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Recently, scientists have been developing sustainable processes, and in this context, mechanochemistry is commonly associated with green chemistry for its ability to reduce waste generation from chemical reactions. The well-known acetate complex, diacetate bis(triphenylphosphine) ruthenium(II) [Ru(OAc)2(PPh3)2], is a versatile precursor for preparing active complexes for several catalytic reactions. This report presents an efficient and straightforward manual grinding protocol for the sustainable synthesis of ruthenium carboxylate complexes starting from the commercially available [RuCl2(PPh3)3] and metal carboxylates. This work represents a novel and preliminary investigation into carboxylate precursors' alternative solventless synthesis route based on manual grinding. To our knowledge, this is the first time [Ru(OAc)2(PPh3)2] has been prepared via a mechanochemical procedure. The synthesis method has also been investigated for other alkali metal carboxylates and yields ranging from 30 to 80% were obtained. A comparison of sustainability and environmental impact between conventional solution synthesis and the grinding route has been carried out using the E-factor and Mass Productivity. While for the acetate complex E-factor and MP were only slightly better compared with the solvent method (3 vs. 4 for E-factor and ~6 vs. 5 for MP), for benzoate higher results were found (1 vs. ~4 for E-factor and 10 vs. 5 for MP). [ABSTRACT FROM AUTHOR]

Ruthenium(II) complexes (Ru1–Ru3) with the general formula [Ru(O-O)(PPh3)2(bipy)]PF6, bearing two triphenylphosphine (PPh3), bipyridine (bipy) and a series of natural and synthetic β-diketones (O,O) ligands were synthesized and characterized using various analytical techniques. The interaction between the complexes and calf thymus DNA (CT-DNA) was investigated and demonstrated a weak interaction. The cytotoxicity of the complexes was investigated against breast cancer cells (MDA-MB-231 and MCF-7), lung cancer cells (A549), cisplatin-resistant ovarian cancer cells (A2780cis), as well as non-tumour lung (MRC-5) and non-tumour breast (MCF-10A) cell lines. All complexes exhibited cytotoxic activity against all the cell lines studied, with half maximal inhibitory concentration (IC50) values ranging from 0.39 to 13 µM. Notably, the three complexes demonstrated selectivity against the A2780cis cell line, with IC50 ranging from 0.39 to 0.82 µM. Among them, Ru2 exhibited the highest cytotoxicity, with an IC50 value of 0.39 µM. Consequently, this new class of complexes shows good selectivity towards cisplatin-resistant ovarian cancer cells and it is promising for further investigation as anti-cancer agents.

Ruthenium(II/III)-based compounds have gained significant interest due to the biocompatibility of ruthenium, its similarity to iron, and the possibility for structural diversification through the choice of ligands. In this contribution, two novel ligands, (2-(2-methoxyethoxy)ethyl nicotinate hydrochloride) and (2-[2-(2-methoxyethoxy)ethoxy]ethyl nicotinate hydrochloride) (pyCOO(CH2CH2O)nCH3: L2, n = 2; L3, n = 3), were synthesized and characterized via ESI-HRMS, as well as IR and NMR spectroscopies. Their structures were optimized at the B3LYP/6-311++G(d,p) level of theory, and NMR chemical shifts were predicted, along with the most important intramolecular interactions. Additionally, two neutral complexes of the general formula [RuCl2(η6-p-cym) (L-κN)] (L = L2: 2; L3: 3) and two cationic complexes of the general formula [RuCl(η6-p-cym)(L-κN)2][PF6] (L = L1: 4; L2: 5) were obtained and characterized. The optimization of the structures was performed at the B3LYP/6-31+G(d,p)(H,C,N,O,Cl)/LanL2DZ(Ru) level of theory. Structural features were described, and intramolecular stabilization interactions were outlined. [ABSTRACT FROM AUTHOR]

Poor responses to medical care and the failure of pharmacological treatment for many high-frequency diseases, such as cancer and viral infections, have been widely documented. In this context, numerous metal-based substances, including cisplatin, auranofin, various gold metallodrugs, and ruthenium complexes, are under study as possible anticancer and antiviral agents. The two Ru(III) and Ru(II) complexes, namely, BOLD-100 and RAPTA-C, are presently being studied in a clinical trial and preclinical studies evaluation, respectively, as anticancer agents. Interestingly, BOLD-100 has also recently demonstrated antiviral activity against SARS-CoV-2, which is the virus responsible for the COVID-19 pandemic. Over the last years, much effort has been dedicated to discovering new dual anticancer–antiviral agents. Ru-based complexes could be very suitable in this respect. Thus, this review focuses on the most recent studies regarding newly synthesized Ru(II) complexes for use as anticancer and/or antiviral agents. [ABSTRACT FROM AUTHOR]

Ruthenium complexes have gained significant attention due to the ruthenium similarity to iron, lower toxicity, and higher anticancer effectiveness than other compounds. In this contribution, five new isonicotinate-polyethylene glycol ester ligands were synthesised and characterised by NMR and IR spectroscopies. The corresponding Ru(II) complexes were also obtained, and their structure was investigated by traditional methods. The optimisation of structures was performed at B3LYP/6-31+G(d,p) level of theory for H, C, N and O atoms and B3LYP/LanL2DZ for Ru. The intramolecular stabilisation interactions were assessed through the natural bond orbital approach. The NMR chemical shifts were predicted by the gauge independent atomic orbital method and compared to the experimental values. High correlation coefficients and low mean absolute errors between these data sets proved that the predicted structures described well the experimental ones. The theoretical and experimental IR spectra were also compared, and differences in the most notable bands were described. One of the ligands (L5) and complexes (5) showed fluorescent properties due to methylisatoic moiety. The electronic spectra of this compound were modelled by the time dependent-density functional theory method. The difference of 11 nm between the experimental and the theoretical wavelength was explained by the interactions between the solvent and the solute. Further biological and theoretical studies are advised for this series of compounds. [ABSTRACT FROM AUTHOR]

A new series of pincer type ruthenium(II) Schiff base complexes namely [Ru(CO)(PPh3)2(L1‒6)] (1–6) (where, L1‒6 ​= ​NOO ‒ donors of tri-dentate ligands) have been synthesized from ruthenium precursor such as [RuHCl(CO)(PPh3)3] containing tri-dentate Schiff bases ligands (H2L1‒H2L6). These ruthenium complexes were analyzed by elemental analysis and diverse characterizations such as FT‒IR, UV–Vis and NMR (1H and 31P) spectroscopy studies. The crystal structure of one of the complexes 5 ([Ru(CO)(PPh3)2L5]) was determined by single crystal X‒ray crystallography that revealed pincer type of coordination mode of complexes. Furthermore, complexes 1–6 have been utilized for transfer hydrogenation of aromatic ketones to secondary alcohols in the presence of i‒PrOH/KOH. The catalytic efficiency of complexes showed an efficient for transfer hydrogenation of ketones with alcohol as moderate to high conversions.

