L1 L7 Research Articles

Pyrene-Modified Cyclic Peptides Detect Cu2+ Ions by Fluorescence in Water

The detection of metal ions is an option for maintaining water quality and diagnosing metal ion-related diseases. In this study, we successfully detected metal ions using fluorescent peptides in water. First, we prepared seven linear (L1–L7) and seven cyclic (C1–C7) peptides containing two pyrenyl (Pyr) units and assessed the response to various metal ions by fluorescence. The results indicated that C1, which contains a hexameric cyclic peptide moiety consisting of Pyr and Gly units, did not show a fluorescent response to metal ions, while the linear L1 corresponding to C1 showed a response to Cu2+, but its selectivity was found to be poor through a competition assay for each metal ion. We then assessed C2–C7 and L2–L7, in which Gly was replaced by His units at various positions in the same manner. The results showed that C2–C7 responded to Cu2+ in a manner dependent on the His position. Additionally, superior selectivity was observed in C7 through a competition assay. These results demonstrate that the structural restriction of peptides and the sequence affect the selective detection of Cu2+ and reveal that peptides with an appropriate structure can accomplish the fluorescent detection of Cu2+ specifically.

The abundance of dark matter haloes down to Earth mass

ABSTRACT We use the voids-within-voids-within-voids (VVV) simulations, a suite of successive nested N-body simulations with extremely high resolution (denoted, from low to high resolution, by L0 to L7), to test the Press–Schechter (PS), Sheth–Tormen (ST), and extended Press–Schechter (EPS) formulae for the halo abundance over the entire mass range, from minihaloes of 10−6 M⊙, to cluster haloes of 1015 M⊙, at different redshifts, from z = 30 to the present. We find that at z = 0 and z = 2, ST best reproduces the results of L0, which has the mean cosmic density (overdensity δ = 0), at 1011−15 M⊙. The higher resolution levels (L1–L7) are biased underdense regions (δ < −0.6). The EPS formalism takes this into account since it gives the mass function of a region conditioned, in this case, on having a given underdensity. EPS provides good matches to these higher levels, with deviations ≲20 per cent, at 10−6−12.5 M⊙. At z ∼ 7−15, the ST predictions for L0 and the EPS for L1–L7 show somewhat larger deviations from the simulation results. However, at even higher redshifts, z ∼ 30, EPS fits the simulations well again. We confirm our results by picking more subvolumes from the L0 simulation, finding that our conclusions depend only weakly on the size and overdensity of the region. The good agreement of EPS with the higher level simulations implies that PS (or ST) gives an accurate description of the total halo mass function in representative regions of the universe.

Synthesis of Geminal Bis‐ and Tetrakisphosphonate Ester Derivatives and Their Coordination Behavior Towards Ca(II) Ions

AbstractThe preparation and thorough characterization of a variety of (arylmethylene)phosphonate ester derivatives (S1–S7) as well as derived geminal bisphosphonate (BP) ester ligands (L1–L7) is presented. Subsequent complexation reactions of CaCl2 with selected BPs (L1–L3) and a known aliphatic tetrakisphosphonate ester (L8) yield the respective Ca(II) coordination compounds [Ca(H2O)2(L1‐‐L3)2]Cl2 (C1‐‐C3) and [Ca(L8)Cl2]n (C4) for potential future application as multi‐delivery systems in osteoporosis treatment. Obtained SCXRD and 1H DOSY‐NMR data provide a detailed insight into their solid‐ as well as solution‐state structures extending the so far scarcely found X‐ray studies on geminal BP‐supported Ca(II) complexes.

