Different Structures Of Complexes Research Articles

Personal/impersonal and subject/null subject phenomena in the multi-structural languages

The study examines the functional potential of impersonal pronouns in different languages. The aim of this study is to analyze personal/impersonal and subject/null subject phenomena in multi-structural languages. The novelty of the study is to establish the role of the pronoun in personal and impersonal aspects. To achieve the aim of the study, the following methods are used: lexico-grammatical analysis, structural analysis, contrast analysis, and interpretative analysis of artistic and lexicographic texts. The comparative research was based on Russian, English, German, and French lexicographic resources and examples from artistic discourse in Russian, English, German, and French with their translations. As a result of the study, it was revealed that the impersonal pronoun is a homonym for the personal pronoun of the 3rd person unit. In grammatical studies, the impersonal pronoun stands out as an independent category. A unit known in grammar as the 3rd person pronoun (in German es, in English it, in French il, ce) has a broader functional potential than other pronouns. Namely, it can act in the text not only as a substitute for another word but can also indicate syntactic structures of different complexity: from a word to a complex of propositions. The prospect is to study the discursive nature of impersonality in various types of discourse in different linguocultures.

Effect of Auxiliary Ligands on the Architectures of Manganese Complexes Constructed by N-Heterocyclic Ligands: Syntheses, Structures, and Properties

Two manganese complexes based on N-heterocyclic ligands, [Mn(bqdca)(2,2'-bipy)(H2O)2]n (1), Mn0.5(4,4'-bipy) (H2O)2?0.5bqdca?2H2O (2) (H2bqdca = 2, 2'-biquinoline-4, 4'-dicarboxylic acid, 2, 2'-bipy = 2, 2'-bipyridine, 4, 4'-bipy = 4, 4'-bipyridine), have been synthesized by hydrothermal methods based on Pearson?s acid-base theory and structurally characterized. In Complex 1, the Mn ions are bridged by bqdca2- anions to form one-dimensional chains, which are further linked by hydrogen bonds to generate a two-dimensional layered structure. In Complex 2, each Mn ion was coordinated by 4, 4'-bipy and water molecules to generate a mononuclear structure accompanied by bqdca2- anion balancing valences. The intermolecular hydrogen bonds can link them to construct a three-dimensional supramolecular structure. The different structures of Complexes 1 and 2 illustrate the great influence of the N-heterocyclic auxiliary ligands on the self-assembly of coordination architectures. 2,2'- bipy and 4,4'-bipy ligands all act as terminal ligands. In addition, Complexes 1 and 2 exhibit the photoluminescent emission at 455 nm and 463 nm, and 455 nm and 465 nm in the solid state, respectively, which may be attributed to intraligand transitions. The redshifts of Complexes 1 and 2 may be due to the ligand-to-metal charge transfer, comparing to the H2bqdca ligand.. KEYWORDS :Crystal structure, Manganese complex, N-Heterocyclic ligand, Photoluminesce.

Bayesian hierarchical modelling of sea-level extremes in the Finnish coastal region

Abstract. Occurrence probabilities of extreme sea levels required in coastal planning, e.g. for calculating design floods, have been traditionally estimated individually at each tide-gauge location. However, these estimates include uncertainties, as sea-level observations typically have only a small number of extreme cases such as annual maxima. Moreover, exact information on sea-level extremes between the tide-gauge locations and incorporation of dependencies between the adjacent stations is often lacking in the analysis. In this study, we use Bayesian hierarchical modelling to estimate return levels of annual maxima of short-term sea-level variations related to storm surges in the Finnish coastal region. We use the generalised extreme value (GEV) distribution as the basis and compare three hierarchical model structures of different complexity against tide-gauge-specific fits. The hierarchical model structures allow us to share information on annual maximum sea levels between the neighbouring stations and also provide a natural way to estimate uncertainties in the theoretical estimates. The results show that compared to the tide-gauge-specific fits, the hierarchical models, which pool information across the tide gauges, provide narrower uncertainty ranges for both the posterior parameter estimates and the corresponding return levels in most locations. The estimated shape parameter of the GEV model is systematically negative for the hierarchical models, which indicates a Weibull type of behaviour for the extremes along the Finnish coast. The negative shape parameter also allows us to calculate the theoretical upper limit for the annual maximum sea levels on the Finnish coast. Depending on the tide gauge and hierarchical model considered, the median value of the theoretical upper limit was 47–73 cm higher than the highest observed sea level.

