Abstract: Well-defined, small-molecule, platinum-centered coordination compounds are of continued interest in both basic and applied research, particularly in medicinal chemistry and pharmaceuticals (i.e., cisplatin). Organoplatinum(IV) complexes have been reported to exhibit substantial in vitro cytotoxicity across a range of cancer cell lines. Compared with coordinatively unsaturated platinum(II) species, electronically and coordinatively saturated platinum(IV) complexes are generally more inert, reducing undesirable side reactions in plasma and cellular environments and potentially improving their safety profiles as chemotherapeutic agents. In addition, the presence of organic ligands can enhance lipophilicity, facilitating passive diffusion across cell membranes. Here, we report the synthesis, structural characterization, and in vitro anticancer activity of a series of organoplatinum(IV) complexes of the general formula Pt(CH₃)₂I₂{n,n′-dimethyl-2,2′-bipyridine} (n,n′ = 4,4′; 5,5′; 6,6′). The 5,5′- and 6,6′-dimethyl isomers were characterized by single-crystal X-ray diffraction. All three dimethyl-substituted complexes, along with the parent compound Pt(CH₃)₂I₂{2,2′-bipyridine}, were evaluated for cytotoxic activity against a panel of 60 human cancer cell lines. Whereas Pt(CH₃)₂I₂{2,2′-bipyridine} and the 4,4′- and 5,5′-dimethyl derivatives displayed limited cytotoxicity, the 6,6′-dimethyl isomer exhibited notable activity, particularly against the colon cancer cell line HCT-116 (LC₅₀ = 8.17 M) and the ovarian cancer cell line OVCAR-3 (LC₅₀ = 7.34 M). The enhanced cytotoxicity of the 6,6′-dimethyl derivative is attributed, at least in part, to the relatively facile dissociation of the 6,6′-dimethyl-2,2′-bipyridine ligand from the platinum(IV) center, suggesting that sterically induced ligand lability plays an important role in modulating biological activity in this particular compound, giving new structural activity impetus for potential drug molecules.

Abstract: This work investigates the potential of wollastonite-based brushite cement (WBC) for the stabilization and solidification of radioactive waste contaminated by ⁹⁰Sr. This phosphate binder was formed by the reaction of wollastonite (CaSiO₃) with a phosphoric acid solution containing borax and metallic cations (Al³⁺, Zn²⁺). Two cement pastes were investigated: a commercial binder (WBC-C) and an optimized formulation (WBC-O), produced using a zinc-free mixing solution with a higher aluminum content than that of WBC-C. Both materials mainly contained amorphous hydrated silica and calcium aluminophosphate, along with crystalline brushite, residual wollastonite, and quartz. The stability of WBC-C under γ-irradiation was evaluated up to a dose of 1 MGy. The only observable effect was water radiolysis, leading to dihydrogen production at yields comparable to Portland cement matrices and geopolymers. Strontium leaching, assessed using the ANSI/ANS-16.1 procedure, followed a two-stage release mechanism combining surface wash-off and diffusion. The apparent diffusion coefficient D_a of Sr in WBC-C was three orders of magnitude lower than typical values reported for Portland cement matrices. WBC-O showed enhanced Sr retention due to its higher aluminum content, which refines mesopores and reduces diffusion pathways accessible to Sr. WBC binders therefore appear to be promising candidates for strontium immobilization.

Abstract: Ammonium N-ethyloxamate (AmEtOxam) was synthesized, fully characterized by microanalytical and spectroscopic means, and assayed as a precursor of calcium oxalate, acting as a protecting agent for white Carrara marble. The monohydrate form of AmEtOxam shows a water solubility of 1.5 mol·L–1 (~23% w/w), significantly higher than that of common calcium oxalate precursors (CaOx), such as ammonium oxalate (0.4 mol·L–1, ~5% w/w). While AmEtOxam is stable in water solution and in the solid state in its monohydrate form, , during the application on carbonate stone it undergoes a complete hydrolysis resulting in the formation of an uniform weddellite layer (CaC2O4·2H2O) on carbonate stone surfaces. Application of 5% w/w aqueous solutions by spraying, brushing, and immersion resulted in different effects. Spraying yielded the most balanced performance, improving mechanical strength, reducing water absorption, recovering superficial tension, and limiting chromatic alteration. Brushing achieved significant gain in surface hardness with minimal aesthetic impact. Immersion most effectively reduced porosity and increased surface tension. These results, coupled with the negligible chromatic changes induced in all cases, make AmEtOxam a promising candidate for the conservation of stone cultural heritage.

