Modulating the Structures and Magnetic Properties of Dy(III) Single-Molecule Magnets through Acid-Base Regulation

Chemical modulation on the structures and physical properties of the coordination complexes is of great interest for the preparation of new functional materials. By changing the acidity or basicity of the reaction medium, the deprotonation degree of a multidentate ligand with multiple active protons, H₄daps (H₄daps = N',N'″-((1E,1'E)-pyridine-2,6-diylbis(ethan-1-yl-1-ylidene))bis(2-hydroxybenzohydrazide)), can be regulated on purpose. With this ligand of different deprotonation and charges, three new Dy^III complexes ([Dy(H₃daps)(CH₃COO)₂(EtOH)]·CH₃COOH (1Dy), [Dy₂(H₂daps)₂(EtOH)₂(H₂O)₂(MeOH)₂](CF₃SO₃)₂·(H₂O)₂ (2Dy), and [Dy₃(H₁daps)₂(H₂daps)(μ₃-OH)(EtOH)(H₂O)] (3Dy)) of different nuclearities (mono-, di-, and trinuclear for 1Dy to 3Dy, respectively) have been synthesized and characterized structurally and magnetically. Analyses on the related bond lengths and resulting hydrogen bond modes in the complexes provide the details of the deprotonation position and the charge of the ligands, which can be in the form of H₃daps^-, H₂daps^2-, and H₁daps^3-. Interestingly, the more deprotonated ligand can act as a bridging ligand between the Dy^III centers using the phenol and/or carbonyl oxygen atoms, which leads to the multinuclear structures. Magnetic studies on these complexes revealed that complex 1Dy is a field-induced single-molecule magnet (SMM), while complexes 2Dy and 3Dy show SMM behavior under a zero dc field.

Macrocycle supported dimetallic lanthanide complexes with slow magnetic relaxation in Dy2 analogues

Six dimetallic lanthanide complexes, [Ln2(L')(acac)4] (1Dy-3Gd) (Ln = Dy (1Dy), Tb (2Tb) and Gd (3Gd)) and [Ln2(L')(tfac)4] (4Dy-6Gd) (Ln = Dy (4Dy), Tb (5Tb) and Gd (6Gd)) (H2L' = 1,9-dichloro-3,7,11,15-tetraaza-1,9(1,3)-dibenzenacyclohexadecaphane-2,10-diene-1,9-diol), have been synthesized by the reaction of lanthanide nitrates with the HL ligand in the presence of acetylacetonate (acac) (or trifluoroacetylacetonate (tfac) and triethylamine (HL = 4-chloro-2,6-bis(-((3-((3-(dimethylamino)propyl)amino)propyl)imino)methyl)phenol). Ln-Assisted modification of the Schiff base HL occurred and led to the formation of a new macrocyclic ligand (H2L'). X-ray crystallographic analysis revealed that the LnIII ions of complexes 1Dy-6Gd are all eight-coordinated in a square antiprismatic geometry with D4d local symmetry. Magnetic measurements of these complexes revealed that 1Dy and 4Dy show single-molecule magnet behaviour with energy barriers of 66.7 and 79.0 K, respectively, under a zero direct magnetic field. The orientations of the magnetic axes and crystal field parameters were obtained from theoretical calculations and an electrostatic model. The magneto-structural correlations of SMMs 1Dy and 4Dy are further discussed in detail.

