bis (phenylterpyridine) (A) and bis (pyridylterpyrazine)iron (II) (B) complexes, provide didactic chromophore species for demonstrating the Raman, resonance Raman, and the surface‐enhanced Raman scattering (SERS) behavior in coordination chemistry, as well as for elucidating the nature of inner‐sphere and outer‐sphere association with plasmonic nanoparticles. Their electrostatically stabilized ion pairs with citrate–gold nanoparticles have been studied in an aqueous solution, from the pronounced changes in the plasmonic band at 540 nm. Complex A, lacking any coordinating site, can only generate outer‐sphere complexes with citrate–gold nanoparticles, but they are stable enough to give a strong SERS response, even at 10−8 M. At 10−6 M, agglomeration accompanies the decrease of the electrostatic repulsion, resulting in a sharp decay of the plasmon resonance band at 540 nm. This is followed by the rise of a plasmon coupling band above 700 nm. However, at 10−4 M, the excess of the complex in the adsorption layer produces a reverse effect, decreasing agglomeration. The observed Raman spectra are essentially similar for the several concentrations employed because the outer‐sphere interaction implies a SERS electromagnetic mechanism. In contrast, complex B exhibits several pyridine and pyrazine N‐atoms available to form inner‐sphere‐associated species. A selective enhancement of the SERS signals is observed at 10−8 M, clearly indicating a chemical mechanism, consistent with a bridging mode. At 10−6 M and above, the agglomeration leads to a plasmon coupling band at 800 nm, while the SERS response indicates a change in the binding modes dictated by the excess of the complexing molecules. [ABSTRACT FROM AUTHOR]

The necessity of the development of compounds with effectiveness in therapy against infective diseases has increased in the last 3 years in connection with the spread of COVID-19. The current study aimed to summarize the pharmacological activities of metal-based organic compounds against different viral diseases, including COVID-19. A systematic literature review was carried out by using data sources in Medline, Pub Med, SCOPUS, and Science Direct. The used methods were collecting data, summarizing, and analyzing information. Antiviral properties exert metal complexes with ligands, such as: hydrazones; thiosemi-carbazones: Pt(II), Pd(II); Ga(III); Pd(II); Co(III), Ni(II), Cu(II)); fluoroquinolones, quinoline: Pd(II); phenylquinoline, phenylpyridine; tetrahydropyrimidines: Ag(I); phenanthroline: Cu(II); Valacyclovir: Cu(II)). Complexes of Zn(II). Co(II), Cu(II), Ni(II), Mg(II), Mn(II), and Zn(II) exert antiviral effects against the DNA Herpes simplex viruses HSV-1, HSV-2. Co(II), effective towards the HIV are complexes of the following metals: Au(II), Co(II), Cu(II), Fe(III), La(III), Mg(II). Ni(II), Pd(II), Pt(II), Ru(II). Against the HIV have been described to be active complexes of the following metals: Au(II), Co(II), Cu(II), Fe(III), La(III), Mg(II), Ni(II), Pd(II), Pt(II), and Ru(II). In connection with the continued spread of the severe acute respiratory syndrome – Coronavirus 2 (SARS-CoV-2), today's very actual strategy is the development of effective COVID therapeutics. The perspective trend in the creation and investigation of potential agents for the effective application towards SARS-CoV-2, are Auranofin and Cu(II), Ni(II), Mn(II), and Zn(II) complexes of Coumarin. [ABSTRACT FROM AUTHOR]

Ductile fracture in metals is a complex phenomenon caused by the nucleation, growth, and aggregation of micron-sized voids. Existing theoretical models for fracture use experimentally determined Fracture Limit Curves (FLCs) in two-dimensional strain space, which require multiple curves to account for anisotropic effects. This paper proposes a practical closed-form analytical function for a Fracture Limit Surface (FLS) which has a conical shape in the Elastic Distortional Deformation Space (EDDS). The EDDS is a space generated by the components of the elastic distortional metric of the microstructural vectors that characterize elastic distortional deformations and the orientations of anisotropy. The FLS is determined by simulating only four experimental FLCs using a large deformation Eulerian formulation of the microstructural vectors and it depends only on the current state of elastic distortional deformation. It is shown that the failure limit points predicted by the FLS agreed very well with those predicted using a popular evolution equation for damage-based ductile fracture. Path-independence of the FLS is also examined using experimental data. In addition, the example of a B-pillar forming process is presented to show that the FLS can be applied to practical engineering problems with material points that experience general loading paths. • An analytical fracture limit surface (FLS) with experimental validation. • The FLS is based on an Eulerian formulation of microstructural vectors. • The FLS predictions show good agreement with those of a popular ductile fracture model. • A B-pillar forming simulation shows that the FLS can be applied to practical problems. [ABSTRACT FROM AUTHOR]

