Consistent pattern printing of the gap structure in femtosecond laser DMD projection lithography.

Maskless lithography technologies have been developed and played an important role in the fabrication of functional micronano devices for microelectronics, biochips and photonics. Optical projection lithography based on digital micromirror device (DMD) is an efficient maskless lithography technology that can rapidly fabricate complex structures. The precise modulation of gap width by DMD maskless optical projection lithography (MOPL) using femtosecond laser becomes important for achieving micronano structures. Herein, we have investigated the relationship between the structure morphology and the light intensity distribution at the image plane by multi-slit diffraction model and Abbe imaging principle, and optimized the gap width more accurately by modulating exposure energy. The aperture diameter of the objective lens has a substantial effect on the pattern consistency. The continuously adjustable structural gap widths of 2144 nm, 2158 nm and 1703 nm corresponding to 6, 12, 24 pixels are obtained by varying the exposure energy in the home-built MOPL system. However, the ideal gap structure cannot be obtained only by adjusting the exposure energy when the gap width is small, such as 1 or 2 pixels. Furthermore, we have proposed an alternative way to achieve fine gap structures through the structural decomposition design and precise control of exposure energy in different regions without changing the MOPL optical system. This study would provide a promising protocol for fabricating gap microstructures with controllable configuration using MOPL technique.

PCDD/Fs and DL-PCBs in Chinese Mitten Crab (Eriocheir sinensis) and Its Farming Environment in Shanghai, China.

Most polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in the human body are acquired from dietary intake. The chronic exposure of humans to PCDD/Fs and DL-PCBs is a major health concern, and these compounds are strictly controlled in many areas. This study measured the levels of PCDD/Fs and DL-PCBs in Chinese mitten crab (Eriocheir sinensis) farms in Shanghai and determined potential sources. The mean concentrations of PCDD/Fs and DL-PCBs in the studied crab samples were 264.20 ± 260.14 and 506.25 ± 226.80 pg/g ww (wet weight), respectively. The range of the toxic equivalent (TEQ) for the total PCDD/Fs and DL-PCBs in the crab samples was 1.20-29.04 pg TEQ/g ww. Further analysis revealed that the TEQ input to crabs in aquacultural water was 1.6 times higher than the TEQ in edible crab parts. Aquatic plants, shore plants, and feed contributed about 0.05% of the total TEQ input to crabs. The TEQ contribution from sediment was 317 times that found in edible crab parts, and sediment may be the most prevalent source of PCDD/Fs and DL-PCBs in farm crabs. The evaluation of the Shanghai market crab revealed different levels of PCDD/Fs and DL-PCBs. The TEQs for the mean PCDD/F and DL-PCB levels were 1.55 ± 1.96 and 1.05 ± 0.55 pg TEQ/g ww, respectively. The tolerable daily intake (TDI) levels of adults and children were lower than the prescribed range (1-4 pg TEQ/kg (weight)·d), indicating no significant chronic or acute ingestion risk for adults and children.

Significant loss of soil inorganic carbon at the continental scale.

Widespread soil acidification due to atmospheric acid deposition and agricultural fertilization may greatly accelerate soil carbonate dissolution and CO2 release. However, to date, few studies have addressed these processes. Here, we use meta-analysis and nationwide-survey datasets to investigate changes in soil inorganic carbon (SIC) stocks in China. We observe an overall decrease in SIC stocks in topsoil (0-30 cm) (11.33 g C m-2 yr-1) from the 1980s to the 2010s. Total SIC stocks have decreased by ∼8.99 ± 2.24% (1.37 ± 0.37 Pg C). The average SIC losses across China (0.046 Pg C yr-1) and in cropland (0.016 Pg C yr-1) account for ∼17.6%-24.0% of the terrestrial C sink and 57.1% of the soil organic carbon sink in cropland, respectively. Nitrogen deposition and climate change have profound influences on SIC cycling. We estimate that ∼19.12%-19.47% of SIC stocks will be further lost by 2100. The consumption of SIC may offset a large portion of global efforts aimed at ecosystem carbon sequestration, which emphasizes the importance of achieving a better understanding of the indirect coupling mechanisms of nitrogen and carbon cycling and of effective countermeasures to minimize SIC loss.

