New palladium complexes with N-heterocyclic carbene and morpholine ligands: Synthesis, characterization, crystal structure, molecular docking, and biological activities.

This work includes the synthesis of a new series of palladium-based complexes containing both morpholine and N-heterocyclic carbene (NHC) ligands. The new complexes were characterized using NMR (1 H and 13 C), FTIR spectroscopic, and elemental analysis techniques. The crystal structure of complex 1b was obtained by utilizing the single-crystal X-ray diffraction method. X-ray studies show that the coordination environment of palladium atom is completed by the carbene carbon atom of the NHC ligand, the nitrogen atom of the morpholine ring, and a pair of bromide ligand, resulting in the formation of slightly distorted square planar geometry. All complexes were determined for some metabolic enzyme activities. Results indicated that all the synthetic complexes exhibited powerful inhibitory actions against all aims as compared to the control molecules. Ki values of new morpholine-liganded complexes bearing 4-hydroxyphenylethyl group 1a-e for hCA I, hCA II, AChE, BChE, and α-glycosidase enzymes were obtained in the ranges 0.93-2.14, 1.01-2.03, 4.58-10.27, 7.02-13.75, and 73.86-102.65 µM, respectively. Designing of reported complexes is impacted by molecular docking study, and interaction with the current enzymes also proclaimed that compounds 1e (-12.25 kcal/mol for AChE and -11.63 kcal/mol for BChE), 1c (-10.77 kcal/mol and -9.26 kcal/mol for α-Gly and hCA II, respectively), and 1a (-8.31 kcal/mol for hCA I) are showing binding affinity and interaction from the synthesized five novel complexes.

Design, synthesis, characterization, crystal structure, in silico studies, and inhibitory properties of the PEPPSI type Pd(II)NHC complexes bearing chloro/fluorobenzyl group.

This work contains synthesis, characterization, crystal structure, and biological activity of a new series of the PEPPSI type Pd(II)NHC complexes [(NHC)Pd(II)(3-Cl-py)]. NMR, FTIR, and elemental analysis techniques were used to characterize all (NHC)Pd(II)(3-Cl-py) complexes. Also, molecular and crystal structures of complex 1c were established by single-crystal X-ray diffraction. Regarding the X-ray studies, the palladium(II) atom has a slightly distorted square-planar coordination environment. Additionally, the enzyme inhibitory effect of new (NHC)Pd(II)(3-Cl-py) complexes (1a-1g) was studied. They exhibited highly potent inhibition effect on acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and carbonic anhydrases (hCAs) (Ki values are in the range of 0.08 ± 0.01 to 0.65 ± 0.06 µM, 10.43 ± 0.98 to 22.48 ± 2.01 µM, 6.58 ± 0.30 to 10.88 ± 1.01 µM and 6.34 ± 0.37 to 9.02 ± 0.72 µM for AChE, BChE, hCA I, and hCA II, respectively). Based on the molecular docking, among the seven synthesized complexes, 1c, 1b, 1e, and 1a significantly inhibited AChE, BChE, hCA I, and hCA II enzymes, respectively. The findings highpoint that (NHC)Pd(II)(3-Cl-py) complexes can be considered as possible inhibitors via metabolic enzyme inhibition.

Synthesis, characterization, crystal structure, α-glycosidase, and acetylcholinesterase inhibitory properties of 1,3-disubstituted benzimidazolium salts.

Chloro-/fluorobenzyl-substituted benzimidazolium salts were synthesized from the reaction of 4-fluorobenzyl/2-chloro-4-fluorobenzyl-substituted benzimidazole and chlorinated aromatic hydrocarbons. They were characterized using various spectroscopic techniques (Fourier-transform infrared and nuclear magnetic resonance) and elemental analysis. In addition, the crystal structures of the complexes 1a -d and 2b were determined by single-crystal X-ray diffraction methods. These compounds were crystallized in the triclinic crystal system with a P-1 space group. The crystal packing of all complexes is dominated by O-H⋯Cl hydrogen bonds, which link the water molecules and chloride anions, forming a chloride-water tetrameric cluster. These synthesized salts were found to be effective inhibitors for α-glycosidase and acetylcholinesterase (AChE), with Ki values ranging from 45.77 ± 6.83 to 102.61 ± 11.56 µM for α-glycosidase and 0.94 ± 0.14 to 10.24 ± 1.58 µM for AChE. AChE converts acetylcholine into choline and acetic acid, thus causing the return of a cholinergic neuron to its resting state. Discovering AChE and α-glycosidase inhibitors is one of the important ways to develop new drugs for the treatment of Alzheimer's disease and diabetes.

