Third ventricular width by transcranial sonography is associated with cognitive impairment in Parkinson's disease.

BACKGROUND: One-fourth of Parkinson's disease (PD) patients suffer from cognitive impairment. However, few neuroimaging markers have been identified regarding cognitive impairment in PD. OBJECTIVE: This study aimed to explore the association between third ventricular width by transcranial sonography (TCS) and cognitive decline in PD. METHOD: Participants with PD were recruited from one medical center in China. Third ventricular width was assessed by TCS, and cognitive function was analyzed by the Mini-Mental State Examination (MMSE). Receiver operating characteristic (ROC) analysis and Cox model analysis were utilized to determine the diagnostic and predictive accuracy of third ventricular width by TCS for cognitive decline in PD patients. RESULT: A total of 174 PD patients were recruited. Third ventricular width was negatively correlated with MMSE scores. ROC analysis suggested that the optimal cutoff point for third ventricular width in screening for cognitive impairment in PD was 4.75 mm (sensitivity 62.7%; specificity 75.6%). After 21.5 (18.0, 26.0) months of follow-up in PD patients without cognitive impairment, it was found that those with a third ventricular width greater than 4.75 mm exhibited a 7.975 times higher risk of developing cognitive impairment [hazard ratio = 7.975, 95% CI 1.609, 39.532, p = 0.011] compared with patients with a third ventricular width less than 4.75 mm. CONCLUSION: Third ventricular width based on TCS emerged as an independent predictor of developing cognitive impairment in PD patients.

A nomogram based on iron metabolism can help identify apathy in patients with Parkinson's disease.

Backgrounds: Apathy is common in Parkinson's disease (PD) but difficult to identify. Growing evidence suggests that abnormal iron metabolism is associated with apathy in PD. We aimed to investigate the clinical features and iron metabolism of apathetic patients with PD, and construct a nomogram for predicting apathy in PD. Methods: Data of 201 patients with PD were analyzed. Demographic data, Apathy Scale (AS) assessments, and serum iron metabolism parameters were obtained. Spearman correlations were used to assess relationships between AS scores and iron metabolism parameters, separately for male and female patients. Additionally, a nomograph for detecting apathetic patients with PD was built based on the results of logistic regression analysis. Results: The serum transferrin (TRF, p < 0.0024) concentration and total iron binding capacity (TIBC, p < 0.0024) were lower in the apathetic group after Bonferroni correction, and they were negatively associated with AS scores in male participants with PD (TRF, r = -0.27, p = 0.010; TIBC, r = -0.259, p = 0.014). The nomogram was developed by incorporating the following five parameters: age, sex, serum iron concentration, TIBC and Hamilton Depression Rating Scale (HAMD) scores, which showed good discrimination and calibration, with a consistency index of 0.799 (95% confidence interval = 0.732-0.865). Conclusion: Abnormal iron metabolism may contribute to apathy in PD, especially among men. TIBC levels in combination with HAMD scores can be effectively used for the prediction of apathetic patients with PD.

Retraction Note: Prognostic value of heart failure in hemodialysis-dependent end-stage renal disease patients with myocardial fibrosis quantification by extracellular volume on cardiac magnetic resonance imaging.

An amendment to this paper has been published and can be accessed via the original article.

Modulation of the properties of dinuclear lanthanide complexes through utilizing different ß-diketonate co-ligands: near-infrared luminescence and magnetization dynamics.