Light‐activated treatments, such as photodynamic therapy (PDT), provide temporal and spatial control over a specific cytotoxic response by exploiting toxicity differences between irradiated and dark conditions. In this work, a novel strategy for developing near infrared (NIR)‐activatable Ru(II) polypyridyl‐based photosensitizers (PSs) was successfully developed through the incorporation of symmetric heptamethine cyanine dyes in the metal complex via a phenanthrimidazole ligand. Owing to their strong absorption in the NIR region, the PSs could be efficiently photoactivated with highly penetrating NIR light (770 nm), leading to high photocytotoxicities towards several cancer cell lines under both normoxic and hypoxic conditions. Notably, our lead PS (Ru‐Cyn‐1), which accumulated in the mitochondria, exhibited a good photocytotoxic activity under challenging low‐oxygen concentration (2 % O2) upon NIR light irradiation conditions (770 nm), owing to a combination of type I and II PDT mechanisms. The fact that the PS Protoporphyrin IX (PpIX), the metabolite of the clinically approved 5‐ALA PS, was found inactive under the same challenging conditions positions Ru‐Cyn‐1 complex as a promising PDT agent for the treatment of deep‐seated hypoxic tumours. [ABSTRACT FROM AUTHOR]

In this work, we report the synthesis and physicochemical characterization of new chloro and aqua mononuclear Ru (II) complexes of formula [Ru(LLL)(dpp)Cl]PF6 and [Ru(LLL)(dpp)OH2](PF6)2 (LLL=tpy =2,2' : 6',2"‐terpyridine; tptz=2,4,6‐tris(2‐pyridyl)‐1,3,5‐triazine and dpp=2,3‐bis(2‐pyridil)pyrazine). For the complex [Ru(tptz)(dpp)Cl]PF6, the complete structure was determined by X‐ray diffraction. Catalytic studies of aqua‐complexes revealed that they are active for the water oxidation reaction at pH 1 using cerium ammonium nitrate (CAN) as a sacrificial oxidant. Also, we were able to establish the reaction mechanism and rate constants of each stage of the catalytic cycle, turnover frequencies (TOFs), and turnover numberes (TONs). The experimental TON values for the aqua complexes were very close to the theoretical value of 7.5, indicating a high degree of recovery. DFT and TD‐DFT calculations of electronic states for all complexes were consistent with experimental results and allowed the complete assignment of their UV‐Visible bands and redox states. [ABSTRACT FROM AUTHOR]

The title complex cis-[Ru(dppm)2(bta)]PF6, dppm = 1,1-bis(diphenylphosphino)methane; bta– = 4,4,4-trifluoro-1-phenyl-1,3-butanedionate, was prepared from the cis-[RuCl2(dppm)2] precursor in mild conditions. Elemental analysis, spectroscopy (FTIR, 1H, 31P{1H} and 19F{1H} NMR) as well as single-crystal X-ray diffraction were used to characterize the new complex. Electronic structure of the complex was described utilizing TD-DFT analysis. All data indicate a good degree of purity, a cis arrangement for the diphosphines and a distorted geometry for the ruthenium center. [ABSTRACT FROM AUTHOR]

Herein, two novel ruthenium(II) complexes coupled by erianin via a flexible carbon chain, [Ru(phen)2(L1-(CH2)4-erianin)](ClO4)2 (L1 = 2-(2-(tri-fluoromethyphenyl))-imidazo [4,5f][1–10]phenanthroline (1) and [Ru(phen)2(L2-(CH2)4-eria)](ClO4)2 (L2 = 2-(4-(tri-fluoromethyphenyl))-imidazo [4,5f][1,10]phenanthroline (2), have been synthesized and investigated as a potential G-quadruplex(G4) DNA stabilizer. Both complexes, especially 2, can bind to c-myc G4 DNA with high affinity by electronic spectra, and the binding constant calculated for 1 and 2 is about 15.1 and 2.05 × 107 M−1, respectively. This was further confirmed by the increase in fluorescence intensity for both complexes. Moreover, the positive band at 265 nm in the CD spectra of c-myc G4 DNA decreased treated with 2, indicating that 2 may bind to c-myc G4 DNA through extern groove binding mode. Furthermore, fluorescence resonance energy transfer (FRET) assay indicated that the melting point of c-myc G4 DNA treated with 1 and 2 increased 15.5 and 16.5 °C, respectively. Finally, molecular docking showed that 1 can bind to c-myc G4 DNA in the extern groove formed by base pairs G7–G9 and G22–A24, and 2 inserts into the small groove of c-myc G4 DNA formed by base pairs T19–A24. In summary, these ruthenium(II) complexes, especially 2, can be developed as potential c-myc G4 DNA stabilizers and will be exploited as potential anticancer agents in the future. [ABSTRACT FROM AUTHOR]

New coumarin ruthenium(II) compounds QY1 – QY4 induced cisplatin-resistant A549/DDP cell apoptosis via mitochondrial dysfunction. [Display omitted] • Four new Ru(II) complexes bearing coumarin derivatives as ligands were prepared. • The Ru(II) complexes exhibited high anticancer activity against lung A549/DDP cancer cells. • The Ru(II) complexes showed low toxicity against embryonic kidney HEK293 normal cells. • The anticancer mechanism involved A549/DDP apoptosis via mitochondrial dysfunction. Toward the development of effective metal-based coordination drugs for the treatment of cisplatin-resistant cancers, we report four new ruthenium(II) coordination compounds, namely, [RuCl 2 (yc1) 2 (DMSO) 2 ] (QY1), [RuCl 2 (yc2) 2 (DMSO) 2 ] (QY2), [RuCl 2 (yc3) 2 (DMSO) 2 ] (QY3), and [RuCl 2 (yc4) 2 (DMSO) 2 ]·1.25H 2 O (QY4), which contain 3-pyridin-2-yl-chromen-2-one (yc1), 8-methyl-3-pyridin-2-yl-chromen-2-one (yc2), 7-methoxy-3-pyridin-2-yl-chromen-2-one (yc3), and 2-pyridin-2-yl-benzo[f]chromen-3-one (yc4) ligands, respectively. Complex QY4 possessing a more extended planar yc4 ligand showed the highest cytotoxicity against cisplatin-resistant A549/DDP lung cancer cells (R9LC), yielding a remarkably low micromolar IC 50 value of 5.02 ± 0.14 μM and low toxicity against embryonic kidney HEK293 (e293) normal cells under equal conditions (IC 50 = 88.04 ± 1.03 μM). Notably, QY4 exhibited higher cytotoxicity than QY1 – QY3 , yc1–yc4, and cisplatin. QY4 and QY1 , especially QY4 , induced R9LC apoptosis via mitochondrial dysfunction, which involved mitochondrial membrane potential (MP) damage, ROS/Ca2+ activation, and apoptosis protein up-regulation. Thus, these coumarin ruthenium(II) coordination compounds are promising mitochondria-targeting anticancer agents. [ABSTRACT FROM AUTHOR]

So far, the polyphenolic components of turmeric have shown a significant pharmacological preventative activity for a wide spectrum of diseases, including oncological disorders. This type of natural product could be of great interest for the inhibition of cancer cell proliferation, displaying less side effects in comparison to classical chemotherapeutics. The poor bioavailability and quick metabolism of such natural compounds require new investigative methods to improve their stability in the organisms. A synthetic approach to increase the efficiency of curcuminoids is to coordinate them to metals through the beta-dicarbonyl moiety. We report the synthesis and the biological attempts on human ovarian carcinoma A2780 of ruthenium(II) complexes 1–4, containing curcuminoid ligands. The cytotoxicity of complexes 1–4 proves their antiproliferative capability, and a correlation between the IC50 values and NF-κB transcription factor, FGF-2, and MMP-9 levels was figured out through the principal component analysis (PCA). [ABSTRACT FROM AUTHOR]

The development of heteronuclear metal complexes as potent anticancer agents has received increasing attention in recent years. In this study, two new heteronuclear Ru(Ⅱ)-Re(Ⅰ) metal complexes, [Ru(bpy)2LRe(CO)3(DIP)](PF6)3 and [Ru(phen)2LRe(CO)3(DIP)](PF6)3 [RuRe-1 and RuRe-2, L = 2-(4-pyridinyl)imidazolio[4,5-f][1,10]phenanthroline, bpy = 2,2′-bipyridine, DIP = 4,7-diphenyl-1,10-phenanthroline, phen = 1,10-phenanthroline], were synthesized and characterized. Cytotoxicity assay shows that RuRe-1 and RuRe-2 exhibit higher anticancer activity than cisplatin, and exist certain selectivity toward human cancer cells over normal cells. The anticancer mechanistic studies reveal that RuRe-1 and RuRe-2 can induce apoptosis through the regulation of cell cycle, depolarization of mitochondrial membrane potential (MMP), elevation of intracellular reactive oxygen species (ROS), and caspase cascade. Moreover, RuRe-1 and RuRe-2 can effectively inhibit cell migration and colony formation. Taken together, heteronuclear Ru(Ⅱ)-Re(Ⅰ) metal complexes possess the prospect of developing new anticancer agents with high efficacy.