Collocations in the English LKS Books for Senior High School Students

This article investigates the types and variations of collocations used in English Lembar Kerja Siswa (LKS) books for senior high school students. The researchers employed corpus analysis in conducting this study. Data were collected from five English LKS books for grade X, XI, and XII Senior High School (SMA/SMK/MA). AntConc 3.5.8 was used to extract the data, which were then analyzed to find out the types and variations of collocations in the books. The findings revealed that the books consisted of Grammatical G1 (1804 tokens), Grammatical G2 (1 token), Grammatical G3 (423 tokens), Grammatical G4 (4664 tokens), Grammatical G5 (1 token), Grammatical G7 (34 tokens), Lexical L1 (3889 tokens), Lexical L3 (533 tokens), Lexical L4 (687 tokens), Lexical L5 (4 tokens), and Lexical L7 (2 tokens) collocations. Grammatical G4 collocation was mostly found in the LKS books. Furthermore, the collocation types in the English LKS books by grade levels were not various. The researchers suggest that English teachers should introduce collocations in their teaching to help the students to acquire the natural use of English.

Efficient Pyrazole Moiety‐Containing Ligands for Cu‐Catalyzed O‐Arylation of Phenols

AbstractSeven pyrazole‐ or pyridine‐containing N2‐ and N3‐ligalitnds (L1–L7) were developed for the ligand‐assisted CuI‐catalyzed coupling reactions of aryl halides with phenols. The structural and electronic effects were studied for various combinations of pyridine and/or imine nitrogen binding sites in the ligands. Screening their abilities showed most of them to be better than 4,4’‐dimethoxybipyridine (L8). Among them, 2‐(1‐pyrazolyl)pyridine (L1) featuring two types of binding sites gave the best results, with yields of up to 95% at 100 °C at a catalyst loading of 10 mol% (CuI/L in 1 : 1 ratio). Free radical scavengers, 2,2,6,6‐tetramethylpiperidin‐1‐yl)oxyl (TEMPO) (1.0 eq.) and cumene (1.0 eq.), lowered the yields by more than half, but the reaction was not completely quenched even when 3.0 eq. of TEMPO was used. A non‐radical and a radical mechanisms, are proposed for the L1‐promoted coupling reaction, well explained the experiments results. In addition, the structure of the catalyst species were elucidated through single crystal XRD and DFT (density functional theory) calculations.

Palladium (II) Complexes Containing 2-Phenylpyridine Derivatives: Synthesis, Molecular Structures, and Catalytic Activity for Suzuki–Miyaura Cross-Coupling Reactions

The preparation and characterization of a series of new 2-phenylpyridine derivative ligands consisting of 2-(R) pyridine (R = mesityl (L1), 2,6-dimethylphenyl (L2), o-tolyl (L3), m-tolyl (L4), p-tolyl (L5), o-methoxyphenyl (L6), and p-methoxyphenyl (L7)) and their Pd complexes [PdCl2L2] (L1–L7) is investigated using a combination of X-ray diffraction spectroscopy, GC-MS, and NMR. The crystal structures show that the Pd complexes adopt a square planar geometry, and the monodentate ligand is coordinated through the N donor of the pyridine ring to the Pd atom. The catalytic activities of the synthesized complexes are investigated. The square planar Pd complex trans-[(2-mesitylpy)2PdCl2)] shows a high efficiency in promoting Suzuki-Miyaura cross coupling in an aqueous solvent under aerobic conditions.

Palladium(II) complexes containing 2-phenylpyridine derivatives: synthesis, molecular structures, and catalytic activity for Suzuki—Miyaura cross-coupling reactions

The preparation and characterization of a series of new 2-phenylpyridine derivative ligands consisting of 2-(R) pyridine (R = mesityl (L1), 2,6-dimethylphenyl (L2), o-tolyl (L3), m-tolyl (L4), p-tolyl (L5), o-methoxyphenyl (L6), and p-methoxyphenyl (L7)) and their Pd complexes [PdCl2L2] (L1—L7) is investigated using a combination of X-ray diffraction spectroscopy, GC-MS, and NMR. The crystal structures show that the Pd complexes adopt a square planar geometry, and the monodentate ligand is coordinated through the N donor of the pyridine ring to the Pd atom. The catalytic activities of the synthesized complexes are investigated. The square planar Pd complex trans-[(2-mesitylpy)2PdCl2)] shows a high efficiency in promoting Suzuki—Miyaura cross coupling in an aqueous solvent under aerobic conditions.

Combined structural and theoretical investigation on differently substituted bispidine ligands: predicting the properties of their corresponding coordination polymers.

