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The benzimidazole core, a fundamental scaffold in medicinal chemistry, has been key in the advancement of this health field, leading to the development of numerous commercially available drugs, including those to treat cancer, which constitutes the most pressing health problem, being the main cause of death globally, whose current chemotherapeutic treatments, although some effective, have serious side effects, highlighting the need to discover safer and more potent drugs. In this context, a series of 1-benzyl-2-aryl benzimidazole derivatives (21‐–29) were synthesized using a selective and affordable method under mild reaction conditions and green chemistry criteria. A hydroxylated Schiff base (23) is also included, evidence of the possible reaction mechanism for synthesizing the different BZM derivatives. All compounds were characterized using spectroscopic techniques and single-crystal X-ray analysis. The latter, including Hirshfeld surface analysis, allowed the study of the main non-covalent interactions that stabilize molecular packing and supramolecular arrangements. A preliminarily evaluated by in vitro assays against a panel of six human cancer cell lines and healthy cells using tamoxifen as a reference drug. The results showed that all the compounds demonstrate bioactivity, highlighting the halogenated structures 1-(4-chlorobenzyl)-2-(4-chlorophenyl)-1H-benzo[d]imidazole (26), 1-(4-bromobenzyl)-2-(4-bromophenyl)-1H-benzo[d]imidazole (27) and 1-(4-methoxybenzyl)-2-(4-methoxyphenyl)-1H-bebioavailability nzo[d]imidazole (29) exhibited the highest biological activity, mainly against the cancer lines leukemia (K562), colon cancer (HCT-15), breast cancer (MCF-7) and lung cancer (SKLU-1). A brief ADME analysis evaluated that the obtained compounds have pharmacodynamic and pharmacokinetic parameters to be potentially administered enterally.

The electrochemical reduction of carbon dioxide (CO2) to methane (CH4) holds tremendous potential in mitigating greenhouse gas emissions and producing renewable fuels. Thus, this review provides a comprehensive overview of the utilization of copper-based metal–organic frameworks (Cu-MOFs) as catalysts for this transformative process. Diverse key aspects of Cu-MOFs that make them ideal candidates for CO2 reduction are discussed, including their high surface areas, tunable pore sizes, and customizable active sites. Furthermore, recent advances in the design and synthesis of Cu-MOFs tailored specifically for enhanced catalytic activity and selectivity towards CH4 production are highlighted. Additionally, mechanistic insights into the CO2 reduction process on Cu-MOF catalysts are examined. Moreover, the recent application of diverse Cu-MOFs and derived materials in electrochemical reduction systems is discussed, and future research directions and potential applications of Cu-MOFs in sustainable energy conversion technologies are outlined. Thus, this review provides valuable insights into the current state of the art and the prospects for utilizing Cu-MOFs as efficient catalysts for the electrochemical conversion of CO2 to CH4, offering a pathway towards a greener and more sustainable energy future.

POCOP-Ni(II) pincer compounds have primarily been explored as catalysts, but their potential biological activity has been scarcely studied. To address this gap, we evaluated the anticancer and antioxidant potential of four POCOP-Ni(II) complexes derived from phloroglucinol. A comprehensive supramolecular analysis, based on single-crystal X-ray diffraction (DRX) structures, was conducted using Hirshfeld surfaces and non-covalent interaction analysis. The cytotoxicity of all complexes was systematically assessed against various cancerous cell lines, as well as a non-cancerous cell line (COS-7). The results revealed that complexes 1b and 1c exhibited remarkable antiproliferative activity, with IC50 values ranging from 2.43 to 7.85 μM against cancerous cell lines U251, K562, HCT-15, MCF-7, and SK-LU-1. To further elucidate their mechanism of action, a competitive fluorescence displacement assay with ethidium bromide (EB) suggested that these complexes possess the ability to intercalate with DNA. This multifaceted investigation not only enhances our understanding of the biological potential of POCOP-Ni complexes but also provides valuable insights into their structural features and interactions, paving the way for future exploration in both catalytic and therapeutic domains.

In recent years, metallodrugs have emerged as captivating and promising compounds in the fields of cancer therapy and antimicrobial agents. While noble metals have shown remarkable biological activity, increasing interest lies in utilizing more abundant and cost-effective metals in medicinal chemistry. This is primarily due to their pivotal role in biological processes and their lower cost compared to precious metals. Among these, copper(II) complexes have emerged with promising applications in medicine. Notably, copper compounds bearing Schiff bases stand out as innovative metallodrugs. They exhibit intriguing cytotoxic properties against a wide range of cancer cell lines, while also demonstrating inhibitory effects on prevalent bacterial and fungal strains. Nevertheless, research into Cu(II) complexes with Schiff bases remains of paramount interest. One strategic avenue to bolster their biological activity involves the introduction of fluorine groups into the ligands. This approach has demonstrated a significant augmentation in efficacy and selectivity, particularly in targeting cancer cells and microbial pathogens, because fluorine incorporation can improve metabolic stability and cellular uptake. This further reinforces the therapeutic potential of these metallodrugs. Thanks to these promising outcomes, research into the development of Cu(II) complexes with fluorinated Schiff bases is advancing significantly. This holds immense potential for progressing the field of medicinal chemistry, with the aim of addressing unmet clinical needs in both cancer therapy and antimicrobial treatment. This review comprehensively explores the latest advancements in Cu(II) complexes bearing fluorinated Schiff bases, encompassing diverse coordination modes. It delves into their scope and applications in cytotoxic evaluations, as well as their efficacy as antimicrobial and antifungal agents.

