Ruthenium Complexes Research Articles

Homobimetallic Ruthenium(II) Complexes Catalysed Selective Transfer Hydrogenation of Aldehydes in Water.

Herein we report chemoselective transfer hydrogenation (TH) of aldehydes in aqueous medium using a series of homobimetallic Ru(II) catalysts. Two homobimetallic complexes (Ru1 and Ru3) and one monometallic complex (Ru2) have been employed in the catalytic reduction of aldehydes. Bimetallic complex [(p-cymene)2(RuCl)2L3] (Ru3) is obtained from the reaction of Schiff base ligand 2,2'-((1E,1'E)-((3,3',5,5'-tetraisopropyl-[1,1'-biphenyl]-4,4'diyl)bis(azaneylylidene))bis(methaneylylidene))bis(4-bromophenol) (H2L3) and characterized by various spectroscopic and analytical techniques. The use of formic acid/formate buffer as the hydride source and a catalyst loading of 0.01 mol% of Ru1 or Ru3 resulted in the conversion of various aldehydes to the corresponding alcohols in good to excellent yield. This method is very efficient for selective reduction of aldehydes in the presence of other reducible functional groups. A loading of 0.0001 mol% of Ru1 catalyst is sufficient to achieve a turnover frequency (TOF) of 5.5× 105 h-1. Furthermore, the catalyst can been recycled and reused for six consecutives cycles without sacrificing the efficiency. A comparison of results obtained between bimetallic and monometallic complexes offers valuable insights into the distinct reactivity patterns of the bimetallic complexes, presumably originating from a cooperative effect. We have explored the mechanistic pathway using DFT methods.

Mechanistic Insights into the cis-Selective Catalytic Ring-Opening Metathesis Polymerization.

Cis-selective ring-opening metathesis polymerization (ROMP) with the commercial Grubbs "nitrato catalyst" has shown promise for synthesizing stereoregular materials, but it comes with the drawback of losing control over the molecular weight due to the poor initiation rate of the catalyst and the need for stoichiometric ruthenium complex loading. To address these issues, we developed a chain transfer polymerization method that allows for the catalytic synthesis of polymers while controlling the degree of polymerization. This allowed us to produce shorter polymers with exceptional chain-end control. Analysis of the polymers revealed a novel double monomer addition mechanism for this catalyst. MALDI-ToF mass spectrometric measurements showed that when using small monomers like norbornene, the polymer chains contained only odd numbers of monomers. In contrast, the polymerization of norbornene-imide-type monomers shows a major distribution with odd numbers of monomers along with a minor distribution of even numbers. This unique distribution of polymer chain types had not been previously observed in ROMP. We explain this phenomenon by the chiral nature of the catalyst that yields two isomeric catalytic species with dissimilar reactivities toward monomer and chain transfer agents.

Innovative electrochemical sensor based on platinum group metal complexes for determination of nitrite: Application for simultaneous detection of nitrite and tartrazine

In the context of this experimental study, new palladium and ruthenium complexes based on a symmetric ligand, named 2E-Peaemp ((3E,3’E)-3,3’-(((piperazine-1,4-diyl bis (ethane-2,1-diyl)) bis (azanediyl)) bis (ethan1-yl-1-ylidene)) bis (6-methyl-2H-pyran-2,4(3 H)-dione), and their hybrid compounds with carbon nanotubes were prepared and characterized. The sensors prepared using a cavity microelectrode (MEC) modified with a mixture of graphite (CG), carbon nanotubes (MWCNT) and the synthesized complexes (Pd-2E-Peaemp and Ru-2E-Peaemp) were applied to detect the pollutants such as Nitrites and Tartrazine separately and simultaneously in aqueous solutions and real samples (Tap water, wastewater and bottled commercial spring water). The detection limits (LODs) determined for nitrites and tartrazine are obtained using MEC/CG-MWCNT-Pd-2E-Peaemp electrode, and the electrochemical measurements demonstrated a sensitive and rapid response in the analysis of these species. LODs are 0.39 µM and 0.11 µM, respectively, within the concentration range of 0–909 µM for nitrites and 0–97 µM for tartrazine. This electrode modified by the palladium complex is also used to simultaneously detect nitrite and tartrazine analytes using the differential pulse voltammetry (DPV) technique, indicating that the proposed sensor can be an interesting alternative tool to measure these species in real samples. The application of this electrode in these natural environments reveals that the developed sensor can detect low concentrations of nitrite (NO2-; trace) without any interference from other ions substances as acetate (CH3COO-), borate (BO3−3), phosphate (PO4−3), dihydrogen ( 2 H+), sulfate (SO4−2), sodium (Na+), hydroxide (OH-), potasium (K+), chloride (Cl-), magnesium (I) ( Mg+), nitrate (NO3-), calcium (Ca2+), carbonate (CO3−2).