Six artesunate (ART) conjugated ruthenium(II) complexes (Ru(II)-ART conjugates) with the formula [Ru(N^N)2bpy(4-CH3-4′-CH2OART)](PF6)2 (Ru-ART-1-3) and [Ru(N^N)2bpy(4-CH2OART-4′-CH2OART)](PF6)2 (Ru-ART-4–6) (N^N = 2,2′-bipyridine (bpy, in Ru-ART-1 and Ru-ART-4), 1,10-phenanthroline (phen, in Ru-ART-2 and Ru-ART-5) and 4,7-diphenyl-1,10-phenanthroline (DIP, in Ru-ART-3 and Ru-ART-6)), were synthesized and characterized. Among them, Ru-ART-1-3 and Ru-ART-4-6 carry one and two ART moieties, respectively. Ru-ART-3 and Ru-ART-6 exhibit better cytotoxicity among six Ru(II)-ART conjugates. These two complexes can be effectively taken up by human cervical carcinoma (HeLa) cells. In addition, they selectively kill cancer cell lines while mildly affect normal cells. Mechanism studies have shown that HeLa cells treated with Ru-ART-3 and Ru-ART-6 show typical apoptotic characteristics (morphology changes, mitochondrial dysfunction, caspase cascade, etc.). On the other hand, the up regulation of Beclin-1 and conversion of LC3-I to LC3-II note the appearance of autophagy. As a result, Ru-ART-3 and Ru-ART-6 induce autophagy-dependent cell apoptosis via mitochondrial dysfunction and reactive oxygen species (ROS) accumulation. [ABSTRACT FROM AUTHOR]

Pincer type coumarin based N -substituted semicarbazone ligands HL 1 – 4 and their corresponding ruthenium(II) complexes (1–4) were synthesized, analyzed and confirmed by various spectro analytical techniques. The molecular structure of the ligand HL 3 and complex 3 was confirmed by single crystal X-ray diffraction analysis. The stoichiometry of complexes 1, 2 and 4 was confirmed by high resolution mass spectroscopy (HRMS). The binding affinity of the compounds with CT-DNA (Calf Thymus DNA) and BSA (Bovine Serum Albumin) was established by absorption and emission titration methods. The results of In vitro cytotoxicity showed the significant cytotoxic potential of the complexes against MDA-MB-231 cells (TNBC- Triple-negative breast cancer). Among the complexes, 1 and 4 have shown appreciable results. Further, antimigratory activity against the MDA-MB-231 cells was studied for the complexes 1 and 4. The percentage cell cycle arrest, apoptosis and necrosis were explored by flow cytometry. The in vivo anti-tumor activity of the complexes 1 and 4 using C. elegans as model organism was established by using the tumoral C. elegans strain JK1466 (gld-1 (q485)), which bears a mutation in the gld- 1 tumor suppressor gene. We have determined the effect of our complexes on tumor gonad reduction and found to be non toxic to the JK1466 worms and they have prolonged their mean lifespan with potential antioxidant ability by overcoming stress responses. Overall, our study reported herein demonstrated that the complexes 1 and 4 could be established as potential metallo-drugs substantiating further exploration. Four ruthenium(II) complexes have been synthesized and characterized by various spectro analytical techniques. X-ray crystallographic study confirmed the molecular structure of the ligand HL 3 and complex 3. The CT-DNA and BSA protein interaction of these complexes were studied by absorption and emission titrations. The cytotoxic activity was evaluated against MDA-MB-231 (human breast cancer cells). An in vivo investigation of the antitumor activity of complexes 1 and 4 in C. elegans showed the non-toxic nature of the complexes without any adverse effects on the growth and reproduction of the JK1466 worms. Ruthenium(II) complexes; C. elegans; anti-metastasis; antioxidant; Lifespan expansion. Effect of ruthenium(II) complexes on MDA-MB-231 cells and lifespan/tumor growth in gld-1mutant , Daf-16 TF and stress productive genes: A perspective study [Display omitted] • Four Ru(II) complexes have been synthesized and characterized. • X-ray crystallographic study confirmed the ONO pincer type coordination of the ligand HL3 in complex 3 • The interaction of the complexes with CT-DNA and BSA was explored by absorption and emission spectroscopic techniques. • The cytotoxicity was evaluated against MDA-MB-231 (human breast cancer cells). • The in vivo cytotoxicity studies of complexes 1 and 4 in c.elegans proved their non toxic nature to JK1466 worms [ABSTRACT FROM AUTHOR]

• Aminoquinoline-based transition metal complexes containing two PGMs (Ir(III) and Ru(II)) were prepared. • Evaluated as potential photosensitisers for PDT. • In vitro cytotoxicity screening against a melanoma cell line (501mel) revealed increased activity upon light irradiation. • Quinolyl-substituted complexes have superior activity compared to pyridyl-substituted ones. Cancer is a devastating noncommunicable disease that remains one of the most pressing health challenges of the twenty-first century. Chemotherapy stands as one of the most common and effective cancer treatment methods. However, severe side effects and acquired drug resistance in many cancers have significantly diminished the efficacy of current chemotherapeutic agents. The urgent demand for novel treatment modalities has led to the development of photodynamic therapy (PDT) for the treatment of various cancer types. In this work, the synthesis of aminoquinoline-based transition metal complexes containing two PGMs (Ir(III) and Ru(II)) as potential photosensitisers is described. Mononuclear N,N -chelated Ru(II) and Ir(III) transition metal complexes were synthesized by reacting 4-aminoquinoline Schiff base ligands, which contain either a pyridyl or a quinolyl entity. The photostable Ru(II) and Ir(III) polypyridyl complexes were investigated for their potential use as PDT agents. In vitro cytotoxicity screenings conducted against a melanoma cell line (501mel) both in the absence and presence of light confirmed that all complexes demonstrated increased biological activity when exposed to visible light at 455 nm. Overall, the Ru(II) complexes are superior phototoxic agents in comparison with their Ir(III) congenors. [Display omitted] [ABSTRACT FROM AUTHOR]

Design, synthesis, characterization, and investigation of photovoltaic properties of 4,5-diazafluorene derived diimine ligands (C2, C3) and their ruthenium(II) complexes are reported. FT-IR, 1H NMR, 13C NMR, and mass spectroscopic methods were used to elucidate the structures of these compounds. The effect of the number and nature of anchoring groups attached to these ligands and complexes as sensitizers were evaluated for optical properties and photovoltaic performance in dye-sensitized solar cells (DSSCs). The sensitizers bearing catechol show higher power conversion efficiency (PCE) than the dyes with boronic acid due to better binding of the catechol anchoring group on the TiO2 surface. Among these sensitizers, DSSC based on [Ru(C2)2(NCS)2](PF6)2 having two catechol anchoring groups gives the best PCE of 2.83%, with Jsc = 6.40 mA cm−2, Voc = 0.632 V and FF = 0.70 in the presence of chenodeoxycholic acid (CDCA) as the coadsorbent, which is attributed to broader spectral response and efficient electron injection. These results suggest that dyes bearing two catechol anchoring groups are promising for efficient DSSCs. [ABSTRACT FROM AUTHOR]

