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The reaction of Ti(NMe2)4 with the salan ligand precursor H2N2O2H2 led to the formation of [(L*)Ti(NHMe2)2] (L*=N2O24−) that forms [(H2N2O2)TiCl2] upon reaction with two equiv. of Me3SiCl. [(L*)Ti(py)2] was obtained from the reaction of [Ti(NtBu)Cl2(py)3] with the sodium salt H2N2O2Na2. Treatment of [(L*)Ti(NHMe2)2] with two equiv. of tBuNCO led to the insertion of the isocyanate molecules into the Ti−Nsalan bonds with the formation of [{L*(N(tBu)CO)2}Ti]. Conversely, the reaction of [(H2N2O2)Ti(OiPr)2] with two equiv. of tBuNCO led to the insertion of one isocyanate molecule into a Ti−Nsalan bond with the formation of [{(HN2O2)(N(tBu)CO)}Ti(OiPr)]. Computational studies were performed to gain insight into the reactivity of isocyanates with salan‐based Ti(IV) complexes. [ABSTRACT FROM AUTHOR]

Novel multicomponent crystal forms were obtained from reactions of trans-disubstituted cyclam derivatives with flufenamic and salicylic acids. The reactions of H2(4-CF3PhCH2)2cyclam with those acids led to the formation of salts of the formulae [H2{H2(4-CF3PhCH2)2cyclam}](3-CF3PhNHC6H4COO)2 and [H2{H2(4-CF3PhCH2)2cyclam}](HOC6H4COO)2, respectively. The reaction of H2(PhCH2)2cyclam with flufenamic acid led to the formation of the salt [H2{H2(PhCH2)2cyclam}](3-CF3PhNHC6H4COO)2, whereas its reaction with salicylic acid afforded the ionic cocrystal [H2(PhCH2)2cyclam](HOC6H4COOH)2·[H2{H2(PhCH2)2cyclam}](HOC6H4COO)2. The compounds obtained were fully characterized and tested against several yeasts as well as Gram-positive and Gram-negative bacterial strains. The results have shown that the new multicomponent forms display relevant antimicrobial activity when compared to their parent cyclam derivatives, highlighting the importance of exploring synergistic effects to unveil new and efficient antimicrobial agents. [ABSTRACT FROM AUTHOR]

Three CoII octaazacryptates, with different substituents on the aromatic rings (Br, NO2, CCH), were synthesised and characterised. These and the already published non‐substituted cryptate catalysed CO2 photoreduction to CO and CH4 under blue visible light at room temperature. Although CO was observed after short irradiation times and a large range of catalyst concentrations, CH4 was only observed after longer irradiation periods, such as 30 h, but with a small catalyst concentration (25 nm). Experiments with 13C labelled CO2 showed that CO is formed and reacts further when the reaction time is long. The CCH catalyst is deactivated faster than the others and the more efficient catalyst for CH4 production is the one with Br. This reactivity trend was explained by an energy decomposition analysis based on DFT calculations. [ABSTRACT FROM AUTHOR]

Abstract: This work describes the crystal structures of two Mg dimers supported by dianionic trans-disubstituted Bn2Cyclam ligands (1,8-dibenzyl-1,4,8,11-tetraazacyclotetradecane). Mg2(Bn2Cyclam)I2 (1) crystallizes in the monoclinic space group P21/c with half-molecule in the asymmetric unit. The two metal centers and the two Namido donors of the cyclam ring define a four-member Mg2N2 metallacycle. The metals’ coordination spheres are completed by one amine of the macrocycle and one iodide defining a trigonal pyramidal coordination geometry. Mg2(Bn2Cyclam){μ-H}{μ-F-C6F4}2BC6F5 (2) crystallizes in the monoclinic space group P21/c with half-molecule in the asymmetric unit. Compound 2 is a rare example of a zwitterionic species of the type [Mg2(Bn2Cyclam)]2+ with two [HB(C6F5)3]− anions coordinating in a k 3-H,F,F tridentate fashion. This compound also displays bridging Namido ligands that bind the two Mg atoms in a Mg2N2 arrangement analogous to 1, promoting a capped square pyramidal coordination geometry. At a supramolecular level C–H⋯I and C–H⋯F hydrogen bonds as well as CH/π and F⋯F interactions are responsible for the crystal packing. [Copyright &y& Elsevier]