Risk factors for noncatheter-related Candida bloodstream infections in intensive care units: A multicenter case-control study.

Candida bloodstream infections are associated with high mortality among critically ill patients in intensive care units (ICUs). Studies that explore the risk factors for candidemia may support better patient care in intensive care units. We conducted a retrospective, multicenter case-control study to investigate the risk factors for noncatheter-related Candida bloodstream infections (CBSI) in adult ICUs. Participants selected controls randomly on a 1:1 basis among all noncase patients stayed during the same period in ICUs. Data on 139 cases and 140 controls were deemed eligible. Among the controls, 69 patients died. The stratified Fine-Gray model was used to estimate the subdistribution Hazard ratios. The subdistribution hazards and 95% confidence intervals for final covariates were as follows: prior exposure to antimycotic agents, 2.21 (1.56-3.14); prior exposure to N-acetylcysteine, 0.11 (0.03-0.34) and prior surgical intervention, 1.26 (0.76-2.11). Of the patients, those exposed to antimycotic drugs, 87.1% (54/62) had breakthrough candidemia. Serious renal, hepatic, or hematologic side effects were comparable between patients those exposed and not-exposed to systemic antimycotic drugs. Untargeted administration of antimycotic drugs did not improve survival among candidemic patients (not-exposed, 63.6% [49/77]; exposed % 66.1 [41/62]; P = .899). This study documented that exposure to an antifungal agent is associated with increased the risk of subsequent development of CBSIs among nonneutropenic adult patients admitted to the ICU. Only two centers regularly prescribed N-acetylcysteine. Due to the limited number of subjects, we interpreted the positive effect of N-acetylcysteine on the absolute risk of CBSIs with caution.

Half-Sandwich Arene Ruthenium(II) Thiosemicarbazone Complexes: Evaluation of Anticancer Effect on Primary and Metastatic Ovarian Cancer Cell Lines.

In this study, we describe the synthesis, characterization and antiproliferative activity of three organo-ruthenium(II) half-sandwich complexes [RuCl(η6-p-cym)(N,S-L)]Cl (I, II, and III). To form these complexes, three thiosemicarbazone ligands (TSCs) were synthesized; L = 5-nitro-2-carboxyaldehyde-thiophen-N-methyl-thiosemicarbazone, (L1); 2-acetyl-5-bromo-thiophen-N-methyl-thiosemicarbazone, (L2) and 2-acetyl-5-bromo-thiophen-N,N-dimethyl-thiosemicarbazone, (L3). The isolated compounds were analyzed using spectroscopic techniques such as elemental analysis, conductance measurements, FT-IR, 1H NMR spectroscopy, MALDI-TOF mass spectrometry, and single-crystal XRD. Our results demonstrated that the synthesized thiosemicarbazone ligands (TSCs) are bound to the metal ion as a bidentate ligand that coordinates through the thiocarbonyl sulfur and azomethine nitrogen atoms in all complexes (I, II, and III). The X-ray crystal structures of L1 and L2 revealed that both compounds are crystallized in the triclinic crystal system with space group P-1. The biological potency of newly synthesized TSC ligands (L1, L2, and L3) and their corresponding ruthenium complexes (I, II, and III) were investigated on human primary ovarian (A2780) and human metastatic ovarian (OVCAR-3) cell lines. To get detailed information respecting antitumor properties, cytotoxicity, DNA/BSA binding affinity, cellular uptake, DNA binding competition, and trans-epithelial resistance measurement assays were performed. Our results demonstrate that newly synthesized ruthenium(II) complexes possess potential biological activity. Moreover, we observe that the ruthenium complexes reported here show anticancer activity on primary (A2780) and metastatic (OVCAR-3) ovarian cancer cells.