New V(IV), Mo(VI), and Ru(II) complexes containing the ligand 2,4‐dihydroxyacetophenone‐S‐methyl dithiocarbazate (H2dhasm); [VO(dhasm)(bpy)] (1) (bpy = 2,2′‐bipyridine), [VO(dhasm)(phen)] (2) (phen = 1,10‐phenanthroline), [MoO2(dhasm)(imz)] (3) (imz = imidazole), [MoO2(dhasm)(DMSO)] (4) (DMSO = dimethylsulfoxide), and [Ru(CO)(PPh3)2(dhasm)] (5) have been synthesized. The ligand and its complexes were structurally characterized by elemental analyses, IR, 1H NMR, EPR, ultraviolet (UV)–visible spectroscopies, magnetic susceptibility, and cyclic voltammetry measurements. Single crystal X‐ray crystallography was used to establish the structure detail of (3) and (4) complexes confirming that the ligand coordinate to the metal ion in a bi‐negative tridentate fashion (dhasm2−, ONS‐donor) in a distorted octahedral geometry. The interaction with calf thymus DNA (CT DNA) of all compounds was studied by UV–visible and fluorescence spectroscopies. Both studies confirmed that these compounds bind to CT DNA through intercalation mode. The DNA cleavage activity of the complexes was also studied on plasmid DNA using gel agarose electrophoresis, and the results revealed that only complexes (2) and (5) have superior cleavage activity in the presence of H2O2. The cytotoxic activity (in vitro) of the complexes on three human cancer cell lines; human liver hepatocellular carcinoma (HepG2), breast adenocarcinoma (MCF7), and epitheliod carcinoma (Hela); and a normal human lung fibroblast (WI‐38) was studied using MTT assay. The complexes exhibited a strong cytotoxicity effect compared with their parent ligand. The ruthenium(II) complex (5) showed the most potent growth inhibition of cancer cells. Also, the mechanism of the apoptotic death in HepG2 cells was studied by observing an increased gene expression of caspase‐3, BAX, P53 and decreased Bcl2 gene expression. The complexes were also screened for their antibacterial activity against gram‐positive and gram‐negative bacteria and showed significant activity against both microorganisms. [ABSTRACT FROM AUTHOR]

In this study, we newly designed and synthesized a small library of ten structurally related C,N‐cyclometalated ruthenium(II) complexes containing various pyridine‐functionalized NHC ligand and chelating bipyridyl ligands (e.g. 2,2′‐bipyridine, 5,5′‐dimethyl‐2,2′‐bipyridine, and 1,10‐phenanthroline (phen)). The complexes were well characterized by NMR, electrospray ionization‐mass spectrometry, and single‐crystal X‐ray structure analyses. Among the new ruthenium(II) derivatives, we identified that the complex Ru8 bearing bulky moieties (i.e. phen and pentamethyl benzene) had the most potent cytotoxicity against all tested cancer cell lines, generating dose‐ and cell line‐dependent IC50 values at the range of 3.3–15.0 μm. More significantly, Ru8 not only efficiently inhibited the metastasis process against invasion and migration of tumor cells but also exhibited potent antivascular effects by suppressing HUVEC cells migration and tube formation in vitro and blocking vessel generation in vivo (chicken chorioallantoic membrane model). In a metastatic A2780 tumor xenograft‐bearing mouse model, administration of Ru8 outperformed antimetastatic agent NAMI‐A and clinically approved cisplatin in terms of antitumor efficacy and inhibition of metastases to other organs. Overall, these data provided compelling evidence that the new cyclometalated ruthenium complex Ru8 is an attractive agent because of synergistically suppressing bulky tumors and metastasized tumor nudes. Therefore, the complex Ru8 deserves further investigations. [ABSTRACT FROM AUTHOR]

Due to their optical and electrochemical properties, ruthenium(II) polypyridyl complexes have been used in a wide array of applications. Since the discovery of the light-switch ON effect of [Ru(bpy)2dppz]2+ when interacting with DNA, the design of new Ru(II) complexes as light-up probes for specific regions of DNA has been intensively explored. Amongst them, G-quadruplexes (G4s) are of particular interest. These structures formed by guanine-rich parts of DNA and RNA may be associated with a wide range of biological events. However, locating them and understanding their implications in biological pathways has proven challenging. Elegant approaches to tackle this challenge relies on the use of photoprobes capable of marking, reversibly or irreversibly, these G4s. Indeed, Ru(II) complexes containing ancillary π-deficient TAP ligands can create a covalently linked adduct with G4s after a photoinduced electron transfer from a guanine residue to the excited complex. Through careful design of the ligands, high selectivity of interaction with G4 structures can be achieved. This allows the creation of specific Ru(II) light-up probes and photoreactive agents for G4 labelling, which is at the core of this review composed of an introduction dedicated to a brief description of G-quadruplex structures and two main sections. The first one will provide a general picture of ligands and metal complexes interacting with G4s. The second one will focus on an exhaustive and comprehensive overview of the interactions and (photo)reactions of Ru(II) complexes with G4s.

The coordination of photosensitizing dyes to zinc oxide nanoparticles (ZnO NPs) has attracted extensive attention as promising candidates for applications in solar cells. Here, we report the synthesis of ZnO NPs functionalized with geometric isomers of ruthenium(II)‐polypyridyl complexes and a preliminary study of their photophysical properties by fluorescence spectroscopy. ZnO NPs synthesis was carried out by direct precipitation. IR, UV‐Vis spectroscopy, XRD and TG‐DTA techniques were used for ZnO NPs characterization. Trans and cis complexes of Ru(II) using 2,2′‐bipyridine and 2,2'‐bipyridine‐4,4'‐dicarboxylic acid as ligands were assembled to ZnO NPs. The presence not only of a band of around 355 nm, but also at 465 nm, in the electronic spectrum indicates the modification of the ZnO surface with the synthesized complexes. The fluorescence behaviour of Ru(II) complexes modified ZnO NPs suggested an electron transfer process through the system. Remarkably, the trans isomer modified system showed better response during the electron transfer. This information could be considered during the design of photoanodes in Dye‐Sensitized Solar Cells. [ABSTRACT FROM AUTHOR]

Hypochromism in absorption titration method and increase in the viscosity of HS DNA suggesting the intercalation mode of binding of complexes. Synthesized complexes exhibit potent nuclease against pUC19 DNA. The octahedral ruthenium(II) complexes [Ru(L n)(PPh 3) 2 Cl 2 ] [L n = biphenyl furanyl pyridine derivatives] were synthesized and characterized using LC–MS, IR spectroscopy, elemental analysis and magnetic measurements. Complexes show enhancement in antibacterial activity compared to free ligands. From the binding mode investigation by absorption titration and viscosity measurement, it is observed that complexes bind to DNA via intercalation and also complexes promote the cleavage of supercoiled pUC19 plasmid DNA. Cytotoxicity analysis shows 100% mortality of Brine shrimp after 48 h. [ABSTRACT FROM AUTHOR]