A family of new dinuclear lanthanide complexes as the simplest entities showing intramolecular magnetic interactions, [Ln2(dbm)2(L)2(CH3OH)2] (Ln = Tb (1), Dy (2), Ho (3), Er (4), Yb (5), Lu (6)), [Ln2(acac)2(L)2(EtOH)2] (Ln = Dy (7), Er (8)), [Dy2(TTA)2(L)2(CH3OH)2]·2CH2Cl2 (9) and [Dy2(tfa)2(L)2(CH3OH)2] (10) (H2L = N'-(2-hydroxy-5-methylphenyl)-pyrazine-2-carbohydrazide, Hdbm = 1,3-diphenyl-1,3-propanedione, Hacac = acetylacetone, HTTA = 2-thenoyltrifluoroacetone, Htfa = trifluoroacetylacetone), were constructed successfully by the reaction of a Schiff base ligand H2L and four different ß-diketonate salts. As for complexes 4, 5 and 8, all exhibit the characteristic emission peaks of the corresponding Er3+, Yb3+ and Er3+ ions, respectively. Meanwhile, the excitation wavelength (510 nm) of 5 is located in the visible region, confirming its significant potential application value. Magnetic studies indicate that complexes 9 and 10 exhibit characteristic slow relaxation of magnetization with the energy barriers (Ueff) of 102 K for 9 and 140 K for 10 under a zero dc field. Under the optimized dc fields, slow magnetic relaxations are present in 2 and 7, and the Ueff values of 9 and 10 have been improved. This proves that the ß-diketonate co-ligands deserve an important role in regulating Dy-SMMs influenced by the diverse perturbations of the axial crystal field originating from minor changes in the coordination environment.

Prognostic value of heart failure in hemodialysis-dependent end-stage renal disease patients with myocardial fibrosis quantification by extracellular volume on cardiac magnetic resonance imaging.

BACKGROUND: End-stage renal disease (ESRD) patients are at high cardiovascular risk, and myocardial fibrosis (MF) accounts for most of their cardiac events. The purpose of this study is to investigate the prognostic value and risk stratification of MF as measured by extracellular volume (ECV) on cardiac magnetic resonance (CMR) for heart failure (HF) in patients with hemodialysis-dependent ESRD. METHODS: Sixty-six hemodialysis ESRD patients and 25 matched healthy volunteers were prospectively enrolled and underwent CMR to quantify multiple parameters of MF by T1 mapping and late gadolinium enhancement (LGE). All ESRD patients were followed up for 11-30 months, and the end-point met the 2016 ESC guidelines for the definition of HF. RESULTS: Over a median follow-up of 18 months (range 11-30 months), there were 26 (39.39%) guideline-diagnosed HF patients in the entire cohort of ESRD subjects. The native T1 value was elongated, and ECV was enlarged in the HF cohort relative to the non-HF cohort and normal controls (native T1, 1360.10 ± 50.14 ms, 1319.39 ± 55.44 ms and 1276.35 ± 56.56 ms; ECV, 35.42 ± 4.42%, 31.85 ± 3.01% and 26.97 ± 1.87%; all p<0.05). In the cardiac strain analysis, ECV was significantly correlated with global radial strain (GRS) (r = - 0.501, p = 0.009), global circumferential strain (GCS) (r = 0.553, p = 0.005) and global longitudinal strain (GLS) (r = 0.507, p = 0.008) in ESRD patients with HF. Cox proportional hazard regression models revealed that ECV (hazard ratio [HR] = 1.160, 95% confidence interval: 1.022 to 1.318, p = 0.022) was the only independent predictor of HF in ESRD patients. It also had a higher diagnostic accuracy for detecting MF (area under the curve [AUC] = 0.936; 95% confidence interval: 0.864 to 0.976) than native T1 and post T1 (all p ≤ 0.002). Kaplan-Meier analysis revealed that the high-ECV group had a shorter median overall survival time than the low-ECV group (18 months vs. 20 months, log-rank p = 0.046) and that ESRD patients with high ECV were more likely to have HF. CONCLUSIONS: Myocardial fibrosis quantification by ECV on CMR T1 mapping was shown to be an independent risk factor of heart failure, providing incremental prognostic value and risk stratification for cardiac events in ESRD patients. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR-DND-17012976, 13/12/2017, Retrospectively registered.

Water Stable [Tb4] Cluster-Based Metal-Organic Framework as Sensitive and Recyclable Luminescence Sensor of Quercetin.