C–H bond activation is a crucial synthetic strategy widely utilized in both academic and industrial settings. Due to the strong and kinetically inert nature of the C–H bond, its functionalization typically requires metal-based catalysts. This review highlights the most significant advancements in homogeneously catalyzed reactions using pincer complexes with metals from groups 8–10, capable of promoting challenging C–H activation, published since 2010. In particular, it focuses on C–H bond activation for borylation, isomerization, and dehydrogenation, among other processes, discussing their scope and mechanistic insights.

Enantiomers (2S, 4S)- and (2R, 4R)-3-(naphthalene-1-ylmethyl) pentane-2,4-diols were synthesized by the reduction of (Z)-4-hydroxy-3-(naphthalene-1-ylmethyl) pent-3-en-2-one with NaBH4 in methanol (MeOH). Crystallization in dichloromethane of this racemic mixture led to simple crystals with a crystalline habit with similar morphologies; however, in a group of them, it was possible to find a barely observable difference that allowed determining a crystal structure for each of the enantiomers, the 2S,4S, and the 2R,4R.

Among their many applications, metal pincer complexes are of interest for their properties as catalysts in cross-coupling reactions. Pincer ligands exhibit tridentate coordination to the metal center and occupy the meridional positions forming two chelate rings. The two Ni(II) POCOP pincer complexes with a fluorothiophenolate ligand reported herein, with formulas [Ni(SC6F4-4-H){C6H2-3-(C2H3O)-2,6-(OPiPr2)2}] (2) and [Ni(SC6F5){C6H2-3-(C2H3O)-2,6-(OPiPr2)2}] (3), are isostructural. Additionally, they are prepared in a facile manner from the chloride compound [NiCl{C6H2-3-(C2H3O)-2-6-(OPiPr2)2}] (1). The complexes exhibited slightly distorted square planar geometries around the metal. The fluorothiophenolate ligands are responsible of the C—H···F, C—F···π and C=O···πF interactions that contribute to stabilize the crystal structure arrays.

Coamorphous salt in a 1:1 ratio prepared by ball milling from Fluvastatin sodium (FLV) and Pioglitazone hydrochloride (PGZ·HCl) can be selectively formed by neat grinding (NG). Furthermore, the salt–cocrystal continuum was preferably formed by employing liquid-assisted grinding (LAG) using ethanol (EtOH). Attempts to prepare the coamorphous salt starting from the salt–cocrystal continuum by NG were unsuccessful. Interestingly, through ball milling by NG or LAG, a great diversity of solid forms (PGZ·HCl-FLV 1:1) could be accessed: NG and hexane (coamorphous); ethyl acetate (physical mixture); EtOH (salt–cocrystal continuum); and water (which presents two Tg, indicating immiscibility of the components). An exploration was performed at different drug-to-drug ratios by NG. By differential scanning calorimetry (DSC), the presence of two endothermic events was observed in this screening: incongruous melting point (solidus) and excess of one of the components (liquidus), except in the 1:1 solid form. From these results, eutectic behavior was observed. Through the construction of a binary phase diagram, it was determined that the 1:1 molar ratio gives rise to the formation of the most stable coamorphous composition. Dissolution profile studies of these solid forms were carried out, specifically on pure FLV and the solid forms of PGZ⋅HCl-FLV (1:2; 1:4; and 1:6), together with the coamorphous 1:1 salt. By itself, pure FLV presented the highest Kint (13.6270 ± 0.8127 mg/cm2⋅min). On the other hand, the coamorphous 1:1 showed a very low Kint (0.0220 ± 0.0014 mg/cm2·min), indicating very fast recrystallization by the FLV, which avoids observing a sudden release of this drug in the solution. This same behavior was observed in the eutectic composition 1:2. In the other solid forms, the value of Kint increases along with the %w of FLV. From the mechanochemical point of view, ball milling by NG or LAG became an important synthetic tool since it allows obtaining a great variety of solid forms to explore the solid-state reactivity of the drug–drug solid-form PGZ HCl-FLV.

Throughout human history, bacteria and fungi have caused infections that are difficult to combat. For this reason, countless research groups have developed novel compounds to solve this problem. Thiazole and benzothiazole are present in different structures with interesting biological effects and are used to develop new effective antimicrobial agents. Moreover, nitrogen atoms that are present in this heterocycle allow for coordination with various metals, forming metal complexes that enhance the biological activity of organic ligands that are often used as commercial drugs. This bibliographical review summarizes the copper complexes that use thiazole and benzothiazole as ligands and that report efficient antimicrobial activity against different bacteria and fungi.