Stimuli-Responsive Naphthalenediimide Cd-MOFs Tuned by Different Aliphatic Dicarboxylic Acids with Extended Spacers.

A series of novel Cd metal-organic frameworks (MOFs) (1-9) with different extended spacers with seven kinds of the aliphatic dicarboxylic acids as secondary building linkers based on N,N'-di(4-pyridylacylamino)-1,4,5,8-naphthalenediimide (NDI-A) have been designed and synthesized by changing the volume ratio of solvents under solvothermal conditions. In addition, the secondary building linkers of aliphatic dicarboxylic acids have different spacer lengths, resulting in different structures of complexes 1-9. So, their packing structures are affected by the degree of distortion of the NDI-A ligand, the different aliphatic dicarboxylic acids ligands, and the hydrogen-bonding patterns. Complexes 1-9 showed stimuli-responsive emission tuned by different aliphatic dicarboxylic acids with extended length spacers under UV light irradiation, accompanied by the color change from light orange to dark brown, and achieved reversible photochromic under heating, which indicates that they could serve as secret erasable inks. Moreover, complexes 1-9 exhibited selective vaporchromic behavior to methylamine (MA), and the vaporchromic sample could be recovered after washing with MeOH. It is worth noting that the preparation of poly(vinyl alcohol) (PVA)-NDI-MOF films enables the photochromic and vaporchromic properties of complexes 1-9 to apply in practice. In addition, complexes 1-9 exhibited good fluorescence properties as sensing probes toward 2,4,6-trinitrophenol (TNP) with lower limits of detection. In short, this work provides a broad field to explore the creative NDI-MOF materials with photoactive and luminescent properties.

Improving Small-Molecule Force Field Parameters in Ligand Binding Studies.

Small molecules are major players of many chemical processes in diverse fields, from material science to biology. They are made by a combination of carbon and heteroatoms typically organized in system-specific structures of different complexity. This peculiarity hampers the application of standard force field parameters and their in silico study by means of atomistic simulations. Here, we combine quantum-mechanics and atomistic free-energy calculations to achieve an improved parametrization of the ligand torsion angles with respect to the state-of-the-art force fields in the paradigmatic molecular binding system benzamidine/trypsin. Funnel-Metadynamics calculations with the new parameters greatly reproduced the high-resolution crystallographic ligand binding mode and allowed a more accurate description of the binding mechanism, when the ligand might assume specific conformations to cross energy barriers. Our study impacts on future drug design investigations considering that the vast majority of marketed drugs are small-molecules.

Microbiome-metabolomics signature in anorexia nervosa (AN) before and after weight regain

IntroductionThe intestinal microbiota has been indicated to have a role in the pathophysiology of AN.ObjectivesAim of this study was to analyze fecal microbiome profiles of AN women before and after weight restoration and to combine them with fecal metabolomic profiles according to a multi-omics approach.MethodsThe gut microbiome and fecal metabolites were characterized in 21 underweight AN women and after weight restoration and compared with those of 20 healthy women. Microbiome data were correlated with the relevant fecal metabolites.ResultsAN subjects showed a decreased intra-individual bacterial richness, an increased Bacteroidetes-to-Firmicutes abundance ratio and significant changes in the relative abundances of several bacteria at different order levels in both the underweight and weight-restored condition compared to healthy women. The untargeted metabolomic procedure allowed the characterization of 224 metabolites involved in energy, lipid and amino acid metabolism. A genetic algorithm identified 49 relevant metabolites. The relationships among these fecal metabolites and bacteria genera showed structures of different complexity in the 3 groups. In particular, a quarter of those relationships showed a divergent direction in the acute phase of AN than in the weight-restored phase or normal controls. Finally, in acute AN 70% of those correlations showed a negative sign suggesting a prevalent metabolites consummation by gut microbiome.ConclusionsOur results provide a picture of the connections between gut bacteria and fecal metabolites in both the acute phase of AN and after short-term weight restoration. Further studies should aim to investigate the significance of gut microbiome perturbations in development and treatment of AN.