A novel 3D metal-organic framework (MOF){[Tb3(CBA)2(HCOO)(µ3-OH)4(H2O)]·2H2O·0.5DMF} n (S-1) was synthesized by the solvothermal method. The crystal structure indicates that [Tb4O4] cubane clusters self-assemble into an infinite chain by sharing vertex, which is further linked to adjacent chains through 1,1-cyclobutanedicarboxylic acid ligand (H2CBA), resulting in a honeycomb arrayed framework. S-1 possesses excellent water stability and still retains intact structure after exposure to water for 10 weeks or boiling water for 10 weeks. Interestingly, S-1 acts as a luminescence sensor to selectively and sensitively detect quercetin with the limit of detection (LOD) as low as 0.23 ppm (7.6 × 10-7 M). The relationship between relative luminescence intensity and concentration obeys linear in the range of 0-300 ppm (0-993 µM), which allows quantitative detection of quercetin. Importantly, S-1 can be reused at least six times with almost no change in luminescent intensity. Compared with the high performance liquid chromatography-mass spectrometry (HPLC-MS) method, S-1 was used to determine the content of quercetin in onionskin and apple peel samples with satisfactory results. Furthermore, a portable S-1 test paper is also developed and expected to be applied in practice. To our knowledge, S-1 is the first example of MOFs as luminescent sensor for quercetin.

A new family of dinuclear lanthanide complexes constructed from an 8-hydroxyquinoline Schiff base and ß-diketone: magnetic properties and near-infrared luminescence.

Six phenoxo-O bridged dinuclear lanthanide(iii) complexes have been assembled utilizing the 2-[(4-nitrophenyl)imino]methyl-8-hydroxyquinoline (HL) and dibenzoylmethane (Hdbm) ligands: [Ln2(dbm)4L2] (Ln = Nd (1), Eu (2), Gd (3), Tb (4), Dy (5) and Er (6)). Complexes 1 and 6 exhibit the characteristic emission peaks of the corresponding Nd3+ and Er3+ ions, respectively. Meanwhile, the excitation wavelength (470 nm) for complex 1 is located in the visible-light region, confirming a practical application value. The studies on magnetic properties reveal that complex 3 features a magnetocaloric effect with a magnetic entropy change of -ΔSm = 14.36 J kg-1 K-1 at 4 K for ΔH = 7 T. What's more, the dynamic magnetic studies for complex 5 show that it exhibits slow magnetic relaxation behavior, typical of SMM behavior, resulting in an energy barrier of ΔE/kB = 75 K with the pre-exponential factor τ0 = 2.2 × 10-7 s. Meanwhile, this research demonstrates that the magnetic properties can be modulated by regulating the electron-donating/withdrawing effects of the substituents on the ligands.

Dual-source computed tomography for quantitative assessment of tracheobronchial anomaly from type IIA pulmonary artery sling in pediatric patients.

PURPOSE: As an extremely rare abnormity, type IIA pulmonary artery sling (PAS) tracheobronchial anomalies should be differentiated from normal airway for therapeutic decision-making. This study aimed to investigate the quantitative characteristics of type IIA PAS tracheobronchial anomalies using dual-source computed tomography (DSCT). MATERIALS AND METHODS: From January 2009 to December 2016, there were 11 type IIA PAS patients enrolled for analysis and compared with 32 controls. The areas of the trachea, right upper lobar bronchus, left main bronchus, right intermediate bronchus [bridging bronchus (BB) in patients], and subcarinal angle [subpseudocarinal angle in patients] were measured. Measurements other than that for the angle were standardized with body surface area. RESULTS: Significant differences were found between the type IIA PAS patients and controls in terms of DSCT measurements in the trachea (0.51 ±â€¯0.32 cm2/m2 vs. 0.92 ±â€¯0.18 cm2/m2, P < 0.001); left main bronchus (0.29 ±â€¯0.14 cm2/m2 vs. 0.43 ±â€¯0.18 cm2/m2, P = 0.01); right intermediate bronchus [BB in patients] (0.36 ±â€¯0.13 cm2/m2 vs. 0.47 ±â€¯0.12 cm2/m2, P = 0.02); and subcarinal angle [subpseudocarinal angle in patients] (116.27 ±â€¯16.45° vs. 79.41 ±â€¯15.71°, P < 0.001). Receiver operating characteristic analysis further revealed that these parameters may be indicators to differentiate tracheobronchial anomalies due to type IIA PAS from controls (AUC, 0.88-0.98; sensitivity, 81.7%-100%; specificity, 91.7%-100%). CONCLUSIONS: DSCT is an alternative technique to detect tracheobronchial anomalies in pediatric patients with type IIA PAS. It can provide accurate anatomic details for surgeons to determine therapeutic strategies.