Ball-milling using neat grinding (NG) or liquid-assisted grinding (LAG) by varying the polarity of the solvents allowed access to various drug–drug solid forms of pioglitazone hydrochloride (PGZ·HCl) and rosuvastatin calcium (RSV). Using NG, the coamorphous form was formed from the reaction of pioglitazone hydrochloride (PGZ·HCl) and rosuvastatin calcium (RSV) in a 2:1 molar ratio. The formation of the expected coamorphous salt could not be corroborated by FT-IR, but DSC data showed that it was indeed a single-phase amorphous mixture. By varying the molar ratios of the reactants, either keeping PGZ·HCl constant and varying RSV or vice versa, another coamorphous form was obtained when a 1:1 molar ratio was employed. In the case of the other outcomes, it was observed that they were a mixture of solid forms coexisting simultaneously with the coamorphous forms (1:1 or 2:1) together with the drug that was in excess. When RSV was in excess, it was in an amorphous form. In the case of PGZ·HCl, it was found in a semicrystalline form. The intrinsic dissolution rates (IDRs) of the solid forms of PGZ·HCl-RSV in stoichiometric ratios (1:1, 2:1, 1:4, 6:1, and 1:10) were evaluated. Interestingly, a synchronized release of both drugs in the dissolution medium was observed. In the case of the release of RSV, there were no improvements in the dissolution profiles, because the acidic media caused the formation of degradation products, limiting any probable modification in the dissolution processes. However, the coamorphous 2:1 form exhibited an improvement of 1.03 times with respect to pure PGZ·HCl. It is proposed that the modification of the dissolution process of the coamorphous 2:1 form was limited by changes in the pH of the media as RSV consumes protons from the media due to degradation processes.

Reactions of group 10 transition metals with the ditopic ligand dipicolyldithiocarbamate (DPDTC) were performed. Thus, 1:2 reactions of [Ni(CH3COO)2], [Pd(COD)Cl2] or [Pt(COD)Cl2] with DPDTC produced monomeric complexes of the type [M(κ2-SCS-DPDTC)2, M = Ni (1), Pd (2) or Pt (3)] with the dithiocarbamate ligand (DTC) coordinated in a typical chelate κ2-SCS fashion. Interestingly, the reaction of [NiCl2] with DPDTC, under similar conditions, afforded the organic compound 2-(pyridin-2-ylmethyl)imidazo[1,5-a]pyri-dine-3(2 H)-thione (4) as unique product. In order to prove the ditopic nature of the ligand DPDTC, complex [Pd(κ2-SCS-DPDTC)2] (2) was further reacted with [ZnCl2] in a 1:2 M ratio to yield the trinuclear complex [Cl2Zn(κ2-NN-DPDTC-SCS-κ2)Pd(κ2-SCS-DPDTC-NN-κ2)ZnCl2] (5). The molecular structures of all compounds were determinate by typical analytical techniques including the unequivocal determination of all structures by single crystal X-ray diffraction analysis. As expected, complexes 1–3 are isostructural, and the metal centres exhibiting slightly distorted square-planar geometries. While in 5, the trinuclear nature of the complex in confirmed exhibiting a nice combination of tetrahedral-square planar-tetrahedral geometries for the Zn-Pd-Zn centres respectively. Keywords: Dithiocarbamate, Metal-sulphur complexes, Trinuclear complexes, Ditopic ligands, Hetero-aromatic compound, Di-(2-picolyl)amine cyclization

Within the current challenges in medicinal chemistry, the development of new and better therapeutic agents effective against infectious diseases produced by bacteria, fungi, viruses, and parasites stands out. With chemotherapy as one of the main strategies against these diseases focusing on the administration of organic and inorganic drugs, the latter is generally based on the synergistic effect produced by the formation of metal complexes with biologically active organic compounds. In this sense, Schiff bases (SBs) represent and ideal ligand scaffold since they have demonstrated a broad spectrum of antitumor, antiviral, antimicrobial, and anti-inflammatory activities, among others. In addition, SBs are synthesized in an easy manner from one-step condensation reactions, being thus suitable for facile structural modifications, having the imine group as a coordination point found in most of their metal complexes, and promoting chelation when other donor atoms are three, four, or five bonds apart. However, despite the wide variety of metal complexes found in the literature using this type of ligands, only a handful of them include on their structures tridentate SBs ligands and their biological evaluation has been explored. Hence, this review summarizes the most important antimicrobial activity results reported this far for pincer-type complexes (main group and d-block) derived from SBs tridentate ligands.

