ABSTRACT
Schwann cells are components of the peripheral nerve myelin sheath, which supports and nourishes axons. Upon injury of the trigeminal nerve, Schwann cells are activated and cause trigeminal neuralgia by engulfing the myelin sheath and secreting various neurotrophic factors. Further, Schwann cells can repair the damaged nerve and thus alleviate trigeminal neuralgia. Here, we briefly describe the development and activation of Schwann cells after nerve injury. Moreover, we expound on the occurrence, regulation, and treatment of trigeminal neuralgia; further, we point out the current research deficiencies and future research directions.
Subject(s)
Schwann Cells/pathology , Trigeminal Neuralgia/pathology , Animals , Humans , Trigeminal Neuralgia/therapyABSTRACT
Neurons critically depend on the long-distance transport of mitochondria. Motor proteins kinesin and dynein control anterograde and retrograde mitochondrial transport, respectively in axons. The regulatory molecules that link them to mitochondria need to be better characterized. Nuclear distribution (Nud) family proteins LIS1, Ndel1 and NudCL are critical components of cytoplasmic dynein complex. Roles of these Nud proteins in neuronal mitochondrial transport are unknown. Here we report distinct functions of LIS1, Ndel1 and NudCL on axonal mitochondrial transport in cultured hippocampal neurons. We found that LIS1 interacted with kinsein family protein KIF5b. Depletion of LIS1 enormously suppressed mitochondrial motility in both anterograde and retrograde directions. Inhibition of either Ndel1 or NudCL only partially reduced retrograde mitochondrial motility. However, knocking down both Ndel1 and NudCL almost blocked retrograde mitochondrial transport, suggesting these proteins may work together to regulate retrograde mitochondrial transport through linking dynein-LIS1 complex. Taken together, our results uncover novel roles of LIS1, Ndel1 and NudCL in the transport of mitochondria in axons.
Subject(s)
Axonal Transport , Carrier Proteins/metabolism , Cysteine Endopeptidases/metabolism , Mitochondria/metabolism , Nerve Tissue Proteins/metabolism , Animals , Axons/metabolism , Carrier Proteins/genetics , Cysteine Endopeptidases/genetics , Gene Deletion , Hippocampus/cytology , Intracellular Signaling Peptides and Proteins , Kinesins/metabolism , Nerve Tissue Proteins/genetics , Rats , Rats, Sprague-DawleyABSTRACT
Herein we report the surfactant-thermal method to prepare two novel one-dimensional mercury selenidostannates, [DBUH]2[Hg2Sn2Se6(Se2)] (1) and [DBUH]2[Hg2Sn2Se7] (2), where DBU = 1,8-diazabicyclo[5.4.0]undec-7-ene, by applying PEG-400 as the reaction medium. It is worth noting that 1 is kinetically stable and can be transformed into thermodynamically stable phase 2 under a longer reaction time. Our strategy "growing crystalline materials in surfactants" could open a new door to preparing novel crystals with diverse structures and interesting properties.
ABSTRACT
PREMISE OF THE STUDY: Microsatellite markers were developed in Dipteronia sinensis to investigate the population genetics of this endangered plant. ⢠METHODS AND RESULTS: Using the Fast Isolation by AFLP of Sequences COntaining repeats (FIASCO) protocol, 19 microsatellite loci were developed in D. sinensis and evaluated for their variability in 29 samples from a natural population. For the 15 polymorphic loci, the number of alleles ranged from nine to 33, while the observed and expected heterozygosities ranged from 0.3793 to 0.9655 and from 0.6029 to 0.9609, respectively. Their cross-taxa transferability was also investigated in Acer miaotaiense, A. palmatum, and A. pictum subsp. mono, and 10 to 15 loci proved amplifiable in these species. ⢠CONCLUSIONS: These microsatellite markers could be employed to investigate the population genetics of D. sinensis and may potentially be applicable to other related species.