Magnetic properties and structure of tetranuclear lanthanide complexes based on 8-hydroxylquinoline Schiff base derivative and ß-diketone coligand.

Five tetranuclear lanthanide complexes [Gd4(dbm)4(L)6(µ3-OH)2]·5CH3CN (1), [Tb4(dbm)4(L)6(µ3-OH)2]·2CH3CH2OH·4CH3CN (2), [Dy4(dbm)4(L)6(µ3-OH)2]·4CH3CN·2H2O (3), [Ho4(dbm)4(L)6(µ3-OH)2]·CH3CH2OH·4CH3CN·2H2O (4) and [Er4(dbm)4(L)6(µ3-OH)2] (5) are obtained from the reaction of 5-(4-pyridinecarboxaldehyde)amino-8-hydroxylquinoline (HL) and Ln(dbm)3·2H2O (dbm = 1,3-diphenyl-1,3-propanedione). Complexes 1-5 are isomorphous and crystallize in the monoclinic space group P21/c. The metal ions in 1-5 adopt an approximately square-antiprismatic coordination environment. Magnetic studies indicate that complex 1 features a magnetocaloric effect (MCE) with the magnetic entropy change of -ΔSm(T) = 16.35 J kg-1 K-1 at 3 K for ΔH = 7 T. Additionally, complex 3 displays single molecule magnet (SMM) behavior, exhibiting an effective energy barrier of the relaxation of magnetization Ueff/kB = 89.38 K and pre-exponential factor τ0 = 3.32 × 10-8 s.

Wheel-like Ln18 Cluster Organic Frameworks for Magnetic Refrigeration and Conversion of CO2.

Two isostructural 2D MOFs ([Ln7(CDA)6(HCOO)3(µ3-OH)6(H2O)8] n, abbreviated as 1-Gd and 2-Dy) were successfully synthesized under solvothermal conditions. The self-assembly of lanthanide(III) nitrate and 1,1'-cyclopropane-dicarboxylic acid (H2CDA) resulted in wheel-like Ln18 cluster second building units (SBU), which are further linked to six neighboring wheels to generate a 2D ordered honeycomb array. Both 1-Gd and 2-Dy exhibit high thermal stability and decompose above 330 °C. Moreover, they have good solvent stability in ten common solvents and pH stability with pH values from 1 to 13. Magnetic studies reveal that 1-Gd exhibits weak antiferromagnetic coupling between adjacent Gd3+ ions and has a large magnetocaloric effect of 47.30 J kg-1 K-1 (Δ H = 7.0 T at 2 K), while 2-Dy shows ferromagnetic interaction between adjacent Dy3+ ions. Interestingly, 1-Gd and 2-Dy can catalyze the cycloaddition of CO2 to epoxides under mild conditions and can be reused at least five rounds with negligible loss of catalytic performance.

Clinicopathological and molecular characteristics of synchronous gastric adenocarcinoma and gastrointestinal stromal tumors.

Synchronous gastric tumors that consist of both gastrointestinal stromal tumor (GIST) and adenocarcinoma are rare. We studied the clinicopathological and molecular characteristics of six cases containing both gastric adenocarcinoma and GIST. By means of immunohistochemical analysis, all GIST cells expressed CD117, CD34 and Dog1 in all six synchronous gastric adenocarcinomas with GIST, and in GIST alone. Sequencing analysis demonstrated that exon 11 c-kit mutations were present in two of six synchronous tumors and four of five GISTs. One of the two exon 11 c-kit mutations in synchronous adenocarcinomas with GISTs was an uncommon mutation of CTT > CCA at amino acid 576, and the other was a GTT deletion at amino acid 560. The mutation was a homozygous A > G mutation in exon 12 (amino acid 567) of PDGFR-α. We concluded that the exon 11 mutations were the most important in both cases of synchronous gastric adenocarcinoma with GIST and GIST alone. The mutation rate was higher in GIST alone than in synchronous adenocarcinoma with GIST.