A family of lanthanide complexes with a bis-tridentate nitronyl nitroxide radical: syntheses, structures and magnetic properties

Eleven new lanthanide complexes based on a bis-tridentate nitronyl nitroxide radical NIT-Pm2Py (2-(4,6-di(pyridin-2-yl)pyrimidin-2-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxy-3-oxide), namely (NIT-Pm2Py)Ln(hfac)₃ (Ln = Gd (1_Gd), Tb (2_Tb), Dy (3_Dy), Ho (4_Ho), Er (5_Er), Yb (6_Yb)), [(NIT-Pm2Py)Ln₂(hfac)₆]·xH₂O (Ln = Gd (7_Gd), Tb (8_Tb), Ho (10_Ho), x = 0.5 for 7_Gd and 1 for 8_Tb and 10_Ho) and (NIT-Pm2Py)Ln₂(hfac)₆ (Ln = Dy (9_Dy), Er (11_Er)) were prepared and characterized. These complexes can be selectively prepared by controlling the reaction ratio of Ln(hfac)₃·2H₂O to the radical ligand NIT-Pm2Py. Single crystal X-ray crystallographic analyses confirmed that 1_Gd-6_Yb are isostructural 2p-4f Ln^III-radical complexes, in which the NIT-Pm2Py radical acts as a terminal tridentate ligand chelating to one Ln^III ion. On the other hand, 7_Gd-11_Er are isostructural 4f-2p-4f Ln^III-radical-Ln^III complexes with the NIT-Pm2Py acting as a bridging ligand between two Ln^III ions. 7_Gd-11_Er represent a rare family of complexes showing the NIT bridged 4f-2p-4f three-spin motif. Alternating-current (ac) magnetic susceptibility investigations revealed that complex 6_Yb exhibits field-induced frequency dependence, suggesting a possible field-induced single-molecule magnet behavior. Ab initio calculations were performed on all these complexes. The fitting of the magnetic susceptibilities of these complexes indicates weak antiferromagnetic coupling between the Ln^III and NIT radical.

[A preliminary prospective study on the efficacy and safety of ultrasound-guided percutaneous lauromacrogol sclerotherapy in benign cystic or predominantly cystic thyroid nodules]

Objective: To investigate the efficacy and safety of percutaneous lauromacrogol injection (PLI) in treatment of cystic or predominantly cystic thyroid nodules. Methods: A total of 114 cystic thyroid nodules and 61 predominantly cystic thyroid nodules with pain or uncomfort or aesthetic complaints were offered PLI. Therapeutic success rates and side effects were evaluated. From October 2012 to December 2015,114 patients with cystic thyroid nodules and 61 with predominantly cystic thyroid nodules with pain or uncomfortable or aesthetic complaints at the outpatient clinic of the First Affiliated Hospital of Wenzhou Medical University were offered percutaneous lauromacrogol sclerotherapy. Cytological results were benign. This study was a prospective trial. Ultrasonography sound examination was performed in all patients before treatment. The baseline data of all the patients and the data of the patients examined at the follow-up of 1, 3, 6 and 12 months were analyzed. Therapeutic success rate (nodule volume reduction >50%) and safety were observed. The data of nodule volume reduction ratio and the function of thyroid were normal distribution and analyzed by Mann-Whitney test and t test. The data of nodule volume, symptoms score and cosmetic score were skewed distribution, which were indicated with median and analyzed by nonparamentic test. Results: The mean volume of the cystic thyroid nodules was reduced from 12.5 cm(3) before PLI to 0.2 cm(3) at 12 months after PLI (χ(2)=266.175, P<0.001), with a therapeutic success rate of 100%, and the mean volume of the predominantly cystic thyroid nodules was reduced from 10.5 cm(3) before PLI to 2.0 cm(3) at 12 months after PLI (χ(2)=203.122, P<0.001) with a therapeutic success rate of 93.4%(57/61). Pressure symptom score and cosmetic grade were significantly improved at 12 months after PLI in patients with cystic or predominantly cystic thyroid nodules. Pressure symptom score and cosmetic grade in patients with cystic thyroid nodules were Z=-6.126 and Z=-13.735, respectively; pressure symptom score and cosmetic grade in patients with predominantly cystic thyroid nodules were Z=-3.126 and Z=-7.212, respectively (all P<0.001) . There no significant difference in the thyroid functions before and after PLI in two groups of patients (all P>0.05) . The side effects of PLI were mild. Conclusion: PLI is a safe and effective alternative to treat benign cystic or predominantly cystic thyroid nodules.