Ruthenium‐Catalyzed Chemoselective Olefin Transfer Hydrogenation of alpha, beta‐Unsaturated Carbonyl Systems By Using EtOH as Hydrogen Source

AbstractThe use of EtOH as hydrogen donor is remarkably under explored in transfer hydrogenation reactions, even though EtOH represents an appealing hydrogen source. With the cationic ruthenium complex [Ru(PYA)(cymene)]+, 1, containing a N,N‐bidentate amino‐functionalized pyridinium amidate (PYA) ligand as catalyst precursor, we here demonstrate the first example of chemoselective room temperature transfer hydrogenation of the C═C bond in α,β‐unsaturated ketones using EtOH as benign hydrogen source to yield a variety of functionalized ketones. The reaction proceeds under mild conditions with K2CO3 as base and conventiently at room temperature. A broad substrate scope, including various functionalized α,β‐unsaturated carbonyl groups, demonstrates the general applicability of this method. Preliminary mechanistic studies suggest the formation of an alkoxide complex [1]–OEt as an initially formed species, and the requirement for EtOH to induce hydride transfer, suggesting a protic activation of the catalyst.

Arene Ruthenium Complexes Specifically Inducing Apoptosis in Breast Cancer Cells

Monocationic arene ruthenium complexes (RuL1–RuL4) incorporating phenothiazinyl-hydrazinyl-thiazole ligands (L1–L4) have been synthesized, characterized and evaluated as anticancer agents. Their cytotoxicity, antiproliferative activity and alteration of apoptotic gene expression were studied on three cancer cell lines, a double positive breast cancer cell line MCF-7 and two triple negative breast cancer cell lines Hs578T and MDA-MB-231. All arene ruthenium complexes were able to reduce the viability of the breast cancer cell lines, with the highest cytotoxicities being recorded for the [(p-cymene)RuL3Cl]+ (RuL3) complex on the MCF-7 (IC50 = 0.019 µM) and Hs578T cell lines (IC50 = 0.095 µM). In the double positive MCF-7 breast cancer cells, the complexes [(p-cymene)RuL1Cl]+ (RuL1) and [(p-cymene)RuL2Cl]+ (RuL2) significantly upregulated pro-apoptotic genes including BAK, FAS, NAIP, CASP8, TNF, XIAP and BAD, while downregulating TNFSF10. In the triple negative breast cancer cell line Hs578T, RuL1 reduced TNFSF-10 and significantly upregulated BAK, CASP8, XIAP, FADD and BAD, while complex RuL2 also increased BAK and CASP8 expression, but had limited effects on other genes. The triple negative MDA-MB-231 cancer cells treated with RuL1 upregulated NOD1 and downregulated p53, while RuL2 significantly downregulated p53, XIAP and TNFSF10, with minor changes in other genes. The significant alterations in the expression of key apoptotic genes suggest that such complexes have the potential to target cancer cells.

Organometallic Ru(III) Catalysts for α-Alkylation of Carbonyl Compounds using Alcohols: Mechanistic Insights via Detection of Key Intermediates.

Three novel cyclometalated ruthenium complexes ([Ru.L(9)] [Ru.L(10)] and [Ru.L(11)]) featuring azo functionalities were synthesized and characterized using a variety of spectroscopic techniques, namely FT-IR, electronic absorption spectroscopy, and ESI-MS. Representative solid-state structures of the acquired complexes were determined through X-ray crystallography. These complexes were evidenced to be efficient catalysts for the synthesis of various α-alkylated compounds utilizing simple acetophenone derivatives with easily affordable and economically viable alcohols, which were isolated and characterized via 1H and 13C NMR spectroscopy. The optimum reaction conditions were found by employing toluene as solvent, potassium tert-butoxide as base at 115 oC temperature utilizing 0.8 mol% of catalyst [Ru.L(10)]. The yield of the desired compounds found to be in the range of 83 - 97%. Additionally, mass spectrometry provided insights into the in-situ generated ruthenium hydride and ruthenium alkoxy intermediates, shedding light on the catalytic mechanism.