Monodisperse palladium-cobalt alloy nanocatalyst supported on activated carbon (AC) as highly effective catalyst for the DMAB dehydrocoupling.

In the study, activated carbon (AC) supported palladium/cobalt (Pd/Co) nanocatalyst was synthesized to achieve hydrogen release from dimethylamine boron (DMAB). Nanocatalyst were produced by the reduction of Pd2+ and Co2+ cations by the ultrasonic double reduction method. Analytical studies of the synthesized nanomaterials were characterized by X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction, transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), electron energy loss spectroscopy, ultraviolet-visible spectroscopy. In this research, nanomaterials exhibited high catalytic activity and reusability, and great performance at low temperatures and concentrations. For the dehydrogenation reaction of dimethylamine borane, TOF and Ea were calculated as 379.5 h-1 and 75.86 kJ mol-1, respectively. The PdCo@AC nanocatalyst can be used as a promising catalyst for the hydrogen production reaction from DMAB.

Synthesis and characterization of thiosemicarbazone-functionalized organoruthenium (II)-arene complexes: Investigation of antitumor characteristics in colorectal cancer cell lines.

In the current study, organoruthenium(II)-arene complexes (I-IV) have been prepared by the reaction of [{(η6-p-cym)RuCl}2(µ-Cl)2] with new thiosemicarbazones (TSC1-4).The isolate was analyzed using elemental analysis, FT-IR, 1H and 13C NMR spectroscopy and single-crystal XRD. Subsequently, the complexes and TSC ligands were assessed for anticancer properties in vitro against three different colorectal cancer stage's cell lines (Caco-2, DLD-1, and SW620) and a noncancerous cell line (CCD18Co). The complexes (I-IV) showed higher cytotoxicity with low IC50 values as 0.1-0.33 µM in colorectal cell lines except for SW620 (47.4-84.20 µM) than in a noncancerous cell. Complex I was 2.8 and 24.5-fold more active against Caco-2 and DLD-1 than CCD18Co, respectively. The complexes (I-IV) accumulated at a high concentration in the cell nuclei and caused cell cycle arrest by affecting the G0/G1 and/or G2/M phase and showed high binding affinity with CT-DNA (Kb = 104 M-1). The expression of Caspase-3 and Caspase-9 apoptosis-related protein levels was slightly upregulated and Atg5 autophagy-related protein level was clearly downregulated according to control and 5-FU-treated cells after complex I and II treatment. Furthermore, it was observed that cytotoxicity of the complexes is decreased while cancer progresses. Altogether, this study indicates that all organoruthenium (II)-arene complexes (particularly complex I) can be a promising alternative to platinum counterparts in cancer treatment.

Use of silica-based homogeneously distributed gold nickel nanohybrid as a stable nanocatalyst for the hydrogen production from the dimethylamine borane.

In this study, the effects of silica-based gold-nickel (AuNi@SiO2) nanohybrid to the production of hydrogen from dimethylamine borane (DMAB) were investigated. AuNi@SiO2 nanohybrid constructs were prepared as nanocatalysts for the dimethylamine borane dehydrogenation. The prepared nanohybrid structures were exhibited high catalytic activity and a stable form. The resulting nanohybrid, AuNi@SiO2 as a nanocatalyst, was tested in the hydrogen evolution from DMAB at room temperature. The synthesized nanohybrids were characterized using some analytical techniques. According to the results of the characterization, it was observed that the catalyst was in nanoscale and the gold-nickel alloys showed a homogenous distribution on the SiO2 surface. After characterization, the turn over frequency (TOF) of nanohybrid prepared for the production of hydrogen from dimethylamine was calculated (546.9 h-1). Also, the prepared nanohybrid can be used non-observed a significant decrease in activity even after the fifth use, in the same reaction. In addition, the activation energy (Ea) of the reaction of DMAB catalyzed AuNi@SiO2 nanohybrid was found to be 16.653 ± 1 kJmol-1 that facilitated the catalytic reaction. Furthermore, DFT-B3LYP calculations were used on the AuNi@SiO2 cluster to investigate catalyst activity. Computational results based on DFT obtained in the theoretical part of the study support the experimental data.