Abstract: In this work, a CdS–MoS₂–rGO thin-film photocathode was fabricated on FTO substrates via a single-ink drop–spin-coating method followed by annealing under N₂ atmosphere. Among the studied compositions, the film containing 86:9:5 wt% of CdS, MoS₂, and rGO exhibited the best photoelectrochemical performance. Under visible-light illumination from a 50 W halogen lamp (~0.25 sun) in neutral electrolyte, the optimized photocathode achieved a photocurrent density of 0.83 mA cm⁻² at −0.75 V vs Ag/AgCl and retained approximately 96% of its initial current during 60 min of chopped-light operation. Electrochemical impedance spectroscopy revealed a reduced charge-transfer resistance (~120 Ω·cm²), while the Tafel slope decreased to ~85 mV dec⁻¹, indicating enhanced charge transfer and hydrogen evolution kinetics. Hydrogen production was confirmed by gas chromatography, with an evolution rate of ~58.6 μmol h⁻¹. The improved performance is attributed to the synergistic roles of CdS as the light absorber, rGO as an electron-transport network, and MoS₂ as a cocatalyst. These results demonstrate the potential of the CdS–MoS₂–rGO architecture for photoelectrochemical hydrogen evolution under neutral conditions.

Abstract: Reported are the synthesis and the detailed analysis of the crystal and electronic structure of the novel Zintl phase Eu9Zn4.5As9. This material was identified in the densely populated Eu–Zn–As compositional space. For structure determination and for property measurements, suitable single crystals of this compound were grown from either Sn- or Pb-flux. Single-crystal X-ray diffraction methods indicate that Eu9Zn4.5As9 crystallizes in the orthorhombic crystal system with the space group Pnma (a = 12.1953(7) Å, b = 4.3730(2) Å, c = 42.674(2) Å) and is formally isostructural to Ca9Mn4+xSb9, the less common “9–4–9” type. The structure is heavily disordered, with multiple partially occupied sites, yet, according to the Zintl-Klemm formalism, a charge-balanced composition (Eu2+)9(Zn2+)4.5(As3−)9 is attained. Electronic structure calculations for a model, disorder-free structure indicate no energy gap between the valence and the conduction bands, and suggest a (semi)metallic behavior. Preliminary susceptibility measurements confirm the expected divalent nature of Eu2+ ([Xe] 4f7 ground state).

Abstract:

The crystal structures of the cobalt(II) metal-organic frameworks or coordination networks [Co(pdb)(DMF)] and [Co₂(pdi)(DMF)₃]·2(DMF)·H₂O (H₂pdb = 3,3′-(phenazine-5,10-diyl)dibenzoic acid, H₄pdi = 5,5′-(phenazine-5,10-diyl)diisophthalic acid, DMF = N,N-dimethylformamide) were synthesized solvothermally from cobalt(II) nitrate and the free acid of the linker in DMF. In catena-[(N,N-dimethylformamide)-μ₄-3,3′-(phenazine-5,10-diyl)dibenzoate-cobalt(II)], [Co(pdb)(DMF)], the Co₂ handles as secondary building units are surrounded by four carboxylate groups from four linkers in a paddle-wheel arrangement giving a three-dimensional (3D) network with cds (or CdSO₄) topology in which the wide openings are filled by two symmetry related nets to a threefold interpenetrated structure. In catena-[tris(N,N-dimethylformamide)-μ₈-5,5′-(phenazine-5,10-diyl)diisophthalate-dicobalt(II)] bis(N,N-dimethylformamide) hydrate, [Co₂(pdi)(DMF)3]·2(DMF)·H₂O, there are two different Co atoms from which only Co₂ is connected to each of the four carboxyl groups of the tetracarboxyl linker and, thus, is responsible for the 3D network formation. The network topology in [Co₂(pdi)(DMF)₃] is pts (or platinum(II) sulfide) when taking the Co₂ atom as a tetrahedral and the linker as a square-planar fourfold node which is, however, inverse from the common square-planar metal and tetrahedral linker nodes in PtS and most pts topologies.

