Chemistry and Materials Science

Abstract: Two diastereoisomers of bis(mepirizole)bis(isothiocyanato-K,N)cobalt(II) (1 and 2) have been isolated from the reaction of cobalt(II) thiocyanate and meperizole depending on the crystallisation solvent (ethanol, 1; acetonitrile, 2). In both crystal structures, the Co(II) ions exhibit distorted octahedral [CoN₄N’₂] environment. The analysis of the packing frameworks shows a cooperative relationship between non-classical Hbonds C(sp³)H···X (X = N, O, S, pi) and pi-hole bonds, which control the arrangement of the supramolecular 3D networks. The values of the shortest intermolecular metal-metal separation are 8.584(2) in 1 and 8.249(1) in 2. Both diatereoisomers exhibit magnetic behavior typical of mononuclear Co(II) systems with significant zero-field splitting (ZFS) values, D being 75.8(1) and 52.9(2) cm-1 for 1 and 2, respectively. Q-band EPR studies confirm the positive value for the D parameters for both compounds. Alternating current dynamic susceptibility measurements show that 1 and 2 exhibit field-induced slow relaxation of the magnetization, which is reminiscent of single-ion magnet (SIM) behavior.

Abstract: The phase-pure syntheses of Fe(dca)₂ and Fe(dca)₂(NH₃)₂ have enabled comprehensive investigation of their structural and magnetic properties. Fe(dca)₂ crystallizes in the orthorhombic space group Pnnm, with Fe²⁺ ions octahedrally coordinated by six dca ligands, forming a rutile-like 3D network. Temperature-dependent structural analysis reveals minor distortions and a slight unit cell volume contraction (~2.5 ų) from 300 K to 25 K. Fe(dca)₂(NH₃)₂ crystallizes in the monoclinic space group P2₁/c, featuring two axial ammonia ligands and dca-bridged Fe²⁺ ions forming layers. Magnetic susceptibility measurements of Fe(dca)₂ reveal a ferrimagnetic transition at T_C = 19.1 K, con-firmed by SQUID data, Mößbauer spectroscopic measurements and low-temperature neutron diffraction. A magnetic hysteresis at 5 K indicates long-range cooperative magnetic ordering. ATR-IR spectroscopic measurements support the structural models and confirm the chemical composition of both compounds. TGA shows the thermal decomposition of Fe(dca)₂.

Abstract: The 17-e anion, [Fe(CO)₄]^- , was first characterised in 1981 by Breeze et al. We subsequently challenged their interpretation, suggesting that they had produced [Fe(CO)₃]^-. In the light of new calculations here, we withdraw that view. We confirm that [Fe(CO)₄]^- has the C_3v structure (as previously reported) and we have calculated the following, new, energy-factored force constants: k₁ = 1437.2 k₂ = 1456.2 k₁₁ = 48.6 k₁₂ = 47.7 where k₁ refers to the three chemically identical equatorial CO groups and k₂ refers to the sole axial CO group ( k₁₁ and k₁₂ are the CO,CO interaction constants). This force field is significantly different from that originally proposed.

Abstract: The treatment of Ce(OH)₄ in thionyl chloride and dimethoxyethane (DME) resulted in the formation of a highly unstable red Ce(IV) complex with the composition [CeCl₄(DME)₂] (1). From the reaction of 1 with the tripodal Kläui ligand η⁵-cyclopentadienyltris(dimethylphosphonato)cobaltate(III), [Co(η⁵-C₅H₅){P(O)(OMe)₂}₃]– (L_OMe), the two new cerium(III) complexes [Ce(L_OMe)₂(H₂O)₂]Cl·2.5H₂O (2), 1D-[Ce(μ-Cl)(L_OMe)(H₂O)₃]Cl (3) and the cerium(IV) complex [CeCl₂(L_OMe)₂]·acetone (4) were obtained and structurally characterized. The complexes 3 and 4 are the first cerium complexes featuring the L_OMe ligand together with chlorido ligands. Due to the potential exchange of the chloride counterions and ligands in 2 - 4, these complexes could serve as precursors in molecular cerium coordination chemistry. The assigned cerium oxidation states are supported by the bond valence sum (BVS) method. The ³¹P-NMR spectra with d(³¹P) = 160.20 ppm (2) and 159.43 ppm (3) are diagnostic of cerium(III).

Abstract: Pure and glycine-doped strontium formate dihydrate [Sr(HCOO)₂·2H₂O] single crystals were grown by slow evaporation using glycine concentrations of 0.005 – 0.1 M. The influence of glycine incorporation on structural, vibrational, electronic, and antimicrobial properties was studied experimentally and using DFT (B3LYP/6-311G**). The HOMO – LUMO gap (7.111 eV) indicates stability, while the hyperpolarizability (6973.787 a.u.) suggests potential nonlinear optical behavior. FT-IR and FT-Raman analyses show characteristic modes with slight shifts due to glycine–lattice interactions. Doped crystals exhibit enhanced antimicrobial activity, with a maximum inhibition zone of 36 mm against Escherichia coli at 0.1 M concentration. Results indicate that glycine affects the electronic and biological properties of strontium formate dihydrate, suggesting potential optical and antimicrobial applications.

