Inorganics

Tethering known drugs to a metalorganic moiety is an efficient approach for modulating the anticancer, antibacterial, and antiparasitic activity of organometallic complexes. This study focused on the synthesis and evaluation of new dinuclear ruthenium(II)–arene compounds linked to several antimicrobial compounds such as dapsone, sulfamethoxazole, sulfadiazine, sulfadoxine, triclosan, metronidazole, ciprofloxacin, as well as menadione (a 1,4-naphtoquinone derivative). In a primary screen, 30 compounds (17 hybrid molecules, diruthenium intermediates, and antimicrobials) were assessed for in vitro activity against transgenic T. gondii tachyzoites constitutively expressing β-galactosidase (T. gondii β-gal) at 0.1 and 1 µM. In parallel, the cytotoxicity in noninfected host cells (human foreskin fibroblasts, HFF) was determined by an alamarBlue assay. When assessed at 1 µM, five compounds strongly impaired parasite proliferation by >90%, and HFF viability was retained at 50% or more, and they were further subjected to T. gondii β-gal dose-response studies. Two compounds, notably 11 and 13, amide and ester conjugates with sulfadoxine and metronidazole, exhibited low IC₅₀ (half-maximal inhibitory concentration) values 0.063 and 0.152 µM, and low or intermediate impairment of HFF viability at 2.5 µM (83 and 64%). The nature of the anchored drug as well as that of the linking unit impacted the biological activity. Full article

Chemical routes for the synthesis of nanostructures are fundamental in nanoscience. Among the different strategies for the production of nanostructures, this article reviews the fundamentals of the bottom-up approaches, focusing on wet chemistry synthesis. It offers a general view on the synthesis of different inorganic and hybrid organic–inorganic nanostructures such as ceramics, metal, and semiconductor nanoparticles, mesoporous structures, and metal–organic frameworks. This review article is especially written for a wide audience demanding a text focused on the basic concepts and ideas of the synthesis of inorganic and hybrid nanostructures. It is styled for both early researchers who are starting to work on this topic and also non-specialist readers with a basic background on chemistry. Updated references and texts that provide a deeper discussion and describing the different synthesis strategies in detail are given, as well as a section on the current perspectives and possible future evolution. Full article

The Lucite Alpha process is the predominant technology for the preparation of acrylics. This two-stage process involves the palladium-catalysed formation of methyl propanoate from ethene, CO, and methanol, followed by the oxidative formylation of methyl propanoate into methyl methacrylate. A range of bis-1,2-disubstituted aminomethylferrocenes has been prepared and characterised. These complexes serve as precursors to a variety of bulky ferrocenylmethyldiphosphanes that, in turn, function as ligands in the palladium-catalysed process. We describe the crystal structures of five ligand precursors and provide a rationale for their design. In situ catalyst testing on palladium complexes derived from ferrocenylphosphanes demonstrates that these are highly selective (>99.5%) catalysts for the formation of methyl propanoate from ethene, CO, and methanol and have turnover numbers exceeding 50,000. This article credits those researchers who worked on this project in the early days, who received little or no credit for their achievements and endeavours. Full article

This review summarizes the current status of the application of metal halide perovskites (MHPs) as photocatalysts in organic syntheses/transformations. It is shown that the optimal and unique electronic properties of MHPs can be advantageously used in several reaction types providing pros with respect to traditional photocatalysts. While still being at infancy, such field of application of MHPs as effective photocatalysts will for sure become a central research topic in the forthcoming years, thanks also to their rich structural and chemical tunability, which may provide tailored materials for most of the envisaged organic reactions. Full article

Although the application of arene-osmium(II) complexes in homogeneous catalysis has been much less studied than that of their ruthenium analogues, different works have shown that, in some instances, a comparable or even superior effectiveness can be achieved with this particular class of compounds. This review article focuses on the catalytic applications of arene-osmium(II) complexes. Among others, transfer hydrogenation, hydrogenation, oxidation, and nitrile hydration reactions, as well as different C-C bond forming processes, are comprehensively discussed. Full article