Novel lanthanide (Ln) compounds [Ln(L)2]Cl.xH2O (Ln = La3+, Ce3+, Sm3+) containing aromatic N,O-chelate ligands [HL1 = 4-amino-2-(1H-benzimidazol-2-yl)phenol; HL2 = 5-amino-2-(1H-benzimidazol-2-yl)phenol] have been synthesized and structurally characterized by elemental analysis, NMR and IR spectroscopy, molar conductance measurements, and mass spectrometry (MS). The spectroscopic data suggested that the benzimidazolyl-phenol ligands act as N,O-chelate ligands through the iminic nitrogen and phenolic oxygen atoms. Elemental analysis indicated that lanthanide compounds were formed in a 1:2 stoichiometry (metal:ligand). In vitro biological evaluation was carried out using these complexes, exhibiting moderate cytotoxicity against six different human tumor cell lines (U251, human glioblastoma; HCT-15, colorectal carcinoma; MCF-7, breast epithelial adenocarcinoma; PC-3, prostate cancer; K562, myelogenous leukemia; SKLU-1, lung carcinoma) and lower toxicity against a non-cancerous cell line (COS-7, primate kidney). In addition, the antibacterial activity of the compounds was assessed against two gram-positive strains (Staphylococcus aureus ATCC 25923, Listeria monocytogenes ATCC 19115) and two gram-negative strains (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27583) using the microdilution method. The results obtained show that the metal complexes exhibit higher biological activity than the free ligands, confirming a synergistic effect. Further benzimidazolyl-phenol derivatives were explored for the detection of bacteria using fluorescence imaging studies. Interestingly, the fluorescent properties of these compounds make them potential candidates to monitor the morphology of bacteria at different compound concentrations. Hence, the interaction of the ligand and complexes with model membranes mimicking those of bacteria was studied by using differential scanning calorimetry (DSC) and molecular dynamics (MD), showing that both compounds decreased the enthalpy of transition in two model membranes as the concentration of the compounds increased. In addition, the main transition temperature was slightly reduced as a result of these interactions.

Fluorination of pharmaceutical agents has afforded crucial modifications to their pharmacological profiles, leading to important advances in medicinal chemistry. On the other hand, metallodrugs are considered to be valuable candidates in the treatment of several diseases, albeit with the caveat that they may exhibit pharmacological disadvantages, such as poor water solubility, low bioavailability and short circulating time. To surmount these limitations, two approaches have been developed: one based on the design of novel metallodrug-delivering carriers and the other based on optimizing the structure of the ligands bound to the metal center. In this context, fluorination of the ligands may bring beneficial changes (physicochemical and biological) that can help to elude the aforementioned drawbacks. Thus, in this review, we discuss the use of fluorinated ligands in the design of metallodrugs that may exhibit potential anticancer activity.

The mechanochemical synthesis of drug–drug solid forms containing metformin hydrochloride (MET·HCl) and thiazide diuretics hydrochlorothiazide (HTZ) or chlorothiazide (CTZ) is reported. Characterization of these new systems indicates formation of binary eutectic conglomerates, i.e., drug–drug eutectic solids (DDESs). Further analysis by construction of binary diagrams (DSC screening) exhibited the characteristic V-shaped form indicating formation of DDESs in both cases. These new DDESs were further characterized by different techniques, including thermal analysis (DSC), solid state NMR spectroscopy (SSNMR), powder X-ray diffraction (PXRD) and scanning electron microscopy–energy dispersive X-ray spectroscopy analysis (SEM–EDS). In addition, intrinsic dissolution rate experiments and solubility assays were performed. In the case of MET·HCl-HTZ (χMET·HCl = 0.66), we observed a slight enhancement in the dissolution properties compared with pure HTZ (1.21-fold). The same analysis for the solid forms of MET·HCl-CTZ (χMET·HCl = 0.33 and 0.5) showed an enhancement in the dissolved amount of CTZ accompanied by a slight improvement in solubility. From these dissolution profiles and saturation solubility studies and by comparing the thermodynamic parameters (ΔHfus and ΔSfus) of the pure drugs with these new solid forms, it can be observed that there was a limited modification in these properties, not modifying the free energy of the solution (ΔG) and thus not allowing an improvement in the dissolution and solubility properties of these solid forms.

Biological membranes are complex dynamic systems composed of a great variety of carbohydrates, lipids, and proteins, which together play a pivotal role in the protection of organisms and through which the interchange of different substances is regulated in the cell. Given the complexity of membranes, models mimicking them provide a convenient way to study and better understand their mechanisms of action and their interactions with biologically active compounds. Thus, in the present study, a new Schiff base (Bz-Im) derivative from 2-(m-aminophenyl)benzimidazole and 2,4-dihydroxybenzaldehyde was synthesized and characterized by spectroscopic and spectrometric techniques. Interaction studies of (Bz-Im) with two synthetic membrane models prepared with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and DMPC/1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) 3:1 mixture, imitating eukaryotic and prokaryotic membranes, respectively, were performed by applying differential scanning calorimetry (DSC). Molecular dynamics simulations were also developed to better understand their interactions. In vitro and in silico assays provided approaches to understand the effect of Bz-Im on these lipid systems. The DSC results showed that, at low compound concentrations, the effects were similar in both membrane models. By increasing the concentration of Bz-Im, the DMPC/DMPG membrane exhibited greater fluidity as a result of the interaction with Bz-Im. On the other hand, molecular dynamics studies carried out on the erythrocyte membrane model using the phospholipids POPE (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine), SM (N-(15Z-tetracosenoyl)-sphing-4-enine-1-phosphocholine), and POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) revealed that after 30 ns of interaction, both hydrophobic interactions and hydrogen bonds were responsible for the affinity of Bz-Im for PE and SM. The interactions of the imine with POPG (1-Palmitoyl-2-Oleoyl-sn-Glycero-3-Phosphoglycerol) in the E. coli membrane model were mainly based on hydrophobic interactions.