Two three-dimensional [MoIII(CN)7]4−-based magnets showing new topologies and ferrimagnetic ordering below 80 K

Two 3D [Mo^III(CN)₇]⁴⁻-based magnets with new topologies and ferrimagnetic ordering below 80 K have been prepared using different amides as auxiliary ligands.

Syntheses and magnetic properties of a bis-tridentate nitronyl nitroxide radical and its metal complexes

A new bis-tridentate nitronyl nitroxide radical was synthesized and characterized. Field-induced slow magnetic relaxation was observed in the radical-bridged Co^II complex.

Spin crossover in hydrogen-bonded frameworks of FeII complexes with organodisulfonate anions

Four spin crossover Fe^II complexes of hydrogen-bonded frameworks were constructed from the charge-assisted hydrogen bonds between the Fe^II complexes and organodisulfonate anions.

Syntheses, structures, and magnetic properties of three two-dimensional cobalt(ii) single-ion magnets with a CoIIN4X2 octahedral geometry

Three two-dimensional Co^II SIMs with (4,4) layer structures have been synthesized and characterized structurally and magnetically.

Heterometallic MIILnIII (M = Co/Zn; Ln = Dy/Y) Complexes with Pentagonal Bipyramidal 3d Centers: Syntheses, Structures, and Magnetic Properties

We herein reported the syntheses, structures, and magnetic properties of three dinuclear heterometallic M^IILn^III complexes, namely, [M^IILn^III(H₂L)(CH₃OH)₂(NO₃)₂](NO₃)·S (M = Co, Ln = Dy, S = MeOH (1_CoDy); M = Zn, Ln = Dy, S = MeOH (2_ZnDy); M = Co, Ln = Y, S = MeNO₂ (3_CoY), H₄L = 2,6-diacetylpyridine bis[2-(semicarbazono) propionylhydrazone]. Synthesized from the predesigned multidentate ligand H₄L, which has two different coordination pockets (smaller N₃O₂ and larger N₂O₄ pockets) suitable for either a 3d or a 4f metal center, all these complexes have very similar structures, where the M^II centers possess a pentagonal bipyramidal (PBP) geometry and the Ln^III sites have a tetradecahedron geometry. Magnetic measurements on these compounds revealed the existence of weak ferromagnetic coupling between the Co²⁺ and Dy³⁺ centers and the field-induced slow magnetic relaxation of all three complexes. Furthermore, theoretical calculation on all these complexes indicates that although the change of the diamagnetic Zn²⁺ ion to the paramagnetic Co²⁺ ion only slightly modifies the local magnetic anisotropy of the Dy³⁺ ion, the weak Co-Dy magnetic interaction decreases the energy barrier. These compounds are the first systematic results of a heterometallic 3d-4f single-molecule magnet containing predesigned PBP 3d metal ions.

Syntheses, structures, and magnetic properties of three new MnII-[MoIII(CN)7]4- molecular magnets

By reaction of K4[MoIII(CN)7]·2H2O, Mn(ClO4)2·6H2O and bidentate chelating ligands, three new cyano-bridged compounds, namely Mn2(3-pypz)(H2O)(CH3CN)[Mo(CN)7] (1), Mn2(1-pypz)(H2O)(CH3CN)[Mo(CN)7] (2) and Mn2(pyim)(H2O)(CH3CN)[Mo(CN)7] (3) (3-pypz = 2-(1H-pyrazol-3-yl)pyridine, 1-pypz = 2-(1H-pyrazol-1-yl)pyridine, pyim = 2-(1H-imidazol-2-yl)pyridine), have been synthesized and characterized structurally and magnetically. Single crystal X-ray analyses revealed that although the chelating ligands are different, compounds 1 to 3 are isomorphous and crystallize in the same monoclinic space group C2/m. Connected by the bridging cyano groups, one crystallographically unique [Mo(CN)7]4- unit and three crystallographically unique MnII ions of different coordination environments form similar three-dimensional frameworks, which have a four-nodal 3,4,4,7-connecting topological net with a vertex symbol of {43}{44·62}2{410·611}. Magnetic measurements revealed that compounds 1-3 display long-range magnetic ordering with critical temperatures of 64, 66 and 62 K, respectively. These compounds are rare examples of a small number of chelating co-ligand coordinated [Mo(CN)7]4--based magnetic materials. Specifically, the bidentate chelating ligands were successfully introduced into the heptacyanomolybdate system for the first time.