A unique zinc-organic framework constructed through in situ ligand synthesis for conversion of CO2 under mild conditions and as a luminescence sensor for Cr2O72-/CrO42.

A novel zinc-organic framework, {[Zn3(tza)2(µ2-OH)2(H2O)2]·H2O}n (1) (H2tza = 1H-tetrazolate-5-acetic acid), was synthesized through an in situ generated tetrazole ligand under hydrothermal conditions. In compound 1, tza2- ligands and Zn2+ are interlinked to form 2D layers, which are further pillared through µ2-OH groups to generate a 3D framework. Thermogravimetric analysis and powder X-ray diffraction confirm that 1 has high thermal stability, pH stability and solvent stability. Catalytic studies show that 1 exhibits excellent catalytic ability for the cycloaddition of CO2 with epoxides under 50 °C and 0.1 MPa. Importantly, 1 can be reused at least six times. Furthermore, luminescence investigations indicate that 1 can serve as a recyclable luminescence sensor to efficiently detect Cr2O72-/CrO42-, and the detection limit can reach 10-6 mol L-1 and 4 × 10-6 mol L-1, respectively.

A Dy4 single-molecule magnet and its Gd(iii), Tb(iii), Ho(iii), and Er(iii) analogues encapsulated by an 8-hydroxyquinoline Schiff base derivative and ß-diketonate coligand.

Five new tetranuclear complexes based on an 8-hydroxyquinoline Schiff base derivative and the ß-diketone coligand, [Ln4(acac)4L6(µ3-OH)2]·CH3CN·0.5CH2Cl2 (Ln = Gd (1), Tb (2), Dy (3), Ho (4) and Er (5); HL = 5-(benzylidene)amino-8-hydroxyquinoline; acac = acetylacetonate) have been synthesized, and structurally and magnetically characterized. Complexes 1-5 have similar tetranuclear structures. Each LnIII ion is eight coordinated and its coordination polyhedra can be described as being in a distorted square-antiprismatic geometry. The magnetic studies reveal that 1 features the magnetocaloric effect (MCE) with the magnetic entropy change of -ΔSm(T) = 25.08 J kg-1 K-1 at 2 K for ΔH = 7 T, and 3 displays the slow magnetic relaxation behavior of Single Molecule Magnets (SMMs) with the anisotropic barrier of 86.20 K and the pre-exponential factor τ0 = 2.99 × 10-8 s.

Preoperative evaluation of coronary artery fistula using dual-source computed tomography.

OBJECTIVES: To evaluate the efficacy of dual-source computed tomography (DSCT) in assessing the morphological features, quantitative features, and associated coronary artery lesions among patients with coronary artery fistula (CAF) before surgery. METHODS: We enrolled 34 patients with CAF that were morphologically and quantitatively analyzed by DSCT and compared the analyses with surgical results (reference standard). The associated coronary artery lesions were also assessed. RESULTS: By DSCT, we identified 15 patients (44.1%) with left-sided CAF, 9 (26.5%) with right-sided CAF, and 10 (29.4%) with bilateral CAF; the left anterior descending coronary artery (50.0%) was most frequently involved. Drainage was most commonly in the main pulmonary artery (41.2%), and those with right-sided CAF had larger feeding coronary arteries and drainage sites than those with left-sided or bilateral CAF (p<0.05). All the morphological features presented by DSCT were confirmed at surgery. In the quantitative analysis of CAF, DSCT was as accurate as surgery (r=0.95-0.98, p<0.001), and it was able to evaluate associated lesions accurately, including arteriosclerotic plaques, coronary artery aneurysms, and myocardial bridges. The evaluation could be completed in a single scan, without requiring an increased radiation dose (mean ED=2.27±1.92mSv). CONCLUSIONS: DSCT is an alternative noninvasive imaging method that enables accurate assessment of morphological features, quantitative features, and associated coronary artery lesions in patients with CAF. It can be used to provide comprehensive information for determining surgical strategies.