Abstract: The amide macrocyclic complexes of zinc (ZnMc1, ZnMc2, and ZnMc3) were synthesized through template condensation of oxalic acid with different diamines (p-phenylenediamine, ethylenediamine, and propylenediamine). These zinc complexes were characterized using FT-IR, UV-Vis, conductance measurements, and DFT analysis, then tested for in vitro antibacterial and anticancer activities against Bacillus subtilis and HCT-15 cell lines, respectively. The results suggest that the complexes have promising antimicrobial and anticancer properties. The molecular structures of these zinc (II) complexes were also optimized theoretically, and their electronic and thermodynamic properties were determined with density functional theory (DFT). Finally, molecular docking studies using AutoDock evaluated the biological relevance of the synthesized complexes, identifying the most effective binding modes between the complexes and the receptor protein's active site. Two protein receptors, 6COX and 7AHL, were used to dock the macrocyclic complexes. The binding energies provide insights into their pharmaceutical potential. SwissADME and pkCSM were used to predict pharmacokinetic properties and toxicity. The ADMET profile of these macrocyclic architectures revealed their oral bioavailability and drug-like properties. Zinc complexes are known for their medicinal applications. So, these complexes were synthesized and studied as promising drug candidates for the future, though further research is needed to develop potent inhibitors.

Abstract: The removal of thorium from contaminated water sources is crucial for environmental protection and nuclear waste management. Herein, we present a dual-strategy design of a thiophene-integrated porphyrin covalent organic framework (TAPP-BTD-COF) that combines rigid macrocyclic scaffolds with flexible thiophene linkages, incorporating complementary N and S donor sites. This tailored COF achieves efficient and selective capture of Th(IV) from acidic aqueous solutions. By leveraging the topological arrangement of the porphyrin core to modulate the conformation of thiophene-based connectors, a coordination environment with N–S synergistic sites is created, which significantly enhances Th(IV) selectivity over competing ions. At pH 4.5, the synthesized TAPP-BTD-COF exhibits a high adsorption capacity of 437.18 mg g-1 and reaches equilibrium within 20 minutes. It demonstrates exceptional selectivity for Th(IV), with a separation factor exceeding 2.6×10³ relative to common interfering ions, and retains over 90% adsorption capacity after three consecutive cycles. Mechanistic studies confirm that the high performance originates from N–Th / S–Th dual-dentate coordination. This work provides a strategic design of functional COFs for thorium recovery and represents a highly efficient adsorbent system for Th(IV) removal from aqueous streams.

Abstract: Reactive oxygen species (ROS)-mediated cancer therapy has attracted extensive attention due to its high spatiotemporal selectivity and minimum side-effects. Herein, we report a nonanuclear Pd-based coordination cage of Pd6-TMPP(Ni), constructed from Ni-chelated TMPP(Ni) as the metalloligand and Pd2+ ions (H2TMPP = meso-tetrakis (6-methylpyridin-3-yl) porphyrin). Pd6-TMPP(Ni) integrates dual ROS-generation for cancer therapy, viz., hydroxyl radical (•OH) production and photoinduced singlet oxygen (1O2) generation. In vitro cytotoxicity assays against cancer cell lines NCI-H82 (lung cancer), A549 (lung cancer), KYSE-510 (esophageal cancer), and Te-1 (esophageal cancer), reveal its potent dark toxicity (IC₅₀: 1.867–2.107 μmol L−1) and phototoxicity (IC₅₀: 0.835–1.528 μmol L−1), which is attributed to enhanced intracellular ROS accumulation. This work develops a versatile therapeutic platform that harnesses Ni-induced •OH for chemodynamic therapy (CDT) and porphyrin-generated ¹O₂ for photodynamic therapy (PDT), thereby mitigating the oxygen dependence of conventional PDT.

Abstract: In this work, the activity of vanadium-doped and undoped phosphomolybdic acids, H3+n PMo12-nVnO40 (n = 0, 1, 2 and 3), was evaluated in the acetalization reaction of furfural with alkyl alcohols. The main focus was to verify how vanadium charge impact catalytic activity of phosphomolybdic acid, and to try to link these effects to changes in their structural properties. The main reaction parameters such as catalyst charge, catalyst concentration, temperature, time, type of alcohol, type of aldehyde, vanadium charge, and H+ ion charge were studied. Various Brønsted acids (sulfuric, p-toluenesulfonic, undoped and doped phosphomolybdic acids) were evaluated in condensation reactions of furfural with methyl alcohol. Notably, H4PMo11V1O40 was the most active and selective catalyst toward the formation of methyl acetal furfural. The water has a leveling effect over the strength of these acids. Nonetheless, under reaction conditions, the presence vanadium impacted the strength of phosphomolybdic acids, allowing distinguish what is the strongest; vanadium monosubstituted phosphomolybdic acid. The superior performance of H4PMo11V1O40 was attributed to its additional acidity, resulting from the presence of very strong (H+) and Lewis and Brønsted acid sites, due to the substitution of Mo6+ by V5+ in its structure.

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.