[The efficacy and safety of insulin degludec versus insulin glargine in insulin-naive subjects with type 2 diabetes: results of a Chinese cohort from a multinational randomized controlled trial]

Objective: To compare the safety and efficacy of insulin degludec (IDeg) with those of insulin glargine (IGlar) in insulin-naive subjects with type 2 diabetes (T2DM). Methods: This was a 26-week, randomized, open-label, parallel-group, treat-to-target trial in 560 Chinese subjects with T2DM (men/women: 274/263, mean age 56 years, mean diabetes duration 7 years) inadequately controlled on oral antidiabetic drugs (OADs). Subjects were randomized 2∶1 to once-daily IDeg (373 subjects) or IGlar(187 subjects), both in combination with metformin. The primary endpoint was changes from baseline in glycosylated hemoglobin(HbA1c) after 26 weeks. Results: Mean HbA1c decreased from 8.2% in both groups to 6.9% in IDeg and 7.0% in IGlar, respectively. Estimated treatment difference (ETD) of IDeg-IGlar in change from baseline was -0.10% points (95%CI-0.25-0.05). The proportion of subjects achieving HbA1c<7.0% was 56.3%and 49.7% with IDeg and IGlar, respectively [estimated odds ratio of IDeg/IGlar: 1.26(95%CI 0.88-1.82)]. Numerically lower rateof overall confirmed hypoglycaemia and statistically significantly lower nocturnal confirmed hypoglycemia were associated with IDeg compared with IGlar, respectively [estimated rateratio of IDeg/IGlar 0.69(95%CI 0.46-1.03), and 0.43(95%CI 0.19-0.97)]. No differences in other safety parameters were found between the two groups. Conclusions: IDeg was non-inferior to IGlar in terms of glycaemic control, and was associated with a statistically significantly lower rate of nocturnal confirmed hypoglycaemia. IDeg is considered to be suitable for initiating insulin therapy in Chinese T2DM patients on OADs requiring intensified treatment. Clinical trail registration: Clinicaltrials.gov, NCT01849289.

Single-ion magnetism in seven-coordinate YbIII complexes with distorted D5h coordination geometry

Two seven-coordinate compounds of pentagonal bipyramidal Yb^III centers exhibiting field-induced slow magnetic relaxation were characterized structurally and magnetically.

A cyano-bridged coordination nanotube showing field-induced slow magnetic relaxation

Field-induced slow magnetic relaxation was observed in a cyano-bridged nanotube constructed from a pentagonal bipyramidal Co^II unit and a hexacyanocobaltate(iii) anion.

Two-dimensional frameworks formed by pentagonal bipyramidal cobalt(ii) ions and hexacyanometallates: antiferromagnetic ordering, metamagnetism and slow magnetic relaxation

Two-dimensional frameworks constructed by pentagonal bipyramidal Co^II and [M(CN)₆]³⁻ units have been synthesized and characterized structurally and magnetically.

Preparation of dihydroquinazoline carbohydrazone Fe(ii) complexes for spin crossover

Mononuclear spin-crossover complexes of dihydroquinazoline derivatives were synthesized to enable the spin crossover phenomenon via the variation of the solvent, anion and substituent.

