Search Results (492)

The anticancer ruthenium complex indazolium trans-[tetrachlorobis(1H-indazole) ruthenate (III)—also known as KP1019—inhibits cancer cell proliferation in vitro, causes tumor regression in animal models, and showed no dose-limiting toxicity in a phase I clinical trial. Previous studies found that KP1019 damages DNA in both cancer cells and the budding yeast Saccharomyces cerevisiae. To identify other potential targets of KP1019 along with pathways that modulate the drug’s cellular effects, we screened the yeast gene deletion strain library by quantitative high-throughput cell array phenotyping (Q-HTCP). Fitness differences, as judged by growth curve analysis, identified genes for which loss of function (gene deletion) interacts with (enhances or suppresses) KP1019 effects. Drug-enhancing deletions were enriched for DNA repair functions, consistent with DNA damage being a primary target of KP1019 in yeast. pH homeostasis also modified the effects of KP1019. Drug-suppressing deletions prominently involved ribosomal proteins. A mechanistic link between ribosomal protein function and KP1019 toxicity was supported by dose-dependent accumulation of Rpl7a-GFP in the nucleolus, which is a hallmark of ribosomal biogenesis stress. Furthermore, KP1019 acted synergistically with the TOR pathway inhibitor everolimus to inhibit cell proliferation. The resulting model, wherein KP1019 perturbs ribosome assembly, can inform the design of future combination therapies. Full article

The technological promise of nonlinear optical (NLO) compounds has stimulated intense interest in optoelectronic devices, data storage, photonics, and anticancer therapy. Thiosemicarbazone ruthenium materials are of growing interest because of their tunable ligand framework and coordination sphere, allowing fine control over geometry, electronics, and functional properties. Here, we report an N-substituted salicylaldehyde thiosemicarbazone ligand and a series of octahedral Ru(III) complexes bearing triphenylphosphine or triphenylarsine and halide (Cl, Br) co-ligands. The complexes were characterized by elemental analysis, FT-IR, UV–Vis, EPR, mass spectrometry, and magnetic susceptibility measurements, which together confirm NS-chelation to a low-spin Ru(III) center in a distorted octahedral environment. Their photophysical and NLO responses were assessed by UV–Vis spectroscopy and powder second-harmonic generation measurements (Kurtz–Perry method), revealing promising NLO behavior. In parallel, antioxidant activity and in vitro anticancer effects against HeLa cells were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity assays. These results provide insight into ligand-controlled structure–activity relationships, in which the halide (Cl/Br) and ancillary triarylphosphine co-ligands regulate electronic interactions and lipophilicity and ultimately increase biological performance, underscoring the dual materials and medicinal potential of these Ru(III) complexes. Full article

A modular synthetic route has been developed to prepare a new series of cationic ruthenium(II) complexes with electron-withdrawing 1,2-diacylcyclopentadienyl ligands. The 2-acyl-6-hydroxyfulvenes were synthesized from cyclopentadienide and acyl chlorides and converted to Tl(I) cyclopentadienyl salts using Tl₂SO₄/KOH. Transmetalation with [Ru(η⁶-p-cymene)(μ-Cl)Cl]₂ followed by PF₆⁻ metathesis gives the complexes [Ru{η⁵-1,2-C₅H₃(CO–R)₂}(η⁶-p-cymene)][PF₆] (R = t-Bu, p-Tol, p-ClC₆H₄, p-IC₆H₄) in moderate to high yields. The new compounds were characterized by NMR and IR spectroscopy; mass spectrometry and elemental analysis were performed where applicable. X-ray analysis of one of the complexes confirms that electron-deficient Cp ligands retain η⁵-coordination and structural planarity within Ru(II)–arene sandwich architectures, highlighting their potential utility in electronically tunable organometallic frameworks. Full article

Noble metal-catalyzed C–H activation has transformed synthetic methodology by enabling direct modification of inert C–H bonds with high levels of efficiency, selectivity, and functional group tolerance. This mini-review provides a focused overview of the mechanistic foundations and emerging advances in C–H functionalization mediated by ruthenium, iridium, rhodium and palladium catalysts. Key activation modes including oxidative addition, concerted metalation deprotonation (CMD), and electrophilic pathways are discussed alongside the roles of high-valent intermediates and ligand control in determining reactivity and regioselectivity. Special emphasis is placed on recent electrochemical strategies, where anodic oxidation replaces traditional chemical oxidants, granting access to unique redox manifolds and expanding the scope of C–C, C–N, C–O, and C–X bond-forming reactions. Representative transformations highlight the versatility of noble metals in constructing heterocycles, enabling enantioselective processes, and facilitating late-stage functionalization of complex molecules. Current challenges and future perspectives are outlined, including the need for improved nondirected activation, deeper mechanistic insight, and enhanced scalability. Collectively, this review underscores the central role of noble metals in advancing sustainable and innovative C–H functionalization chemistry. Full article