Subject(s)
DNA, Plant/genetics , DNA, Plant/isolation & purification , Endangered Species , Genetic Loci/genetics , Microsatellite Repeats/genetics , Polymorphism, Genetic , Sapindaceae/genetics , Molecular Sequence DataABSTRACT
The endangered perennial plant Saruma henryi Oliv. is endemic to China and has phylogenetic, ecological, and medicinal value. We used 10 microsatellite (SSR) loci to investigate genetic diversity and differentiation in 16 natural populations. Genetic diversity was high at the species level (H(E) = 0.9427, h = 0.9410, I = 3.0213) and low at the population level (H(E) = 0.4441, h = 0.4307, I = 0.6822). Pronounced genetic differentiation was detected among populations (G(ST) = 0.5428, F(ST) = 0.5524), in line with the limited among-population gene flow (Nm = 0.21). The significant isolation-by-distance pattern revealed by a Mantel test (r = 0.311, P = 0.001) suggested a clear geographic tendency in the distribution of genetic variability. Bayesian assignment and principal coordinates analyses supported the clustering of 16 populations into three groups. The present SSR results were also compared with previously published ISSR results. These results have significant implications for conservation of the species.
Subject(s)
Aristolochiaceae/genetics , Genetic Variation , Microsatellite Repeats , Bayes Theorem , China , Embryophyta/genetics , Expressed Sequence Tags , Genetic Structures , Genetics, Population , PhylogeographyABSTRACT
In the current study, nano-hydroxyapatite/ß-tricalcium phosphate (HA/ß-TCP) ceramics scaffolds loaded with cationic liposomal ceftazidime (CLCs) prepared by modified reverse phase evaporation method, the investigations of their release characteristics were performed by the dissolution tests, in vitro anti-biofilm activity of the scaffolds was studied by the determination of bacterial susceptibility with ELISA. The mean particle size, zeta potential, pH and entrapment efficiency of the CLCs studied were 161.5 ± 5.37 nm, 60.60 ± 5.24 mV, 6.90 ± 0.07 and 16.57 ± 0.13%, respectively. Electron microscopic images of the samples indicated that the liposomes were well preserved in the scaffolds and that it was the CLCs rather than free ceftazidime releasing from the scaffolds. The minimal inhibitory concentrations (MICs) to Staphylococcus aureus of free ceftazidime and its liposomal formulation were 6.00 µg/mL and the release behaviors of both CLCs and free ceftazidime from scaffolds were based on the dissolution/diffusion processes, Fick's law. These results demonstrated that CLCs could inhibit remarkably the formation of S. aureus biofilm more effectively than free ceftazidime (P < 0.05). The study demonstrated that the HA/ß-TCP ceramic scaffolds was such a material that could sustain release CLCs and maintain the adequate amounts of CLCs to absorb to biofilm. It provided an ideal way to inhibit bacterial biofilms for clinical practices.
Subject(s)
Anti-Bacterial Agents/chemistry , Biocompatible Materials/chemistry , Biofilms/drug effects , Ceftazidime/chemistry , Ceramics/chemistry , Drug Carriers/chemistry , Hydroxyapatites/chemistry , Nanostructures/chemistry , Staphylococcus aureus , Anti-Bacterial Agents/administration & dosage , Anti-Bacterial Agents/pharmacology , Bone Substitutes/chemistry , Cations , Ceftazidime/administration & dosage , Ceftazidime/pharmacology , Drug Compounding , Liposomes , Microbial Sensitivity Tests , Microscopy, Electron, Scanning , Porosity , Solubility , Staphylococcus aureus/drug effects , Staphylococcus aureus/physiology , Surface PropertiesABSTRACT
Saruma henryi Oliv. (Aristolochiaceae) is an endangered herb endemic to China. In this study, chloroplast microsatellites (cpSSRs) and sequences of the atpB-rbcL intergenic spacers were employed to reveal its genetic diversity and phylogeographic patterns. We detected high within-species genetic diversity (H(T)=0.939 for cpSSR; H(T)=0.862 for atpB-rbcL) and pronounced among-population genetic differentiation (H(S)=0.182, G(ST)=0.811, R(ST)=0.9, F(ST)=0.93 for cpSSR; H(S)=0.238, G(ST)=0.724, N(ST)=0.758, F(ST)=0.79 for atpB-rbcL) with a strong phylogeographic pattern (R(ST)>G(ST), P<0.01 for cpSSR; N(ST)>G(ST), U=0.25 for atpB-rbcL). Eleven haplotypes were distinguished by cpSSRs and atpB-rbcL intergenic spacers, respectively. The molecular phylogenetic data, together with the geographic distribution of the haplotypes, suggested the existence of multiple localized glacial refugia in Mts. Qinling, eastern Mts. Bashan and the southeastern edge of Yunnan-Guizhou Plateau. Nested clade analysis (NCA) and population genetic analyses supported the limited gene flow (caused by low dispersal capacity and complex topography of its habitats) as the major factor responsible for the strong population differentiation and phylogeographic pattern. Past fragmentation and allopatric fragmentation were inferred as important processes responsible for the modern phylogeograhpic pattern. In addition, contiguous range expansions occurred in western Mts. Qinling and eastern Mts. Bashan.