Abstract:

The family of N,N-dimethylaminomethylferrocenes is one of the most important in ferrocene chemistry. They serve as precursors for a range of anti-malaria and anti-tumour medicinal compounds in addition to being key precursors for ferrocene ligands in the Lucite alpha process. A brief discussion on the importance of, and the synthesis of N,N-dimethylaminomethyl-substituted ferrocenes preludes the synthesis of the new ligand 1,1´,2,2´-tetrakis-(N,N-dimethylaminomethyl)ferrocene. The crystal structure of this compound is reported and a comparison is made with its disubstituted analogue, 1,2-bis-(N,N-dimethylaminomethyl)ferrocene. The tetrahedral nickel dichloride complexes of both these ligands have been crystallographically characterised. Finally, a pointer to future research in the area is given which includes a discussion of a new method to extract ferrocenylmethylamines from mixtures using additives and a new synthetic avenue from substituted cyclopentadiene itself.

Abstract:

Chromium complexes with triamidoamine derivatives bearing bulky substituents at the terminal positions of the ligands, tris(2-(3-pentylamino)ethyl)amine (H₃L^Pen) and tris(3-dicyclohexylmethylaminoethyl)amine (H₃L^Cy), have been prepared: [{Cr(L^Pen)}₂(m-N₂)] (1), [{CrK(L^Pen)(m-N₂)(Et₂O)}₂] (2), [CrCl(L^Pen)] (3), [Cr(L^Cy)] (4), [CrK(L^Cy)(m-N₂)(18–crown–6)(THF)] (5(THF)), and [CrCl(L^Cy)] (6)). The preparation of these complexes has been confirmed by X-ray diffraction analysis. Complexes 1, 2, and 5(THF) have coordinated dinitrogen molecules, with N–N bond lengths of 1.185(3), 1.174(9), and 1.162(3) Å, respectively. These lengths are significantly elongated compared to that of free dinitrogen molecule (1.10 Å), indicating that the N₂ ligands are activated. The n(¹⁴N–¹⁴N) values of 1, 2, and 5(THF) are 1715 cm^-1 (n(¹⁵N–¹⁵N): 1651 cm^-1) for 1 (Raman, in solution), 1787, 1743 cm^-1 (n(¹⁵N–¹⁵N) 1728, 1687 cm^-1) for 2 (IR, in solid), and 1824 cm^-1 (n(¹⁵N–¹⁵N) 1757 cm^-1) for 5(THF) (IR, in solid), respectively. These values are markedly smaller than free nitrogen (2331 cm^-1), confirming that the dinitrogen is interacting with the metal ions and activated. The structures of 2 and 5(THF) in solution have also been studied by ¹H NMR and solution IR spectroscopies. ¹H NMR spectra of these complexes have revealed that the peaks of 2 and 5(THF) have been observed in the diamagnetic region, whereas those for the other complexes (1, 3, 4, and 6) have exhibited paramagnetic shifts. The reactions of these complexes with K[C₁₀H₈] and HOTf under N₂ in THF have yielded hydrazine and a small amount of ammonia, however, they have not been catalytic. The ¹H NMR and IR spectra of the products obtained by reacting 1 or 3 with reductant K in THF under N₂ atmosphere have indicated that 2 has been formed based on spectral agreement. Similarly, upon examining for 4 or 6, it has been confirmed that a species similar to 5(THF) has been generated.