Metal-based drugs, including lanthanide complexes, have been extremely effective in clinical treatments against various diseases and have raised major interest in recent decades. Hence, in this work, a series of lanthanum (III) and cerium (III) complexes, including Schiff base ligands derived from (1H-benzimidazol-2-yl)aniline, salicylaldehyde, and 2,4-dihydroxybenzaldehyde were synthesized and characterized using different spectroscopic methods. Besides their cytotoxic activities, they were examined in human U-937 cells, primate kidney non-cancerous COS-7, and six other, different human tumor cell lines: U251, PC-3, K562, HCT-15, MCF-7, and SK-LU-1. In addition, the synthesized compounds were screened for in vitro antiparasitic activity against Leishmania braziliensis, Plasmodium falciparum, and Trypanosoma cruzi. Additionally, antibacterial activities were examined against two Gram-positive strains (S. aureus ATCC® 25923, L. monocytogenes ATCC® 19115) and two Gram-negative strains (E. coli ATCC® 25922, P. aeruginosa ATCC® 27583) using the microdilution method. The lanthanide complexes generally exhibited increased biological activity compared with the free Schiff base ligands. Interactions between the tested compounds and model membranes were examined using differential scanning calorimetry (DSC), and interactions with calf thymus DNA (CT-DNA) were investigated by ultraviolet (UV) absorption. Molecular docking studies were performed using leishmanin (1LML), cruzain (4PI3), P. falciparum alpha-tubulin (GenBank sequence CAA34101 [453 aa]), and S.aureus penicillin-binding protein 2a (PBP2A; 5M18) as the protein receptors. The results lead to the conclusion that the synthesized compounds exhibited a notable effect on model membranes imitating mammalian and bacterial membranes and rolled along DNA strands through groove interactions. Interactions between the compounds and studied receptors depended primarily on ligand structures in the molecular docking study.

A series of benzo [d] [1,3] azoles 2-substituted with benzyl- and allyl-sulfanyl groups were synthesized, and their cytotoxic activities were in vitro evaluated against a panel of six human cancer cell lines. The results showed that compounds BTA-1 and BMZ-2 have the best inhibitory effects, compound BMZ-2 being comparable in some cases with the reference drug tamoxifen and exhibiting a low cytotoxic effect against healthy cells. In silico molecular coupling studies at the tamoxifen binding site of ERα and GPER receptors revealed affinity and the possible mode of interaction of both compounds BTA-1 and BMZ-2.

Mechanochemistry is considered an alternative attractive greener approach to prepare diverse molecular compounds and has become an important synthetic tool in different fields (e.g., physics, chemistry, and material science) since is considered an ecofriendly procedure that can be carried out under solvent free conditions or in the presence of minimal quantities of solvent (catalytic amounts). Being able to substitute, in many cases, classical solution reactions often requiring significant amounts of solvents. These sustainable methods have had an enormous impact on a great variety of chemistry fields, including catalysis, organic synthesis, metal complexes formation, preparation of multicomponent pharmaceutical solid forms, etc. In this sense, we are interested in highlighting the advantages of mechanochemical methods on the obtaining of pharmaceutical cocrystals. Hence, in this review, we describe and discuss the relevance of mechanochemical procedures in the formation of multicomponent solid forms focusing on pharmaceutical cocrystals. Additionally, at the end of this paper, we collect a chronological survey of the most representative scientific papers reporting the mechanochemical synthesis of cocrystals.

A series of 2-benzylsulfanyl benzothiazole (BTA) derivatives were synthesized and fully characterized and in vitro tested against two strains of T. cruzi (NINOA and INC-5), exhibiting good activities at low concentrations.

1,2,3-Benzotriazinones were synthesized in excellent yields by the reaction of 2-(o-aminophenyl)oxazolines and isoamyl nitrite in methanol. The crystal structure of the acetyl derivative of one of the 1,2,3-benzotriazinones provided additional support for the spectroscopic structural characterization of the title compounds.

In the title compound, [ZnBr3(C4H12N5)], the ZnII cation is tetrahedrally coordinated by three bromide ions and the (N-{amino[(diaminomethylene)amino]methylene}-N-methylmethanaminium) cation that binds through the central N atom. The complex is of interest as a potential antidiabetic drug of the biguanide family. The crystal structure is stabilized by an extensive series of N—H...Br and C—H...Br hydrogen bonds, which combine to form a three-dimensional structure.

In the title compound, C23H16O2S, the thiophene group is rotationally disordered into two fractions almost parallel to each other, with occupation factors of 0.523 (7) and 0.477 (7), and subtending dihedral angles of 10.5 (5) and 9.3 (5)°, respectively, to the thiophene group. The molecules are held together by weak C—H...O and C—H...π hydrogen bonds, producing a laminar arrangement, which are further connected in a perpendicular fashion by S...π contacts [S...centroid = 3.539 (8) and 3.497 (8) Å]. In spite of the presence of the entended pyrene group, the structure does not present any parallel π–π stacking interactions. The structure was refined as an inversion twin.

The title compound, C17H12O, crystallized with three independent molecules (A, B and C) in the asymmetric unit. In the crystal, the three independent molecules are linked by π–π interactions [centroid–centroid distances = 3.551 (3)–3.977 (2) Å], which lead to the formation of trimers. Between the trimers there are a number of C—H...π interactions generating a laminar arrangement parallel to (010). The methoxymethyl group in molecule A is disordered over two sets of sites, with an occupancy ratio of 0.56 (9):0.44 (9).