Pyridine-based bispidine ligands L1-L7, which differ in the substituent at the N7 position of the bispidine scaffold, have been studied by single crystal X-ray diffraction and density functional theory (DFT) calculations, also including solid-state algorithms. Qualitative description of the packing interactions and quantitative data on the stability of each ligand in the solid-state have been employed to draw reasonable predictions on the ligand potential for the formation of linear 1D coordination polymers (CPs) with Mn(ii)Cl2 and on their resulting dynamic properties, in terms of adsorption and solvent exchange capabilities. The basic assumption lies in the fact that volume and polarizability of the ligands would similarly affect packing energies in both molecular solids and CP materials. The results here obtained confirm the data previously reported on CPs (those made from L4 are less dynamic than the ones with L1), but they also allow the prediction that CPs made with L2 and L5 should be more dynamic than expected, while CPs with L6 and L7 should not form altogether. This latter prediction was derived from the analysis of the steric and electronic factors of the ligand substituents on the N7 position and it is further substantiated by the obtainment of a 2 : 1 molecular complex, and not a CP, by crystallization of L6 with MnCl2.

Effects of electrochemical properties of ferrocenylpyrazolylnickel(ii) and palladium(ii) compounds on their catalytic activities in ethylene oligomerisation reactions.

Palladium complexes of ferrocenylpyrazolylpyridine and ferrocenylpyrazolylamine were synthesised and screened as pre-catalysts (1–4) for olefin polymerisation. The pre-catalysts 1–4 on activation with EtAlCl2 in the presence of ethylene with chlorobenzene or hexane as solvent were highly active with 1 being the most active, with an activity of 360 kg mol Pd−1 h−1. The major product from the reaction was 1-butene and high carbon content oligomers. The molecular weight (m/z) of the high carbon content oligomers is as high as 623.0. When toluene is used as solvent, the products obtained were ethyltoluene and butyltoluene and 1-butene. The electronic properties of the ligands (L1–L7) and complexes (1–10) were determined by cyclic voltammetry (CV) and molecular modelling. The CV results show that the ferrocenyl is easily oxidized upon the introduction of pyrazolyl derivatives, the process is quasi-reversible. However, complexation of the ligands with palladium or nickel results in difficulty in oxidizing the ferrocenyl moiety. This is an indication of the electrophilic nature of both the palladium and nickel centres. The mechanism of the oxidation was observed to be diffusion-controlled and is independent of scan rate. Molecular modelling experiments show that nickel and palladium complexes have lower HOMO–LUMO gaps and high global descriptors, an indication of a highly electrophilic metal centre. A plot of the electrophilicity indices of the pre-catalysts against yield of the oligomers show a linear correlation, an indication that the electrophilicity of the metal centre plays an important role in the activity of these pre-catalysts.

Coordination polymers of silver(I) with ditopic cross-conjugated dienone

The reaction of the silver salts AgX (a: X = BF4-, b: X = ClO4-, c: X = OTf–) with α,α'-di(3/4-pyridylmethylene)cycloalkanones (L1–L3) and piperidones (L4–L7) results in the formation of coordination products of general composition [AgX(L n )(solvent)] and [AgX(L n )] (L n = L1–L7). All complexes were characterized by elemental analysis and IR-spectroscopy. The structures of [Ag(ClO4)(L1)(MeC≡N)]∞ (1b · MeC≡N) and [Ag(ClO4)(L1)]∞ (1b) in the solid state are reported. In both structures {Ag(L1)}+ building units are linked to each other via Ag–Npyridine primary bonds resulting in the formation of infinite chains. In both structures the ligands L1 are fixed in transoid conformations, thus forming zig-zag polar chains. The structure of 1b · MeC≡N consists of pairs of tightly and loosely stacked chains. The tightly packed chains are weakly coupled by perchlorate anions acting as μ-bridges in between Ag(I) centers as well as by π–π-stacking interactions of unsaturated fragments of the respective ligands. In contrast, polar 2D layers composed of {Ag(L1)} m m+ chains, which interdigitate via multiple weak interactions by Ag–O contacts, are found in the solid structure of 1b. The dissolution of coordination products in coordinating solvents like MeCN or DMSO leads to the decomposition of complexes due to formation of silver-solvent coordination compounds. The coordination products 1–5 are stable in solid state against exposure to the ambient light, whereas solutions of the compounds, especially in DMSO-d6, appeared to be photochemically labile. As revealed by NMR spectroscopic studies, the organic components undergo trans-cis isomerization.

