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This article considers the concept and significance of transformative research in the context of geography education. It provides an overview of how the capacity-building activities and management ...

Four new MnII- and CoII-containing magnetic coordination polymers, [{Mn(Br-isa)(bpe)·1/2H2O}n (1), {Co(Br-isa)(bpe)1.5·1/2H2O}n (2), [{Mn(Br-isa)(4-bpmh)}4·6H2O]n (3), and [{Co(Br-isa)(4-bpmh)}2·21/2H2O]n (4)] [isa = isophthalic acid, bpe = 1,2-bis-(4-pyridyl)ethylene and 4-bpmh = N,N′-bispyridine-4-yl-methylene-hydrazine], have been synthesized at room temperature, using 5-bromo isophthalic acid (Br-H2isa) and two different N-donating ancillary ligands. The complexes have been characterized by single-crystal X-ray diffraction and other physicochemical techniques. Structure determination reveals two-dimensional (2D) coordination network architectures for all the complexes. In 1, 3, and 4, MnII and CoII dinuclear units are connected via Br-H2isa ligands to form infinite 1D chains. The ancillary N,N′-donor spacer ligands interconnect the 1D chains into 2D coordination layers. Complex 2, on the other hand, can be viewed as being composed of cationic [{Co(bpe)}4]8+ square units that are joined by anionic Br-i...

The design of redox-active metal-organic frameworks and coordination networks (CNs), which exhibit metal- and/or ligand-centered redox activity, has recently received increased attention. In this study, the redox-active metalloligand (RML) [Me4N]3fac-[CrIII(mp)3] (1) (mp = 2-mercaptophenolato) was synthesized and characterized by single-crystal X-ray diffraction analysis, before its reversible ligand-centered one-electron oxidation was examined by cyclic voltammetry and spectroelectrochemical measurements. As complex 1 contains OS coordination sites in three directions, complexation with K+ ions led to the formation of a two-dimensional honeycomb sheet-structured [K3fac-{CrIII(mp)3}(H2O)6]n (2·6H2O), which is the first example of a redox-active CN constructed from a RML with o-disubstituted benzene ligands. Herein, we unambiguously demonstrate the ligand-centered redox activity of the RML, which is incorporated in the redox-active CN 2·6H2O in the solid state.

Using scanning tunnelling microscopy (STM), we demonstrate that Au-pyridyl coordination can be used to assemble two-dimensional coordination network structures on metal surfaces. The polymorphism of the coordination network structures can be manipulated at both the micro- and nanoscale. Using the same organic ligand, we assembled two distinct polymorphic network structures, which were assisted by threefold Au-pyridyl coordination on Ag(111) with predeposited Au atoms (α-network), and by twofold Au-pyridyl coordination on Au(111) (β-network), respectively. Specifically on the Au(111) surface, single-oriented β-network domains as large as ≈400 nm were selected by thermal annealing. We ascribe this global control strategy to distinct Au bonding modes tuned by molecule-substrate interactions. Using an STM tip, we succeeded in creating α-network domains (≈10 nm) locally within the homogeneous β-network domain areas on Au(111) in a controlled manner.

Two coordination polymers, 1 and 2 were developed utilizing the favorable hexacoordinated zinc(II) center in porphyrins. Single crystal X-ray structure analysis revealed that 1 forms one dimensional array whereas 2 display three dimensional network structures. Scanning tunnelling microscopic studies have shown that compounds 1 and 2 can tunnel the electric current through the crystal lattice indicating the conducting behavior of these solid crystals. The self-assembled solid crystal 2 has shown uniform conductance whereas 1 does not. The thermal stability of these crystals were determined by TGA analysis and found to be stable up to a higher temperature of 400°C. A temperature dependent current–voltage analysis were also performed and the results indicate that the conductivity of crystals 1 and 2increases with increase in temperature. It is found that the temperature coefficient of resistance ([Formula: see text] at 100°C for 1 and 2 as -0.009 and 0.017 K[Formula: see text].