Modulation of the relaxation dynamics of linear-shaped tetranuclear rare-earth clusters through utilizing different solvents.

Nine new tetranuclear centrosymmetric linear complexes, [RE4(dbm)8L2(DMF)2]·nCH2Cl2·mC2H3N (RE = Y (1), Tb (2), Dy (3), Ho (4), Er (5), Lu (6)) and [RE4(dbm)8L2(C2H5OH)2]·nCH3CN (RE = Tb (7), Dy (8), Ho (9)) (HL = 2-[(2-(hydroxyimino)propanehydrazide)methyl]-8-hydroxyquinoline and dbm = 1,3-diphenyl-1,3-propanedione) have been synthesized. Complexes 1-9 are tetranuclear complexes. Magnetic studies reveal that both DyIII-based complexes (3 and 8) exhibit single-molecule magnet (SMM) behavior under a zero dc field. Furthermore, complex 3 presents one relaxation process under a zero dc field, while application of an external dc field (1500 Oe) induces multi-relaxation signals of the ac magnetic susceptibility.

Single-Molecule-Magnet Behavior and Fluorescence Properties of 8-Hydroxyquinolinate Derivative-Based Rare-Earth Complexes.

Five tetranuclear rare-earth complexes, [RE4(dbm)4L6(µ3-OH)2] [HL = 5- (4-fluorobenzylidene)-8-hydroxylquinoline; dbm = 1,3-diphenyl-1,3-propanedione; RE = Y (1), Eu (2), Tb (3), Dy (4), Lu (5)], have been synthesized and completely characterized. The X-ray structural analyses show that each [RE4] complex is of typical butterfly or rhombus topology. Each RE(III) center exists in an eight-coordinated square-antiprism environment. Magnetic studies reveal that complex 4 displays single-molecule-magnet behavior below 10 K under a zero direct-current field, with an effective anisotropy barrier (ΔE/kB = 56 K). The fluorescence properties of complexes 1-5 were also investigated. Complexes 2-4 showed their characteristic peaks for the corresponding RE(III) center, while complexes 1 and 5 showed the same emission peaks with the ligand when they were excited at the same wavelength.

Structures and magnetic properties of several phenoxo-O bridged dinuclear lanthanide complexes: Dy derivatives displaying substituent dependent magnetic relaxation behavior.

Nine dinuclear Ln(iii) complexes, [Ln(dbm)2(L)]2 (Ln = Eu (), Tb (), Dy (), Ho (), Er ()) and [Ln(dbm)2(L')]2 (Ln = Tb (), Dy (), Ho (), Er ()) (dbm = 1,3-diphenyl-1,3-propanedione, HL = 2-[[(4-methoxy-phenyl)imino]methyl]-8-hydroxy-quinoline and HL' = 2-[[(4-ethoxyphenyl)imino]methyl]-8-hydroxyquinoline) have been synthesized, and structurally and magnetically characterized. The nine complexes are all phenoxo-O bridged binuclear complexes, in which Ln1 and Ln1a are in an eight-coordinated environment bridged by two phenoxido oxygen atoms of two 8-hydroxyquinoline Schiff base ligands. Although complexes and have very similar structures, magnetic studies reveal that they exhibit different magnetic relaxation behaviors with the effective barriers (ΔE/kB) of 34.5 K for and 67.6 K for . The dissimilar dynamic magnetic behaviors of and mostly result from the different electron-donating effect induced by the two alkoxy (-OCH3 and -OC2H5) of the 8-hydroxyquinoline Schiff base ligands. Meanwhile, for complexes , , and , there are no observed magnetic relaxation behaviors under a zero dc field. In addition, the luminescence properties of , and were studied.

Seven phenoxido-bridged complexes encapsulated by 8-hydroxyquinoline Schiff base derivatives and ß-diketone ligands: single-molecule magnet, magnetic refrigeration and luminescence properties.