The isomers 4′-(4-(trifluoromethyl)phenyl)-4,2′:6′,4″-terpyridine (1), 4′-(3-(trifluoromethyl)phenyl)-4,2′:6′,4″-terpyridine (2), 4′-(4-(trifluoromethyl)phenyl)-3,2′:6′,3″-terpyridine (3), and 4′-(3-(trifluoromethyl)phenyl)-3,2′:6′,3″-terpyridine (4) have been prepared and characterized. The single crystal structures of 1 and 2 were determined. The 1D-polymers [Cu₂(hfacac)₄(1)₂]_n·2nC₆H₄Cl₂ (Hhfacac = 1,1,1,5,5,5-hexafluoropentane-2,4-dione), [Cu(hfacac)₂(2)]_n·2nC₆H₅Me, [Cu₂(hfacac)₄(3)₂]_n·nC₆H₄Cl₂, [Cu₂(hfacac)₄(3)₂]_n·nC₆H₅Cl, and [Cu(hfacac)₂(4)]_n·nC₆H₅Cl have been formed by reactions of 1, 2, 3 and 4 with [Cu(hfacac)₂]·H₂O under conditions of crystal growth by layering and four of these coordination polymers have been formed on a preparative scale. [Cu₂(hfacac)₄(1)₂]_n·2nC₆H₄Cl₂ and [Cu(hfacac)₂(2)]_n·2nC₆H₅Me are zig-zag chains and the different substitution position of the CF₃ group in 1 and 2 does not affect this motif. Packing of the polymer chains is governed mainly by C–F...F–C contacts, and there are no inter-polymer π-stacking interactions. The conformation of the 3,2′:6′,3″-tpy unit in [Cu₂(hfacac)₄(3)₂]_n·nC₆H₄Cl₂ and [Cu(hfacac)₂(4)]_n·nC₆H₅Cl differs, leading to different structural motifs in the 1D-polymer backbones. In [Cu(hfacac)₂(4)]_n·nC₆H₅Cl, the peripheral 3-CF₃C₆H₄ unit is accommodated in a pocket between two {Cu(hfacac)₂} units and engages in four C–H_phenyl...F–C_hfacac contacts which lock the phenylpyridine unit in a near planar conformation. In [Cu₂(hfacac)₄(3)₂]_n·nC₆H₄Cl₂ and [Cu(hfacac)₂(4)]_n·nC₆H₅Cl, π-stacking interactions between 4′-trifluoromethylphenyl-3,2′:6′,3″-tpy domains are key packing interactions, and this contrasts with the packing of polymers incorporating 1 and 2. We use powder X-ray diffraction to demonstrate that the assemblies of the coordination polymers are reproducible, and that a switch from a 4,2′:6′,4″- to 3,2′:6′,3″-tpy metal-binding unit is accompanied by a change from dominant C–F...F–C and C–F...H–C contacts to π-stacking of arene domains between ligands 3 or 4. Full article

Six pseudohalide zinc(II) containing a variety of N-donor auxiliary amines were structurally characterized. These include two mononuclear trigonal bipyramidal [Zn(NTB)(N₃)]ClO₄·½H₂O (3) and [Zn(TPA)(NCS)]ClO₄ (4), two distorted octahedral [Zn(1,8-damnph)₂(dca)₂] (5) and [Zn(8-amq)₂(dca)₂] (6a) as well as two 1D polymeric chains catena-[Zn(isq)₂(μ_1,5-dca)₂] (7) and catena-[Zn(N,N-Me₂en)₂(μ_1,5-dca)]dca (8), where NTB = tris(2-benzimidazolylmethyl)amine, TPA = tris(2-pyridylmethyl)amine, 1,8-damnph = 1,8-diaminonaphthalene, 8-amq = 8-amino-quinoline, isq = isoquinoline (isq) and N,N-Me₂en = N,N-dimethylethylenediamine. In general, with the exception of 6 and 8, the complexes exhibited luminescence emission in MeOH associated with red shift of the emission maxima, and the strongest visible fluorescence peak was detected at 421 nm (λ_ex = 330 nm) in the case of Complex 5. Full article