Novel heteroleptic ruthenium complexes incorporating 6,7-dichloro-2,3-di(pyridine-2-yl)quinoxaline as polypyridyl bridging ligand: Synthesis, characterization, photophysical, electrochemistry, in vitro biological activity and molecular docking studies

Novel heteroleptic ruthenium complexes incorporating 6,7-dichloro-2,3-di(pyridine-2-yl)quinoxaline as polypyridyl bridging ligand: Synthesis, characterization, photophysical, electrochemistry, in vitro biological activity and molecular docking studies

Binding studies of ruthenium complexes with antithyroid drug

Medicinal substances are essential to our daily existence. A prudent approach to metal complexation with already available medications may result in more stylish, intelligent, and effective drug compositions. Thus, the binding of [Ru(NN)3]2+ (NN = 2,2ˈ-bipyridine, 1,10-phenanthroline) with the antithyroid medication thyronorm has been studied in the current attempt. The use of absorption and emission spectrum techniques allowed researchers to examine the complexes' interactions with antithyroid medications. Studies of absorption and emission spectra show that the complex and medication interact through coordinated ligand hydrophobic and hydrogen bonding interactions.Analysis has also been done on the binding of the antithyroid medication Thyronorm to ruthenium complexes. The Benesi-Hildebrand plot was used to determine the binding constants of the drug complexes. Current research indicates that the Thyronorm pill has good affinity with [Ru(phen)3]2+complex.

Ruthenium Complexes of Phenylbenzothiazole‐Quinoline based Ligands for Selective α‐Olefination of Methylazaarenes

This report describes synthesis of a new ligand (E)‐N‐(4‐(benzo[d]thiazol‐2‐yl)phenyl)‐1‐(quinolin‐2‐yl)methanimine (L1) and its three ruthenium(II) arene complexes with [RuCl2(p‐cymene)]2 (C1), [RuCl2(benzene)]2 (C2), and [RuCl2(hmb)]2 [hmb = hexamethylbenzene] (C3). The new ligand and complexes were characterized with the help of standard spectroscopic and analytical techniques like 1H and 13C{1H} Nuclear Magnetic Resonance (NMR), Fourier transform infrared (FTIR), High‐resolution mass spectrometry (HRMS), UV‐Visible, cyclic voltammetry, and elemental analysis. The structure of ruthenium complex (C1) and its binding mode with ligand were authenticated with the help of single crystal X‐ray diffraction. The ruthenium arene complexes (C1‐C3) were used as a catalyst for the α‐olefination of Methylazaarenes. First, methylazaarenes were reacted with alcohols under optimized reaction conditions to produce α‐olefinated products (up to 66%) selectively. Among the three ruthenium complexes, C1 demonstrated the highest yield of olefinated products with 5 mol% catalyst loading. Finally, selected olefin derivatives were tested for their inhibitory potential towards the aggregation of amyloid‐b‐40 (Aβ40) peptide relevant to Alzheimer’s disease. Overall, these complexes are promising catalysts for organic transformations, and the synthesized α‐olefinated derivatives could have potential applications for the development of therapeutic agents for Alzheimer’s disease.

Benzo[1,2-b:4,5-b’]dithiophene diethynyl bridged bimetallic ruthenium complexes: syntheses and characterization, (spectro)electrochemistry combined with theoretical calculations

We have constructed isomeric triruthenium ethynyl complexes 1 and 2 linked by benzo[1,2-b:4,5-b’]dithiophene. The electronic properties of 1 and 2 were compared by (spectro)electrochemical and theoretical calculations. DFT (density functional theory) fully-optimized structures 1 and 2 showed that the ruthenium terminal groups both exhibit a similar pseudo-octahedral configuration as reported for the crystal structure of 1. With step-by-step oxidation, the bond length of Ru-C decreases and the bond length of C≡C increases, which indicated that the complexes undergo a transition from Ru-C≡C to Ru = C = C. The electrochemical results of 1 and 2 featured two consecutive single-electron redox processes, and the ΔE value of 2 (329 mV) was significantly higher than that of 1 (140 mV). The near-IR broad absorptions of 2 + from UV-Vis-NIR spectroelectrochemistry exhibited a blue shift relative to that of 1 +, which could be attributed to MLCT (metal to ligand charge transfer) absorptions and confirmed by TDDFT (time dependent) calculations. The results suggested that the bridge ligands are involved in the redox process. The ν(C≡C) stretch of 2 + from IR spectroelectrochemistry exhibited a strong single peak at 1969 cm-1, while the isomer 1 + showed three asymmetric peaks. These results showed excellent charge delocalization ability of 2.