Highly conserved exposed immunogenic peptides of Omp34 against Acinetobacter baumannii: An innovative approach

Omp34, also known as Omp34kDa or Omp33–36 is a virulence factor associated with A. baumannii metabolic fitness or its adherence and invasion to human epithelial cells. This protein is also introduced as a specific antigen which could induce strong antibody responses. In the present in silico study, recent vaccine design strategies such as ‘antigen minimization’ and ‘high epitope density’ were invoked to design a soluble immunogen with higher antigenicity. As an advantage, the tools employed in the current study are easily available. Exposed peptides in linear B-cell epitopes were predicted and their conservancy and immunogenicity were evaluated. In this regard, constructs were designed by removal of inappropriate regions. Based on the obtained results the external loops (L1–L7) were exclusively considered of which L3, L6 and L7 were the most appropriate of which the most appropriate were in L3>L6>L7 order while L2 was assigned as an inappropriate peptide. The final construct, named Omp34-4, encompasses three copies of L3, two copies of L6 and L7 and one copy of L1, L4 and L5. The designed construct is predicted to be a soluble antigen with enhanced epitope density and antigenicity. Omp34 is present in >1600 strains of A. baumannii with ≥98% identity. So, it could be applicable in diagnostic kits and an immunotherapy choice against A. baumannii. It could be presumed that co-administration of Omp34-4 and a recently designed OmpA-derived antigen could confer sufficient protection against A. baumannii-associated infections. In vitro and in vivo experiments are needed to confirm all these data. The innovative approach could be generalized to vaccine designs focused on OMPs.

Phylogeny and evolution of achenial trichomes in theLucilia‐group (Asteraceae: Gnaphalieae) and their systematic significance

AbstractThe Gnaphalieae (Asteraceae) are a cosmopolitan tribe with around 185 genera and 2000 species. The New World is one of the centers of diversity of the tribe with 24 genera and over 100 species, most of which form a clade called theLucilia‐group with 21 genera. However, the generic classification of theLucilia‐group has been controversial with no agreement on delimitation or circumscription of genera. Especially controversial has been the taxonomic value of achenial trichomes and molecular studies have shown equivocal results so far. The major aims of this paper are to provide a nearly complete phylogeny of theLucilia‐group at generic level and to discuss the evolutionary trends and taxonomic significance of achenial trichome morphology. We conducted a phylogenetic analysis of the New World Gnaphalieae with nrDNA (ETS, ITS) sequence data from a sampling of 18 genera of theLucilia‐group and utilized these results to examine morphological evolution of achenial trichome types and presence of apical myxogenic cells. Seven well‐supported subclades can be recognized within theLucilia‐group (L1–L7). These results support Brazilian and AndeanBerroa,Facelis,Lucilia, andMicropsisforming a clade (L1), the inclusion of ChileanLuciliaunderBelloa(L2), the monophyly ofStuckertiella+Gamochaeta+Gamochaetopsis(L3),Chevreulia+Cuatrecasasiella(L4) andAntennaria(L5) excludingAntennaria linearifolia, which is resolved in a monophyletic group together withJalcophila,LoricariaandMniodes(L6), and the recognition ofGnaphaliothamnus(L7) removed from Brazilian taxa ofChionolaena(L2). Ancestral character state reconstruction of achenial trichome morphology suggests that clades are homogeneous in terms of trichome type, but with exceptions that make it highly homoplastic. Conversely, our results suggest that the presence of myxogenic apical cells is less homoplastic and that closely related species tend to resemble each other more than expected under random variation.