A new series of mononuclear ruthenium(II) complexes of the type [Ru(PPh3)2(N,S-L1–3)2] 2H3O+.(Cl−)2.XH2O, [RuCl(dmso)3(N,S-L1–3)], and [Ru2(Cl−)2(N,S-L1–3)2].XH2O, where L1 is ethyl 4-(3-hydroxyphenyl)-6-methyl-2-thioxo-pyrimidine-5-carboxylate (monastrol), and L2 and L3 are the 4-hydroxyphenyl and 4-bromophenyl analogs of monastrol have been prepared and characterized by elemental analysis, 1H, and 13C NMR spectroscopy. All the complexes were assayed for their anti-HIV-1 and HIV-2 activity in MT-4 cells, and cytotoxicity was also investigated in mock-infected in MT-4 cells by using MTT assay. All the complexes exhibited no anti-HIV activity, however complexes [RuCl(dmso)3(N,S-L1)] (7) and [RuCl(dmso)3(N,S-L2)] (8) showed cytotoxicity values of > 0.21 and > 2.14 µM, respectively against mock-infected MT-4 cells. In addition, complexes [Ru(PPh3)2(N,S-L3)2].2H3O+.2Cl−.H2O (4), 7, and [RuCl2(N,S-L1)] (10) have been selected for evaluation of their dual inhibition activity against dual-specificity tyrosine phosphorylation-regulated kinase (Dyrk1A). [ABSTRACT FROM AUTHOR]

A comparative study between two novel, highly water soluble, ruthenium(II) polypyridyl complexes, [Ru(phen)2L′] and [Ru(phen)2Cu(II)L′] (L and L‐CuII), containing the polyaazamacrocyclic unit 4,4′‐(2,5,8,11,14‐pentaaza[15])‐2,2′‐bipyridilophane (L′), is herein reported. L and L‐CuII interact with calf‐thymus DNA and efficiently cleave DNA plasmid when light‐activated. They also possess great penetration abilities and photo‐induced biological activities, evaluated on an A375 human melanoma cell line, with L‐CuII being the most effective. Our study highlights the key role of the Fenton active CuII center within the macrocycle framework, that would play a synergistic role with light activation in the formation of cytotoxic ROS species. Based on these results, an optimal design of RuII polypyridyl systems featuring specific CuII‐chelating polyamine units could represent a suitable strategy for the development of novel and effective photosensitizers in photodynamic therapy. [ABSTRACT FROM AUTHOR]

cis-Ru(deeb)32+ (R1; where deeb is 4,4′-diethanoate-2,2′-bipyridine) and cis-Ru(phen)32+ (R2; where phen is 1,10-phenanthroline) were synthesized. Although the presence of the cell wall (a structure that is present in yeasts and bacteria,) was previously described as a natural barrier that hampers the uptake of d6-based luminescent complexes, we previously demonstrated that rhenium(I) tricarbonyl complexes were useful to stain both yeasts and bacteria. Even though several studies of classical ruthenium(II) complexes can be found, none of those studies aimed to determine the potential of these compounds as biomarkers for walled cells, testing only cell lines that lack this permeability barrier. Walled cells exhibit a relatively rigid structure, mainly constituted by carbohydrates and proteins, and surround the plasma membrane. In this manuscript, we observed that both R1 and R2 exhibited very low cytotoxicity in different walled-cell models (including bacteria and yeasts). More importantly, we found that both R1 and R2 were able to fluorescently stain Candida albicans (yeast), with a simple and fast procedure, without the need of additional permeabilizer molecules and antibodies. Interestingly, R1 remained retained in a discrete central structure consistent with the cell nucleus, whereas R2 seemed to be accumulated in the cell wall. These results show that these two complexes can be used as biomarkers for walled cells as differential staining, supporting the fact that, as well as with rhenium(I) complexes, biomarkers properties can be modulated by changing the substituents in ruthenium(II)-derivative luminescent stains, even for walled cells. [ABSTRACT FROM AUTHOR]

Three new ruthenium(II) polypyridyl complexes were synthesized and characterization. The cytotoxic activity in vitro, apoptosis, comet assay, cell cycle arrest, mitochondrial membrane potential and the expression of Bcl-2 family proteins were investigated. In recent years, ruthenium complexes have attracted extensive attention as new anticancer drugs. In this paper, three new ruthenium complexes [Ru(dmb) 2 (HMNPIP)](PF 6) 2 (1), [Ru(bpy) 2 (HMNPIP)](PF 6) 2 (2) and [Ru(phen) 2 (HMNPIP)](PF 6) 2 (3) (HMNPIP = 2-hydroxy-3-methoxy-5-nitrophenylimidazo[4,5-f][1,10]phenanthroline) were synthesized and characterized by elemental analysis, ESI-MS, 1H NMR and 13C NMR. The MTT assays showed that the complexes have no cytotoxic activity in vitro. However, upon irradiation with white light, the complexes display high anticancer activity toward A549 cells. The cell cycle distribution and apoptosis of A549 cells induced by the complexes were investigated by flow cytometry. The intracellular ROS and calcium ion levels were studied. The change of mitochondrial membrane potential, cell invasion were also investigated. The expression of caspase 3, p53 and Bcl-2 family proteins was explored by western blot. The complexes induce apoptosis in A549 cells through intrinsic pathway. [ABSTRACT FROM AUTHOR]

Graphical abstract The synthesis and characterization of two simple Ruthenium(II) thiocyanate free complexes and the exploitation of a new carbon doped anatase TiO 2 paste in dye-sensitized solar cells (DSSCs) photoanode are described. Highlights • Synthesis of interesting Ru-thiocyanate free dyes. • Synthesis of a new carbon doped anatase TiO 2 paste. • The proper combination of Ru dyes and C-doped titania affords working DSSC. Abstract The synthesis and characterization of two simple Ruthenium(II) complexes of the type [Ru(X^N) 2 (4,4′-dicarboxybipyridine)]+ (with X C, X^N benzoquinolinate, 1 ; with X N, X^N 2-pyridyl tetrazolate, 2) and the exploitation of a new carbon doped anatase TiO 2 paste in dye-sensitized solar cells (DSSCs) photoanode are described. In particular, glucose (C 6 H 12 O 6) is used as a new chemical eco-friendly C-dopant during the doping process of anatase TiO 2 nanoparticles. The proper combination of Ru(II) sensitizers and C-doped titania can afford efficient DSSC photoanodes. All the relevant photovoltaic parameters have been determined. [ABSTRACT FROM AUTHOR]

Graphical abstract Ruthenium(II) trithiacyclononane complexes of three naturally occurring flavones are obtained in yields of 23–43%. One of these, [Ru(II)([9]aneS 3)(thflv)(DMSO)], (thflv = 7,3′,4′-trihydroxyflavone) exhibits coordination at the catechol group, a rare feature in Ru(II)-O,O′ complexes. The in vitro cytotoxic activity of the flavones and their corresponding Ru(II) complexes is presented. Highlights • 7,3′,4′-Trihydroxyflavone forms a neutral Ru(II) complex via catechol O,O′-coordination. • Chrysin and techtochrysin form cationic complexes with Ru(II) via bidentate chromenone binding. • Chrysin may be a natural alternative to cisplatin in osteosarcoma treatment. Abstract This study describes a simple, two-step method for obtaining ruthenium(II) trithiacyclononane ([9]aneS 3) flavonate complexes in yields ranging from 23% to 34%. With 7,3′,4′-trihydroxyflavone (thflv), a neutral complex, [Ru(II)([9]aneS 3)(DMSO)(thflv)] (1), is formed by coordination at the catechol group. With chrysin (chrys) and tectochrysin (tchrys), Ru(II) binds to the chromenone fragment to form cationic complexes that are isolated as [Ru(II)([9]aneS 3)(chrys)(DMSO)]Cl (2) and [Ru(II)([9]aneS 3)(DMSO)(tchrys)]Cl (3). The structure of the complexes is characterised by FT-IR, NMR and ESI+-MS. Furthermore, the flavones and the corresponding complexes, 1 – 3 , were investigated regarding their in vitro cytotoxic activity towards four different human tumour cell lines, PC-3 (prostate), MG-63 (osteosarcoma), MCF-7 and MDA-MB-231 (both breast adenocarcinoma). [ABSTRACT FROM AUTHOR]