Associations of depression with impaired glucose regulation, newly diagnosed diabetes and previously diagnosed diabetes in Chinese adults

AIM

To examine the association between depression and impaired glucose regulation, newly diagnosed diabetes and previously diagnosed diabetes in middle-aged and elderly Chinese people, and whether depression was associated with different treatment regimens or durations of diabetes.

METHODS

A cross-sectional study was performed among 229,047 adults living in the community aged ≥ 40 years from 25 centres in China. The self-reported depression rating scale Patient Health Questionnaire 9 (PHQ-9) was used to diagnose probable and sub-threshold depression. Glucose metabolism status was determined according to World Health Organization 1999 diagnostic criteria.

RESULTS

The numbers of participants with normal glucose regulation, impaired glucose regulation, newly diagnosed diabetes and previously diagnosed diabetes were 120,458, 59,512, 24,826 and 24,251, respectively. The prevalence of sub-threshold depression in the total sample of participants was 4.8% (4.8%, 4.8%, 4.4% and 5.6% from normal glucose regulation to previously diagnosed diabetes, respectively), and the prevalence of probable depression was 1.1% (1.1%, 1.0%, 0.9% and 1.8% from normal glucose regulation to previously diagnosed diabetes, respectively). Compared with participants with normal glucose regulation, those with previously diagnosed diabetes had increased odds of probable depression [odds ratio (OR) = 1.61, 95% confidence interval (CI) 1.39-1.87] and sub-threshold depression (OR = 1.14, 95% CI 1.06-1.24), after adjustment for multiple confounding factors. Newly diagnosed diabetes or impaired glucose regulation was not associated with depression. Among those with previously diagnosed diabetes, insulin treatment was associated with greater odds of depression compared with no treatment or oral anti-diabetic medicine.

CONCLUSION

Previously diagnosed diabetes, but not newly diagnosed diabetes or impaired glucose regulation, was associated with a higher prevalence of depression. Patients receiving insulin were more likely to have depression than those not receiving treatment or being treated with oral anti-diabetic medicine.

Genetic analysis of STR markers on chromosome 21 in a Han population from southeast China

Short tandem repeats (STRs) are highly polymorphic sequences and have been extensively used as genetic markers in mapping studies, disease diagnosis, and human identity testing. In this study, 11 STR markers on chromosome 21, including D21S1432, D21S11, D21S1246, D21S1412, D21S1437, D21S1442, D21S2039, D21S1270, D21S1435, D21S1409, and D21S1446, were analyzed in 740 unrelated Han individuals from southeast China. A total of 132 alleles, ranging from 7-21 for each locus, were named according to the guidelines of the International Society for Forensic Haemogenetics. The distributions of allelic frequencies for the 11 STRs and population genetic parameters were determined. All 11 STR markers showed high polymorphism and heterogeneity in the southeast Han population, with polymorphism information content of 0.61-0.87, heterogeneity of 64.5-86.1%, and power of discrimination of 0.835-0.973. Among the 11 STR markers, D21S1412, D21S1270, D21S11, and D21S1442 showed relatively higher heterogeneity. Their combination was relatively informative and was used in a quantitative fluorescence-polymerase chain reaction assay to diagnose Down syndrome (trisomy 21) in a southeast Chinese Han population. The genetic information and population data for these 11 STRs may be used not only in quantitative fluorescence-polymerase chain reaction assays but also in forensic studies and other genetic tests.

Development and application of an indirect immunohistochemical method for the detection of duck plague virus vaccine antigens in paraffin sections and localization in the vaccinated duckling tissues