Abstract:

Microwave heating has a good number of advantages in the synthesis of inorganic compounds when opportunely exploited. A deep knowledge of the interaction of the electromagnetic waves and matter is necessary to optimize irradiation of the reactor vessel so that to obtain homogeneous heating for homogeneous nucleation and growth of particle, localized heating of starting self-sustained high temperature synthesis and generate superfast heating and cooling profile to get metastable crystals. Case studies of pure oxides, mixed oxides, composites, phosphates, zeolites, and high entropy alloys have been discussed in the international frame of the academic and industrial research covering the last 20 years of microwave chemistry where Italian researchers covered a relevant role.

Abstract: Platinum-based drugs play a pivotal role in contemporary cancer treatment, but their therapeutic utility is often limited by acquired resistance. The diiodido analogue, cis-PtI2(NH3)2 is a promising derivative that has demonstrated the ability to overcome cis-platin resistance in vitro. To establish the molecular basis for this superior activity, we integrated experimental 14N Nuclear Magnetic Resonance (NMR) spectroscopy with computational density functional theory (DFT) methods to precisely and comparatively understand the drug activation mechanisms. Comparative 14N NMR experiments elucidated the initial ligand substitution step, confirming halide displacement and a markedly higher tendency for ammonia release from cis-PtI2(NH3)2, particularly when reacting with sul-fur-containing amino acids. Complementary DFT calculations determined the substitution energy values, revealing that the superior leaving-group ability of iodide results in a thermodynamically more favorable activation. Conceptual DFT parameters (softness, hardness, and Fukui indices) further demonstrated that initial substitution induces a strong trans effect, leading to the electronic sensitization of the remaining iodide ligand. This strong agreement between computational predictions and experimental data establishes a coherent molecular activation mechanism for cis-PtI2(NH3)2 demonstrating that iodide substitution promotes both thermodynamic and electronic activation of the plati-num center, which is the key to its distinct pharmacological profile and ability to circumvent resistance.

Abstract: This paper presents the synthesis of novel copper(II) metal complex with ethyl 2-(methylcarbamoyl)phenyl) carbamate and 3-methylquinazoline-2,4(1H,3H)-dione. The charac-terization of compound was conducted through various techniques, including melting point de-termination, IR, 1H NMR, and 13C NMR spectroscopy. The coordination compound was obtained after mixing water solutions of the metal salt and the ligand dissolved in DMSO and water solu-tions of NaOH, in metal-to-ligand to base ratio 1:2:2. The ligand and the metal chloride were brought in to reaction at room temperature in DMSO and H2O as solvents, respectively. We as-sume that the ligands are coordinated through N-donor atom. The results indicate the successful formation of a stable mixed-ligand Cu(II) coordination compound involving N-donor ligands. Spectroscopic data suggest that the deprotonated ligand (3-methylquinazoline-2,4(1H,3H)-dione) by using (NaOH) coordinated to metal ion as monodentate ligand through the nitrogen atom of the NH and ethyl 2-(methylcarbamoyl)phenyl) carbamate coordinated as a monodentate through the nitrogen atom of amide group.

Abstract: The synthesis and systematic investigation of inorganic and organic compounds represent a crucial area in medicinal and pharmaceutical chemistry, particularly in the pursuit of novel therapeutic agents. This study reports on the preparation, structural analysis, and evaluation of selected inorganic and organic compounds with emphasis on their physicochemical characteristics and biological activities. Both categories of compounds were examined for their potential therapeutic relevance, including anticancer, antimicrobial, and anti-inflammatory properties. Inorganic complexes, particularly those incorporating transition metals, demonstrated promising activity that may be attributed to their ability to interact with bimolecular targets and modulate cellular pathways. Similarly, organic derivatives revealed bioactive features that merit further exploration. Collectively, the results underscore the therapeutic potential of synthesized compounds and contribute to the growing field of drug design involving both inorganic and organic frameworks. This work emphasizes the integration of synthetic chemistry, as well as natural products with biological evaluation as a pathway toward identifying effective molecules with clinical relevance. Here, we highlighted some of the most recently developed Au(I/III), Pt(II/IV) and Ru(II/III) complexes that have shown significant in vivo antitumor properties between 2016 and 2025, as well as the antimicrobial and anti-inflammatory properties of different inorganic and organic compounds. Our review emphasizes on gold, platinum and ruthenium complexes synthesis and characterizations of inorganic and organic compounds with biomedical potential. The main focus is on the antitumor effects reported in 89 articles of inorganic and organic compounds, 53 on antimicrobial action and 17 on anti-inflammatory activities. In our review we cover the synthesis (30 articles) and characterizations (30 papers) of inorganic and organic compounds with potential biological and therapeutic effects. It is anticipated that this review will serve as a valuable resource in the future, particularly for professionals engaged in clinical, medical, and health-related disciplines.