The potential use of Ru(II) complexes as photosensitizers (PSs) in photodynamic therapy (PDT) has gained significant attention. In comparison with fluorophores with aggregation-caused quenching (ACQ), fluorophores with aggregation-induced emission (AIE) characteristics exhibit sustained fluorescence and dispersibility in aqueous solutions. PSs with AIE characteristics have received much attention in recent years. Herein, we reported two novel biotin-conjugated Ru(II) polypyridyl complexes (Ru1 and Ru2) with AIE characteristics. When exposed to 460 nm (10 mW cm−2) light, Ru1 and Ru2 exhibited outstanding photostability and photocatalytic activity. Ru1 and Ru2 could efficiently generate singlet oxygen and induce pUC19 DNA photolysis when exposed to 460 nm light. Interestingly, both Ru1 and Ru2 also functioned as catalysts for NADH oxidation when exposed to 460 nm light. The presence of biotin fragments in Ru1 and Ru2 enhanced the specific uptake of these complexes by tumor cells. Both complexes showed minimal toxicity to selected cells in the dark. Nevertheless, the phototoxicity of both complexes significantly increased upon 460 nm light irradiation for 15 min. Further experiments revealed that Ru2 primarily accumulated in mitochondria and might bind to mitochondrial DNA. Under 460 nm light irradiation, Ru2 induced the generation of reactive oxygen species (ROS) and NADH depletion disrupting intracellular redox homeostasis in A549 cells, activating the mitochondrial apoptosis pathway resulting in up-regulation of apoptotic marker caspase-3, effectively damaged A549 cell DNA and arrested A549 cell cycle in the S phase. In vivo anti-tumor experiments were conducted to assess the effects of Ru2 on tumor growth in A549 tumor-bearing mice. The results showed that Ru2 effectively inhibited tumor growth under 460 nm light irradiation conditions. These findings indicate that Ru2 has great potential as a targeted photosensitizer for mitochondrial targeting imaging and photodynamic therapy of tumors. [Display omitted] • Two biotin-conjugated Ru(II) complexes with AIE characteristics were synthesized. • Ru1 and Ru2 exhibited outstanding photostability and photocatalytic activity. • Ru2 had potent targeting abilities for A549 cells and mitochondria. • Ru2 could enhance photodynamic therapy by disrupting cellular redox balance. • Ru2 could suppress tumor growth in A549 xenograft-bearing mice under 460 nm light. [ABSTRACT FROM AUTHOR]

Ruthenium complexes have attracted considerable interest as potential antitumor agents. Therefore, antitumor activity and systemic toxicity of ruthenium(II) terpyridine complexes were evaluated in heterotopic mouse colon carcinoma. In the present study, cytotoxic effects of recently synthesized ruthenium(II) terpyridine complexes [Ru(Cl-tpy)(en)Cl][Cl] (en = ethylenediamine, tpy = terpyridine, Ru-1) and [Ru(Cl-tpy)(dach)Cl][Cl] (dach = 1,2-diaminocyclohexane, Ru-2) towards human and murine colon carcinoma cells were tested in vitro and in vivo and compared with oxaliplatin, the most commonly used chemotherapeutic agent against colorectal carcinoma. Ruthenium(II) complexes showed moderate cytotoxicity with IC50 values ranging between 19.1 to 167.3 μM against two human, HCT116 and SW480, and one mouse colon carcinoma cell line, CT26. Both ruthenium(II) terpyridine complexes exerted a moderate apoptotic effect in colon carcinoma cells, but induced significant necrotic death. Additionally, both complexes induced cell cycle disturbances, but these effects were specific for the cell line. Further, Ru-1 significantly reduced the growth of primary heterotopic tumor in mice, similarly to oxaliplatin. Renal damage in Ru-1 treated mice was lower in comparison with oxaliplatin treated mice, as evaluated by serum levels of urea and creatinine and histological evaluation, but Ru-1 induced higher liver damage than oxaliplatin, evaluated by the serum levels of alanine aminotransferase. Additionally, the interaction of these ruthenium(II) terpyridine complexes with the tripeptide glutathione (GSH) was investigated by proton nuclear magnetic resonance (1H NMR) spectroscopy. All reactions led to the formation of monofunctional thiolate adducts [Ru(Cl-tpy)(en)GS-S] (3) and [Ru(Cl-tpy)(dach)GS-S] (4). Our data highlight the significant cytotoxic activity of [Ru(Cl-tpy)(en)Cl][Cl] against human and mouse colon carcinoma cells, as well as in vivo antitumor activity in CT26 tumor-bearing mice similar to standard chemotherapeutic oxaliplatin, accompanied with lower nephrotoxicity in comparison with oxaliplatin.

Tuberculosis (TB) is an infectious, airborne disease caused by the bacterium Mycobacterium tuberculosis that mainly affects the lungs. Fortunately, tuberculosis is a curable disease, and in recent years, death rates for this disease have decreased. However, the existence of antibiotic-resistant strains and the occurrence of co-infections with human immunodeficiency virus (HIV), have led to increased mortality in recent years. Another area of concern is that one-third of the world′s population is currently infected with M. tuberculosis in its latent state, serving as a potential reservoir for active TB. In an effort to address the failure of current TB drugs, greater attention is being given to the importance of bioinorganic chemistry as an ally in new research into the development of anti-TB drugs. Ruthenium (Ru) is a chemical element that can mimic iron (Fe) in the body. In previous studies involving the following heteroleptic Ru complexes, [Ru(pic)(dppb)(bipy)]PF6 (SCAR1), [Ru(pic)(dppb)(Me-bipy)]PF6 (SCAR2), [Ru(pic)(dppb)(phen)]PF6 (SCAR4), cis-[Ru(pic)(dppe)2]PF6 (SCAR5), and [Ru(pic)(dppe)(phen)]PF6 (SCAR7), we observed excellent anti-TB activity, moderate cell-toxicity, and a lack of oral bioavailability in an in vivo model of these complexes. Therefore, the objective of this study was to evaluate the toxicity and oral bioavailability of these complexes by loading them into a nanostructured lipid system. The nanostructured lipid system was generated using different ratios of surfactant (soybean phosphatidylcholine, Eumulgin®, and sodium oleate), aqueous phase (phosphate buffer with a concentration of 1X and pH 7.4), and oil (cholesterol) to generate a system for the incorporation of Ru(II) compounds. The anti-TB activity of the compounds was determined using a microdilution assay with Resazurin (REMA) against strains of M. tuberculosis H37Rv and clinical isolates resistant. Cytotoxicity assay using J774.A1 cells (ATCC TIB-67) and intra-macrophage activity were performed. The oral bioavailability assay was used to analyze blood collected from female BALB/C mice. Plasma collected from the same mice was analyzed via inductively coupled plasma mass spectrometry (ICP-MS) to quantify the number of Ru ions. The complexes loaded into the nanostructured lipid system maintained in vitro activity and toxicity was found to be reduced compared with the compounds that were not loaded. The complexes showed intra-macrophagic activity and were orally bioavailable.