Use of the monodisperse Pt/Ni@rGO nanocomposite synthesized by ultrasonic hydroxide assisted reduction method in electrochemical nonenzymatic glucose detection.

An electrochemical non-enzymatic sensor was developed for the detection of glucose based on an electrode modified with monodisperse platinum-nickel nanocomposites-decorated on reduced graphene oxide (Pt/Ni@rGO) which was synthesized using a new ultrasonic hydroxide assisted reduction method. Because the nanocomposites prepared by using NaOH (OH- ligands) are much smaller nanocomposites on the supports compared to the ones without OH- ligands. Such a monodisperse Pt/Ni@rGO nanocomposites-based electrode exhibited a high electrochemical activity for electrocatalytic oxidation of glucose in alkaline solution. Amperometric analysis showed a glucose sensitivity of 171.92 µA/mM cm2 of, the detection limit of 6.3 µM and a linear range of 0.02-5.0 mM glucose concentration. Fabricated sensor platform demonstrated long-term stability and good reproducibility, in addition to high selectivity.

Highly monodispersed palladium-ruthenium alloy nanoparticles assembled on poly(N-vinyl-pyrrolidone) for dehydrocoupling of dimethylamine-borane: An experimental and density functional theory study.

This study reports on one of the best heterogeneous catalysts for the dehydrogenation of dimethylamine-borane (DMAB). This new catalytic system consists of highly monodisperse Pd and Ru alloy nanoparticles supported by poly(N-vinyl-pyrrolidone) (PdRu@PVP). The prepared heterogeneous catalyst can be reproducibly formed using an ultrasonic reduction technique for DMAB dehydrogenation under mild conditions. For the characterization of PdRu@PVP nanomaterials, several spectroscopic and microscopic techniques were used. The prepared PdRu@PVP nanomaterials with an average particle size of 3.82 ±â€¯1.10 nm provided an 808.03 h-1 turnover frequency (TOF) in the dehydrogenation of DMAB and yielded 100% of the cyclic product (Me2NBH2)2 under mild conditions. Furthermore, the activities of catalysts were investigated theoretically using DFT-B3LYP calculations. The theoretical results based on density functional theory were in favorable agreement with the experimental data.

Composites of Platinum-Iridium Alloy Nanoparticles and Graphene Oxide for the Dimethyl Amine Borane (DMAB) dehydrogenation at ambient conditions: An Experimental and Density Functional Theory Study.

In this paper, we present the synthesis, characterization, catalytic and computational studies of Composites of Platinum-Iridium Alloy Nanoparticles and Graphene Oxide (PtIr@GO) for dimethylamine borane (DMAB) dehydrogenation. The prepared PtIr@GO nanocatalysts were synthesized using an ethanol super-hydride method, and the characterization procedures for PtIr@GO alloy nanoparticles were carried out by various advanced spectroscopic methods like X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission Electron Microscopy(TEM) and high-resolution transmission electron microscopy (HRTEM). Additionally, catalytic activity, reusability, substrate concentration, and catalyst concentration experiments were performed for DMAB dehydrogenation catalyzed by PtIr@GO alloy nanomaterials. According to the results obtained in this study, PtIr@GO NPs catalyst was found to be active and reusable for the DMAB even at ambient conditions. Besides, DFT-B3LYP calculations have been utilized on PtIr@GO cluster to reveal the prepared catalyst activity. The calculated findings based on DFT was found to be a good agreement with experimental results.

Crystal structures, spectroscopic properties of new cobalt(II), nickel(II), zinc(II) and palladium(II) complexes derived from 2-acetyl-5-chloro thiophene thiosemicarbazone: Anticancer evaluation.