Makroavertebrata Bentos sebagai Bioindikator Kualitas Air Sungai Nimbai Manokwari, Papua Barat

Benthos macroinvertebrates have been used as bioindicators to assess the waters quality of the stream, but still are very rarely to applied in West Papua streams. Benthos macroinvertebrates can describe the stream water quality so that very well be used as bioindicators, due to each species has a different tolerance to interference organic pollutants in waters. This study aimed to assess the water quality of Nimbai stream using benthos macroinvertebrates tolerance level and several water quality parameters. Data retrieval was conducted in JuneJuly and SeptemberOctober 2012 in seven stations (L1L7) from Nimbai upstream to downstream that connected to Prafi river. The water macroinvertebrates were taken using surber with mesh size 200 μm and then was identified at the family level. At L5 station near the oil palm waste disposal installations was contains oil and fat (<1-3 mg/l), which resulted in dissolved oxygen (DO) and pH is lower than the other stations. Similarly the value of H' is low (0.83), however, the value of C (0.79) was high that dominated by Oligochaeta. Famili biotic index (FBI) value obtained showed that water quality in the L1L4 stations was in good to excellent condition, but the quality at L5 station is classified as very poor. As the distance far away from the sources of pollution in the L5 station, water quality tends to improve as shown in the L6 and L7 stations. The result of this study shows the important benefits of benthos macroinvertebrates as bioindicators for assessing the quality of stream waters, and can be described aquatic environments disturbance to the benthos macroinvertebrates habitats in Nimbai stream.

Synthesis, characterization and anticancer activity of a series of curcuminoids and their half‐sandwich ruthenium(II) complexes

A series of curcuminoids (L1–L7) and their corresponding (η6‐p‐cymene)RuII(Cur)Cl complexes (1–7) were synthesized and characterized using 1H NMR spectroscopy, elemental analysis and high‐resolution electrospray ionization mass spectrometry. The molecular structures of L2, L4, 1 and 4 were determined using single‐crystal X‐ray diffraction analysis. The stability of 1–7 was investigated by monitoring their UV profiles. The compounds were further evaluated for their in vitro antiproliferative activities against the HepG2 human liver and HeLa human cervical cancer cell lines and HEK‐293 T noncancerous cell line.

Detection and delineation of glacial lakes and identification of potentially dangerous lakes of Dhauliganga basin in the Himalaya by remote sensing techniques

Glaciers are retreating and thinning in the high altitude of the Himalayas due to global warming, causing into formation of numerous glacial lakes. It is necessary to monitor these glacial lakes consistently to save properties and lives downstream from probable disastrous glacial lake outburst flood. In this study, image processing software ArcGIS and ERDAS Imagine have been used to analyse multispectral image obtained by Earth resource satellite Landsat for delineating the glacial lakes with the help of image enhancement technique like NDWI. Landsat data since 1972 through 2013 have been used and maximum seven glacial lakes (L1–L7) have been detected and delineated in Dhauliganga catchment, they are situated above 4000 masl. The Glacial Lake L2 (Lat 30°26′45″E and Long 80°23′16″N) is the largest whose surface area was 132,300 m2 in Sept 2009, and L6 (Lat 30°23′27″E and Long 80°31′52″N) is highly unstable with variation rate −55 to +145 % with increasing trend. Additionally, glacial lakes L2 (Lat 30°26′45″E and Long 80°23′16″N) and L6 (Lat 30°23′27″E and Long 80°31′52″N) have been identified as potentially hazardous. These lakes may probably burst; as a result, huge reserve of water and debris may be released all on a sudden. This may transform into hazardous flash flood in downstream causing loss of lives, as well as the destruction of houses, bridges, fields, forests, hydropower stations, roads, etc. It is to note that Dhauliganga river considered in this study is a tributary of Kaliganga river, and should not be confused with its namesake the Dhauliganga river, which is a tributary of Alaknanda river.