The Swiss Army Knife of Electrodes: Pillar[6]arene-Modified Electrodes for Molecular Electrocatalysis Over a Wide pH Range.

Molecularly-modified electrode materials that maintain stability over a broad pH range are rare. Typically, each electrochemical transformation necessitates a specifically tuned system to achieve strong binding and high activity of the catalyst. Here, we report the functionalisation of mesoporous indium tin oxide (mITO) electrodes with the macrocyclic host molecule pillar[6]arene (PA[6]). These electrodes are stable within the pH range of 2.4-10.8 and can be equipped with electrochemically active ruthenium complexes through host-guest interactions to perform various oxidation reactions. Benzyl alcohol oxidation serves as a model reaction in acidic media, while ammonia oxidation is conducted to assess the systems performance under basic conditions. PA[6]-modified electrodes demonstrate catalytic activity for both reactions when complexed to different guest molecules and can be reused by reabsorption of the catalyst after its degradation. Furthermore, the system can be employed to perform subsequent reactions in electrolyte with varying pH, enabling the same electrode to be utilised in multiple different electrocatalytic reactions.

The Swiss Army Knife of Electrodes: Pillar[6]arene‐Modified Electrodes for Molecular Electrocatalysis Over a Wide pH Range

AbstractMolecularly‐modified electrode materials that maintain stability over a broad pH range are rare. Typically, each electrochemical transformation necessitates a specifically tuned system to achieve strong binding and high activity of the catalyst. Here, we report the functionalisation of mesoporous indium tin oxide (mITO) electrodes with the macrocyclic host molecule pillar[6]arene (PA[6]). These electrodes are stable within the pH range of 2.4–10.8 and can be equipped with electrochemically active ruthenium complexes through host–guest interactions to perform various oxidation reactions. Benzyl alcohol oxidation serves as a model reaction in acidic media, while ammonia oxidation is conducted to assess the systems performance under basic conditions. PA[6]‐modified electrodes demonstrate catalytic activity for both reactions when complexed to different guest molecules and can be reused by reabsorption of the catalyst after its degradation. Furthermore, the system can be employed to perform subsequent reactions in electrolyte with varying pH, enabling the same electrode to be utilised in multiple different electrocatalytic reactions.

Autocatalytic Activation of a Ruthenium-PNN-Pincer Hydrogenation Catalyst.

In this article, we describe a detailed experimental and computational study of the activation mechanism for a highly active pincer ruthenium(0) precatalyst for the hydrogenation of polar organic compounds. The precatalyst activates by reaction with 2 equiv of hydrogen, resulting in a net oxidative addition to ruthenium and hydrogenation of an imine functional group on the supporting ligand. The kinetics of precatalyst hydrogenation were measured by UV-visible spectroscopy under catalytically relevant conditions (10-39 bar hydrogen, 298 K). The kinetic data, in combination with density functional theory calculations, support an intriguing autocatalytic mechanism, where the product ruthenium(II) complex catalyzes the hydrogenation of the ruthenium(0) precatalyst.

Developing an Arene Binuclear Ruthenium(II) Complex to Induce Ferroptosis and Activate the cGAS-STING Pathway: Targeted Inhibiting Growth and Metastasis of Triple Negative Breast Cancer.

To effectively inhibit the growth and metastasis of triple-negative breast cancer (TNBC), we developed a high-efficiency and low-toxicity arene ruthenium (Ru) complex based on apoferritin (AFt). To achieve this, we optimized a series of Ru(II) 1,10-phenanthroline-2,9-diformaldehyde thiosemicarbazone complexes by studying their structure-activity relationships to obtain an arene binuclear Ru(II) complex (C5) with significant cytotoxicity and high accumulation in the mitochondria of tumor cells. Subsequently, a C5-AFt nanoparticle (NPs) delivery system was constructed. We found that the C5/C5-AFt NPs effectively inhibited TNBC growth and metastasis with few side effects. The C5-AFt NPs improved the anticancer and targeting abilities of C5 in vivo. Moreover, we confirmed the mechanism by which C5/C5-AFt NPs inhibit tumor growth and metastasis via mitochondrial damage-mediated ferroptosis and activation of the cGAS-STING pathway.