Distinguishing Planting Structures of Different Complexity from UAV Multispectral Images.

This study explores the classification potential of a multispectral classification model for farmland with planting structures of different complexity. Unmanned aerial vehicle (UAV) remote sensing technology is used to obtain multispectral images of three study areas with low-, medium-, and high-complexity planting structures, containing three, five, and eight types of crops, respectively. The feature subsets of three study areas are selected by recursive feature elimination (RFE). Object-oriented random forest (OB-RF) and object-oriented support vector machine (OB-SVM) classification models are established for the three study areas. After training the models with the feature subsets, the classification results are evaluated using a confusion matrix. The OB-RF and OB-SVM models’ classification accuracies are 97.09% and 99.13%, respectively, for the low-complexity planting structure. The equivalent values are 92.61% and 99.08% for the medium-complexity planting structure and 88.99% and 97.21% for the high-complexity planting structure. For farmland with fragmentary plots and a high-complexity planting structure, as the planting structure complexity changed from low to high, both models’ overall accuracy levels decreased. The overall accuracy of the OB-RF model decreased by 8.1%, and that of the OB-SVM model only decreased by 1.92%. OB-SVM achieves an overall classification accuracy of 97.21%, and a single-crop extraction accuracy of at least 85.65%. Therefore, UAV multispectral remote sensing can be used for classification applications in highly complex planting structures.

Multi-omics data integration in anorexia nervosa patients before and after weight regain: A microbiome-metabolomics investigation

We have recently reported specific fecal metabolomic changes in acute and short-term weight restored patients with anorexia nervosa (AN). In this study we explored the association between those metabolomic changes and patients' gut microbiome composition. The gut microbiome of AN women was sequenced in both the underweight phase (n=21) and after short-term weight restoration (n=16) and compared to that of 20 healthy women. According to a multi-omics approach, microbiome data were correlated with 49 relevant fecal metabolites previously characterized in our participants by an untargeted metabolomic procedure. Compared to healthy women, AN patients showed a decreased intra-individual bacterial richness, an increased Bacteroidetes-to-Firmicutes abundance ratio and significant changes in the relative abundances of several bacteria at phylum, class, order, family and genus levels. These changes were observed in both the underweight and weight-restored condition. Moreover, the relationships among the 49 previously selected fecal metabolites and bacteria genera showed structures of different complexity among the 3 groups. In particular, a quarter of those relationships showed a divergent direction in the acutely ill patients with respect to the weight-restored ones or normal controls. Finally, in acutely ill patients 70% of those correlations showed a negative sign suggesting a prevalent metabolites consummation by gut microbiome. These data confirm a profound perturbation in the gut microbiome composition of AN patients. Moreover, for the first time, they provide the evidence that in AN gut bacteria are connected with several fecal metabolites in a different way from normal controls and with divergent directions in the acute phase with respect to the weight-restored phase.

Prenylated Curcumin Analogues as Multipotent Tools To Tackle Alzheimer's Disease.

Alzheimer's disease is likely to be caused by copathogenic factors including aggregation of Aβ peptides into oligomers and fibrils, neuroinflammation, and oxidative stress. To date, no effective treatments are available, and because of the multifactorial nature of the disease, it emerges the need to act on different and simultaneous fronts. Despite the multiple biological activities ascribed to curcumin as neuroprotector, its poor bioavailability and toxicity limit the success in clinical outcomes. To tackle Alzheimer's disease on these aspects, the curcumin template was suitably modified and a small set of analogues was attained. In particular, derivative 1 turned out to be less toxic than curcumin. As evidenced by capillary electrophoresis and transmission electron microscopy studies, 1 proved to inhibit the formation of large toxic Aβ oligomers, by shifting the equilibrium toward smaller nontoxic assemblies and to limit the formation of insoluble fibrils. These findings were supported by molecular docking and steered molecular dynamics simulations which confirmed the superior capacity of 1 to bind Aβ structures of different complexity. Remarkably, 1 also showed in vitro anti-inflammatory and antioxidant properties. In summary, the curcumin-based analogue 1 emerged as multipotent compound worthy to be further investigated and exploited in the Alzheimer's disease multitarget context.