The objective of the present study was to develop and apply a streptavidin-alkaline phosphatase labeling system of indirect immunohistochemistry (SP-IHC) to detect antigenic distribution and localization regularity of duck plague virus (DPV) vaccine antigens in paraformaldehyde-fixed paraffin-embedded tissues of experimentally vaccinated ducklings. Male New Zealand rabbits were immunized with purified DPV antigens, which were engaged by a combination of differential centrifugation and sucrose-density gradient ultracentrifugation. The rabbit anti-DPV polyclonal antibodies were purified and used as the primary antibodies. Forty-eight 28-d-old DPV-free Pekin ducklings were subcutaneously inoculated with attenuated DPV vaccine in the immunization group and sterile PBS in the control group. The tissues were collected at sequential time points between 4 h and 18 wk postvaccination (PV) and were prepared for SP-IHC observation. The presence of DPV-specific antigens was first observed in the liver and spleen at 12 h PV; in the bursa of Fabricius, thymus, Harderian gland, esophagus, and intestinal tract at 1 d PV; and in the heart, lung, kidney, pancreas, and brain at 3 d PV. The positive staining reaction could be detected in the vaccinated duckling tissues until 18 wk PV, and no positive staining cells could be observed in the controls. The highest levels of positive staining reaction were found in the liver, spleen, bursa of Fabricius, thymus, and intestinal tract, whereas a few DPV vaccine antigens were distributed in the heart, pancreas, and esophagus. The target cells had a ubiquitous distribution, especially in the mucosal epithelial cells, lamina propria cells, macrophages, hepatocytes, and lymphocytes, which served as the principal sites for antigen localization. These findings demonstrated that SP-IHC was a reliable method for detecting antigenic distribution and localization regularity of DPV vaccine antigens in routine paraffin sections. The present study may be useful for describing proliferation and distribution regularity of DPV vaccine in the vaccinated duckling tissues and enhance further studies and clinical application of attenuated DPV vaccine.

Effects of angiopoietin-1 on vascular endothelial growth factor-induced angiogenesis in the mouse brain

A better understanding of angiogenic factors and their effects on angiogenesis in brain is necessary to treat cerebral vascular disorders such as ischemic brain injury. Vascular endothelial growth factor (VEGF) induces angiogenesis and increases blood-brain barrier (BBB) permeability in adult mouse brain. The effect of angiopoietin-1 on BBB leakage during the angiogenesis process is unclear. We sought to identify the effects of combining VEGF with angiopoietin-1 on cerebral angiogenesis and BBB. Adult male CD-1 mice underwent AdFc (adenoviral vector control), AdAng-1, VEGF protein, VEGF protein plus AdAng-1, or saline (negative control) injection. Brain microvessels were counted using lectin staining on tissue sections after 2 weeks of adenoviral gene transfer. The presence of zonula occludens-1 (ZO-1) was determined by Western blot analysis and immunohistochemistry. Microvessel count and augmented capillary diameter increased in mice treated with either VEGF protein or AdAng-1 plus VEGF protein compared to saline, AdFc, or AdAng-1 alone (p < 0.05). Double-labeled immunostaining demonstrated that ZO-1-positive staining was more complete on the microvessel wall in the AdAng-1 and AdAng-1 plus VEGF protein treated group compared to VEGF protein group. The results of ZO-1 expression from Western blot analysis paralleled that from immunohistochemistry (p < 0.05). We conclude that focal VEGF and angiopoietin-1 hyperstimulation in mouse brain increases microvessel density while maintaining ZO-1 protein expression, suggesting that angiopoietin-1 plays a role in synergistically inducing angiogenesis and BBB integrity.

Role of EAC1q4 in C1a transfer reaction (C1aTR) and further information on the nature of the EAC1q4 site

The complement intermediates EAC1, EAC4, and EAC1q4 were prepared with guinea pig, porcine, as well as human complement. EAC4 and EAC1q4 were made from EC4 and EAC14 respectively. The C1a transfer reaction (C1aTR), the second step of Borsos' C1a fixation and transfer test, was carried out with various combinations of these intermediates. It was found that the EAC1q4, instead of the EAC4, was the C1a acceptor, and the C1rs subcomponents rather than the whole C1 molecule should have to transfer in the C1aTR. The EAC41 derived from EC4 generated no EAC1q4 in EDTA medium as the EAC14 did. This presented evidence for the joining of C4 to A in the EAC1q4 site.