Platinum group metals (PGMs)—comprising platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), and osmium (Os)—are indispensable strategic materials for key industries, including automotive manufacturing, petrochemical engineering, and the new energy sector. Given the uneven global distribution of primary PGM reserves and the widening supply–demand gap, recovering PGMs from secondary sources—primarily metallurgical by-products and spent catalysts—has become a strategic priority. synergistic smelting, leveraging “multi-feedstock complementarity” and “multi-technology coupling,” offers an efficient approach to overcoming challenges associated with secondary resources, such as low grades, complex matrices, and refractory separation. This paper systematically reviews the technological evolution of synergistic smelting for PGMs recovery, focusing on three aspects: the characteristics and processing bottlenecks of PGMs-bearing secondary resources, the development trajectory of traditional metallurgical technologies, and innovative breakthroughs in microwave-assisted synergistic smelting. A comparative analysis between traditional and microwave-based technologies is conducted across four dimensions: resource adaptability, technical performance, environmental sustainability, and industrial maturity. Finally, the core challenges currently confronting microwave-assisted synergistic smelting and future directions for industrial demonstration are elaborated on. This study serves as a comprehensive reference for the efficient and sustainable recovery of PGMs, with significant implications for the circular economy and strategic resource security. Full article

The use of metal-based species bearing existing pharmaceuticals as ligands—often resulting in enhanced bioactivity—represents an attractive strategy for the development of novel therapeutic formulations. In this context, five well-known non-steroidal anti-inflammatory drugs (NSAIDs) were employed to substitute both PPh₃ and hydride ligands in [Ru(H)₂(CO)(PPh₃)₃] (1), thereby selectively affording neutral κ²-(O,O)–chelate complexes in satisfactory yields via molecular hydrogen release. Among the obtained species, two complexes coordinating diclofenac (4) and aspirin (5) were further investigated by single-crystal X-ray diffraction (SCXRD). Preliminary biological studies were conducted on the ruthenium–salicylic acid species 2 and ibuprofen 6. The former showed promising antiproliferative activity against HeLa cancer cells, consistent with the well-established role of NSAID–ruthenium(II) complexes as a platform for the development of novel anticancer metallotherapeutics. Full article

Cancer ranks as a major cause of morbidity and mortality across the globe, notably in economically developed regions, and its incidence is predicted to rise in the coming decades. Metal-based compounds represent a particularly promising class of pharmaceuticals for the treatment of cancer. Following the success of platinum in cancer therapy, attention soon turned to other transition metals, particularly the platinum group metals such as ruthenium and palladium. Despite the high anticancer efficacy of many of its compounds, osmium remained one of the least investigated of these metals for a long time, partly due to concerns about its toxicity. However, there has been a recent resurgence in the preparation and evaluation of osmium complexes, which exhibit high structural variability and demonstrate promising anticancer activity. The present review aims to survey recent developments in this exciting field, focusing on osmium complexes of the non-arene type reported during the last decade. Full article

Skin cancer (SC) is the most prevalent malignancy worldwide, with subtypes varying in aggressiveness: basal cell carcinoma tends to be locally invasive, squamous cell carcinoma has a higher metastatic risk, and melanoma remains the deadliest form. Current treatments such as surgery, radiotherapy, and systemic chemotherapy are associated with aesthetic and functional morbidity, recurrence, and/or systemic toxicity. Although targeted therapies and immunotherapies offer clinical benefits, their high cost and limited accessibility underscore the need for innovative, affordable alternatives. Metal-based compounds (metallopharmaceuticals) are promising anticancer agents due to their ability to induce oxidative stress, modulate redox pathways, and interact with DNA. However, clinical translation has been limited by poor aqueous solubility, rapid degradation, and low skin permeability. This review discusses the most recent preclinical findings on gold, silver, platinum, palladium, ruthenium, vanadium, and copper complexes, mainly in topical and systemic treatments of SC. Advances in chemical and physical enhancers, such as hydrogels and microneedles, and in drug delivery systems, including bacterial nanocellulose membranes and nanoparticles, as well as liposomes and micelles, for enhancing skin permeation and protecting the integrity of metal complexes are also discussed. Additionally, we examine the contribution of photodynamic therapy to SC treatment and the use of mathematical and computational modeling to simulate skin drug transport, predict biodistribution, and support rational nanocarrier design. Altogether, these strategies aim to bridge the gap between physicochemical innovation and clinical applicability, paving the way for more selective, stable, and cost-effective SC treatments. Full article