Abstract: Photoactivatable nitric oxide donors (photoNORMs) are promising agents for con-trolled NO release and real-time optical tracking in biomedical theranostics. Here, we report a comprehensive density functional theory (DFT) and time-dependent DFT (TDDFT) study on a series of hybrid ruthenium–gold nanocluster systems of the gen-eral formula [(L)Ru(NO)(SH)@Au₂₀], where L = salen, bpb, porphyrin, or phthalocya-nine. Structural and bonding analyses reveal that the Ru–NO bond maintains a formal {RuNO}⁶ configuration with pronounced Ru→π*(NO) backbonding, leading to partial reduction of the NO ligand and an elongated N–O bond. NBO, NEDA, and ETS–NOCV analyses confirm that Ru–NO bonding is dominated by charge-transfer and polariza-tion components, while Ru–S and Au–S linkages exhibit delocalized, donor–acceptor character coupling the molecular chromophore with the metallic cluster. TDDFT re-sults reproduce visible–NIR absorption features arising from mixed metal-to-ligand and cluster-mediated charge-transfer transitions. The calculated zero–zero transition and reorganization energies predict NIR-II emission (1.8–3.8 μm), a region of high bi-omedical transparency, making these systems ideal candidates for luminescence-based NO sensing and therapy. This study establishes fundamental design principles for next-generation Ru-based photoNORMs integrated with plasmonic gold nanoclusters, highlighting their potential as multifunctional, optically trackable theranostic platforms.

Abstract: We report the synthesis, structural characterization, and ultrafast photophysical in-vestigation of a novel series of homoleptic and heteroleptic Zn(II) β-diketonates de-rived from donor–acceptor ligands. Single-crystal X-ray diffraction revealed that all complexes adopt monomeric octahedral geometries, with ancillary nitrogen-based ligands inducing variable distortions. UV–Vis absorption and femtosecond transient absorption spectroscopy established that the chelated β-diketonate ring constitutes the primary optically active chromophore, while Zn coordination markedly alters excit-ed-state dynamics. In contrast to the free ligand, which undergoes rapid internal con-version, Zn binding stabilizes the triplet state, generating a long-lived and chemically reactive species. Thermal and mass spectrometric analyses confirmed their stability and decomposition pathways, supporting their potential use as precursors for la-ser-induced three-dimensional ZnO growth. Such features underline the relevance of these complexes in photonic and electronic applications where controlled nanostruc-ture development is required. Overall, these findings provide fundamental insights into structure–photophysics relationships in Zn β-diketonates. They demonstrate how tailored ligand environments can be exploited to tune excited-state properties, offering a rational framework for the design of functional precursors suitable for nonlinear photolysis and advanced nanomaterial synthesis.

Abstract:

The oxygen deficient tungsten oxide W₁₈O₄₉ was synthesized through lattice oxygen escaping at high temperature in N₂ atmosphere. The temperature and inert atmosphere were critical conditions to initiate the lattice oxygen escaping to obtain W₁₈O₄₉. The synthesized tungsten oxides were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS) and ultraviolet-visible absorption spectroscope (UV-Vis). The composite gel was fabricated by the oxygen deficient tungsten oxide insertion into PVA-based gel, which was cross linked by glutaraldehyde. The gel was characterized by Fourier transform infrared (FTIR) spectroscopy and solar steam generation test. The result of the solar steam generation shows that the W₁₈O₄₉-PVA gel (steam generation rate 2.63 kg m^-2 h^-1) was faster than that of the pure PVA gel.