Three new trinuclear complexes containing either nickel(II), copper(II) or zinc(II), [Ni3L2(NO3)2(CH3OH)2]·2CH3OH (1), [Cu3Br2L2] (2), [Zn3L2(NCS)2(CH3OH)2]·0.5CH3OH·0.5H2O (3), and a new dioxidomolybdenum(VI) complex, [MoO2L] (4), have been prepared from the bis-Schiff base N,N'-bis(4-bromosalicylidene)-1,3-propanediamine (H2L) with various metal salts in methanol. The complexes were characterized by elemental analysis, IR and UV–Vis spectra. Molecular structures were confirmed by single crystal X-ray diffraction experiments. The Ni ions in 1 adopt an octahedral coordination environment, bridged by phenolate oxygen and nitrate ligands. The Cu ions in 2 are square pyramidal and square planar, and the Zn ions in 3 are square pyramidal and octahedral. The metal atoms in 2 and 3 are bridged by phenolate oxygen donors. The Mo ion in 4 is octahedral. The Schiff base ligand coordinates to the metal atoms through two phenolate O and two imino N donors. Biological assays revealed that the nickel and copper complexes have effective urease inhibition. [ABSTRACT FROM AUTHOR]

Ferromagnetic metallic cobalt and nickel nanoparticles were synthesized by intramolecular metal-hydrazine ligand oxidation reduction reaction in basic media and the solid state. Nickel nanoparticles Ni1 and Ni2 are obtained from two complexes, Ni(N2H4)2(C2O4) and Ni(N2H4)2(HCO2)2, respectively. X-ray powder diffraction (XRD) and energy-dispersive X-ray (EDX) data show pure fcc crystal structures of nanoparticles. Scanning electron microscopy (SEM) images revealed both Ni1 and Ni2 nanoparticles have agglomerated sphere morphologies. The crystallite size estimated by using the Scherer method for Ni1 and Ni2 were 18.7 and 6.2 nm. Vibrating sample magnetometer (VSM) data show the coercivity of metallic nickel samples Ni1 and Ni2 are 50 and 153 Oe, respectively. Both nanoparticles cause an increase in the temperature of water under applied alternative magnetic field and showed specific loss power (SLP) of 70 W/g and 104.8 W/g, respectively. The same method is used in preparation of cobalt nanoparticles from two complexes, Co(N2H4)2(C2O4) and Co(N2H4)2(HCO2)2. XRD analysis data show both nanoparticles have hcp crystal structure. SEM images show nanosheet structure with sheet thickness of 10 to 30 nm. Coercivity of Co1 and Co2 nanoparticles obtained by VSM and Hc are 182 and 171 Oe, respectively. In spite of high coercivity in both Co1 and Co2 nanoparticles, the magnetic hyperthermia heating effects are not observed in practice and specific loss power (SLP) is zero. [ABSTRACT FROM AUTHOR]

This document is a summary of a special issue in the International Journal of Molecular Sciences that focuses on the potential therapeutic uses of metals and metal-containing compounds/complexes. The studies included in the special issue cover a range of topics, including the effects of vanadium on the central nervous system, the therapeutic potential of vanadium compounds, the anticancer activities of platinum prodrugs, the biological activity of copper derivatives, the antimicrobial and antitumor properties of guanidine derivatives, the CT imaging properties of polyoxometalates, the antibacterial activity of zinc complexes, and the use of UV-C radiation for seed sterilization and biofortification. The findings from these studies provide valuable information for future research on new therapeutics and clinical applications. The document concludes by stating that the information provided in the special issue will be of interest to readers interested in metals, human health, and nutrition, as well as those interested in metal interactions and diseases such as cancer and neurodegenerative disorders. [Extracted from the article]

This study used micro-analyses, (FTIR, UV-Vis) spectra, magnetic, thermogravimetric, X-ray powder diffraction (XRD) patterns, and transmittance electron microscopy (TEM) techniques to characterize three synthesized theophylline (TPH) complexes with ruthenium(III), platinum(IV), and iridium(III) metal ions. The metal ions indicated above were found to align with the TPH drug chelate as a mono-dentate ligand via the deprotonated NH group at the nitrogen atom position N7, as verified by FTIR measurements. Additionally, the complexes conductivity and magnetic susceptibility were examined. The octahedral geometry for the synthesized complexes was proposed by the current data. Except for the iridium(III) complex, which has a non-electrolytic nature due to the presence of a chlorine atom inside the chelation sphere, the molar conductivity of the complexes in DMSO solution was electrolyte in nature. Theophylline complexes with a (metal: ligand) stoichiometry of 1:2 were produced. The TPH complexes have also been tested in vitro against G(+) bacteria (Bacillus subtilis and Staphylococcus Aureus) and G(-) bacteria (Pseudomonas aeruginosa and Escherichia coli) to evaluate their antibacterial efficacy. Human breast and liver cancer cell lines were used as a test for the TPH complexes in vitro anti-cancer properties. [ABSTRACT FROM AUTHOR]

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