The single-crystal to single-crystal (SC–SC) transformation from a 1D coordination chain to a 3D coordination network, which is triggered by both solvent and anion exchanges, has been revealed to suffer from a tandem mechanism as proved by isolation of the intermediate state. The resulting porous crystalline material shows a high efficiency for the capture of dichromates (207 mg g−1) via the SC–SC anion-exchange.

A multistate redox-active coordination network was prepared by stepwise synthesis via mechanochemical reaction to overcome the low solubility of ligands. Solid-state grinding between sparingly solu...

Ciliated protists have attracted wide interest among researchers from the Indian subcontinent in the last few years. An International Symposium on Ciliate Biology (ISCB) 2018 was held on 04-06 April 2018 at the India Habitat Centre, New Delhi, India. The symposium represented a synergy with International Research Coordination Network for Biodiversity of Ciliates (IRCN-BC), an affiliate society of International Society of Protistologists (ISOP). The symposium provided a platform for Indian and International delegates to exchange knowledge, present their latest research findings, and establish collaborations as well as creating a networking opportunity for undergraduate and postgraduate students. Nine foreign delegates from 5 countries and 300 Indian delegates actively participated in the event which included 22 oral and 57 poster presentations.

The synthesis and characterization of 4′-(4-methoxyphenyl)-3,2′:6′,3″-terpyridine (2) (IUPAC PIN 24-(4-methoxyphenyl)-12,22:26,32-terpyridine) are described, and its coordination behaviour with cobalt(II) thiocyanate has been investigated. In a series of experiments, crystals were grown at room temperature by layering a MeOH solution of Co(NCS)2 over a CHCl3 solution of 2 using 1:1, 1:2 or 2:1 molar ratios of metal salt-to-ligand. Crystals harvested within 2–3 weeks proved to be the 1D-coordination polymer [Co(2)(NCS)2(MeOH)2]n and powder X-ray diffraction (PXRD) confirmed that the crystals selected for single-crystal X-ray diffraction were representative of the bulk samples. Longer crystallization times with a Co(NCS)2 to 2 molar ratio of 1:1 yielded crystals of [Co(2)(NCS)2(MeOH)2]n (1D-chain) and the pseudopolymorphs [{Co(2)2(NCS)2}·3MeOH]n and [{Co(2)2(NCS)2}·2.2CHCl3]n ((4,4)-nets), each type of crystal originating from a different zone in the crystallization tube. PXRD for this last experiment confirmed that the dominant product in the bulk sample was the 1D-coordination polymer.

We overview the coordination chemistry of ditopic and tetratopic ligands with 4,2':6',4''-terpyridine metal-binding domains and illustrate the adaptability of these divergent ligands as building blocks in 2D- and 3D-coordination networks. The ditopic ligands we discuss are limited to roles as linkers in coordination assemblies, while the tetratopic ligands have the potential to be 4-connecting nodes. Both di- and tetratopic ligands are equipped with functionalities, typically alkyloxy chains, the nature of which has a profound effect upon the coordination assembly. Combinations of 4-connecting ligand nodes with metal-linkers lead to both 2D- and 3D-networks, while combinations of 4-connecting metal and ligand nodes give 3D-architectures. We also demonstrate constraint of the coordination assembly to 2-dimensions by depositing ditopic 4,2':6',4"-terpyridine ligands onto Au(111) or Cu(111) platforms with Cu adatoms in the former case; highly ordered ladder assemblies result which are independent of solvent molecules or anions.

A key remit of the NSF‐funded “Arabidopsis Research and Training for the 21st Century” (ART‐21) Research Coordination Network has been to convene a series of workshops with community members to explore issues concerning research and training in plant biology, including the role that research using Arabidopsis thaliana can play in addressing those issues. A first workshop focused on training needs for bioinformatic and computational approaches in plant biology was held in 2016, and recommendations from that workshop have been published (Friesner et al., Plant Physiology, 175, 2017, 1499). In this white paper, we provide a summary of the discussions and insights arising from the second ART‐21 workshop. The second workshop focused on experimental aspects of omics data acquisition and analysis and involved a broad spectrum of participants from academics and industry, ranging from graduate students through post‐doctorates, early career and established investigators. Our hope is that this article will inspire beginning and established scientists, corporations, and funding agencies to pursue directions in research and training identified by this workshop, capitalizing on the reference species Arabidopsis thaliana and other valuable plant systems.