Subject(s)
Aristolochiaceae/genetics , Evolution, Molecular , Genetic Variation , Phylogeny , Aristolochiaceae/classification , China , DNA, Chloroplast/genetics , DNA, Plant/genetics , DNA, Ribosomal Spacer/genetics , Gene Flow , Genetics, Population , Haplotypes , Microsatellite Repeats , Phylogeography , Sequence Analysis, DNAABSTRACT
Hydrothermal reactions of lanthanide(III) chlorides with 4-HOOC-C(6)H(4)-CH(2)NHCH(2)PO(3)H(2) (H(3)L) at different ligand-to-metal (L/M) ratios afforded nine new lanthanide(III) carboxylate-phosphonates with two types of 3D network structures, namely, LnCl(HL)(H(2)O)(2) (Ln = Sm, 1; Eu, 2; Gd, 3; Tb, 4; Dy, 5; Er, 6) and [Ln(2)(HL)(H(2)L)(L)(H(2)O)(2)].4H(2)O (Ln = Nd, 7; Sm, 8; Eu, 9). Compounds 1-6 are isostructural and feature a 3D network in which the LnO(7)Cl polyhedra are interconnected by bridging CPO(3) tetrahedra into 2D inorganic layers parallel to the bc plane. These layers are further cross-linked by organic groups of the carboxylate-phosphonate ligands via the coordination of the carboxylate groups into a pillared-layered architecture. Compounds 7-9 are also isostructural and feature a 3D open-framework composed of 1D lanthanide(III) phosphonate inorganic slabs which are further bridged by organic groups of the carboxylate-phosphonate liagnds via the coordination of the carboxylate groups, forming large 1D tunnels along the b-axis which are filled by lattice water molecules. Luminescent measurements indicate that compounds 2, 4, and 5 show strong emission bands in red, green, and yellow light region, respectively. Magnetic properties of 2, 3, 5, and 7 have also been studied.
Subject(s)
Carboxylic Acids/chemistry , Lanthanoid Series Elements/chemistry , Luminescence , Organometallic Compounds/chemistry , Organometallic Compounds/chemical synthesis , Organophosphonates/chemistry , Crystallography, X-Ray , Ligands , Magnetics , Models, Molecular , Molecular StructureABSTRACT
Hydrothermal reactions of manganese(II) salts with o-sulfophenylarsonic acid (o-HO(3)S-C(6)H(4)-AsO(3)H(2), H(3)L) afforded Mn(3)(L)(2)(H(2)O)(3).H(2)O (1) with a layered structure. When 1,10-phenanthroline (phen), 2,2'-bipyridine (bipy), and 2,2':6',2''-terpyridine (terpy) were used as auxiliary chelating ligands, a series of mixed-ligand manganese(II) sulfonate-arsonates with lower dimensional structures, namely, [Mn(HL)(phen)(2)](2).8.5H(2)O (2), Mn(HL)(phen)(2)(H(2)O).2H(2)O (3), [Mn(HL)(bipy)(2)][Mn(H(2)L)(bipy)(2)](ClO(4)).3H(2)O (4), [Mn(HL)(phen)][Mn(HL)(phen)(H(2)O)] (5), [Mn(2)(HL)(phen)(4)(H(2)O)](ClO(4))(2).4H(2)O (6), [Mn(2)(HL)(phen)(4)(H(2)O)](ClO(4))(2).H(2)O (7), Mn(2)(HL)(2)(bipy)(3)(H(2)O).H(2)O (8), [Mn(HL)(terpy)](2) (9), Mn(7)(OH)(2)(L)(4)(phen)(8).10H(2)O.phen (10), and Mn(HL)(bipy)(H(2)O).2H(2)O (11) have been obtained. 2-4 are mononuclear (4 contains two different mononuclear cluster units) whereas 5-9 feature three types of isolated dinuclear cluster units in which the two Mn(2+) ions are bridged by one or two sulfonate-arsonate ligands. 10 exhibits an interesting heptanuclear cluster in which the Mn(2+) centers are bridged by arsonate, sulfonate groups and hydroxyl anions. 11 features a one-dimensional (1D) chain in which two neighboring Mn(2+) centers are bridged by an arsonate group of a sulfonate-arsonate ligand. Magnetic measurements indicate that 1 exhibits an unprecedented spin topology and behaves as a homospin ferrimagnet whereas 2-4 are essentially paramagnetic. 5-9 and 11 are weakly antiferromagnetic.