Abstract: Although spontaneous or complexation-induced reductions of Cu^II to Cu^I have occasionally been observed, controlling these processes remains a challenge. Herein, we report the synthesis of Cu^I complexes via the complexation-induced reduction of Cu^II complexes with pyridine-containing N₄ Schiff-base ligand L incorporating a biphenyl unit (L = N,N'-([1,1'-biphenyl]-2,2'-diyl)bis(1-(6-methylpyridin-2-yl)methanimine)). Such a reduction has not yet been observed in previously reported Cu^II complexes with pyridine-containing N₄ Schiff-base ligands, strongly suggesting that the torsional distortion of the ligand framework induced by the biphenyl moiety effectively promotes the complexation-induced reduction of Cu^II to Cu^I. The Cu^I complexes were thoroughly characterized by ¹H NMR spectroscopy, UV–vis–NIR spectroscopy, and single-crystal X-ray diffraction analyses. The [Cu^I(L)]⁺ complex undergoes a reversible redox process with its oxidized species, which was identified as a Cu^II complex based on spectroelectrochemical measurements and theoretical calculations.

Abstract: Two Nitrogen-modified mesoporous MCM-41 type silicas were synthesized by the sol-gel route and post-grafting surface modification procedure, obtaining an aminopropyl-modified MCM-41 (denoted MCM-41-N) and an aminoethyl-aminopropyl-modified MCM-41 (denoted MCM-41-NN). Hexavalent chromium removal from acidified water by adsorption and reduction to Cr(III) on the solid mesophases was analyzed. The modified silicas were characterized by powder X-ray diffraction, infrared spectroscopy, nitrogen adsorption-desorption measurements at -196 °C, X-ray photoelectron spectroscopy, 29Si solid state Nuclear Magnetic Resonance, and thermogravimetric analysis. Both samples exhibited very high capacities for decreasing Cr(VI) concentrations in water, according to the Langmuir isotherm model: 129.9 mg·g-1 for MCM-41-N and 133.3 mg·g-1for MCM-41-NN. The chromium speciation in the supernatant after 24 h indicates that MCM-41-N had a higher capacity to reduce Cr(VI) to the less toxic Cr(III) species than MCM-41-NN: 92.9 % vs 72.5 % when the initial Cr(VI) concentration was 10 ppm. These differences were related to the different capacity of nitrogen atoms in MCM-41-N and MCM-41-NN to interact with the surrounding surface silanols which are required for the chemical reduction of the hexavalent species to take place, as evidenced by infrared spectroscopy and X-ray photoelectron spectroscopy analysis. Also, the Cr(III)/Cr(VI) atomic ratios on the solid’s surfaces were higher for MCM-41-N. These results highlight the characteristics that nitrogen atoms incorporated to silica matrices must possess in order to maximize the transformation of Cr(VI) into the trivalent species, thereby reducing the generation of toxic waste harmful to living organisms.

Abstract: In recent years, researchers have made great efforts to develop effective semiconductor photocatalysts to harness the visible spectrum of sunlight in photocatalytic applications. Bismuth vanadate, BiVO4, has emerged as one of the most promising candidates for photocatalytic applications among few non-titania based visible light driven semiconductor photocatalysts. The BiVO4-based structures are intensively studied due to their exceptional ionic conductivity, photocatalytic behavior under ultra-violet and visible light, dielectric properties, ferroelastic and paraelastic phase transitions, and strong pigmentation. BiVO4 occurs in nature in three crystalline structures: orthorhombic pucherite, tetragonal dreyerite (tz), and monoclinic clinobisvanite (ms). All three crystal structures of BiVO4 are n-type semiconductors with corresponding energy gap values of 2.34, 2.40 and 2.90 eV, respectively. Different methods of synthesis have been reported for preparation of BiVO4 structures of varying morphologies and sizes. The morphology of BiVO4 is strongly influenced by the preparation method and reaction parameters. A comprehensive systematic study of developments, preparation methods, structure, different properties and advances in different applications over the past decade in research on BiVO4 based structure will be described. Finally, the current challenges and future outlook of the BiVO4 based structure will be highlighted, in the hope of contributing to guidelines for the future applications.