Hydride abstraction from [MCpBz(CO)3H] (M= Mo, W; CpBz= C5(CH2Ph)5) using trityl cations led to [M{η5:η2-C5Bz4CH2Ph}(CO)3]BArF(BArF= B(3,5-C6H3(CF3)2)4; M = Mo (3), W (4)) or [MCpBz(CO)3(FBF3)] (M = Mo (5), W (6)) dependingon the trityl counterions. The stabilization of the acidic metal centersin 3and 4is made through the coordinationof a CC bond of one phenyl ring, generating ansa-bridged cyclopentadienyl–phenylcarbonyl complexes. 5and 6are zwitterioniccompounds stabilized by the coordination of the BF4anion.An exchange process between coordinated and noncoordinated phenylrings occurs in dichloromethane solutions of 3. VT NMRexperiments gave the exchange rate at various temperatures and ΔG⧧298= 10.1 ± 0.2 kcalmol–1. In 4the phenyl bonding is staticat room temperature, on the NMR time scale. Reactions of 3and 4with CO and H2O led to [MCpBz(CO)4]BArF(M = Mo (7), W (8)) and [MCpBz(CO)3(OH2)]BArF(M = Mo (11), W (12)). In CH2Cl2solutions 3and 4convert slowly to 7and 8, respectively.DFT calculations attest to the stability of 3to H2O bonding and also show that the replacement of phenyl coordinationby CO is a favorable process (ΔH= −13.8kcal mol–1). [ABSTRACT FROM AUTHOR]

The development of new strategic antimicrobial therapeutic approaches, such as drug repurposing, has become an urgent need. Previously, we reported that tamoxifen presents therapeutic efficacy against multidrug-resistant (MDR) Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli in experimental infection models by modulating innate immune system cell traffic. The main objective of this study was to analyze the activity of N-desmethyltamoxifen, 4-hydroxytamoxifen, and endoxifen, three major metabolites of tamoxifen, against these pathogens. We showed that immunosuppressed mice infected with A. baumannii, P. aeruginosa, or E. coli in peritoneal sepsis models and treated with tamoxifen at 80 mg/kg/d for three days still reduced the bacterial load in tissues and blood. Moreover, it increased mice survival to 66.7% (for A. baumannii and E. coli) and 16.7% (for P. aeruginosa) when compared with immunocompetent mice. Further, susceptibility and time-kill assays showed that N-desmethyltamoxifen, 4-hydroxytamoxifen, and endoxifen exhibited minimum inhibitory concentration of the 90% of the isolates (MIC90) values of 16 mg/L, and were bactericidal against clinical isolates of A. baumannii and E. coli. This antimicrobial activity of tamoxifen metabolites paralleled an increased membrane permeability of A. baumannii and E. coli without affecting their outer membrane proteins profiles. Together, these data showed that tamoxifen metabolites presented antibacterial activity against MDR A. baumannii and E. coli, and may be a potential alternative for the treatment of infections caused by these two pathogens. [ABSTRACT FROM AUTHOR]

Systemic mycoses are one major cause of morbidity/mortality among immunocompromised/debilitated individuals. Studying the mechanism of action is a strategy to develop safer/potent antifungals, warning resistance emergence. The major goal of this study was to elucidate the mechanism of action of three (Z)-5-amino-N'-aryl-1-methyl-1H-imidazole-4-carbohydrazonamides (2h, 2k, 2l) that had previously demonstrated strong antifungal activity against Candida krusei and C. albicans ATCC strains. Activity was confirmed against clinical isolates, susceptible or resistant to fluconazole by broth microdilution assay. Ergosterol content (HPLC-DAD), mitochondrial dehydrogenase activity (MTT), reactive oxygen species (ROS) generation (flow cytometry), germ tube inhibition and drug interaction were evaluated. None of the compounds inhibited ergosterol synthesis. Ascorbic acid reduced the antifungal effect of compounds and significantly decreased ROS production. The metabolic viability of C. krusei was significantly reduced for values of 2MIC. Compounds 2h and 2k caused a significant increase in ROS production for MIC values while for 2l a significant increase was only observed for concentrations above MIC. ROS production seems to be involved in antifungal activity and the higher activity against C. krusei versus C. albicans may be related to their unequal sensitivity to different ROS. No synergism with fluconazole or amphotericin was observed, but the association of 2h with fluconazole might be valuable due to the significant inhibition of the dimorphic transition, a C. albicans virulence mechanism. [ABSTRACT FROM AUTHOR]