Seven dinuclear complexes based on 8-hydroxyquinoline Schiff base derivatives and ß-diketone ligands, [RE2(hfac)4L2] (RE = Y (1), Gd (2), Tb (3), Dy (4), Ho (5), Er (6) and Lu (7); hfac(-) = hexafluoroacetylacetonate; HL = 2-[(4-chloro-phenylimino)-methyl]-8-hydroxyquinoline), have been synthesized, and structurally and magnetically characterized. Complexes 1-7 have similar dinuclear structures, in which each RE(III) ion is eight coordinated by two L(-) and two hfac(-) ligands in a distorted dodecahedron geometry. The luminescence spectra indicate that complex 3 exhibits characteristic Tb(III) ion luminescence, while 1 and 7 show HL ligand luminescence. The magnetic studies reveal that 2 features a magnetocaloric effect with the magnetic entropy change of -ΔSm = 16.83 J kg(-1) K(-1) at 2 K for ΔH = 8 T, and 4 displays slow magnetic relaxation behavior with the anisotropic barrier of 6.7 K and pre-exponential factor τ0 = 5.3 × 10(-6) s.

Multiple magnetic relaxation processes, magnetocaloric effect and fluorescence properties of rhombus-shaped tetranuclear rare earth complexes.

Seven new tetranuclear rare earth (RE) complexes [RE4(acac)4L6(µ3-OH)2] (HL = 5-(4-fluorobenzylidene)-8-hydroxylquinoline; acac = acetylacetonate; RE = Y (1), Eu (2), Gd (3), Tb (4), Dy (5), Tm (6) and Lu (7)) have been synthesized and completely characterized. Complex exhibits multiple zero-field slow magnetic relaxation processes typical of Single Molecule Magnets (SMMs). Two distinct slow magnetic relaxation processes, with effective energy barriers of Ueff = 48 K for the slow relaxation (SR) process and Ueff = 121 K for the fast relaxation (FR) process, are mainly attributed to the presence of two crystallographically independent Dy(III) sites. The magnetocaloric effect (MCE) was detected as -ΔSm(T) = 20.8 J kg(-1) K(-1) for complex . The fluorescence properties of complexes 1, 2, 4, 5 and 7 were also investigated. Complexes 2, 4 and 5 show the characteristic peaks for their corresponding RE(III) center, while complexes 1 and 7 show similar emission peaks to the Schiff base ligand when they are excited at the appropriate wavelength.

Ligand Field Affected Single-Molecule Magnet Behavior of Lanthanide(III) Dinuclear Complexes with an 8-Hydroxyquinoline Schiff Base Derivative as Bridging Ligand.

New dinuclear lanthanide(III) complexes based on an 8-hydroxyquinoline Schiff base derivative and ß-diketonate ligands, [Ln2(hfac)4(L)2] (Ln(III) = Gd (1), Tb (2), Dy (3), Ho (4), Er (5)), [Ln2(tfac)4(L)2] (Ln(III) = Gd (6), Tb (7), Dy (8), Ho (9)), and [Dy(bfac)4(L)2·C7H16] (10) (L = 2-[[(4-fluorophenyl)imino] methyl]-8-hydroxyquinoline, hfac = hexafluoroacetylacetonate, tfac = trifluoroacetylacetonate, and bfac = benzoyltrifluoroacetone), have been synthesized. The single-crystal X-ray diffraction data show that complexes 1-10 are phenoxo-O-bridged dinuclear complexes; each eight-coordinated center Ln(III) ion is in a slightly distorted dodecahedral geometry with two bidentate ß-diketonate coligands and two µ2-O bridging 8-hydroxyquinoline Schiff base derivative ligands. The magnetic study reveals that 1 and 6 display cryogenic magnetic refrigeration properties, whereas complexes 3, 8, and 10 show different SMM behaviors with energy barriers of 6.77 K for 3, 19.83 K for 8, and 25.65 K for 10. Meanwhile, slow magnetic relaxation was observed in 7, while no out-of-phase alternating-current signals were found for 2. The different dynamic magnetic behaviors of two Tb2 complexes and the three Dy2 complexes mainly derive from the tiny crystal structure changes around the Ln(III) ions. It is also proved that the ß-diketonate coligands can play an important role in modulating magnetic dynamics of the lanthanide 8-hydroxyquinoline Schiff base derivative system.