In the cation of the title molecular salt, C6H16NO+·Cl−, the N—C—C—O torsion angle is 176.5 (2)°. In the crystal, the cations and chloride ions are linked by N—H...O and O—H...O hydrogen bonds, generating a two-dimensional network parallel to (100).

The asymmetric unit of the title compound, [PdCl2(C10H8N2)]·0.5C4H8O2, consists of one PdII complex molecule and a half-molecule of 1,4-dioxane, the complete molecule being generated by inversion symmetry. The PdII atom has an almost square-planar coordination formed by the 2,2′-bipyridine ligand and two chloride ligands. Two intramolecular C—H...Cl hydrogen bonds occur. In the crystal, the PdII complex and 1,4-dioxane molecules are connected by C—H...O hydrogen bonds, forming a layer parallel to (10-1). Within the layer, weak π–π interactions [centroid–centroid distance = 3.817 (4) Å] are observed between the pyridine rings.

The title compound, [PdCl2(C18H24N2)]·(CH3)2SO·H2O, the PdII ion is in a distorted square-planar geometry. The Pd—N bond distances are 2.022 (2) and 2.027 (2) Å, the Pd—Cl bond distances are 2.2880 (7) and 2.2833 (7) Å, and the ligand bite angle is 80.07 (9)°. The dimethyl sulfoxide and water molecules form linear chains along [100] by O—H...O and O—H...S hydrogen bonds, generating eight- and 12-membered rings. C—H...Cl interactions link the chains, forming a three-dimensional arrangement. In addition, the 4,4-di-tert-butyl-2,2′-bipyridine ligand exhibits π–π stacking interactions [centroid–centroid distances = 3.8741 (15) and 3.8353 (15) Å]. The DMSO solvent is disordered and was refined with an occupancy ratio of 0.866 (3):0.134 (3).

The title compound, C12H6Cl4S2, features an S—S bond [2.0252 (8) Å] that bridges two 2,3-dichlorophenyl rings with a C—S—S—C torsion angle of 88.35 (11)°. The benzene rings are normal one to the other with a dihedral angle of 89.83 (11)°. The crystal structure features intermolecular Cl...Cl [3.4763 (11) Å] and π–π stacking interactions [centroid–centroid distances = 3.696 (1) and 3.641 (2) Å]. Intramolecular C—H...S interactions are also observed.

The title compound, [Pd(SC6H4F-p)Cl(PPh3)2]·0.5CH3OH, features a PdII complex with two triphenylphosphane (PPh3) ligands arranged in a trans conformation, with one chloride and one 4-fluorobenzenethiolate ligand completing the coordination sphere, giving rise to a slightly distorted square-planar geometry of the PdII ion. The methanol solvent molecule is disordered about an inversion centre with an occupancy of 0.25 for each molecule. In the crystal, weak C—H...Cl hydrogen-bonding interactions between the complex molecules generate chain frameworks parallel to [010].

In the cation of the title compound C9H14ON+·C3H2O3N3−, the benzylamine C—N bond subtends a dihedral angle of 78.3 (2)° with the phenyl ring. The cyanurate anion is in the usual keto-form and shows an r.m.s. deviation from planarity of 0.010 Å. In the crystal, the cyanurate anions form N—H...O hydrogen-bonded zigzag ribbons along [001]. These ribbons are crosslinked by the organocations via O—H...N and N—H...O hydrogen bonds, forming bilayers parallel to (010) which are held together along [010] by slipped π–π interactions between pairs of cyanurate anions [shortest contact distances C...C = 3.479 (2), O...N = 3.400 (2); centroid–centroid distance= 4.5946 (9) Å] and between cyanurate and phenyl rings [centroid–centroid distance = 3.7924 (12) Å, ring–ring angle = 11.99 (10)°].

The title compound, [Pd2Cl2(C6H5S)2(C18H15P)2]·2CHCl3, contains a centrosymmetric dinuclear palladium complex with the PdII cation in a slightly distorted square-planar coordination environment. The PdII cations are bridged by the S atoms of two benzenethiolate ligands with different Pd—S distances [2.2970 (11) and 2.3676 (11) Å]. The coordination of the metal atom is completed by a chloride anion [2.3383 (11) Å] and a triphenylphosphane ligand [2.2787 (11) Å]. Weak C—H...Cl interactions are present between complex molecules and the CHCl3 solvent molecule. The latter is disordered over two positions in a 0.792 (8):0.208 (8) ratio. The crystal under investigation was found to be twinned by nonmerohedry, with a fraction of 73.4 (1)% for the major twin component.

In the title compound, [Ru(CH3OCS2)2(C18H15P)2], the RuII atom is in a distorted octahedral coordination by two xanthate anions (CH3OCS2) and two triphenylphosphane (PPh3) ligands. Both bidentate xanthate ligands coordinate the RuII atom with two slightly different Ru—S bond lengths but with virtually equal bite angles [71.57 (4) and 71.58 (3)°]. The packing of the complexes is assured by C—H...O and C—H...π interactions.