The insertion of isocyanates in (Bn 2Cyclam)ZrX 2 is regioselective; (Bn 2Cyclam)Zr(OR) 2 produces urea-like moieties by the insertion of RN═C═O in the Zr-N amido bonds of the cyclam ring. Depending on the bulkiness of the isocyanate R groups, O- and N-bound ureates are formed. (Bn 2 Cyclam)Zr(NH Bu)2 reacts with MesN═C═O at the terminal Zr-N bonds. [ABSTRACT FROM AUTHOR]

A new class of half‐sandwich (η6‐p‐cymene) ruthenium(II) complexes supported by 2‐aminofluorene derivatives [Ru(η6‐p‐cymene)(Cl)(L)] (L = 2‐(((9H‐fluoren‐2‐yl)imino)methyl)phenol (L1), 2‐(((9H‐fluoren‐2‐yl)imino)methyl)‐3‐methoxyphenol (L2), 1‐(((9H‐fluoren‐2‐yl)imino)methyl)naphthalene‐2‐ol (L3) and N‐((1H‐pyrrol‐2‐yl)methylene)‐9H‐fluorene‐2‐amine (L4)) were synthesized. All compounds were fully characterized by analytical and spectroscopic techniques (IR, UV–Vis, NMR) and also by mass spectrometry. The solid state molecular structures of the complexes [Ru(η6‐p‐cymene)(Cl)(L2)], [Ru(η6‐p‐cymene)(Cl)(L3)] and [Ru(η6‐p‐cymene)(Cl)(L4)] revealed that the 2‐aminofluorene and p‐cymene moieties coordinate to ruthenium(II) in a three‐legged piano‐stool geometry. The synthesized complexes were used as catalysts for the dehydrogenative coupling of benzyl alcohol with a range of amines (aliphatic, aromatic and heterocyclic). The reactions were carried out under thermal heating, ultrasound and microwave assistance, using solvent or solvent free conditions, and the catalytic performance was optimized regarding the solvent, the type of base, the catalyst loading and the temperature. Moderately high to very high isolated yields were obtained using [Ru(η6‐p‐cymene)(Cl)(L4)] at 1 mol%. In general, microwave irradiation produced better yields than the other two techniques irrespective of the nature of the substituents. [ABSTRACT FROM AUTHOR]

Keywords: carbon dioxide; cryptates; methane; photoreduction; visible light Carbon dioxide, cryptates, methane, photoreduction, visible light. [Extracted from the article]

The reaction of Ti(NMe 2 ) 4 with the salan ligand precursor H 2 N 2 O 2 H 2 led to the formation of [(L*)Ti(NHMe 2 ) 2 ] (L*=N 2 O 2 4- ) that forms [(H 2 N 2 O 2 )TiCl 2 ] upon reaction with two equiv. of Me 3 SiCl. [(L*)Ti(py) 2 ] was obtained from the reaction of [Ti(N t Bu)Cl 2 (py) 3 ] with the sodium salt H 2 N 2 O 2 Na 2 . Treatment of [(L*)Ti(NHMe 2 ) 2 ] with two equiv. of t BuNCO led to the insertion of the isocyanate molecules into the Ti-N salan bonds with the formation of [{L*(N( t Bu)CO) 2 }Ti]. Conversely, the reaction of [(H 2 N 2 O 2 )Ti(O i Pr) 2 ] with two equiv. of t BuNCO led to the insertion of one isocyanate molecule into a Ti-N salan bond with the formation of [{(HN 2 O 2 )(N( t Bu)CO)}Ti(O i Pr)]. Computational studies were performed to gain insight into the reactivity of isocyanates with salan-based Ti(IV) complexes., (© 2024 Wiley-VCH GmbH.)