Dianionic N,N-chelating ligands play a crucial role in coordination chemistry, but reports on related complexes remain limited to certain types of ligands. In here, the reactions of two diprotic ligands, i.e., a biguanide and a carbothiamide, with trimethylaluminium, are reported, which give rise to mono- and dinuclear aluminium(III) complexes. In addition, single deprotonation of the diprotic biguanide using potassium bis(trimethylsilyl)amide gives rise to a one-dimensional coordination polymer. All complexes have been fully characterized, and their solid-state structures were determined by single crystal X-ray diffraction analysis. Full article

The complexes of lanthanide metals, especially dysprosium, can generally exhibit excellent magnetic properties. By means of modifying ligands, dual functions or even multi-functions can be achieved. Here, we synthesized an eight-coordinate Dy(III) complex 1, [Dy(HL-o)₂(MeOH)₂](ClO₄)₃·4.5MeOH, which is single-molecule magnet (SMM), and the introduction of the rhodamine 6G chromophore in the ring-opened ligand HL-o realizes ligand-centered fluorescence in addition to SMM. Magnetic measurements and ab initio calculations indicate that the magnetic relaxation for complex 1 should be due to the Raman relaxation process. Studies on magneto-structural correlationship of the rhodamine salicylaldehyde hydrazone Dy(III) complexes show that the calculated energy of the first Kramers Doublet (E_KD1) is basically related to the O_phenoxy-Dy-O_phenoxy bond angle, i.e., the larger O_phenoxy-Dy-O_phenoxy bond angle corresponds to a larger E_KD1. Full article

The reactions between the bis(1,10-phenantro[5,6-b])tetrathiafulvalene triad (L) and the metallo-precursors Yb(hfac)₃(H₂O)₂ (hfac⁻ = 1,1,1,5,5,5-hexafluoroacetylacetonato anion) and Dy(facam)₃ (facam⁻ = 3-trifluoro-acetyl-(+)-camphorato anion) lead to the formation of two dinuclear complexes of formula [Yb₂(hfac)₆(L)]·2(C₇H₁₆) ((1)·2(C₇H₁₆)) and [Dy₂((+)facam)₆(L)]·2(C₆H₁₄) ((2)·2(C₆H₁₄)). The X-ray structures reveal that the L triad bridges two terminal Yb(hfac)₃ or Dy(facam)₃ units. (1)·2(C₇H₁₆) behaved as a near infrared Yb^III centered emitter and a field-induced Single-Molecule Magnet (SMM) while (2)·2(C₆H₁₄) displayed SMM behavior in both zero- and in-dc field. The magnetization mainly relaxes through a Raman process for both complexes under an optimal applied magnetic field. Full article

In this paper we report the binding properties, by combined ¹H NMR, optical absorption, and fluorescence studies, of a molecular tweezer composed of two Zn(salen)-type Schiff-base units connected by a flexible spacer, towards a series of ditopic diamines having a strong Lewis basicity, with different chain length and rigidity. Except for the 1,2-diaminoethane, in all other cases the formation of stable 1:1 Lewis acid-base adducts with large binding constants is demonstrated. For α,ω-aliphatic diamines, binding constants progressively increase with the increasing length of the alkyl chain, thanks to the flexible nature of the spacer and the parallel decreased conformational strain upon binding. Stable adducts are also found even for short diamines with rigid molecular structures. Given their preorganized structure, these latter species are not subjected to loss of degrees of freedom. The binding characteristics of the tweezer have been exploited for the colorimetric and fluorometric selective and sensitive detection of piperazine. Full article