The ruthenium(II) complex cis-[RuCl2(PPh3)2(L1)] (1) where L1 = 2-(2’-pyridyl)quinoline was obtained in high yield from the reaction of [RuCl2(PPh3)3] with L1. The new compound was characterized by different spectroscopic methods including FT-IR, UV-Vis, NMR (1H, 31P) spectroscopy along with a mass spectrometric analysis (ESI-MS) and conductivity measurements. 31P NMR spectroscopy provided evidence that the two PPh3 ligands are orientated trans to each other in an octahedral environment. Complex (1) was tested in the transfer hydrogenation of various ketones in 2-propanol at 82 oC. The catalytic activity of (1) displayed quantitative conversions for benzophenone and 4-chloroacetophenone.

Graphical abstract Highlights • New olefin-tethered organoruthenium carbene complexes have been synthesized and epitomized. • X-ray studies confirmed an octahedral geometry of the new complexes. • The newly synthesized complexes catalyze the hydrogenation of esters efficiently. Abstract A series of Ru(II) complexes encompassing imidazolylidene olefin arm have been designed. The newly synthesized ligands and complexes were fully characterized by 1H, 13C NMR, and elemental analyses. Structural geometry for one of the envoy Ru(II) carbene complexes 3a was confirmed by single-crystal X-ray diffraction studies. The complexes acquired a distorted octahedral geometry. The highly active [Ru(II)-NHC] complex 3b , showed excellent catalytic performance for the hydrogenation of esters in 1,4-dioxane medium. The effects of solvent, base, wingtip substituents, time and catalyst loading were also investigated. The reported catalyst performed exceptionally well for a range of esters and furnishes very good yield of hydrogenated products. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Two piano-stool Ru(II) complexes were synthesized and characterized. • The K b and the K sv constants reveal that complex (2) binds well to CT-DNA • QM, Docking simulation and PM6-D3H4 Reaction path evaluation have been done. • MTT assay has been conducted on MCF-7, A-549, HT-29, HeLa and MRC-5 cell lines. • WB and FC analysis show the PARP expression and apoptosis, respectively. Abstract Two piano-stool ruthenium(II) complexes [Ru(η 6- p -cymene)(N -MeIm) 3 ]Cl 2 ·2H 2 O (1) and [Ru(η 6- p -cymene)(N -PrIm)Cl 2 ] (2) respectively have been synthesized and characterized by elemental, spectral and structural analysis. Crystal structures of (1) and (2) have been verified by X-ray diffraction analysis. Docking experiments toward DNA dodecamer have been done. Good ΔG binding values of the complexes with imidazole derivatives comparable with ethylene-diamine complex indicate a high potential of these compounds in the formation of DNA lesions and therefore their good cytotoxic status. The interaction of CT-DNA with ruthenium(II) complexes has been studied by means of absorption and fluorescence measurements. The binding constant, K b and the Stern–Volmer quenching constant reveal that complex (2) binds well to CT-DNA. The cytotoxic activity of Ru(II) complexes with N- RIm (R = methyl or propyl) were evaluated by MTT assay. A-549, HT-29 and HeLa cells were sensitive to all compounds tested, while the breast carcinoma cell line MCF-7 was resistant only to the complex (1). Flow cytometric analysis and fluorescent microscopy showed that ruthenium(II) complexes in HeLa cells induce apoptosis and G0/G1 cell cycle arrest and almost completely inhibit DNA synthesis. Western blot also demonstrated proteolytic cleavage of poly-(ADP-ribose) polymerase (PARP) in HeLa cells after treatment with both tested substances. [ABSTRACT FROM AUTHOR]

Abstract: A family of novel imine‐N‐heterocyclic carbene ruthenium(II) complexes of the general formula [(η6‐p‐cymene)Ru(C^N)Cl]PF6− (where C^N is an imine‐N‐heterocyclic carbene chelating ligand with varying substituents) have been prepared and characterized. In this imine‐N‐heterocyclic carbene chelating ligand framework, there are three potential sites that can be modified, which distinguishes this class of ligand and provides a body of flexibilities and opportunities to tune the cytotoxicity of these ruthenium(II) complexes. The influence of substituent effects of three tunable domains on the anticancer activity and catalytic ability in converting coenzyme NADH to NAD+ is investigated. This family of complexes displays an exceedingly distinct anticancer activity against A549 cancer cells, despite their close structural similarity. Complex 9 shows the highest anticancer activity in this series against A549 cancer cells (IC50=14.36 μ m), with an approximately 1.5‐fold better activity than the clinical platinum drug cisplatin (IC50=21.30 μ m) in A549 cancer cells. Mechanistic studies reveal that complex 9 mediates cell death mainly through cell stress, including cell cycle arrest, inducing apoptosis, increasing intracellular reactive oxygen species (ROS) levels, and depolarization of the mitochondrial membrane potential (MMP). Furthermore, lysosomal damage is also detected by confocal microscopy. [ABSTRACT FROM AUTHOR]

Herein, novel ruthenium(II) complexes containing 1-methylimidazole as a ligand were obtained with the following formulas: [RuCl(1Meim)(dppb)(bpy)]Cl ( 1 ), [RuCl(1Meim)(dppb)(4,4′-DMbpy)]Cl ( 2 ), [RuCl(1Meim)(dppb)(5,5′-DMbpy)]Cl ( 3 ) and [RuCl(1Meim)(dppb)(phen)]Cl ( 4 ) where, 1Meim = 1-methylimidazole, dppb = 1,4-Bis(diphenylphosphino)butane, bpy = 2,2′-bipyridine, 4,4′-DMbpy = 4,4′-dimethyl-2,2′-bipyridine, 5,5′-DMbpy = 5,5′-dimethyl-2,2′-bipyridine and phen = 1,10-phenanthroline. Additionally, crystal structures containing the cations of ( 1 ) and ( 3 ) were obtained when the counter ion was exchanged, leading to the formation of [RuCl(1Meim)(dppb)(bpy)]PF 6 ( 5 ) and [RuCl(1Meim)(dppb)(5,5′-DMbpy)]PF 6 methanol solvate ( 6 ) where PF 6  = hexafluorophosphate, showing one 1-methylimidazole molecule coordinated through the imidazole nitrogen, as expected. The complexes were characterized by elemental analysis, molar conductivity, infrared and UV–Vis spectroscopy, 1 H, 13 C{ 1 H} and 31 P{ 1 H} NMR, mass spectrometry and cyclic voltammetry. The interactions of complexes 1 – 4 with DNA and human serum albumin (HSA) were evaluated, and the cytotoxicity profiles of compounds 1 – 4 were determined using four different tumor cell lines derived from human cancers (melanoma: HT-144, colon: HCT-8, breast: MDA-MB-231 and lung: A549). A higher cytotoxic activity was observed for compound ( 3 ) against non-small cell lung cancer (A549). Complex ( 3 ) inhibited the clonogenic capacity and cell cycle progression of A549 cells and induced apoptosis involving mitochondrial pathway activation. Therefore, the data obtained in the present study support further investigations concerning molecular targets of complex ( 3 ) in non-small cell lung cancer. [ABSTRACT FROM AUTHOR]