ABSTRACT
OBJECTIVE: To construct COL1A1-targeted short hairpin RNA (shRNA) vector with pSilencer 4.1-CMV neo siRNA expression vector and to evaluate its effect on proliferation and migration of gastric cancer BGC-823 cells in vitro. METHODS: Three COL1A1-shRNA plasmids (COL1A1-shRNA-1, COL1A1-shRNA-2, COL1A1-shRNA-3), targeting different sites of COL1A1 gene, were constructed using pSilencer 4.1-CMV neo siRNA expression vector and transfected into gastric cancer BGC-823 cells. Real time quantitative RT-PCR and Western blot were performed to detect expression levels of COL1A1. MTT and Transwell migration assays were employed to evaluate the effects of COL1A1 gene silence on cell proliferation and migration. RESULT: Three recombinant plasmids targeting COL1A1 were constructed successfully. The expressions of COL1A1 in BGC-823 cells, including mRNA and protein levels, were significantly inhibited by the COL1A1-shRNA transfectants, which resulted in a clear reduction of cell proliferation and migration capacity. CONCLUSION: The COL1A1-shRNA can effectively knock down gene expression and inhibit proliferation and migration of gastric cancer BGC-823 cells.
Subject(s)
Collagen Type I/genetics , Genetic Vectors , RNA, Small Interfering/genetics , Stomach Neoplasms/pathology , Cell Line, Tumor , Cell Proliferation , Collagen Type I/metabolism , Collagen Type I, alpha 1 Chain , Humans , Plasmids/genetics , RNA, Messenger/genetics , Transfection , Transformation, BacterialABSTRACT
BACKGROUND AND AIMS: The aim of this study was to investigate whether rectal administration of muscovite can ameliorate colonic inflammation in a rat model of experimental colitis, and its possible mechanism. METHODS: Female Sprague-Dawley (SD) rats with trinitrobenzene sulfonic acid (TNBS)-induced colitis were treated with rectal administration of muscovite or 5-aminosalicylic acid (5-ASA) daily for 14 days. The changes in body weight, macroscopic damage and histologic scores were subsequently evaluated. Gene expression of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), mucin2 (MUC2) and trefoil factor 3 (TFF3) in the colonic tissues was assessed by semiquantitative reverse transcription polymerase chain reaction (RT-PCR) while protein levels of TNF-alpha and IL-1beta were detected by ELISA. Mucin2 expression in colonic mucosa was detected by immunohistochemistry. The capacity of muscovite to adsorb cytokines in vitro was determined by the changes in the amount of TNF-alpha, IL-1beta secreted by lipopolysaccharide (LPS)-stimulated THP-1 cells and IL-8 secreted by LPS-stimulated HT-29 cells. RESULTS: Rectal administration of muscovite improved the loss of body weight, macroscopic and histologic scores of TNBS-induced colitis in a dose-dependent manner. Trinitrobenzene sulfonic acid-induced expression of TNF-alpha and IL-1beta was reduced by muscovite and 5-ASA treatment. Reduction of MUC2 expression in colitis rats was reversed by muscovite and 5-ASA treatment. However, the expression of TFF3 mRNA in colonic mucosa was not affected. In addition, we found muscovite inhibited the expression of TNF-alpha, IL-1beta secreted by THP-1 and IL-8 secreted by HT-29 cells in a dose-dependent manner. CONCLUSIONS: Our study demonstrated for the first time that rectal administration of muscovite can ameliorate colonic inflammation of TNBS-induced colitis. Further confirmatory studies are needed to prove that muscovite might be a potential therapeutic agent for the treatment of ulcerative colitis.