Effect of formal and informal likelihood functions on uncertainty assessment in a single event rainfall-runoff model

In the present study, DREAM(ZS), Differential Evolution Adaptive Metropolis combined with both formal and informal likelihood functions, is used to investigate uncertainty of parameters of the HEC-HMS model in Tamar watershed, Golestan province, Iran.In order to assess the uncertainty of 24 parameters used in HMS, three flood events were used to calibrate and one flood event was used to validate the posterior distributions. Moreover, performance of seven different likelihood functions (L1–L7) was assessed by means of DREAM(ZS)approach. Four likelihood functions, L1–L4, Nash–Sutcliffe (NS) efficiency, Normalized absolute error (NAE), Index of agreement (IOA), and Chiew–McMahon efficiency (CM), is considered as informal, whereas remaining (L5–L7) is represented in formal category. L5 focuses on the relationship between the traditional least squares fitting and the Bayesian inference, and L6, is a hetereoscedastic maximum likelihood error (HMLE) estimator. Finally, in likelihood function L7, serial dependence of residual errors is accounted using a first-order autoregressive (AR) model of the residuals.According to the results, sensitivities of the parameters strongly depend on the likelihood function, and vary for different likelihood functions. Most of the parameters were better defined by formal likelihood functions L5 and L7 and showed a high sensitivity to model performance. Posterior cumulative distributions corresponding to the informal likelihood functions L1, L2, L3, L4 and the formal likelihood function L6 are approximately the same for most of the sub-basins, and these likelihood functions depict almost a similar effect on sensitivity of parameters. 95% total prediction uncertainty bounds bracketed most of the observed data. Considering all the statistical indicators and criteria of uncertainty assessment, including RMSE, KGE, NS, P-factor and R-factor, results showed that DREAM(ZS) algorithm performed better under formal likelihood functions L5 and L7, but likelihood function L5 may result in biased and unreliable estimation of parameters due to violation of the residualerror assumptions. Thus, likelihood function L7 provides posterior distribution of model parameters credibly and therefore can be employed for further applications.

Enantioselective syntheses of β-amino alcohols catalyzed by recyclable chiral Fe(iii) metal complex

An efficient asymmetric desymmetrization of meso-epoxides with anilines catalyzed by a series of simple and environmentally benign in situ generated Fe(iii) complexes based on chiral tridentate ligands L1–L7 was carried out at rt.

Achieving optimum performance in a loose-housed farrowing system for sows: The effects of space and temperature

Piglet survival relies on interactive influences of the sow, her piglets and their environment. There are a number of design challenges in a loose-housed farrowing and lactation system to optimise this dynamic, including achieving farrowing in the desired location (i.e. a protected nest area) and minimising crushings. The PigSAFE (Piglet and Sow Alternative Farrowing Environment) pen was developed with these challenges in mind. It has different areas to fulfil different biological and managerial needs, including a solid-floored nest area with piglet protection features (sloped walls, heated creep) intended for farrowing. Two hypotheses regarding pen design features to optimise farrowing location and improve piglet survival were tested: (i) greater space would improve maternal behaviour; and (ii) a heated nest-site would be more attractive to the farrowing sow. PigSAFE was adapted to give a LARGE treatment, 9.7m2 in total with a nest area of 4.0m2, and a SMALL treatment, same design but 7.9m2 in total with a nest area of 3.3m2. The nest floor was heated to either 30°C (T30) or 20°C (T20) from 48h before until 24h after farrowing. A 2×2 factorial design saw 88 Large White×Landrace sows randomly assigned to space and temperature treatments. Generalised linear mixed models were used to analyse performance data. Farrowing location analysis involved dividing the pen into seven areas (L1–L7); L1 deemed the safest location for the piglets to be born (in the nest, furthest from dunging area, closest to creep) and L7 the least protected (in the dunging area). Of all the piglets born 97% were born in the nest area. The majority of sows started farrowing in L1 (56%), with 39% of remaining piglets being born in this location. There was a significant Space×Temperature interaction for farrowing location (P=0.011) with SMALL_T20 achieving the most L1 births. Temperature had no significant influence on piglet survival (Total mortality P=0.401; Live-born mortality P=0.826). However space influenced mortality, with significantly greater live-born mortality when sows were afforded a larger farrowing space (LARGE=18.1% vs. SMALL=10.9% P=0.028). There were no significant interactions between space and temperature for either total mortality (P=0.394) or live-born mortality (P=0.685). The overall design successfully promoted farrowing in the nest location, irrespective of nest size and floor temperature. The higher piglet mortality in the LARGE treatment suggests that the larger nest size was less protective for the piglets and thus a smaller nest, within an adequate total pen size for differentiation of functional areas, would be recommended.