Temperature dependence of solution properties of anionic polyelectrolyte-cationic surfactant complexes in ethanol

Abstract Stoichiometric polyelectrolyte-surfactant complexes, PSCs, were prepared from poly(acrylate), PA - , and poly(styrenesulfonate), PSS - , anions and dodecyltrimethylammonium cations, DTA + , and their properties were investigated by density and viscosity measurements in ethanol solutions in dependence on concentration and temperature. The measured densities were used to calculate the apparent molar volumes of the repeat units of DTAPA and DTAPSS complexes. Apparent molar volumes at infinite dilution, so as the reduced viscosities, in ethanol solutions are only weakly dependent on temperature. Through features typical for polyelectrolytes, viscosity curves suggest some small dissociation of complexes in ethanol. Light scattering, LS, measurements performed in the angular range from 50 to 150° did not reveal so called slow relaxation mode, which is typical for strongly charged polyelectrolytes in aqueous solutions without or with only a low amount of added salt. Size distributions were therefore calculated from the measured correlation functions. They were multimodal at all angles and for both PSCs, identifying 3 populations: particles with average hydrodynamic radii (i) below 10 nm, (ii) in the range 20–30 nm, and (iii) in the range 200–300 nm. Analysis of angular dependency of LS intensity for the largest particle population enabled the determination of the radius of gyration and the shape parameter ρ of these species. Large sizes, ρ values (ρ = 1.6 and 1.9 for DTAPA and DTAPSS, respectively), and the Kratky plots of the scattering data suggest that these particles are associates of more than one PSC (reverse micelle). Dynamic vapor sorption experiments with thin films of the studied PSCs show that the DTAPSS complex absorbs at the most 35% of water per its weight, whereas the DTAPA one absorbs considerably more (around 75%). Different structure of complexes was taken as responsible for large differences in water uptake.

Vereinfachte Modelle zur Schweißverzugsberechnung

Joining by means of welding has a vital importance in many sectors of industry. However, the uneven heating of the welded structure results in unwanted distortions, which has to be removed by cost-intensive after treatments. Knowing the welding distortions in an early stage of the product development cycle enables taking countermeasures or define after treatments, already in the product planning. The aim of this research study is the development and implementation of an analytic numerical hybrid model for the distortion calculation of large welded structures. The basis of the hybrid model is the analytical shrinkage force model, which is upgraded for modern welding processes and new materials. By means of experimental as well as numerical investigations, the instability of thin walled structures during welding is reviewed and a possibility for capturing is proposed. The linking of the analytical and the numerical method opens up the possibility for calculating the distortions caused by curved trajectories. To simplify the application of the hybrid model, a software will be programmed, including the complex mathematical approach of the shrinkage force model. It determines the mechanical loads, depending on the geometry of the welded structure, material data and weld parameters. The verification of the program as well as the coupling procedure is done on butt joints. The same welded structures are used for the investigation of the stability and the sensibility of the hybrid model afterwards. Finally the hybrid model will be applied to welded structures of different complexity and the results will be compared with experimental measurements. At the beginning butt and T-joints are determined, followed by the distortion calculation of a evaluation model made up of 8 welds. At the end an entire section of a ship deck, whereupon different elements are assembled by about 90 welds on a 20x16 meter large ground plate, is estimated.