The title compound, [Pd(C26H45S4)Cl]·CH2Cl2, crystallizes with a disordered dichloromethane solvent molecule [occupancy ratio = 0.67 (4):0.33 (4)]. Two of the tert-butyl groups are also disordered [occupancy ratios = 0.70 (5):0.30 (5) and 0.63 (4):0.37 (4)]. Although the pincer ligand offers the possibility for coordination of two different metal atoms, the present structure shows only the coordination of a single PdII atom in a typical S—C—S tridentate pincer manner. The PdII atom is in a slightly distorted square-planar environment with the two tert-butylsulfanyl groups arranged in a trans conformation and with a chloride ligand trans to the σ-bonded aromatic C atom. The structure exhibits a durene-like ligand frame, forming a dihedral angle of 13.6 (4)° with the metal coordination (Pd/S/S/Cl/C) environment. It is noteworthy that the tert-butyl groups are found in a syn arrangement, this being different to that found previously by Loeb, Shimizu & Wisner [(1998). Organometallics, 17, 2324–2327].

The title compound, C12H10N2O, a second monoclinic polymorph of (E)-phenyl(pyridin-2-yl)methanone oxime crystallizes in the space group P21/n (Z = 4). The previously reported polymorph [Taga et al. (1990). Acta Cryst. C46, 2241–2243] occurs in the space group C2/c (Z = 8). In the crystal, pairs of bifurcated O—H...(N,O) hydrogen bonds link the molecules into inversion dimers. The dimers are linked by C—H...π interactions, forming a linear arrangement. The dihedral angle between the pyridine and phenyl rings is 67.70 (8)°.

The complete molecule of the title compound, C19H32S2, is generated by crystallorgaphic twofold symmetry, with three C atoms lying on the axis. The Car—C—S—C (ar = aromatic) torsion angle is 156.2 (2) °. In the crystal, the molecules are linked by very weak C—H...S interactions, generating [001] chains.

In the title ylide, C31H28ClO2P [common name α-acetyl-α-p-chlorobenzoylmethylenetri(p-tolyl)phosphorane], the dihedral angle between the 4-chlorophenyl ring and that of the ylide moiety is 66.15 (10)°. The geometry around the P atom is slightly distorted tetrahedral [angle range = 105.22 (8)–115.52 (9)°] and the carbonyl O atoms are syn-oriented with respect to the P atom. The ylide group is close to planar [maximum deviation from the least-squares plane = 0.006 (2) Å] and the P—C, C—C and C=O bond lengths are consistent with electron delocalization involving the O atoms.

Crystals of the title compound were obtained as a 1:1 dimethyl sulfoxide solvate, C20H16N2O2·C2H6O. The molecular conformation of the organic molecule is similar to that in the previously reported unsolvated structure [Eltayeb et al. (2009). Acta Cryst. E65, o1374–o1375]. Thus, the dihedral angles formed by the benzimidazole moiety with the two benzene rings are 57.54 (4) and 76.22 (5)°, and the dihedral angle between the benzene rings is 89.23 (5)°. In the crystal, a three-dimensional network features O—H...O, O—H...N and O—H...S hydrogen bonds, as well as C—H...O and C—H...π interactions.

In the title dinuclear complex, (acetonitrile-1κN)[μ-N-(pyridin-2-ylcarbonyl)pyridine-2-carboxamidato-1:2κ5N,N′,N′′:O,O′][N-(pyridin-2-ylcarbonyl)pyridine-2-carboxamidato-2κ3N,N′,N′′]bis(trifluoromethanesulfonato-1κO)dicopper(II), [Cu2(C12H8N3O2)2(CF3O3S)2(CH3CN)], one of the CuII ions is five-coordinated in a distorted square-pyramidal N3O2 environment provided by two N-(pyridin-2-ylcarbonyl)pyridine-2-carboxamidate (bpca) ligands, while the second CuII ion is six-coordinated in a distorted octahedral N4O2 environment provided by one bpca ligand, two trifluoromethansulfonate ligands and one acetonitrile molecule. Weak intermolecular C—H...O and C—H...F hydrogen bonds and π–π stacking interactions with centroid–centroid distances of 3.6799 (15) and 3.8520 (16) Å stabilize the crystal packing and lead to a three-dimensional network.

In the title organic salt, C5H7N2+·C8H5O4−, the carboxylic group is nearly coplanar with the benzene ring [dihedral angle 1.9 (4)°] whereas the carboxylate group is twisted relative to the benzene ring by 13.6 (4)°. In the crystal, N-H...O and O—H...O hydrogen bonds connect the components into a three-dimensional framework consisting of stacks of alternating pairs of anions and cations exhibiting π–π stacking interactions with centroid–centroid distances in the range 3.676 (2)–3.711 (1) Å. The π–π stacks extend along [110] and [-110].

Molecules of the title compound, C28H22S2, are located on a crystallographic mirror plane with one half-molecule in the asymmetric unit. The dihedral angle between the phenyl ring and the naphthyl unit is 83.14 (7)°. In the crystal, molecules are interconnected by C—H...S and C—H...π interactions.