Subject(s)
Aluminum Silicates/administration & dosage , Anti-Inflammatory Agents/administration & dosage , Colitis/drug therapy , Colon/drug effects , Gastrointestinal Agents/administration & dosage , Administration, Rectal , Animals , Body Weight/drug effects , Colitis/chemically induced , Colitis/metabolism , Colitis/pathology , Colon/metabolism , Colon/pathology , Disease Models, Animal , Dose-Response Relationship, Drug , Female , HT29 Cells , Humans , Interleukin-1beta/genetics , Interleukin-1beta/metabolism , Mesalamine/administration & dosage , Mucin-2/genetics , Mucin-2/metabolism , Neuropeptides/genetics , Neuropeptides/metabolism , Rats , Rats, Sprague-Dawley , Trefoil Factor-3 , Trinitrobenzenesulfonic Acid , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolismABSTRACT
In the title Schiff base, C(22)H(20)N(2)O(2), the benzene ring forms dihedral angles of 53.92â (1) and 3.62â (1)° with the two salicylaldimine groups. There are two strong O-Hâ¯N intra-molecular hydrogen bonds. The crystal packing is stabilized by weak inter-molecular C-Hâ¯O hydrogen bonds and π-π stacking inter-actions (average distance 3.39â Å).
ABSTRACT
OBJECTIVE: To explore the feasibility for therapy of spinal cord injury (SCI) by genetic engineering neural stem cell (NSC) modified by lentiviral vector. METHODS: Following the construction of the genetic engineering NSC modified by lentivirus to secrete both neurotrophic factor-3 (NT-3) and green fluorescence protein (GFP), hemisection of spinal cord at the level of T10 was performed in 56 adult Wistar rats that were randomly divided into 4 groups (n = 14), namely 3 therapeutic groups and 1 control group. The therapeutic groups were dealed with NSC, genetic engineering NSC, and concentrated lentiviral supernatant which carries both GFP and NT-3, respectively. Then used fluorescence microscope to detect the transgenic expression in vitro and in vivo, migration of the grafted cells in vivo, and used the Basso, Beattie, and Bresnahan (BBB) open-field locomotor test to assess the recovery of function. RESULTS: The transplanted cells could survive for long time in vivo and migrate for long distance. The stable transgenic expression could be detected in vivo. The hindlimb function of the injured rats in 3 therapeutic groups, especially those dealed with genetic engineering NSC, improved obviously. CONCLUSION: It is feasible to combine NSC with lentivirus for the repair of SCI. NSC modified by lentivirus to deliver NT-3, acting as a source of neurotrophic factors and function cell in vivo, has the potential to participate in spinal cord repair.
Subject(s)
Genetic Engineering/methods , Spinal Cord Injuries/therapy , Animals , Cell Line , Embryonic Stem Cells/transplantation , Female , Genetic Vectors , Green Fluorescent Proteins/genetics , Lentivirus/genetics , Neurons/transplantation , Neurotrophin 3/genetics , Rats , Rats, WistarABSTRACT
OBJECTIVE: To explore the feasibility to construct genetic engineering human neural stem cells (hNSCs) mediated by lentivirus to express multigene in order to provide a graft source for further studies of spinal cord injury (SCI). METHODS: Human neural stem cells from the brain cortex of human abortus were isolated and cultured, then gene was modified by lentivirus to express both green fluorescence protein (GFP) and rat neurotrophin-3 (NT-3); the transgenic expression was detected by the methods of fluorescence microscope, dorsal root ganglion of fetal rats and slot blot. RESULTS: Genetic engineering hNSCs were successfully constructed. All of the genetic engineering hNSCs which expressed bright green fluorescence were observed under the fluorescence microscope. The conditioned medium of transgenic hNSCs could induce neurite flourishing outgrowth from dorsal root ganglion (DRG). The genetic engineering hNSCs expressed high level NT-3 which could be detected by using slot blot. CONCLUSIONS: Genetic engineering hNSCs mediated by lentivirus can be constructed to express multigene successfully.