A series of three heteroleptic ruthenium complexes containing 2,2′-bipyridine-4,4′-dicarboxamide ligands with different substituents (propyl, benzyl or 2-phenylethyl) was synthesized as possible sensitizers for dye sensitized solar cells (DSSCs). Their structure was characterized with 1 H NMR and FTIR while their optical and electrochemical properties were also investigated. The observed optical differences were associated to structural properties of the three complexes and different electron donor strength of the ancillary ligands. In particular, ruthenium complex with propyl based ligand showed higher molar extinction coefficient succeeding better light harvesting. Semitransparent dye sensitized solar cells employing quasi-solid-state electrolyte and the three ruthenium complexes were constructed under the same fabrication conditions and electrically characterized under standard conditions of light irradiance (100 mW/cm 2 , AM 1.5). Their behavior was compared with that of commercially available ruthenium complex D907 with increased conjugation length of the ancillary ligand, in terms of current–voltage characteristic curves under simulated solar light and in the dark while electrochemical impedance spectroscopy was also used for local resistance to charge transfer across the TiO 2 -dye/electrolyte interface. The influence of ancillary ligands into ruthenium complexes was discussed in terms of the cells’ efficiency. A maximum overall performance of 5.0% was monitored for ruthenium complex with propyl substituent in comparison to 5.1% that was measured for semitransparent quasi-solid state devices with commercial D907. [ABSTRACT FROM AUTHOR]

Despite their past triumphs, platinum-based therapeutics remain limited by chemo-resistance and severe side effects. As an alternative therapeutic modality which bypasses these issues, photodynamic therapy (PDT) holds great promise. The first FDA approved PDT agent, Photofrin, stimulated an outpouring of porphyrin-motif studies, while metallodrugs have long been underappreciated in this area. Due to their unique and versatile properties, ruthenium complexes are receiving increasing attention in the field of PDT. Herein, we introduce the recent advances in Ru(II)-based PDT agents ranging from single molecules to delicate nanomaterials, how these agents are unique suited to PDT and the merits provided by their various forms. [ABSTRACT FROM AUTHOR]

New phosphine-amino-alcohol tridentate ligands ( 3a-c ) and six new ruthenium complexes ( 4a-c and 5a-c ) were synthesized and characterized. Catalytic activities of the metal complexes were tested on aryl alkyl ketones. All of the substrates were converted to related sec -alcohols in excellent yields (up to 99%), but enantioselectivities were insufficient (up to 40% ee). Despite the catalytic performance of 5a-c complexes can be considered as better than 4a-c , actually the catalytic activity of the complexes has been differed according to substrate. The ketones with less positive carbonyl carbons tend to give S -configuration with 5a-c and R -configuration with 4a-c . The catalytic performance of the complexes was rationalized by means of DFT calculations. [ABSTRACT FROM AUTHOR]

Abstract: A series of metal‐free compounds, ie, planar triprotonated triazine, triazineH3Cl(PF6)2 (1), planar triprotonated triazineH3Br(PF6)2 (2), and nonplanar monoprotonated triazineHPF6 (3), were prepared. Abbreviations used are triazine = tri‐2‐pyridyltriazine. Ruthenium complexes [RuCl(bpy)(L)](PF6), [RuCl(bpy)(L)](PF6)2, and [Ru(L)2](PF6)2 were also prepared, where bpy is 2,2′‐bipyridine and L's are triazine (4) and monoprotonated triazine (5), respectively. Ruthenium complexes [Ru(triazine)2](PF6)2 (6) were also prepared and crystallized. The X‐ray crystal structures of the 3 compounds 1, 2, and 3 and the complex 6 were determined. They were also characterized by electrospray ionization mass spectrometry, UV‐vis spectroscopy, and density functional theory calculations. [ABSTRACT FROM AUTHOR]

A pair of ruthenium(II) complex enantiomers, Δ - and Λ -[Ru(bpy) 2 PBIP] 2 + {bpy = 2,2′-bipyridine, PBIP = 2-(4-bromophenyl)imidazo[4,5- f ]1,10-phenanthroline} have been synthesized and characterized. The systematic comparative studies between two enantiomers on their DNA binding-behaviors with calf thymus DNA (CT DNA) were carried out by viscosity measurements, spectrophotometric methods and molecular simulation technology. Additional assays were performed to explore the cytotoxicity of the ruthenium(II) enantiomers against tumor cell lines. DNA-binding studies show that both the enantiomers can bind to CT DNA via intercalative mode, and the Δ form binds to CT DNA more strongly than the Λ form does. Molecular simulation further shows that both the two enantiomers intercalate between base pairs of DNA in minor groove, and that the Δ form intercalates into DNA more deeply than the Λ form does. In addition, the cell proliferation assays show that the Δ form induces a greater cytotoxicity than the Λ form on human cervical cancer HeLa cells, which is positive correlated with the results in DNA binding studies and molecular docking, and implies that the DNA binding affinities of ruthenium(II) polypyridyl complexes might be constitute to the part of their anticancer mechanisms. [ABSTRACT FROM AUTHOR]

Inspired by the enormous importance attributed to the biological function of miRNA, we pour our attention into the design and synthesis of four ruthenium(II) complexes and evaluate their applications as miR-185 detection agents by spectroscopic measurements. It was found that all complexes can form sensing platform for the detection of the complementary target miR-185 through the introduction of carboxyfluorescein (FAM) labeled single stranded DNA (P-DNA), giving the detection limits of 0.42 nM for Ru 1 , 0.28 nM for Ru 2 , 0.32 nM for Ru 3 , 0.85 nM for Ru 4 , all with instantaneous detection time in 1 min. The results of the binding constant, fluorescence anisotropy (FA) and polyacrylamide gel electrophoresis experiments (PAGE) revealed that the ruthenium(II) complexes prefer to bind P-DNA other than hybrid duplexes DNA@RNA upon recognition, resulting in the detection of miR-185. These results provide useful suggestions in the new type of metal-based miRNA detection agents. [ABSTRACT FROM AUTHOR]

We have investigated the bonding features of 18 Ruthenium(II) polypyridyl complexes of the type [Ru(tpy)(L)-(Guo)] n + , containing a tridentate 2,2 ′ :6 ′ ,2 ′ ′ -terpyridine ligand (tpy) and various bidentate ancillary ligands L, which form monofunctional adducts with guanine derivatives, such as guanosine (Guo). The main scaffold is motivated by the work of Simović et al. (2019). These complexes have been proposed to form a covalent bond with the nucleobase Guanine at its N 7 position. This work illustrates the power of our local mode analysis in characterizing the strength of chemical interactions for experimentalists and theoreticians alike. [Display omitted] • Proposes a series of complexes targeting DNA and their structure–activity profile. • Features local mode analysis (LMA) in extracting local bond strength character. • Compares local descriptors of LMA to global descriptors of bond dissociation energies. [ABSTRACT FROM AUTHOR]

Tuberculosis is one of the world’s deadliest infectious disease with 1.5 millions deaths annually. It is imperative to discover novel compounds with potent activity against M. tuberculosis. In this study, susceptibilities of M. smegmatis to the octahedral ruthenium(II) polypyridyl complexes, 1 {[(bpy)3Ru] (PF6)2 (bpy = 2,2′-bipyridine)}, 2 {[(phen)2Ru(dppz)](PF6)2 (phen = 1,10-phenanthroline, dppz = dipyridophenazine)} and 3 {[(phen)3Ru](PF6)2} were measured by broth microdilution and reported as the MIC values. Toxicities of complex 3 to LO2 and hepG2 cell lines were also measured. Complex 2 inhibited the growth of M. smegmatis with MIC value of 2 µg/mL, while complex 3 was bactericidal with MIC value of 26 µg/mL. Furthermore, the bactericidal activity of complex 3 was dependent on reactive oxygen species production. Complex 3 showed no cytotoxicity against LO2 and hepG2 cell lines at concentration as high as 64 µg/mL, paving the way for further optimization and development as a novel antibacterial agent for the treatment of M. tuberculosis infection.