Expanding the family of heteroleptic oxidovanadium(IV) compounds with salicylaldehyde semicarbazones and polypyridyl ligands showing anti-Trypanosoma cruzi activity

Searching for prospective vanadium-based drugs for the treatment of Chagas disease, a new series of heteroleptic [VIVO(L-2H)(NN)] compounds was developed by including the lipophilic 3,4,7,8-tetramethyl-1,10-phenanthroline (tmp) NN ligand and seven tridentate salicylaldehyde semicarbazone derivatives (L1–L7). The compounds were characterized in the solid state and in solution. EPR spectroscopy suggests that the NN ligand is bidentate bound through both nitrogen donor atoms in an axial–equatorial mode. The EPR and 51V-NMR spectra of aerated solutions at room temperature indicate that the compounds are stable to hydrolysis and that no significant oxidation of VIV to VV takes place at least in 24h. The complexes are more active in vitro against Trypanosoma cruzi, the parasite responsible for Chagas disease, than the reference drug Nifurtimox and most of them are more active than previously reported [VIVO(L-2H)(NN)] complexes of other NN co-ligands. Selectivity towards the parasite was analyzed using J-774 murine macrophages as mammalian cell model. Due to both, high activity and high selectivity, L2, L4, L5 and L7 complexes could be considered new hits for further drug development. Lipophilicity probably plays a relevant role in the bioactivity of the new compounds. The [VIVO(L-2H)(NN)] compounds were designed aiming DNA as potential molecular target. Therefore, the novel L1–L7 tmp complexes were screened by computational modeling, comparing their DNA-binding features with those of previously reported [VIVO(L-2H)(NN)] compounds with different NN co-ligands. Whereas all the complexes interact well with DNA, with binding modes and strength tuned in different extents by the NN and semicarbazone co-ligands, molecular docking suggests that the observed anti-T. cruzi activity cannot be explained upon DNA intercalation as the sole mechanism of action.

A series of silver(i) coordination polymers of a new linear 4-((pyridin-4-ylthio)methyl)pyridine ligand: the role of organic and inorganic anions

Ten silver(I) coordination polymers {[Ag2(PTMP)2(L1)2]·3H2O}∞ (1), {[Ag2(PTMP)2(L2)]·7H2O}∞ (2), {[Ag2(PTMP)2(L3)]·2CH3OH}∞ (3), {[Ag2(PTMP)2(L4)]·5H2O}∞ (4), {[Ag(PTMP)]·0.5(L5)·2H2O}∞ (5), {[Ag(PTMP)(L6)0.5]·H2O}∞ (6), {[Ag3(PTMP)3(L7)]·2.25H2O}∞ (7), [Ag(PTMP)(NO3)]∞ (8), {[Ag(PTMP)]·(BF4)}∞ (9) and {[Ag(PTMP)]·(CF3SO3)·0.5H2O}∞ (10) derived from a new flexible 4-((pyridin-4-ylthio)methyl)pyridine ligand (abbreviated as PTMP) have been synthesized and fully characterized (L1 = pentafluoropropionate, L2 = malonate, L3 = 2,2,3,3,4,4-hexafluoropentanedioate, L4 = 1,4-cyclohexanedicarboxylate, L5 = 1,4-benzenedicarboxylate, L6 = 1,1′-biphenyl-4,4′-dicarboxylate and L7 = 2-hydroxypropane-1,2,3-tricarboxylate). These coordination polymers exhibit fascinating 1-D chains and 2-D and 3-D network structures with the PTMP functioning as a linear building block. Under a solvent medium with small van der Waals volume, the tuning effect of various anions from monocarboxylate to polycarboxylate (L1–L7) and the inorganic NO3−, BF4− and CF3SO3− on the construction of complexes 1–10 have been systematically investigated and discussed.