Periostin: a predictable molecule to prognosis and chemotherapy responses of gastrointestinal and hepato-biliary-pancreatic malignant tumors?

With the continuous development of medical science and technology, the medical community's understanding of the disease is constantly updated, just as strategies for treating malignant tumors are constantly updated. New diagnoses, follow-up indicators, and treatment plan formulations need more evidence to be supported. To date, radical surgical resection is still the preferred treatment for advanced digestive system malignancies, and combination therapy including chemotherapy and targeted therapy before or after surgery is aimed at improving the prognosis and quality of life of patients. However, if tumor recurrence, metastasis, chemotherapy, and drug resistance to targeted agents after surgery prevent the achievement of the desired therapeutic effect, and if neoadjuvant chemotherapy and targeted therapy cannot reduce the staging of the tumor, surgery cannot be performed. These are huge problems that we face now and will continue to face for some time. Relevant scientific data and evidence have been produced to explain unsatisfactory efficacy, such as epithelial-mesenchymal transformation, the tumor microenvironment, extracellular matrix proteins, cancer-related fibroblasts, and other factors that may be related to tumor progression and poor therapeutic effects. An extracellular matrix protein, periostin (POSTN), influences the above factors and has received multidisciplinary attention. In this paper, periostin and digestive system-related tumors are reviewed, and the production, mechanism of action, drug resistance correlation analysis, and coping strategies of periostin are summarized to further understand its characteristics. This work provides evidence for potential therapeutic targets for digestive system tumors in the future.

Phenotypic characterization of CADASIL patients with the Arg332Cys mutation in the NOTCH3.

BACKGROUND: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary vascular disease caused by mutations in NOTCH3, that are primarily localized in exons 4, 3, and 11. The Arg332Cys mutation in exon 6 has been rarely reported in patients with CADASIL. METHODS: A case study and the results of a comprehensive systemic search of the PubMed database, using the keywords "CADASIL", "Arg332Cys", "R332C", and "exon 6", are reported. The results obtained, combined with the data obtained from the largest published case series on CADASIL, the clinical and imaging characteristics of patients with the Arg332Cys mutation, were compared and analyzed. RESULTS: A 48-year-old woman with a rare Arg332Cys mutation in exon 6 of NOTCH3, who presented with rapidly developing dementia and recurrent ischemic stroke, was investigated herein. Magnetic resonance imaging (MRI) revealed abnormal signals in the cerebral white matter, bilateral thalamus, internal and external capsules, basal ganglia, corpus callosum, and brainstem. Literature review identified an additional 21 individuals, comprising 11 Europeans and 10 Asians, with the Arg332Cys mutation; of these identified individuals, clinical data was available for 2 Italian and 9 Asian patients. Analysis of the clinical characteristics of the 11 patients and the patient we reported showed that their mean age at disease onset was 37.82±9.36 years, much earlier than 57.0±9.36 years reported in literature. The most frequent manifestations were transient ischemic stroke or stroke (83.3%), followed by cognitive impairment (58.3%), psychiatric symptoms (50%), and migraine (33.3%). Among the 10 Asian patients with available imaging data, the characteristic high signals for the external capsule and brainstem accounted for 90% and 71.43% respectively, and anterior temporal high signal took proportion of 60% (higher than 34.5% reported for Asian patients in literature). None of the 6 patients with available gradient echo imaging data had cerebral microbleeding. CONCLUSIONS: CADASIL patients with the Arg332Cys mutation in exon 6 have been reported in Europe and Asia. The majority of patients had early disease onset. Diffuse high signals involving the external capsule, brainstem, and bilateral temporal pole are the main neuroimaging characteristics.

Comparison of gemcitabine and anthracycline antibiotics in prevention of superficial bladder cancer recurrence.