In the quest for cheap and abundant feedstocks for sustainable hydrogen production, glycerol is emerging as a cost-effective, promising liquid organic hydrogen-rich carrier (LOHC) that can be catalytically activated to produce hydrogen alongside valuable organic products. Selective catalytic acceptorless dehydrogenation of glycerol to lactate and hydrogen gas was achieved with a maximum turnover number (TON_max) of ca. 1600, using a pincer-type ruthenium(II) complex bearing a bis(aminophosphine)pyridine PN³P ligand as a homogeneous catalyst under moderate reaction conditions (24 h, 140 °C) in the presence of KOH as base. NMR experiments and DFT calculations provided insights into key steps of the catalytic process and the energetics of the proposed reaction pathway. Full article

The development of efficient and recyclable catalysts is a central pursuit in modern chemistry. Homogeneous catalysts, while effective, often suffer from challenges in separation and recovery, driving the exploration of heterogeneous systems. In this context, this study introduces a novel composite photocatalyst, Ru(bpy)₂(bda)-Ru(bda)(cp)₂@DE (PS/Cat@DE), synthesized by attaching a catalyst (Cat) and a photosensitizer (PS) to diatomaceous earth (DE). The hypothesis that covalently binding the photosensitizer and photocatalyst to the surface of DE could enhance their reactivity and may protect them from degradation was supported by the enhanced photocatalytic performance observed in this study. The composite materials and single components were characterized using UV-Vis and FTIR spectroscopy, as well as SEM, and EDS microscopy. Photocatalytic experiments demonstrated the significantly higher activity of the PS/Cat@DE material compared to equivalent concentrations of the single photosensitizer or photocatalyst components, indicating the crucial role of DE in promoting oxygen evolution. Full article

Redox mediators are central to electrochemical biosensors, enabling electron transfer between deeply buried enzymatic cofactors and electrode surfaces when direct electron transfer is kinetically inaccessible. Among all design parameters, the reversibility of mediator redox cycling remains the most decisive yet under-examined factor governing biosensor stability, drift and long-term reproducibility. This review establishes reversibility as a unifying framework grounded in inorganic and organometallic redox chemistry, with particular emphasis on coordination environments, ligand-field effects and outer-sphere electron-transfer pathways. Recent advances (2010–2025) in ruthenium and osmium polypyridyl complexes, cobalt macrocycles, hexacyanoferrates and Prussian Blue analogues are examined alongside ferrocene derivatives and other organometallic mediators, which together define the upper limits of reversible behaviour. Organic mediator families, including quinones, phenazines, indophenols, aminophenols and viologens, are discussed as mechanistic contrasts that highlight the structural and thermodynamic constraints that limit long-term cycling in aqueous media. Mechanistic indicators of reversibility, including peak separation, current ratios and heterogeneous electron-transfer rate constants, are linked to mediator architecture, coordination chemistry and immobilisation environment. By integrating molecular electrochemistry with applied sensor engineering, this review provides a mechanistically grounded basis for selecting or designing redox mediators that sustain efficient electron transfer, minimal fouling and calibration stability across diverse sensing platforms. Full article

Our previous study demonstrated that thiophene-substituted synthetic curcumin analogs possessed better antibacterial activity and stability than natural curcumin, demethoxycurcumin, or bisdemethoxycurcumin in antibacterial photodynamic therapy (aPDT). In addition, the activity of the furan-substituted analogs was weaker than that of the thiophene-substituted compounds. As oxygen, sulfur, and selenium belong to the same group in the periodic table, the antibacterial and anticancer activities of these three different elemental analogs were compared and investigated. The thiophene-substituted analog (compound 3) exhibited the most potent antibacterial activity in aPDT experiments. However, the furan-substituted analog (compound 1) exhibited the most potent anticancer activity. These results indicate that the differences in atomic radii or energy levels in these compounds produce different cell-attack results on generated free radicals. Ruthenium(II) complexes have a good reputation for use in PDT for cancer treatment. Our results show that complexation of ruthenium(II) with thiophene-substituted curcumin analogs does not enhance their antibacterial or anticancer activity. Full article