A New N‐functionalized Pyrrole Derivative Bearing Ruthenium Tris(2,2’‐bipyridine) Subunit

AbstractIn recent years, nitrogen‐based ruthenium complexes have become an important material for dye‐sensitized solar cells and photo‐catalytic H2O and CO2 reduction research and applications, thanks to their charge transfer feature from the metal to the ligand. The electronic and spectral properties of such materials can be easily modified by changing the substituents and ligands. In this study, a new ruthenium (II) complex with N‐functionalized pyrrole derivative ([Ru(bpy)2(bpyCONHArPy)]+2 complex) was successfully synthesized and characterized. Its optical and electrochemical properties were studied by means of fluorescence, UV‐vis spectrometry, FTIR spectroscopy and cyclic voltammetry. These results were compared with that of its components (4‐(1H‐pyrrol‐1‐yl) aniline, N4,N4′‐bis(4‐(1H‐pyrrol‐1‐yl)phenyl)‐[2,2′‐bipyridine]‐4,4′‐dicarboxamide and ligand [Ru(bpy)3]+2). Related theoretical studies were also studied to find energy levels of complex. The present work is carried out to understand what chemical changes bring when combination of all the pieces of the puzzle into a chemical structure step by step.

Discovery of Arene Ruthenium(II) Complexes as Potential VEGF Inhibitors for Glioblastoma Metastasis Suppression.

Developing drugs for treating glioblastoma has been a significant challenge. Herein, a series of arene ruthenium(II) complexes have been synthesized and investigated as potential candidates to suppress the proliferation and metastasis of glioblastoma. It is found that para-substituent-modified molecules, especially 6, exhibit higher antitumor activity than ortho-substituents. Further studies show that 6 can trigger tumor cell autophagy by regulating the PI3K/AKT/mTOR pathway. Moreover, it is also found that 6 can induce DNA damage in glioblastoma cells through binding and stabilizing VEGF G-quadruplex DNA. Furthermore, it is confirmed that 6 can inhibit the proliferation and metastasis of U87-MG glioblastoma cell in situ xenograft in the zebrafish model. Hence, arene ruthenium(II) complexes can be developed as promising therapeutic agents for glioblastoma treatment in the future.

Advanced-designed Ru(II) complexes containing phosphinite ligands derived from chiral amino alcohols: Electrochemical behavior, DFT calculations, and biological activity

We report two phosphinite ligands derived from chiral amino alcohols, and their complexes with ruthenium(II). These compounds were characterized by spectroscopic methods. Then, antimicrobial, antioxidant, and DNA binding activities of the chiral Ru(II)-phosphinite complexes were tested. Complex (1R)-2-{benzyl[(1S)-1-(naphthalen-1-yl)ethyl]amino}-1-phenylethyl diphenylphos- phinito[dichloro(η6-p-cymene)ruthenium(II)], 7 showed both the highest radical scavenging activity (90.93 ± 0.98 %) and the highest metal chelating activity (65.45 ± 1.46 %) at 200.0 mg l-1 concentration. In addition, all of complexes had different rates of binding activity to calf thymus DNA (CT-DNA). Moreover, extensive theoretical and experimental investigations were conducted to gain a more profound understanding of the chemical descriptors and the diverse electronic transitions taking place within the ruthenium complexes, as well as their electrochemical characteristics.