BACKGROUND: Because of the failure, shortage and related toxicities of Bacillus Calmette-Guérin (BCG), the other intravesical chemotherapy drugs are also widely used in clinical application. Gemcitabine and anthracycline antibiotics (epirubicin and pirarubicin) are widely used as first-line or salvage therapy, but which drug is better is less discussed. METHODS: A total of 124 primary NMIBC patients administered intravesical therapy after transurethral resection of bladder tumor (TURBT) at Nanjing Drum Tower hospital from January 1996 to July 2018. After TURBT, all patients accepted standard intravesical chemotherapy. Recurrence was defined as the occurrence of a new tumor in the bladder. Progression was defined as confirmed tumor invading muscular layer. Treatment failure was defined as need for radical cystectomy (RC), systemic chemotherapy and radiation therapy. RESULTS: Of the 124 patients who underwent intravesical chemotherapy, 84 patients were given gemcitabine, 40 patients were given epirubicin or pirarubicin, with mean follow-up times (mean ± SD) of (34.8 ± 17.9) and (35.9 ± 22.1) months respectively. The clinical and pathological features of patients show no difference between two groups. Recurrence rate of patients given gemcitabine was 8.33% (7 out of 84), the recurrence rate was 45% (18 out of 40) for epirubicin or pirarubicin (P < 0.0001). The progression rates of gemcitabine, anthracycline antibiotics groups were 2.38% (2 out of 84) and 20% (8 out of 40), respectively (P < 0.001). The rate of treatment failure is 8.33% (7 out of 84) and 25% (10 out of 40), respectively (P = 0.012). Gemcitabine intravesical chemotherapy group was significantly related to a lower rate of recurrence (HR = 0.165, 95% CI 0.069-0.397, P = 0.000), progression (HR = 0.160, 95% CI 0.032-0.799, P = 0.026) and treatment failure (HR = 0.260, 95% CI 0.078-0.867, P = 0.028). CONCLUSION: In conclusion, gemcitabine intravesical chemotherapy group was significantly related to a lower rate of recurrence, progression and treatment failure. Gemcitabine could be considered as a choice for these patients who are not suitable for BCG.

Spatial-temporal evolution and prediction of urban landscape pattern and habitat quality based on CA-Markov and InVEST model.

The change of urban landscape caused by human activities is one of the most important factors affecting terrestrial ecosystem. The distribution of urban landscape pattern has great impacts on the service function of regional biodiversity. To reveal the variation of landscape pattern and habi-tat quality in cities and its driving factors, we extracted landscape type information of Wuhan in 2005, 2010, 2015, and analyzed spatial-temporal evolution of landscape pattern using Markov transition model. The CA-Markov model was used to simulate the landscape pattern in 2020 under the natural growth scenario. The driving factor for landscape variation was analyzed using Logistic regression model. Combined with InVEST model, spatial pattern of habitat quality and its variation in three phases were calculated and evaluated. The simulated habitat quality in 2020 was obtained and its distribution characteristics were analyzed. The relationship between variation of landscape pattern and human activities was explored. The results showed that cultivated land and manufactured surface were the landscape types with highest variations between 2005 and 2015. The area of cultivated land continued to decline, with most of the area being transferred into manufactured surface. The area of manufactured surface continued to increase, most of which was transferred from paddy field and dry land. From 2005 to 2015, the habitat quality declined, with a large number of landscapes with high habitat quality level being changed to low habitat quality level. The overall index of habitat quality decreased and the biodiversity service function declined, indicating the degeneration of habitat quality. In 2015-2020, the evolutionary trend of landscape pattern and habitat quality would keep consistent with the past decade, with an increasing area of artificial surface, decreasing index of habitat quality, weakening biodiversity service function, and degenerating habitat quality. The most important factor accounted for the landscape pattern change in the study area was the changes in Gross Domestic Product (GPD) and regional fiscal revenue. Human socio-economic activities were the key driving force for the spatial variation of landscape and degeneration of habitat quality. Urbanization and land reclamation by filling lakes were the main reasons for landscape pattern variation in Wuhan.

DTI and pathological changes in a rabbit model of radiation injury to the spinal cord after 125I radioactive seed implantation.