The photochemistry of transition metal complexes has been crucial for the development of many fundamental topics, as well as to pave the way for several important applications. However, in most cases, photoactive transition metal complexes involved precious metals, with luminescent ruthenium polypyridine complexes playing the dominant role. Developing photoactive species based on earth-abundant metals is highly important for fundamental and applicative reasons. Iron is one of the most abundant metals on Earth’s crust, so luminescent iron complexes are highly desired. The recent search for iron complexes with long-lived and luminescent excited states is here presented, including Fe(II) species with metal-to-ligand charge transfer (MLCT) excited states and Fe(III) species with luminescent ligand-to-metal charge transfer (LMCT) states. The excited-state equilibration approach to prolong the luminescence lifetimes of Fe(III) compounds in multichromophoric species is also discussed. This latter approach can increase the possibility of luminescent iron complexes being involved in bimolecular processes as well as in photoinduced electron and energy transfer at interfaces, which is relevant for many applications. Full article

Photo-induced bond linkage isomerization (BLI) in metal–nitrosyl compounds provides a molecular mechanism for controlling light-induced changes in refractive index and phase modulation. In this study, the ground and metastable states of a series of Ru–NO complexes and their Au₂₀, Ag₂₀, and mixed Au₁₀Ag₁₀ nanocluster hybrids were investigated by DFT and TDDFT calculations. The photochemical rearrangement between the linear, side-on, and O-bound forms of Ru–NO was examined together with their electronic transitions, oscillator strengths, and characteristic vibrational shifts. From these data, parameters describing radiative efficiency, non-radiative coupling, and metastable-state stability were derived to identify compounds with favorable properties for holography and photonic applications. Particular attention was given to the [(Salen)Ru(NO)(HS)@Au₂₀] complex, which shows a strong red-to-NIR response and balanced stability among its linkage isomers. Frequency-dependent polarizabilities α(ω) were calculated for its ground and metastable states and compared with those of the classical holographic material [Fe(CN)₅NO]²⁻ (nitroprusside). The refractive-index changes derived from α(ω) reveal that the Au₂₀–salen hybrid produces a much larger and more strongly wavelength-dependent Δn(λ) than nitroprusside. At 635 nm, the modulation reaches approximately 0.06 for the hybrid, compared with 0.02 for nitroprusside. This enhancement reflects the cooperative effect of the Ru–NO chromophore and the Au₂₀ nanocluster, which amplifies both polarizability and optical dispersion. The results demonstrate that coupling molecular photo-linkage isomerism with nanoplasmonic environments can significantly improve the performance of molecular systems for holography and optical-phase applications. Full article

This study describes a series of water-soluble half-sandwich ruthenium(II), rhodium(III), and iridium(III) complexes with α-diimine ligands containing substituted aromatic groups. These ligands were derived from glyoxal and 2-aminophenol (a), 4-methyl-2-aminophenol (b), 4-aminophenol (c), phenyl hydrazine (d), and 1-aminonaphthalene (e). The ruthenium(II) (1b–1e), rhodium(III) (2a–2c, 2e), and iridium(III) complexes (3a–3e) were obtained by reacting the ligands (a–e) with the corresponding dimeric precursor [(η⁶-p-cym)RuCl₂]₂ (p-cym = p-cymene) or [(η⁵-Cp*)MCl₂]₂ (Cp* = pentamethylcyclopentadienyl, M = Rh, Ir) in air and under nonanhydro conditions. The air-stable and water-soluble ruthenium(II), rhodium(III), and iridium(III) complexes were characterized via nuclear magnetic resonance spectroscopy and electrospray ionization–mass spectrometry. The structures of complexes [(η⁶-p-cym)Ru(d)Cl]Cl, 1d; [(η⁵-Cp*)Ir(a)Cl]Cl, 3a; and [(η⁵-Cp*)Ir(c)Cl]Cl, 3c were determined via single-crystal X-ray diffraction. Additionally, the complexes exhibited catalytic activity as precatalysts in formic acid decomposition. Complex [(η⁵-Cp*)Ir(d)Cl]Cl, 3d achieved turnover number (TON) and turnover frequency (TOF) values of up to 2150 and 3861 h⁻¹, respectively, at short reaction times. In the hydrogenation of carbon dioxide, [(η⁶-p-cym)Ru(e)Cl]Cl, 1e attained TON and TOF values of up to 1385 and 69.25 h⁻¹, respectively. Full article