The Development of Episodic Memory

Episodic memory involves the formation of relational structures that bind information about the stimuli people experience to the contexts in which they experience them. The ability to form and retain such structures may be at the core of the development of episodic memory. In the first experiment reported here, 4- and 7-year-olds were presented with paired-associate learning tasks requiring memory structures of different complexity. A multinomial-processing tree model was applied to estimate the use of different structures in the two age groups. The use of two-way list-context-to-target structures and three-way structures was found to increase between the ages of 4 and 7. Experiment 2 demonstrated that the ability to form increasingly complex relational memory structures develops between the ages of 4 and 7 years and that this development extends well into adulthood. These results have important implications for theories of memory development.

Effect of organic polycarboxylates on the architectures of cadmium(II) coordination polymers based on dipyrazino[2,3-f:2′3′-h]quino-xaline: Syntheses, crystal structures, and photoluminescence properties

Three new CdII coordination polymers tuned by the polycarboxylates, namely, [Cd(dpq)(L1)(H2O)] (1), [Cd(dpq)(L2)] (2) and [Cd2(μ3-OH)(dpq)2(L3)]·H2O (3) (dpq=dipyrido[3,2-d:2′3′-f]quinoxaline, H2L1=2-carboxymethylsulfanyl nicotinic acid, H2L2=2,5-(s-acetic acid) dimercapto-1,3,4-thiadiazole and H3L3=5-sulfoisophthalic acid), have been synthesized under hydrothermal conditions and structurally characterized by elemental analysis, IR, and single crystal X-ray diffraction analysis. X-ray analysis reveals that the CdII ions of complex 1 are bridged by L1 anions to form a one-dimensional (1D) linear chain. In complex 2, bimetallic CdII subunits were bridged by L2 anions to generate a 2D (4,4) network, which is stabilized by intra-molecular π–π stacking interactions. In complex 3, the CdII ions are connected by μ3-OH and carboxyl groups from L3 anion to form tetra-nuclear CdII clusters, which are further linked by L3 anions to generate a 2D (3,6)-connected binodal network with a (43)2(46·66·83) topology. The different structures of complexes 1–3 illustrate the great influence of the polycarboxylate ligands on the self-assembly of polymeric coordination architectures. In addition, the thermal and fluorescent properties of complexes 1–3 have been investigated.

Testing the structure of a hydrological model using Genetic Programming

Genetic Programming is able to systematically explore many alternative model structures of different complexity from available input and response data. We hypothesised that Genetic Programming can be used to test the structure of hydrological models and to identify dominant processes in hydrological systems. To test this, Genetic Programming was used to analyse a data set from a lysimeter experiment in southeastern Australia. The lysimeter experiment was conducted to quantify the deep percolation response under surface irrigated pasture to different soil types, watertable depths and water ponding times during surface irrigation. Using Genetic Programming, a simple model of deep percolation was recurrently evolved in multiple Genetic Programming runs. This simple and interpretable model supported the dominant process contributing to deep percolation represented in a conceptual model that was published earlier. Thus, this study shows that Genetic Programming can be used to evaluate the structure of hydrological models and to gain insight about the dominant processes in hydrological systems.

Assembly of novel phenanthroline-based cobalt(II) coordination polymers by selecting dicarboxylate ligands with different spacer length: From 1-D chain to 3-D interpenetrated framework

Abstract Three novel CoII coordination polymers [Co(Dpq)2(1,4-NDC)0.5] · (1,4-HNDC) (1), [Co(Dpq)(2,6-NDC)] (2), and [Co2(Dpq)2(BPEA)4(H2O)] · H2O (3) have been obtained from hydrothermal reaction of cobalt nitrate with the mixed ligands dipyrido[3,2-d:2′,3′-f]quinoxaline (Dpq) and three dicarboxylate ligands with different spacer length [1,4-naphthalene-dicarboxylic acid (1,4-H2NDC), 2,6-naphthalene-dicarboxylic acid (2,6-H2NDC) and biphenylethene-4,4′-dicarboxylic acid (BPEA)]. All these complexes are fully structurally characterized by elemental analysis, IR, and single-crystal X-ray diffraction analysis. Single-crystal X-ray analysis reveal that complex 1 is infinite one-dimensional (1-D) chains bridged by 1,4-NDC ligands, which are extended into a two-dimensional (2-D) supramolecular network by π–π interactions between the Dpq molecules. Complex 2 is a distorted three-dimensional (3-D) PtS network constructed from infinite Co–O–C rod units. Complex 3 has a 5-fold interpenetrated 3-D structure with diamondoid topology based on dinuclear [Co2(CO2)2(μ2-OH2)N4O2] units and BPEA molecules. The different structures of complexes 1–3 illustrate the influence of the length of dicarboxylate ligands on the self-assembly of polymeric coordination architectures. In addition, the thermal properties of complexes 1–3 and fluorescent properties of complexes 2 and 3 have been investigated in the solid state.