Excessive radiation exposure may lead to edema of the spinal cord and deterioration of the nervous system. Magnetic resonance imaging can be used to judge and assess the extent of edema and to evaluate pathological changes and thus may be used for the evaluation of spinal cord injuries caused by radiation therapy. Radioactive 125I seeds to irradiate 90% of the spinal cord tissue at doses of 40-100 Gy (D90) were implanted in rabbits at T10 to induce radiation injury, and we evaluated their safety for use in the spinal cord. Diffusion tensor imaging showed that with increased D90, the apparent diffusion coefficient and fractional anisotropy values were increased. Moreover, pathological damage of neurons and microvessels in the gray matter and white matter was aggravated. At 2 months after implantation, obvious pathological injury was visible in the spinal cords of each group. Magnetic resonance diffusion tensor imaging revealed the radiation injury to the spinal cord, and we quantified the degree of spinal cord injury through apparent diffusion coefficient and fractional anisotropy.

The effects of rainfall regimes and terracing on runoff and erosion in the Three Gorges area, China.

Changes in natural rainfall regimes have taken place and are expected to become more pronounced in future decades. These changes are also likely to be accompanied by changes in crop management practices. The main purpose of this study was to analyze runoff and soil loss in relation to rainfall regimes and terracing in the Three Gorges area, China. Based on 10 years of field observation and k-mean clusters, 101 rainfall events were grouped into three rainfall regimes. Rainfall regime I was the group of events with strong rainfall intensity, high frequency, and short duration. Rainfall regime III consisted of events with low intensity, long duration, and high rainfall amount. Rainfall regime II was the aggregation of events of high intensity and amount, and less frequent occurrence. The results showed that event runoff coefficients were not significantly different among rainfall regimes. However, the average soil erosion rates in rainfall regimes I and II were significantly higher than that in regime III. The average erosion rates under rainfall regimes I, II, and III were 21.6, 39.7, and 9.8 g m-2, respectively. The effect of rainfall regime on soil erosion also was changed by terracing. On unterraced cropland, soil erosion rate in rainfall regime I is significantly higher than that in regime III. However, the situation did not exist in unterraced orchard. Terracing significantly reduced runoff and soil erosion, and compensated the effects of rainfall regime on soil erosion, which indicated that runoff and erosion in terraced system may be little influenced by climate change. Based on these results, it was suggested more attention should be paid to the timing of rainfall events in relation to crop development and the high erosion on unterraced citrus orchard to control soil erosion in this area.

Effects of vegetation on runoff generation, sediment yield and soil shear strength on road-side slopes under a simulation rainfall test in the Three Gorges Reservoir Area, China.

Vegetation recolonization has often been used to control roadside slope erosion, and in this paper, four restoration models - Natural Restoration, Grass, Grass & Shrub, Sodded Strip - were chosen to recolonize the plants on a newly built unpaved roadside slope in the Three Gorges Reservoir Area. After eight months growth, eight rainfall simulations (intensity of 90 mm h(-1) for 60 min) and in-situ soil shear strength test were then carried out to identify the impacts of vegetation on roadside slope erosion and soil shear strength. The erosion on cutslopes was higher than that on fillslopes. The runoff coefficient and soil detachment rate were significantly lower on the Grass & Shrub model (4.3% and 1.99 g m(-2) min(-1), respectively) compared with the other three, which had the highest surface cover (91.4%), aboveground biomass (1.44 kg m(-2)) and root weight density (3.94 kg m(-3)). The runoff coefficient and soil detachment rate on roadside slopes showed a logarithmic decrease with the root weight density, root length density and aboveground biomass. The soil shear strength measured before and after the rainfall was higher on Grass & Shrub (59.29 and 53.73 kPa) and decreased on Grass (46.93 and 40.48 kPa), Sodded Strip (31.20 and 18.87 kPa) and Natural Restoration (25.31 and 9.36 kPa). Negative linear correlations were found between the soil shear strength reduction and aboveground biomass, root weight density and root length density. The variation of soil shear strength reduction was closely related to the roadside slope erosion, a positive linear correlation was found between runoff coefficient and soil shear strength reduction, and a power function was shown between soil detachment rate and soil shear strength reduction. This study demonstrated that Grass and Grass & Shrub were more suitable and highly cost-effective in controlling initial period erosion of newly built low-volume unpaved road.

Solvent-induced single-crystal-to-single-crystal transformation in multifunctional chiral dysprosium(III) compounds.