Subject(s)
Genetic Engineering/methods , Genetic Vectors/genetics , Lentivirus/genetics , Neurons/metabolism , Stem Cell Transplantation , Stem Cells/metabolism , Transgenes , Animals , Cell Differentiation , Cells, Cultured , Feasibility Studies , Gene Expression , Genetic Therapy/methods , Green Fluorescent Proteins , Humans , Immunohistochemistry , Microscopy, Fluorescence , RatsABSTRACT
Gastric cancer is a leading cause of cancer-related deaths. However, the mechanisms underlying gastric carcinogenesis remain largely unclear. The association of non-coding RNAs (ncRNAs) with cancer has been widely studied during the past decade. In general, ncRNAs have been classified as small ncRNAs, including microRNAs (miRNAs), and long non-coding RNAs (lncRNAs). Emerging evidence shows that miRNAs and lncRNAs play key roles in the formation and progression of many cancers. In this review, we focus on the regulation of miRNAs and lncRNAs in gastric cancer. miRNAs and lncRNAs appear to be involved in gastric tumor growth, invasion, and metastasis and in establishment of the gastric tumor microenvironment through various mechanisms. Furthermore, we also discuss the possibilities of establishing miRNAs and lncRNAs as potential biomarkers and therapeutic targets for gastric cancer. Taken together, we summarize the emerging roles of ncRNAs in gastric cancer development and their possible clinical significance.
Subject(s)
Biomarkers, Tumor/genetics , RNA, Untranslated/genetics , Stomach Neoplasms/genetics , Animals , Biomarkers, Tumor/metabolism , Cell Movement , Cell Proliferation , Gene Expression Regulation, Neoplastic , Genetic Predisposition to Disease , Humans , MicroRNAs/genetics , MicroRNAs/metabolism , Neoplasm Invasiveness , Phenotype , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism , RNA, Untranslated/metabolism , Risk Factors , Stomach Neoplasms/metabolism , Stomach Neoplasms/pathology , Tumor MicroenvironmentABSTRACT
Three new octanuclear Th(iv) arsonates, namely [Th(8)(O)(L)(6)(HL)(6)(H(2)O)(12)]·19.5H(2)O (1) (H(3)L = o-HO(3)S-C(6)H(4)-AsO(3)H(2)), [Th(8)(O)(L)(6)(HL)(6)(H(2)O)(10)]·17H(2)O (2) and [Th(8)(O)(L)(6)(HL)(6)(H(2)O)(5)]·0.5H(2)O (3), with o-sulfophenylarsonic acid as the bridging ligand, have been prepared under hydrothermal conditions. Each complex contains [Th(8)O(13)](6+) octanuclear cluster cores composed of two [Th(4)O(6)](4+) units bridged by a µ(2)-oxo anion. The structure of compound features a 0D highly symmetric polynuclear cluster encapsulating the octanuclear core of [Th(8)O(13)](6+) which is further decorated by six L(3-) and six HL(2-) ligands. Compound 2 features one-dimensional chains along the b-axis in which the neighboring clusters similar to are bridged by a pair of sulfophenylarsonate ligands via M-O-S-O-M bridges. Compound 3 with chiral P2(1)2(1)2(1) features two-dimensional cluster layers, in which each cluster connects with four neighbors via four M-O-S-O-M linkages. Compounds 2 and 3 display unusual broad green light emission bands at 523 nm (λ(ex) = 320 nm) and 517 nm (λ(ex) = 312 nm), respectively, which originate from the ligand-to-metal charge transfer (LMCT) transition.