Habitat structure and fish: assessing the role of habitat complexity for fish using a small, semiportable, 3‐D underwater observatory

In contrast to terrestrial ecology, three‐dimensional (3‐D) imaging technology is not well established as a method for studying species‐habitat interactions in aquatic ecology. In this study, we used a semi‐portable, digital, 3‐D underwater observatory designed for long‐term exposure in shallow water habitats to assess fish‐habitat interactions to artificial structures of different complexity. The observatory was mounted on a cable‐car system and was moved along a 50 m transect parallel to five artificial structures of different complexity and one control site. The optical unit took high‐resolution digital images, in pairs, from each structure and the control site at a frequency of 30 min over 24 h and was then moved remotely to the next structure. The system was operated for 2 mo without being recovered and took a total of 2160 stereoscopic image pairs. The system proved highly valuable in assessing small‐scale temporal patterns in fish‐habitat interactions, as well as changes in habitat preferences of fish over the diel cycle. Such small‐scale temporal and spatial patterns are important for a detailed understanding of specieshabitat interactions, not only in fish but also in most aquatic macro‐organisms. Nevertheless, such patterns can hardly be assessed using classical sampling devices due to labor and animal protection restrictions. However, the possibility of a significant increase in quantity of sampling through the use of remote imaging technology is accompanied by a significant increase in labor costs for image analysis. Therefore, further progress in semi‐ and fully automated systems for image analysis is needed, including 3‐D imaging tools, for ecological studies.

Solvothermal syntheses and crystal structures of new Cu(II) complexes with phenylsuccinic acid

Five new Cu(II) complexes [Cu(psa)(phen)] · 3H 2O ( 1), [Cu(psa)(2bpy)] · 0.5H 2O ( 2), [Cu(psa)(2bpy)(H 2O)] · 3H 2O ( 3), [Cu(psa)(4bpy)] · H 2O ( 4), and [Cu(psa) 0.5(N 3)(2bpy)] ( 5) (H 2psa = phenylsuccinic acid, phen = 1,10-phenanthroline, 2bpy = 2,2′-bipyridine, and 4bpy = 4,4′-bipyridine) were obtained under solvothermal conditions and characterized by single-crystal X-ray diffraction. Complexes 2 and 3 were formed by one-pot reaction. In complex 2, Cu(II) ion is four-coordinated and locates at a slightly distorted square center. In complex 3, the coordinated water molecule occupies the axial site of Cu(II) ion forming a tetragonal pyramid geometry. Complexes 1 and 3 are of 1D chain structures, and extended into 2D supramolecular network by hydrogen bonds. Complex 2 is of zipper structure, and further assembled into 2D supramolecular network by hydrogen bonds and π–π stacking interactions. Complex 4 is a 3D CdSO 4-like structure with twofold interpenetration, while complex 5 is a dinuclear compound. The different structures of complexes 1– 5 can be attributed to using the auxiliary ligands, indicating an important role of the auxiliary ligands in assembly and structure of the title complexes.

Reaction of methanol ligated manganese(II) silanethiolate with pyridine related ligands – Different structures of complexes with MnNO 2S 2 kernel

The reaction of [Mn{SSi(OBu t ) 3} 2(MeOH) 4] with pyridine and its three monosubstituted methyl derivatives leads to the formation of two distinct types of complexes, although both with the MnO 2NS 2 kernel. The first two compounds (with pyridine or 2-picoline) contain two silanethiolate ligands, heterocyclic base and two methanol molecules. In the second case (3- and 4-picoline) the role of O-donor and simultaneously S-donor ligand is fulfilled by tri- tert-butoxysilanethiolate rest which under favorable conditions can serve as a chelating agent.