Two new enantiomeric ionic chiral dysprosium(III) compounds were designed and synthesized. These compounds show simultaneously the optical activity, ferroelectric effects, nonlinear-optical effects, and slow magnetic relaxation behavior. More interestingly, these compounds exhibit reversible single-crystal-to-single-crystal transformations associated with the release or absorption of solvent molecules. The structure transformations are accompanied by distinct changes in the physical properties.

[Effects of different vegetation protection measures on erosion prevention of unpaved roadside slopes in Three Gorges Reservoir Area].

One of the main impacts of road construction is the creation of bare and steep slopes when lack of vegetation protection, which usually generates serious soil loss, a major erosion source in mountainous areas. In this study, six treatments including planting grass (GRA), grass and bush (GBC), building terrace combined with grass and bush (TGB), planting sod strip (SS), building sloping farmland (SFL), and building sloping farmland combined with grass (SFLG) were installed on the newly constructed unpaved roadside slopes in Three Gorges Reservoir Area to investigate the effects of these measures on the erosion prevention of the unpaved roadside slopes under natural rainfall. Among the six treatments, GBC had the best effect, which had the quickest revegetation rate (the mean vegetation coverage increased from 20.2% to 91.6%), decreased the soil bulk density by 9.5%, and increased the saturated hydraulic conductivity by 678.1%, followed by GRA and SS. TGB had the greatest potential in mitigating soil loss and runoff, with the efficiency in trapping sediment and runoff reached 80.2% and 72.3%, respectively, being appropriate for the cut slopes with a gradient greater than 45 degrees, followed by GBC and GRA. GRA had a higher efficiency on fill slope than on cut slope, while GBC showed greater applicability on cut slope. On the fill slope with a moderate gradient 15 degrees, SFLG had a potential of trapping 23.0% of sediment, which was equivalent to that of GRA and GBC, but the efficiency in trapping runoff was only 2.0%. When the fill slopes with a gradient less than 15 degrees were utilized as farmland, a grass buffer strip of 2 m length was needed on the upslope for erosion control.

Distinct magnetic dynamic behavior for two polymorphs of the same Dy(III) complex.

Two polymorphs of the same Dy(III) complex show distinct slow magnetic relaxation behaviors due to the different local environments of Dy(III) in the crystal. This work represents the first example where the magnetic dynamic property of neutral rare earth complexes could be tuned by growing polymorphic crystals without changing the ligand.

Co3(2-OOCC6H4PO3)2(H2O)3·H2O: a layered metal phosphonate showing reversible dehydration-rehydration behavior and ferrimagnetism.

Two isostructural metal phosphonates M3(2-cpp)2(H2O)3·H2O [M(II) = Co (1), Zn (2), 2-cppH3 = 2-carboxyphenylphosphonic acid] are synthesized and structurally characterized. Both exhibit layer structures in which -Co-O- "columns" are connected by the {PO3C} linkages. The "column" consists of triangular shaped {M3O3} trimers, inter-linked through either corner- or edge-sharing of the {MO6} octahedra. The phenyl groups are grafted on the two sides of the inorganic layer. Thermal analyses suggest that the layer structures of 1 and 2 are stable after removal of the lattice and coordination water. The dehydrated sample can be rehydrated reversibly in the case of compound 1. Magnetic studies reveal that antiferromagnetic interactions dominate in both 1 and 1-de, resulting in ferrimagnetic layers in both cases. The large inter-layer distance in 1 favors a ferromagnetic interaction between the layers. Hence ferrimagnetism is observed in both cases at low temperature. For 1-de, slow magnetization relaxation is also observed below ca. 2.8 K.

Diruthenium compounds bearing equatorial fc-containing ligands: synthesis and electronic structure.