The reactions of cobalt(II), nickel(II), zinc(II) chlorides and [Pd(DMSO)2Cl2] with 2-acetyl-5-chloro-thiophene thiosemicarbazone (HL) leads to the formation of a series of new complexes: [CoCl2(S-HL)2], 1; [Ni(N,S-L)2], 2 [ZnCl2(S-HL)2], 3 and [PdCl2(N,S-HL)], 4. All the complexes have been characterized by elemental analysis, IR, LC-MS. 1H and 13C NMR spectroscopy have been performed for Zn(II) and Pd(II) complexes. The crystal structures of the complexes 1-3 have been determined by single-crystal X-ray diffraction methods. The compounds, (1) and (3), crystallized in the monoclinic crystal system with C2/c space group. In both complexes, the metal centers are four-coordinated in a distorted tetrahedral configuration by two sulfur atoms from two thiosemicarbazone ligands and two Cl anions. The crystal structure of (2) consists of monomeric entities where the nickel(II) ion exhibit distorted square planar geometry. The coordination geometry around nickel ion is four-coordinate with four atoms of the two chelating thiosemicarbazone ligands which are in cis position. The τ4 value of 0.255 obtained from the τ4 analysis of complex (2) shows that the four-coordinate geometry around the central nickel ion is close to square planar. Complex (4) is mononuclear, the central ion is coordinated through the sulfur and the azomethine nitrogen atom of neutral ligand. The cytotoxic effects of all complexes were analyzed for three cancer cell lines, Caco-2, DLD-1, and SW620 compared to normal colon epithelial cell line, CCD18Co. Complex (4) is more active against DLD-1, SW620 and Caco-2 than CCD18Co. The efficiency of complex (4) is more effective in aggressive cancer cell lines. Therefore, it can be used as a new chemotherapeutic, especially in the treatment of resistant cancer types caused by long-term use of platinum-based drugs.

1,3-Di-3-pyridyl-2,3-dihydro-1H-naphth[1,2-e][1,3]oxazine.

In the crystal structure of the title compound, C(22)H(17)N(3)O, the oxazine ring has a half-chair conformation. The dihedral angles between the best least-squares plane through the pyridine rings and the planar part (O-C-C-C-N) of the oxazine ring are 72.14 (6) and 35.44 (7)°, the smaller angle involving the pyridine ring adjacent to the oxazine O atom. The mol-ecule has two stereogenic centers at the oxazine carbons, RS and SR. The crystal packing reveals that symmetry-related mol-ecules are linked by inter-molecular N-H⋯N hydrogen bonds to form chains parallel to the b axis.

Highly efficient monodisperse Pt nanoparticles confined in the carbon black hybrid material for hydrogen liberation.

Dimethylamine borane (DMAB) has been considered as one of the important hydrogen sources with a simple process by the help of the efficient catalyst. For this purpose, herein, platinum nanoparticles (Pt NPs), placed inside carbon black hybrid (Pt NPs@CBH), activated carbon (Pt NPs@AC) and Vulcan carbon (Pt NPs@VC), have been prepared as highly monodisperse catalysts for dehydrogenation reactions of DMAB at room temperature. The morphological and physical structure of the monodisperse catalysts have been identified by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) etc. The typical face-centered cubic (fcc) structure of the all prepared catalysts was verified from X-ray diffractogram. All prepared catalytic materials were measured as high-performance catalysts for dehyrocoupling of DMAB; but, Pt NPs@CBH catalyst indicated the better catalytic activity compared to the other prepared ones. Easy utilization at very small concentrations and temperature, monodisperse Pt NPs@CBH perform an eye-catching catalytic activity with providing one of the best TOF (70.28 h-1) and Ea (93.56 ±â€¯2 kJ/mol) for dehydrocoupling of DMAB.

Highly sensitive glucose sensor based on monodisperse palladium nickel/activated carbon nanocomposites.