peer-reviewed Coordination networks that reversibly switch between closed and open phases are of topical interest since their stepped isotherms can offer higher working capacities for gas‐storage applications than the related rigid porous coordination networks. To be of practical utility, the pressures at which switching occurs, the gate‐opening and gate‐closing pressures, must lie between the storage and delivery pressures. Here we study the effect of linker substitution to fine‐tune gate‐opening and gate‐closing pressure. Specifically, three variants of a previously reported pcu‐topology MOF, X‐pcu‐5‐Zn, have been prepared: X‐pcu‐6‐Zn, 6=1,2‐bis(4‐pyridyl)ethane (bpe), X‐pcu‐7‐Zn, 7=1,2‐bis(4‐pyridyl)acetylene (bpa), and X‐pcu‐8‐Zn, 8=4,4′‐azopyridine (apy). Each exhibited switching isotherms but at different gate‐opening pressures. The N2, CO2, C2H2, and C2H4 adsorption isotherms consistently indicated that the most flexible dipyridyl organic linker, 6, afforded lower gate‐opening and gate‐closing pressures. This simple design principle enables a rational control of the switching behavior in adsorbent materials.

The single crystal X-ray structure determination of {[Cu(tpt)(o-phthalate)]·31/3(C2H2Cl4)}n (tpt = 2,4,6-tri-4-pyridyl-1,3,5-triazine, C2H2Cl4 = 1,1,2,2-tetrachloroethane = TCE) shows a 3D network in which CuII centres are linked by 3-connecting tpt ligands with the topology of a 12,3 net. CuII centres are further linked by o-phthalate dianions. The copper coordination geometry is square pyramidal, with o-phthalate oxygen donors trans to each other in the basal plane and the remaining positions taken by the pyridines of three linking tpt units. The solvent accessible void space is ∼65 %. The pale blue-green crystalline desolvate, obtained by heating to 200°C or washing the TCE solvate with acetone is formulated as [Cu(tpt)(o-phthalate)]n. Powder X-ray diffraction and electron paramagnetic resonance spectroscopy show that the crystal structure and the CuII geometry changes upon desolvation. The crystalline desolvated phase sorbs two equivalents of ammonia per copper ion. The adduct, mauve [Cu(tpt)(o-phthalate)(NH3)2]n, shows reasonable crystallinity and is stable up to ∼150°C under ambient conditions before the reversible desorption (minimum 10 cycles) of the guest ammonia. The colour change and high desorption temperature, along with changes in g values, is suggestive of chemisorption in two steps with Cu-ammine bonding in the loaded phase.

Adaptive optics (AO) systems and image reconstruction algorithms are indispensable tools when it comes to high-precision astrometry. In this paper, we analyze the potential of combining both techniques, i.e., by applying image reconstruction on partially AO-corrected short exposures. Therefore we simulate speckle clouds with and without AO corrections and create synthetic observations. We apply holographic image reconstruction to the obtained observations and find that (i) the residual wavefronts decorrelate slowlier and to a lower limit when AO systems are used, (ii) the same reference stars yield a better reconstruction, and (iii) using fainter reference stars we achieve a similar image quality. These results suggest that holographic imaging of speckle observations is feasible with ∼2 – 3 × longer integration times and ∼3 mag fainter reference stars, to obtain diffraction-limited imaging from low-order AO systems that are less restricted in sky coverage than typical high-order AO systems. © 2019. The Astronomical Society of the Pacific. All rights reserved., F.B. acknowledges support by the Optical Infrared Coordination Network for Astronomy (OPTICON) under a Horizon2020 Grant and from the International Max Planck Research School for Astronomy and Cosmic Physics at the University of Heidelberg (IMPRS-HD). The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement n° [614922].