The title complex, [Pd(C2H2N3S2)2(C18H15P)2]·2C2H6OS·0.5H2O, was obtained from the reaction of trans-[(Ph3P)2PdCl2] with 5-amino-1,3,4-thiadiazole-2-thione (SSNH2) in a 2:1 molar ratio. The PdII atom, located in a crystallographic center of symmetry, has a square-planar geometry with two triphenylphosphine P-coordinated molecules and two SSNH2 ligands with the S atoms in a trans conformation. The latter ligand exhibits N—H...N hydrogen-bonding contacts formed by the amino group with the thiadiazole ring, generating a chain along the c axis. The asymmetric unit contains one half of the complex molecule along with disordered dimethyl sulfoxide and water molecules.

The title compound, C9H10N2O4·H2O, was obtained as a zwitterion derived from the nucleophilic attack of 3-aminopyridine on the fumaric α,β-system. Within the molecule, the aminopyridine moiety and the carboxylate and carboxylic acid fragments form dihedral angles of 68.6 (2) and 62.8 (2)°, respectively. The geometry adopted by the molecule does not allow the formation of centrosymmetric dimeric hydrogen-bonded units; instead chains along the a axis are linked by COO—H...OOC motifs. These chains are interconnected by N—H...O and O—H...O hydrogen bonds involving the carboxylic acid and carboxylate units and the solvent water molecules.

The dihedral angle between the aromatic rings in the title compound, C15H14S, is 72.38 (7)°. In the crystal, the molecules are connected by C—H...π interactions.

The asymmetric unit of the title compound, [NiCl2(C19H9F6N3)], contains one half-molecule residing on a crystallographic twofold rotation axis. The title compound crystallizes in space group C2/c while the previously reported polymorph was reported in P21/c [Baldovino-Pantaleón et al. (2006). Adv. Synth. Catal. 348, 236–242]. The Ni2+ ion exhibits a pentacoordinate distorted trigonal–bipyramidal NiCl2N3 geometry, with two Cl atoms in the equatorial plane. In the crystal, molecules are linked by intermolecular C—F...π [F...centroid = 2.9676 (14) Å] interactions.

The title compound, C25H23NO, consists of a biphenyl-4-carbonyl unit attached to an exocyclic double bond group at position 2 of an indole unit, which presents methyl groups as substituents at positions 1 and 3. The molecular conformation is s-cis with an E configuration, supported by weak intramolecular C—H...O contacts involving the methyl groups and the carbonyl function. The rings of the biphenyl group are twisted by 37.13 (5)°. In the crystal, C—H...O and C—H...π interactions link the molecules.

The title compound, [Pd(C2H3OS2)2(C18H15P)], features a palladium complex with a triphenylphosphane ligand and two xanthate ligands, one of them coordinates in a bidentate and the other in a monodentate fashion, giving rise to a slightly distorted square-planar coordination of the PdII ion. As a result of this difference in the coordination modes, the C—S bond lengths are different, viz. 1.687 (2) and 1.692 (2) Å in the bidentate ligand and 1.723 (2) Å in the monodentate ligand, whereas the non-coordinating S atom has a C—S distance of 1.649 (2) Å. The crystal packing is stabilized by C—H...O interactions.

In the title compound, [Pd(C5H4NS)(C18H14PS)(C18H15P)], the PdII atom has a slightly distorted square-planar environment. Two coordination sites are occupied by a P,S-chelating 2-(diphenylphosphanyl)benzenethiolate ligand and the other two by a P atom from a triphenylphosphine ligand and an S atom from a pyridine-2-thiolate ligand, exhibiting a trans arrangement of the two P-donor atoms. In the crystal structure, weak intra- and intermolecular C—H...π and π–π interactions are observed. The pyridyl ring is equally disordered over two positions.

The asymmetric unit of the title compound, [Ru2Br4(C10H14)2], contains one half of the centrosymmetric molecule. Each Ru center is coordinated by tetramethylbenzene ring in a η6-coordination mode, and one terminal and two bridging bromine atoms. The aromatic rings and the Ru2Br2 four-membered ring form a dihedral angle of 55.99 (8)°. In the crystal structure, weak intermolecular C—H...Br interactions link molecules into chains propagated in [001].

Dimeric molecules of the title compound, [Ru2Cl4(C12H18)2], are located on a crystallographic centre of inversion with one molecule in the asymmetric unit. The hexamethylbenzene rings are in an η6-coordination to the ruthenium centres, which are bridged by two chloride ligands. In addition, the ruthenium centres are bonded to another chloride ligand. The aromatic rings and the Ru2Cl2 four-membered ring enclose a dihedral angle of 55.85 (6)°.

The title compound, [Rh(C15H16PS)(C18H15P)(CO)], was synthesized from the reaction of the ligand rac-[Ph2PCH2CH(CH3)SH] with trans-[Rh(F)(CO)(PPh3)2] in a 1:1 molar ratio in toluene. The Rh atom is four-coordinated in a distorted square-planar geometry with the P—S ligand [Ph2PCH2CH(CH3)S] acting as a chelate and the PPh3 and disordered CO [site occupation factors of 0.61 (5) and 0.39 (5)] ligands completing the coordination.