Abstract: Given the outstanding magnetic characteristics of lanthanide ions, the development of lanthanide complexes, transitioning from mononuclear to multinuclear, becomes imperative. Previous research utilized rhodamine Schiff base ligands to synthesize a series of mononuclear complexes exhibiting remarkable single-molecule magnetic properties alongside fluorescence characteristics. In the current study, we designed analogous ligands to synthesize complexes [Dy(HL1-o)(NO3)2(CH3OH)2]NO3·CH3OH (complex 1) and tetranuclear [Ln4(L1-c)2(L2)2(μ3-OH)2(NO3)2(CH3OH)4](NO3)2·2CH3CN·5CH3OH·2H2O (Ln = Dy, complex 2; Ln = Gd, complex 3), spanning from mononuclear to tetranuclear molecules. Magnetic susceptibility measurements show that 1 is a single-molecule magnet with Ueff = 33.2(10) K, 2 shows slow magnetic relaxation and 3 is a magnetic cooling material with the magnetic entropy change of 9.81 J kg−1 K−1 at 2 K and 5 T.

Abstract: Searching for new and efficient transfer hydrogenation catalysts, a series of new organometallic ruthenium(II)-arene complexes of the formulae [Ru(η6-p-cymene)(L)Cl][PF6] (1–8) and [Ru(η6-p-cymene)(L)Cl][Ru(η6-p-cymene)Cl3] (9–11) were synthesized and fully characterized. These were prepared from the reaction of pyridine-quinoline and biquinoline-based ligands (L) with [Ru(η6-p-cymene)(μ-Cl)Cl]2, in 1:2 and 1:1, metal (M) to ligand (L) molar ratios. Characterization includes a combination of spectroscopic methods (FT-IR, UV-Vis, multi nuclear NMR), elemental analysis and single-crystal X-ray crystallography. The pyridine-quinoline organic entities encountered, were prepared in high yield either via the thermal decarboxylation of the carboxylic acid congeners, namely 2,2′-pyridyl-quinoline-4-carboxylic acid (pqca), 8-methyl-2,2′-pyridyl-quinoline-4-carboxylic acid (8-Mepqca), 6′-methyl-2,2′-pyridyl-quinoline-4-carboxylic acid (6′-Mepqca) and 8,6′-dimethyl-2,2′-pyridyl- quinoline-4-carboxylic acid (8,6′-Me2pqca), affording the desired ligands pq, 8-Mepq, 6′-Mepq and 8,6′-Me2pq, or by the classical Friedländer condensation, to yield 4,6′-dimethyl-2,2′-pyridyl-quinoline (4,6΄-Me2pq) and 4-methyl-2,2′-pyridyl-quinoline (4-Mepq) respectively. The solid-state structures of complexes 1–4, 6, 8 and 9 were determined showing a distorted octahedral coordination geometry. The unit cell of 3 contains two independent molecules (Ru-3), (Ru′-3) in a 1:1 ratio, due to a slight rotation of the arene ring. All complexes catalyze the transfer hydrogenation of acetophenone, using 2-propanol as a hydrogen donor in the presence of KΟiPr. Among them, complexes 1 and 5 bearing methyl groups at the 8 and 4 position of the quinoline moiety, convert acetophenone to 1-phenylethanol quantitatively, within approximately 10 minutes with final TOFs of 1600 h–1. The catalytic performance of complexes 1–11, towards the transfer hydrogenation of p-substituted acetophenone derivatives and benzophenone, ranges from moderate to excellent. An inner-sphere mechanism has been suggested based on the detection of ruthenium(II) hydride species.