We report a spin crossover material based on a cyanido-bridged FeII–MoIV assembly, FeII2[MoIV(CN)8](1-(3-pyridyl)ethanol)8⋅4H2O. This compound has a cubic crystal structure in the I a 3 ¯ d space group and is composed of a three-dimensional cyanido-bridged FeII–MoIV coordination network with one crystallographic FeII site. It exhibits incomplete spin crossover, because 21% of the high-spin FeII sites (S = 2) changes to low-spin FeII sites (S = 0) in the temperature range between 200 and 50 K. Thermal hysteresis is not observed. Such an incomplete and gradual spin crossover is attributed to the elastic frustration between the high-spin and the low-spin FeII sites (e.g., alternating arrangement such as –HS–LS–HS–LS–).

With the growing demand of gold for research laboratories and industrial technologies, there is high needed to extract gold from related waste other than natural resources. Herein, we designed a novel adsorbent denoted as PCN-222-MBA (Thiol-functionalized PCN-222), by functionalizing Zr6-nodes of PCN-222 (PCN = Porous Coordination Network) with 4-mercaptobenzoic acid (MBA) through solvent-assisted ligand incorporation (SALI) approach for selective and facile extraction of gold ions from aqueous media. The mesoporous MOF was characterized by different techniques. The performance of PCN-222-MBA as solid adsorbent was assessed under batch conditions, with significant parameters studied and optimized. The maximum adsorption capacity of the respective adsorbent was 714.3 mg/g at pH 6.1 and 1 min. PCN-222-MBA exhibited high affinity for Au(III) than other coexisting ions and could be regenerated at least six cycles. Gold ions were also extracted and determined in real samples.

Catassembly is a new concept in molecular assembly that is analogous to catalysis in chemical synthesis. However, for most molecular-assembled processes, the catassembler contributions are rather inconspicuous due to the low activation barriers. As a result, few systems dealing with the catassembly are available until now. In this paper, we report that naphthalene diimide coordination networks are formed under the catassembly of lone-pair-bearing catassemblers (e.g., N,N-dimethylacetamide, N-methylpyrrolidin-2-one). During such molecular assembly, a stable transition state between the electron-deficient naphthalene diimide tectons and catassemblers via the less common lone pair-π interactions was observed, which is supposed to play the key role in the enhancement of coordination abilities of organic tectons and thus formation of the final coordination networks.

A tetrathiafulvalene derivative has been incorporated into a diamond-like structure for the first time. The coordination network shows highly unusual 8-fold interpenetration with redox-active and photoelectric properties.

Hydrothermal reaction of zinc oxide, 1,2-benzenedicarboxylic acid (H2pa) and 1,2,4-triazole (Htrz) yielded a (3,12)-connected 2-D coordination network [Zn8(trz)4(OH)4(pa)4]n (1), in which rare tetragonal prism-like ZnII8 clusters and tridentate 1,2-benzenedicarboxylate act as 12- and 3-connected nodes, respectively. Moreover, the luminescent emission spectra and thermostability of 1 have been investigated.

Iodinated pores of a Zn-based coordination network were modified by Br2 oxidation to produce brominated pores in a polycrystalline-to-polycrystalline manner while maintaining the same network topology. Ab initio X-ray powder diffraction analysis and Raman spectroscopy revealed that the brominated pore can trap Br2 or I2 by strong σ/π-type interactions. A kinetic study in solution revealed that the pore modification by Br2 oxidation is much faster than the Br2 encapsulation process.

A comparative investigation of the coordination behaviour of the regio-isomers (o-L and p-L) of the tribenzo-O2S2-macrocycle (L) is reported. On silver(I) complexation, the macrocycle incorporating an o-xylyl group (o-L) yields a discrete endo/exocyclic tetranuclear bis(macrocycle) complex. On the other hand, the corresponding p-xylyl analogue (p-L) gives a 2D square-grid coordination network via exocyclic coordination.