Bacterial infection remains a worldwide problem that requires urgent addressing. Overuse and poor disposal of antibacterial agents abet the emergence of bacterial resistance mechanisms. There is a clear need for new approaches for the development of antibacterial therapeutics. Herein, the antibacterial potential of molecules based on dithiocarbamate anions, of general formula R(R’)NCS₂⁽⁻⁾, and metal salts of transition metals and main group elements, is summarized. Preclinical studies show a broad range of antibacterial potential, and these investigations are supported by appraisals of possible biological targets and mechanisms of action to guide chemical syntheses. This bibliographic review of the literature points to the exciting potential of dithiocarbamate-based therapeutics in the crucial battle against bacteria. Additionally, included in this overview, for the sake of completeness, is mention of the far fewer studies on the antifungal potential of dithiocarbamates and even less work conducted on antiparasitic behavior. Full article

Important applications of the Ni^II, Pd^II and Pt^II complexes [M(Hdmg)₂] (H₂dmg = dimethylglyoxime) stem from their metal^...metal stacked virtually insoluble aggregates. Given the virtual insolubility of the materials, we postulated that the rare reports on dissolved species in solution do not represent monomolecular species but oligomers. We thus studied the structural and spectral properties of the monomolecular entities of these compounds using density functional theory (DFT) and time-dependent DFT computations in dimethyl sulfoxide (DMSO) as a solvent. The molecular geometries, IR and UV-vis spectra, and frontier orbitals properties were computed using LANL2DZ ecp and def2TZVP as basis sets and M06-2X as the functional. The results are compared with the available experimental and other calculated data. The optimised molecular geometries proved the asymmetric character of the two formed O–H^…O bonds which connect the two Hdmg^‒ ligands in the completely planar molecules. Calculated UV-vis spectra revealed the presence of three absorptions in the range 180 to 350 nm that are red-shifted along the series Ni–Pd–Pt. They were assigned to essentially ligand-centred π−π* transitions in part with metal(d) to ligand(π*) charge transfer (MLCT) contributions. The notorious d‒p transitions dominating the colour and electronics of the compounds in the solid-state and oligomeric stacks are negligible in our monomolecular models strongly supporting the idea that the previously reported spectroscopic observations or biological effects in solutions are not due to monomolecular complexes but rather to oligomeric dissolved species. Full article

Most of the commercially available anti-infective agents are organic molecules. In fact, though, during the pioneering times of modern medicine, at the beginning of the 20th century, several inorganic compounds of transition metals were used for medicinal application, to date, only a small number of inorganic drugs are used in clinical practice. Beyond the transition metals, metalloids—or semimetals—offer a rich chemistry in between that of metallic and non-metallic elements, and accordingly, peculiar features for their exploitation in medicinal chemistry. A few important examples of metalloid-based drugs currently used for the treatment of various diseases do exist. However, the use of this group of elements could be further expanded on the basis of their current applications and the clinical trials they entered. Considering that metalloids offer the opportunity to expand the “chemical-space” for developing novel anti-infective drugs and protocols, in this paper, we briefly recapitulate and discuss the current applications of B-, Si-, As-, Sb- and Te-based anti-infective drugs. Full article

Physical adsorption remains a promising method for achieving fast, reversible hydrogen storage at both ambient and cryogenic conditions. Research in this area has recently shifted to focus primarily on the volumetric (H₂ stored/delivered per volume) gains achieved within an adsorptive storage system over that of pure H₂ compression; however, the methodology for estimating a volumetric stored or delivered amount requires several assumptions related to the ultimate packing of the adsorbent material into an actual storage system volume. In this work, we critically review the different assumptions commonly employed, and thereby categorize and compare the volumetric storage and delivery across numerous different porous materials including benchmark metal-organic frameworks, porous carbons, and zeolites. In several cases, there is a significant gain in both storage and delivery by the addition of an adsorbent to the high-pressure H₂ storage system over that of pure compression, even at room temperature. Lightweight, low-density materials remain the optimal adsorbents at low temperature, while higher density, open metal-containing frameworks are necessary for high-density room temperature storage and delivery. Full article