Glucose enzyme biosensors have been used for a variety of applications such as medical diagnosis, bioprocess engineering, beverage industry and environmental scanning etc. and there is still a growing interest in glucose sensors. For this purpose, addressed herein, as a novel glucose sensor, highly sensitive activated carbon (AC) decorated monodisperse nickel and palladium alloy nanocomposites modified glassy carbon electrode (Ni-Pd@AC/GCE NCs) have been synthesized by in-situ reduction technique. Raman Spectroscopy (RS), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), cyclic voltammetry (CV) and chronoamperometry (CA) were used for the characterization of the prepared non-enzymatic glucose sensor. The characteristic sensor properties of the Ni-Pd@AC/GCE electrode were compared with Ni-Pd NCs/GCE, Ni@AC/GCE and Pd@AC/GCE and the results demonstrate that the AC is very effective in the enhancement of the electrocatalytic properties of sensor. In addition, the Ni-Pd@AC/GCE nanocomposites showed a very low detection limit of 0.014 µM, a wide linear range of 0.01 mM-1 mM and a very high sensitivity of 90 mA mM-1 cm-2. Furthermore, the recommended sensor offer the various advantageous such as facile preparation, fast response time, high selectivity and sensitivity. Lastly, monodisperse Ni-Pd@AC/GCE was utilized to detect glucose in real sample species.

Highly efficient polymer supported monodisperse ruthenium-nickel nanocomposites for dehydrocoupling of dimethylamine borane.

In the present study, highly effective and reusable monodisperse ruthenium-nickel (Ru-Ni) nanomaterials supported on poly(N-vinyl-2-pyrrolidone) (Ru-Ni@PVP) were synthesized (3.51 ±â€¯0.38 nm) by a facile sodium-hydroxide-assisted reduction method; Ru and Ni reduction in PVP solution was accomplished. The prepared nanocomposites were characterized by TEM, HRTEM, XRD, and XPS and performed as a catalyst for dehydrocoupling of dimethylamine-borane (DMAB). It was found that Ru-Ni nanomaterials are one of the most active catalysts at low concentrations and temperature for dehydrocoupling of DMAB. This catalyst with its turnover frequency of 458.57 h-1 exhibits one of the best results among all the catalysts prepared in the literature for dehydrocoupling of DMAB. Significantly low Ea value (36.52 ±â€¯3 kJ mol-1) was also found for dehydrocoupling of DMAB.

A hydrogen peroxide sensor based on TNM functionalized reduced graphene oxide grafted with highly monodisperse Pd nanoparticles.

Addressed herein, we report the synthesis and characterization of a tert-nonyl mercaptan (TNM) functionalized reduced graphene oxide (rGO) supported palladium (Pd) nanoparticles (NPs) (Pd/TNM@rGO) as electrochemical sensor. The highly monodisperse Pd/TNM@rGO nanocomposite was applied for electrochemical determination of hydrogen peroxide (H2O2) at a potential range of -0.6 to +0.8 V. The Pd/TNM@rGO sensor demonstrated very high activity, sensitivity, reusability and durability toward H2O2 sensing. The well dispersed Pd/TNM@rGO nanocomposite has been characterized by using several analytical techniques such as, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS) and electrochemical impedance spectroscopy (EIS). The catalytic performance of prepared biosensor was also characterized by using cyclic voltammetry (CV) and chronoamperometry (CA) methods. The proposed H2O2 biosensor showed a broad linear range up to 12 mM, and a very low detection limit of 0.0025 µM, with a quick response time of less than 10 s. Additionally, the biosensor exhibited great capability, reproducibility and durability for the examination of H2O2.

2-Methoxy-4-[(5-oxo-2-phenyl-4,5-dihydro-1,3-oxazol-4-ylidene)methyl]phenyl 4-methylbenzenesulfonate.

Molecules of the title compound, C(24)H(19)NO(6)S, adopt the Z configuration and have a distorted tetrahedral geometry around the S atom. The oxazolone, 2-phenyl and methoxyphenyl rings are approximately coplanar. The C atom between the methoxyphenyl and oxazolone rings displays a distorted trigonal bonding geometry. Pairs of molecules are linked into dimers through weak C-H...O hydrogen bonds.