openaire: EC/FP7/610446/EU//PAMS We report on first stages toward the formation of a surface-confined metal-organic coordination network (MOCN) by sequential deposition of biphenyl-4,4′-dicarboxylic acid and iron atoms on the surface of a bulk insulator, calcite (10.4). The influence of the deposition order on the structure formation is studied by noncontact atomic force microscopy operated in ultrahigh vacuum at room temperature. It is found that sequential deposition facilitates MOCN formation when the organic linker molecules are first adsorbed on the surface, followed by iron deposition. This observation is explained by first-principles computations, indicating that the metal-molecule interaction dominates over the molecule-molecule interaction on the surface. The observed MOCN islands are elongated in the [010] substrate direction, demonstrating a templating effect of the underlying substrate. This experimental finding is confirmed by calculations suggesting that the MOCN network matches the calcite lattice periodicity in the [010] direction but not in the [421] direction. This work, thus, demonstrates the decisive influence of both deposition order and lattice matching on the formation of an extended MOCN on a bulk insulator surface.

Heating of a pink two-dimensional Co(II) coordination network {[Co2(μ2-OH2)(bdc)2(S-nia)2(H2O)(dmf)]·2(dmf)·(H2O)}n (1) built from 1,4-benzenedicarboxylic acid (H2bdc) residues and thionicotinamide (S-nia) ligands initiates a single-crystal-to-single-crystal transition accompanied by removal of both coordinated and co-crystallized solvents. In the dry blue form, [Co(bdc)(S-nia)]n (dry_1), the Co(II) centers changed from an octahedral to a square pyramidal configuration.

Upon combining enantiopure bis-4-pyridylphenyl-substituted cyclotetrapeptides with HgCl2 and CdCl2, homochiral 1D zigzag coordination polymers were obtained, while the use of a bis-4-pyridyl-substituted cyclotetrapeptide with HgCl2 led to the formation of a different type of 1D coordination network.

International audience; Depending on the nature of the anion (NO3-or BF4-) and stoichiometry, combinations, under self-assembly conditions, of the [1.1.1.1]metacyclophane 2 adopting a blocked 1,3-alternate conformation and bearing four cyanomethylene groups, with silver cations, lead either to the formation of a 1D coordination network or a discrete binuclear metallomacrocycle.

We present an extended metal-coordinated structure obtained by deposition of trimesic acid (TMA) onto the Ag(111) surface under ultra-high vacuum conditions followed by annealing to 510 K. Scanning tunneling microscopy and density functional theory calculations reveal the structure to consist of metal clusters containing seven Ag atoms each, coordinated by six dehydrogenated TMA molecules. The molecules are asymmetrically arranged, resulting in a chiral structure. The calculations confirm that this structure has a lower free energy under the experimental conditions than the hydrogen-bonded structures observed after annealing at lower temperatures. We show that the formation of such large metal clusters is possible due to the low adatom formation energy on silver and the relatively strong Ag-O bond in combination with a good lattice match between the structure and the Ag surface. Published by AIP Publishing.

The study of how the observable features of organisms, i.e., their phenotypes, result from the complex interplay between genetics, development, and the environment, is central to much research in biology. The varied language used in the description of phenotypes, however, impedes the large scale and interdisciplinary analysis of phenotypes by computational methods. The Phenoscape project (www.phenoscape.org) has developed semantic annotation tools and a gene–phenotype knowledgebase, the Phenoscape KB, that uses machine reasoning to connect evolutionary phenotypes from the comparative literature to mutant phenotypes from model organisms. The semantically annotated data enables the linking of novel species phenotypes with candidate genes that may underlie them. Semantic annotation of evolutionary phenotypes further enables previously difficult or novel analyses of comparative anatomy and evolution. These include generating large, synthetic character matrices of presence/absence phenotypes based on inference, and searching for taxa and genes with similar variation profiles using semantic similarity. Phenoscape is further extending these tools to enable users to automatically generate synthetic supermatrices for diverse character types, and use the domain knowledge encoded in ontologies for evolutionary trait analysis. Curating the annotated phenotypes necessary for this research requires significant human curator effort, although semi-automated natural language processing tools promise to expedite the curation of free text. As semantic tools and methods are developed for the biodiversity sciences, new insights from the increasingly connected stores of interoperable phenotypic and genetic data are anticipated. We thank all participants in the Phenotype Ontology Research Coordination Network (RCN) (NSF 0956049) for their vision, contributions, and commitment to developing shared and interoperable resources. During the course of this work the Phenoscape project has been supported by NSF awards 1062404, 1062542, 0641025, 1661529, and the National Evolutionary Synthesis Center (NSF 0905606 and 0423641). This manuscript is based in part on work done by P.M.M. while serving at the U.S. National Science Foundation. The views expressed in this paper do not necessarily reflect those of the National Science Foundation or the United States 314 Government.