Previously, the synthesis of compounds Ru(2)(D(3,5-Cl(2)Ph)F)(4-n)(O(2)CFc)(n)Cl (n = 1, 3a; 2, 4a), where D(3,5-Cl(2)Ph)F is N,N'-di(3,5-dichlorophenyl)formamidinate, from the carboxylate exchange reactions between Ru(2)(D(3,5-Cl(2)Ph)F)(4-n)(OAc)(n)Cl and ferrocene carboxylic acid was communicated. Reported herein is the preparation of analogous compounds Ru(2)(DmAniF)(4-n)(O(2)CFc)(n)Cl (n = 1, 3b; 2, 4b), where DmAniF is N,N'-di(3-methoxyphenyl)formamidinate, from Ru(2)(DmAniF)(4-n)(OAc)(n)Cl. Compounds 3 and 4 were characterized with various techniques including X-ray structural determinations of 3a and 4a. Voltammetric behaviors of compounds 3 and 4 were investigated, and stepwise one-electron ferrocene oxidations were observed for both compounds 4a and 4b. Spectral analysis of the monocations [4](+) indicated that they are the Robin-Day class II mixed valent [Fc···Fc](+) species. Measurement and fitting of magnetic data (χT) of 4a between 2 and 300 K revealed a typical zero-field splitting of a S = 3/2 center with D = 77 cm(-1), while those of [4a]BF(4) are consistent with the presence of S = 3/2 (Ru(2)) and S = 1/2 (Fc(+)) centers that are weakly coupled (zJ = -0.76 cm(-1)).

Three-dimensional metal phosphonodicarboxylates with GIS-zeolite topology: syntheses, structures and magnetic studies.

Compounds [M(2)(4-pi)(H(2)O)(4)]·1.5H(2)O [M(II) = Mn(1), Co(2), Ni(3)] and a heterometallic analogue [Co(1.14)Ni(0.86)(4-pi)(H(2)O)(4)]·1.5H(2)O (4) have been synthesized utilizing a rigid 4-phosphonoisophthalic acid (4-piH(4)). Compounds 1-4 are isostructural, confirmed by their powder XRD measurements. Single crystal structural determinations of 1 and 2 reveal that these compounds display a novel pillared layered open framework structure with zeolite gismondine (GIS) topology. Within the layer, edge-sharing {MO(6)} octahedra are found, which are connected by carboxylate and phosphonate groups along the c- and b-axis, respectively. Dominant antiferromagnetic interactions are propagated between the magnetic centers in 1, 2 and 4. While in 3, ferromagnetic exchange couplings are observed.

Manganese(II)-octacyanometallate(V) bimetallic ferrimagnets with T(c) from 41 to 53 K obtained in acidic media.

A series of three-dimensional (3D) octacyanometallate-based bimetallic magnets, {[Mn(H(2)O)][Mn(0.75)(HCOO)(0.5)(H(2)O)(0.5)][W(CN)(8)] x H(2)O}(4n) (1), {[Mn(2)(HCOO)(HCOOH)][M(CN)(8)] x H(2)O}(n) (M = W (2) and Mo (3)), and {[Mn(2)(HCOO)(HCOOH)][W(CN)(8)] x CH(3)OH}(n) (M = W (4) and Mo (5)), were synthesized by the reaction of octacyanometallates A(3)[M(CN)(8)] x nH(2)O (A = Na, Cs, and (C(4)H(9))(3)NH; M = W and Mo; and n = 2 or 4) with manganese salt (Mn(CH(3)COO)(2) x 4 H(2)O, Mn(ClO(4))(2) x 6 H(2)O, and MnCl(2) x 4 H(2)O) in aqueous or methanolic solution containing formic acid. All complexes crystallize in the tetragonal or orthorhombic system. Complex 1 shows an unexpected 3D network structure by connections of manganese ions and octacyanotangstate-manganese double layers via cyanide bridges, while other complexes have typical structure constructions similar to the reported complexes {[MnL](m)[M(CN)(8)]}(n) (L = CH(3)COO(-), Cl(-), and H(2)O), which the CN group of [W(V)(CN)(8)] coordinates to eight Mn(II) ions forming a -[W(CN)(8)]-Mn(4)-[W(CN)(8)]-Mn(4)- columnar chain, and then all chains share Mn(II) ions as the nodes interlocking with each other to form the 3D networks. Magnetic studies indicate that the cyanide group mediates the antiferromagnetic coupling between octacyanometallates and manganese ions in all complexes, and the ferrimagnetic phase transition temperatures are 53, 52, 42, 49, and 41 K for 1-5, respectively.

Single-ion magnets based on mononuclear lanthanide complexes with chiral Schiff base ligands [Ln(FTA)3L] (Ln = Sm, Eu, Gd, Tb and Dy).