Complexes of trivalent lanthanides (Ln) with the hydridotris(1-pyrazolyl)borato (Tp) ligand Ln[η³-HB(N₂C₃H₃)₃]₃ (LnTp₃) were subjected to a joint experimental–theoretical analysis. X-ray diffraction experiments have been performed on CeTp₃, NdTp₃, SmTp₃, GdTp₃, and TbTp₃ in the nine-fold coordination and on DyTp₃, HoTp₃, ErTp₃, TmTp₃, YbTp₃, and LuTp₃ in the eight-fold coordination form. Density functional theory (DFT) calculations were carried out for all 15 LnTp₃ complexes. They extended the X-ray diffraction data available on the LnTp₃ compounds and facilitated a straightforward interpretation of trends in the structural parameters. As a result of the joint analysis, significant steric strain in the equatorial coordination sites of the nine-coordinate structures was recognized. Trends in the bonding properties were elucidated by energy decomposition and quantum theory of atoms in molecules (QTAIM) analysis of the electron density distribution. These results revealed the major electrostatic character of the Ln…Tp bonding and fine variation of charge transfer effects across the Ln row. Full article

Nanoclays are widespread materials characterized by a layered structure in the nano-scale range. They have multiple applications in diverse scientific and industrial areas, mainly due to their swelling capacity, cation exchange capacity, and plasticity. Due to the cation exchange capacity, nanoclays can serve as host matrices for the stabilization of several molecules and, thus, they can be used as sensors by incorporating electroactive ions, biomolecules as enzymes, or fluorescence probes. In this review, the most recent applications as bioanalyte sensors are addressed, focusing on two main detection systems: electrochemical and optical methods. Particularly, the application of electrochemical sensors with clay-modified electrodes (CLME) for pesticide detection is described. Moreover, recent advances of both electrochemical and optical sensors based on nanoclays for diverse bioanalytes’ detection such as glucose, H₂O₂, organic acids, proteins, or bacteria are also discussed. As it can be seen from this review, nanoclays can become a key factor in sensors’ development, creating an emerging technology for the detection of bioanalytes, with application in both environmental and biomedical fields. Full article

The vanadium(V) complexes have been investigated as potential anticancer agents which makes it essential to evaluate their toxicity for safe use in the clinic. The large-scale synthesis and the acute oral toxicity in mice of the oxidovanadium(V) Schiff base catecholate complex, abbreviated as [VO(HSHED)dtb] containing a redox-active ligand with tridentate Schiff base (HSHED = N-(salicylideneaminato)-N’-(2-hydroxyethyl)-1,2-ethylenediamine) and dtb = 3,5-di-(t-butyl)catechol ligands were carried out. The body weight, food consumption, water intake as well biomarkers of liver and kidney toxicity of the [VO(HSHED)dtb] were compared to the precursors, sodium orthovanadate, and free ligand. The 10-fold scale-up synthesis of the oxidovanadium(V) complex resulting in the preparation of material in improved yield leading to 2–3 g (79%) material suitable for investigating the toxicity of vanadium complex. No evidence of toxicity was observed in animals when acutely exposed to a single dose of 300 mg/kg for 14 days. The toxicological results obtained with biochemical and hematological analyses did not show significant changes in kidney and liver parameters when compared with reference values. The low oral acute toxicity of the [VO(HSHED)dtb] is attributed to redox chemistry taking place under biological conditions combined with the hydrolytic stability of the oxidovanadium(V) complex. These results document the design of oxidovanadium(V) complexes that have low toxicity but still are antioxidant and anticancer agents. Full article

We examined the effects of concentrations and identities of various glymes, from monoglyme up to tetraglyme, on H₂ release from the thermolysis of Mg(BH₄)₂ at 160–200 °C for 8 h. ¹¹B NMR analysis shows major products of Mg(B₁₀H₁₀) and Mg(B₁₂H₁₂); however, their relative ratio is highly dependent both on the identity and concentration of the glyme to Mg(BH₄)₂. Selective formation of Mg(B₁₀H₁₀) was observed with an equivalent of monoglyme and 0.25 equivalent of tetraglyme. However, thermolysis of Mg(BH₄)₂ in the presence of stoichiometric or greater equivalent of glymes can lead to unselective formation of Mg(B₁₀H₁₀) and Mg(B₁₂H₁₂) products or inhibition of H₂ release. Full article