In the two dimensional network [Fe(ebbtr)2(CH3CN)2](ClO4)2·4CH3CN a sequence of LS → HS → LS → HS transitions occurs as the exclusive result of the change in temperature. This property results from the extraordinary flexibility/elasticity manifested in the hierarchical arrangement of structural events involving the reorientation of coordinated/noncoordinated molecules as well as with the deformation and the mutual shift of the polymeric units.

Debris disks are usually detected through the infrared excess over the photospheric level of their host star. The most favorable stars for disk detection are those with spectral types between A and K, while the statistics for debris disks detected around low-mass M-type stars is very low, either because they are rare or because they are more difficult to detect. Terrestrial planets, on the other hand, may be common around M-type stars. Here, we report on the discovery of an extended (likely) debris disk around the M-dwarf GSC 07396-00759. The star is a wide companion of the close accreting binary V4046 Sgr. The system probably is a member of the $\beta$ Pictoris Moving Group. We resolve the disk in scattered light, exploiting high-contrast, high-resolution imagery with the two near-infrared subsystems of the VLT/SPHERE instrument, operating in the YJ bands and the H2H3 doublet. The disk is clearly detected up to 1.5" ($\sim110$ au) from the star and appears as a ring, with an inclination $i\sim83$ degree, and a peak density position at $\sim 70$ au. The spatial extension of the disk suggests that the dust dynamics is affected by a strong stellar wind, showing similarities with the AU Mic system that has also been resolved with SPHERE. The images show faint asymmetric structures at the widest separation in the northwest side. We also set an upper limit for the presence of giant planets to $2 M_J$. Finally, we note that the 2 resolved disks around M-type stars of 30 such stars observed with SPHERE are viewed close to edge-on, suggesting that a significant population of debris disks around M dwarfs could remain undetected because of an unfavorable orientation., Comment: 10 pages, 10 figures, in press by A&A

Context. A low-mass brown dwarf has been recently imaged around HR 2562 (HD 50571), a star hosting a debris disk resolved in the far infrared. Interestingly, the companion location is compatible with an orbit coplanar with the disk and interior to the debris belt. This feature makes the system a valuable laboratory to analyze the formation of substellar companions in a circumstellar disk and potential disk-companion dynamical interactions. Aims. We aim to further characterize the orbital motion of HR 2562 B and its interactions with the host star debris disk. Methods. We performed a monitoring of the system over ~10 months in 2016 and 2017 with the VLT/SPHERE exoplanet imager. Results. We confirm that the companion is comoving with the star and detect for the first time an orbital motion at high significance, with a current orbital motion projected in the plane of the sky of 25 mas (~0.85 au) per year. No orbital curvature is seen in the measurements. An orbital fit of the SPHERE and literature astrometry of the companion without priors on the orbital plane clearly indicates that its orbit is (quasi-)coplanar with the disk. To further constrain the other orbital parameters, we used empirical laws for a companion chaotic zone validated by N-body simulations to test the orbital solutions that are compatible with the estimated disk cavity size. Non-zero eccentricities (>0.15) are allowed for orbital periods shorter than 100 yr, while only moderate eccentricities up to ~0.3 for orbital periods longer than 200 yr are compatible with the disk observations. A comparison of synthetic Herschel images to the real data does not allow us to constrain the upper eccentricity of the companion., Accepted for publication in A&A. 14 pages, 14 figures, 3 tables. Updated to match published paper. Bug in the computation of the distributions of times at periastron passages corrected, minor effects on other orbital parameters