Tailoring Ruthenium(II) and Rhenium(I) Complexes for Turn-On Luminescent Sensing of Antimony(III)

Antimony (Sb) is currently a widespread element with key roles in telecommunication, sustainable energy, and military industries, among others. Its significant toxicity determines the need to realize sensors for water, air, and soil and the industrial process monitoring of Sb species. Unfortunately, no antimony sensors exist so far, and just laboratory analysis methods are in use. We aimed to contribute to the development of optical sensors for the metalloid by tailoring, for the first time, luminescent Ru(II) and Re(I) polypyridyl complexes to probe and quantify the presence of Sb(III). The molecular design of the complexes includes the multifunctional Sb-binding 2-(2,2′-bithien-5-yl)-1H-imidazo[4,5-f]-1,10-phenanthroline (btip) ligand that ensures the molecular binding of Sb(III) in organic media. The Ru(II)-btip complex is additionally endowed with one 2,2′-bipyrazine (bpz) or two 1,4,5,8-tetraazaphenanthrene (tap) ligands, namely [Ru(bpz)(btip)2]2+ and [Ru(tap)2(btip)]2+, that boost the excited state oxidation potential of the probe, leading to an intramolecular photoinduced electron transfer from btip to the Ru(II) core. The latter is suppressed upon interaction with Sb(III), leading to an 11-fold increase in both the luminescence intensity and lifetime of [Ru(bpz)(btip)2]2+ in the presence of ca. 50 μmol L−1 of SbCl3 in organic medium. The fluorescence intensity of [Re(CO)3(H2O)(btip)]+ also increases upon interaction with Sb(III) but to a much lesser extent due to the intraligand π*→π nature of its emission compared to the Ru(II) ligand-to-metal excited state deactivation. However, the weak π*→d emission band in the red spectral region of the former is quenched by the semimetallic element. The sensing mechanisms of the Ru(II)- and Re(I)-btip probes that allow luminescence intensity (Ru, Re), ratiometric (Ru), and lifetime measurements (Ru) are compared and discussed in this initial solution sensing study.

Targeted Modulation of Photocatalytic Hydrogen Evolution Activity by Nickel-Substituted Rubredoxin through Functionalized Ruthenium Phototriggers.

Light-driven hydrogen evolution is a promising means of sustainable energy production to meet global energy demand. This study investigates the photocatalytic hydrogen evolution activity of nickel-substituted rubredoxin (NiRd), an artificial hydrogenase mimic, covalently attached to a ruthenium phototrigger (RuNiRd). By systematically modifying the para-substituents on Ru(II) polypyridyl complexes, we sought to optimize the intramolecular electron transfer processes within the RuNiRd system. A series of electron-donating and electron-withdrawing groups were introduced to tune the photophysical, photochemical, and electrochemical properties of the ruthenium complexes. Our findings reveal that electron-donating substituents can increase the hydrogen evolution capabilities of the artificial enzyme to a point; however, the complexes with the most electron-donating substituents suffer from short lifetimes and inefficient reductive quenching, rendering them inactive. The present work highlights the intricate balance required between driving force, lifetime, and quenching efficiency for effective light-driven catalysis, providing valuable insights into the design of artificial enzyme-photosensitizer constructs.

Synthesis, Characterization, and Biological Activity of New 4`-Functionalized Bis-Terpyridine Ruthenium(II) Complexes: Anti-inflammatory Activity Advances.

Ruthenium complexes incorporating 2,2':6',2''-terpyridine ligands have emerged as promising candidates due to their versatile biological activities including DNA-binding, anti-inflammatory, antimicrobial, and anticancer properties. In this study, three novel 4'-functionalized bis(terpyridine) ruthenium (II) complexes were synthesized. These complexes feature one ligand as 4-(2,2':6',2''-terpyridine-4'-yl) benzoic acid and the second ligand as either 4'-(2-thienyl)-2,2':6',2''-terpyridine, 4'-(3,4-dimethoxyphenyl)-2,2':6',2''-terpyridine, or 4'-(4-dimethylaminophenyl)-2,2':6',2''-terpyridine. Besides the chemical characterization by 1H and 13C NMR, mass spectrometry, and absorption and emission spectroscopy, the complexes were tested for their biological activity as anti-inflammatory, anticancer, and antimicrobial agents. Moreover, the toxicity of the Ru(II) complexes was assessed and benchmarked against diclofenac potassium and ibuprofen using a haemolysis assay. Biological evaluations demonstrate that these ruthenium complexes exhibit promising therapeutic potential with reduced haemolytic activity compared to standard drugs. They demonstrate substantial anti-inflammatory effects through inhibition of albumin denaturation along with moderate cytotoxicity against cancer cell lines and broad-spectrum antimicrobial activity. These findings highlight the multifaceted biomedical applications of 4'-functionalized bis(terpyridine) ruthenium (II) complexes, suggesting their potential for further development as effective and safe therapeutic agents.