ABSTRACT
Complete coding sequences of beta-arrestin1 (1A and 1B) were cloned through application of bioinformatics analysis to the dbEST database. beta-arrestin1A was overexpressed in E.coli with partial expression products as inclusion body. Anti-beta-arrestin1 antibodies were prepared by using purified inclusion body. Results also demonstrate that activation of inhibitory G protein mediated by delta and kappa pioid receptors was strongly attenuated by overexpression of beta-arrestin1A in co-transfected 293 cells.
ABSTRACT
The first examples of lanthanide(III) organoarsonates, Ln(L(1))(H(2)O)(3) (Ln = La (1), H(3)L(1) = 4-hydroxy-3-nitrophenylarsonic acid), Ln(L(1))(H(2)O)(2) (Ln = Nd (2), Gd (3)), and mixed-ligand lanthanide(III) organoarsonates, Ln(2)(HL(1))(2)(C(2)O(4))(H(2)O)(2) (Ln = Nd (4), Sm (5), Eu (6)), were hydrothermally synthesized and structurally characterized. Compounds 1-3 feature a corrugated lanthanide arsonate layer, in which 1D lanthanide arsonate inorganic chains are further interconnected via bridging L(1)(3-) ligands. Compounds 4-6 exhibit a complicated 3D network. The interconnection of the lanthanide(III) ions by the bridging arsonate ligand leads to the formation of a novel 3D framework with long narrow 1D tunnels along the a-axis, with the oxalate anions are located at the above tunnels and bridging with lanthanide(III) ions. Compounds 2 and 4 exhibit the characteristic emission bands of the Nd(III) ion, whereas compound 6 displays the characteristic emission bands of the Eu(III) ion. The magnetic properties of compounds 3-6 were also investigated.
ABSTRACT
Four new quaternary molybdenum selenites, namely, HRb(3)(Mo(5)O(15))(SeO(3))(2)(H(2)O)(2)1, α-Rb(4)Mo(5)O(15)(SeO(3))(2)(H(2)O)(2)2, ß-Rb(4)Mo(5)O(15)(SeO(3))(2)(H(2)O)(2)3 and K(4)Mo(5)O(15)(SeO(3))(2)(H(2)O)(2)4 were synthesized by hydrothermal reactions. All of the four compounds feature a zero-dimensional (0D) [(Mo(5)O(15))(SeO(3))(2)](4-) anionic unit composed of a five-member MoO(6) octahedral ring capped by two SeO(3)(2-) trigonal pyramids, with the Rb(+)/K(+) or/and H(+) cations and water molecules acting as spacers and keeping charge balance. Although these compounds exhibit similar chemical formula, their structures are slightly different. HRb(3)(Mo(5)O(15))(SeO(3))(2)(H(2)O)(2)1 crystallizes in a polar space group (Pca2(1)). α-Rb(4)Mo(5)O(15)(SeO(3))(2)(H(2)O)(2)2 crystallizes in a centrosymmetric (CS) space group (P2(1)/n) whereas ß-Rb(4)Mo(5)O(15)(SeO(3))(2)(H(2)O)(2)3 and K(4)Mo(5)O(15)(SeO(3))(2)(H(2)O)(2)4 are isomorphous, crystallize in a chiral space group (C2). The chiral structures of 3 and 4 contain two similar polyanions of [Mo(5)O(15)(SeO(3))(2)](4-) with opposite handedness. Second-harmonic-generation (SHG) measurements indicate that 1, 3 and 4 are all SHG-active. Compound 1 displays a weak SHG response of about 20% of that of KDP (KH(2)PO(4)) and is phase-matchable whereas the SHG responses of 3 and 4 are very weak (less than 5% of that of KDP). Thermal analyses and optical property measurements have also been performed.
ABSTRACT
An unusual ligand-conformation driving chiral generation and symmetry-breaking crystallization occurred simultaneously in the formation of a layered zinc(II) arsonate Zn(Hcapa)(4,4'-bipy) (1P) and its enantiomorph (1M) without any chiral sources, indicating that the asymmetrical crystallization of the coordination polymer from achiral precursors may be induced by the conformation control of the ligand.