A series of mononuclear lanthanide complexes with chiral Schiff base ligands [Ln(FTA)(3)L] [Ln = Dy(1), Sm(2), Eu(3), Gd(4), and Tb(5), L = (S,S)-2,2'-Bis(4-benzyl-2-oxazoline)] were synthesized and characterized. Among these complexes, complex 1 represents the first example of mononuclear lanthanide complexes displaying single-ion magnet behavior and ferroelectricity.

Slow relaxation processes and single-ion magnetic behaviors in dysprosium-containing complexes.

A series of one-dimensional complexes [Ln(L(1))(3)(HOCH(2)CH(2)OH)](n) (L(1) = 2-furoate anion; Ln = Nd (1), Sm (2), Gd (3), Tb (4), Dy (5), Er (6)) have been synthesized. The complexes were crystallized in the monoclinic space group P2(1)/c and show a chain-like structure determined by single-crystal X-ray diffraction. Magnetic properties indicate that carboxyl group of 2-furoate mediates different magnetic couplings in light and heavy rare earth complexes, namely, antiferromagnetic interaction between light rare earth ions and ferromagnetic interaction between heavy ones. Noticeably, complex 5 displays a strong frequency dependence of alternating current (AC) magnetic properties. Further magnetic studies show a distribution of a single relaxation process in 5. While 1,10-phenanthroline and phthalate anion (L(2)) were employed, [Dy(2)(L(2))(6)(H(2)O)](n) (7) was isolated by hydrothermal reactions and characterized magnetically. Research results also show the frequency dependence of AC magnetic susceptibilities, although the phthalate anions mediate antiferromagnetic coupling between Dy(III) ions. Further magnetic investigation of a neutral mononuclear complex with the formula [Dy(TTA)(3)(L(3))] (8) (TTA = 2-thenoyltrifluoroacetonate; L(3) = 4,5-pinene bipyridine) suggests that the single-ion magnetic behavior originates the slow relaxation of Dy(III)-containing complexes.

Diamond- and graphite-like octacyanometalate-based polymers induced by metal ions.

By using cyclohexane-1,2-diamine (chxn), Ni(ClO(4))(2) x 6 H(2)O and Na(3)[Mo(CN)(8)] x 4 H(2)O, a 3D diamond-like polymer {[Ni(II)(chxn)(2)](2)[Mo(IV)(CN)(8)] x 8 H(2)O}(n) (1) was synthesised, whereas the reaction of chxn and Cu(ClO(4))(2) x 6 H(2)O with Na(3)[M(V)(CN)(8)] x 4 H(2)O (M = Mo, W) afforded two isomorphous graphite-like complexes {[Cu(II)(chxn)(2)](3)[Mo(V)(CN)(8)](2) x 2 H(2)O}(n) (2) and {[Cu(II)(chxn)(2)](3)[W(V)(CN)(8)](2) x 2 H(2)O}(n) (3). When the same synthetic procedure was employed, but replacing Na(3)[Mo(CN)(8)] x 4 H(2)O by (Bu(3)NH)(3)[Mo(CN)(8)] x 4 H(2)O (Bu(3)N = tributylamine), {[Cu(II)(chxn)(2)Mo(IV)(CN)(8)][Cu(II)(chxn)(2)] x 2 H(2)O}(n) (4) was obtained. Single-crystal X-ray diffraction analyses showed that the framework of 4 is similar to 2 and 3, except that a discrete [Cu(chxn)(2)](2+) moiety in 4 possesses large channels of parallel adjacent layers. The experimental results showed that in this system, the diamond- or graphite-like framework was strongly influenced by the inducement of metal ions. The magnetic properties illustrate that the diamagnetic [Mo(IV)(CN)(8)] bridges mediate very weak antiferromagnetic coupling between the Ni(II) ions in 1, but lead to the paramagnetic behaviour in 4 because [Mo(IV)(CN)(8)] weakly coordinates to the Cu(II) ions. The magnetic investigations of 2 and 3 indicate the presence of ferromagnetic coupling between the Cu(II) and W(V)/Mo(V) ions, and the more diffuse 5d orbitals lead to a stronger magnetic coupling interaction between the W(V) and Cu(II) ions than between the Mo(V) and Cu(II) ions.