Assembly and structures of five new Cu(II) complexes based on the V-shaped building block [Cu(dbsf)

Five new copper(II) complexes [Cu(dbsf)(H 2O)] n · 0.5 n( i-C 3H 7OH) ( 1), [Cu(dbsf)(4,4′-bpy) 0.5] n · nH 2O ( 2), [Cu(dbsf)(2,2′-bpy)(H 2O)] 2 · ( n-C 3H 7OH) · 0.5H 2O ( 3), [Cu(dbsf)(phen)(H 2O)] 2 · 1.5H 2O ( 4) and [Cu(dbsf)(2,2′-bpy)(H 2O)] n · n( i-C 3H 7OH) ( 5) (H 2dbsf = 4,4′-dicarboxybiphenyl sulfone, 4,4′-bpy = 4,4′-bipyridine, 2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline, i-C 3H 7OH = isopropanol, n-C 3H 7OH = n-propanol) have been synthesized under hydro/solvothermal conditions. All of the complexes are assembled from V-shaped building blocks, [Cu(dbsf)]. Complex 1 is composed of 1D double-chains. In complex 2, dbsf 2− ligands and 4,4′-bpy ligands connect Cu(II) ions into catenane-like 2D layers. These catenane-like 2D layers stack in an ABAB fashion to form a 3D supramolecular network. Complexes 3 and 4 are 0D dimers, in which two [Cu(dbsf)] units encircle to form dimetal macrocyclic molecules. However, in complex 5, the V-shaped building blocks [Cu(dbsf)] are joined head-to-tail, resulting in the formation of infinite tooth-like chains. The different structures of complexes 3 and 5 may be attributed to the different solvent molecules included.

Syntheses, Crystal Structures, and Magnetic Properties of Novel Manganese(II) Complexes with Flexible Tripodal Ligand 1,3,5-Tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene

Two novel metal-organic frameworks (MOFs)--[Mn(titmb)(N3)2] x 1.5H2O (1) and [Mn3(titmb)2(C2O4)3(H2O)] x 10H2O (2)--were obtained by reactions of the flexible tripodal ligand 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene (titmb) with Mn(OAc)2 x 4H2O, together with NaN3 and K2C2O4, respectively. The structures of these MOFs were established by single-crystal X-ray diffraction analysis. The crystal data for 1 were as follows: monoclinic, C2/c, a = 20.956(13) A, b = 9.884(6) A, c = 24.318(14) A, beta = 95.87(5) degrees, Z = 8. The crystal data for 2 were as follows: triclinic, P1, a = 12.400(9) A, b = 16.827(12) A, c = 17.196(11) A, alpha = 66.35(5), beta = 95.87(5) degrees, gamma = 71.03(6), Z = 2. Complex 1 is a novel noninterpenetrating three-dimensional (3D) framework, in which the azide ligand connects Mn(II) atoms in an end-to-end (EE) mode to give [Mn-N-N-N-]n infinite one-dimensional (1D) chains, and complex 2 has a two-dimensional (2D) network structure in which the Mn(II) ions are linked by the oxalate anions to form 1D [Mn(C2O4)]n chains. Each titmb in these two complexes connects three metal atoms and serves as a three-connecting ligand. The magnetic properties of 1 and 2 were investigated. The results showed that the antiferromagnetic interactions occurred between the Mn(II) ions linked by the azide ligands in complex 1, and those linked by the oxalate anions and the carboxylate in syn-anti coordination mode in complex 2. The entirely different structures of complexes 1 and 2, on one hand, indicate that the azide and the oxalate ligands affected the structures of MOFs greatly, and on the other hand, reveals the potential applications of MOFs with the azide and oxalate ligands, which are efficient magnetic couplers.