Two Chiral YbIII Enantiomeric Pairs with Distinct Enantiomerically Pure N-Donor Ligands Presenting Significant Differences in Photoluminescence, Circularly Polarized Luminescence, and Second-Harmonic Generation.

Using enantiomerically pure bidentate and tridentate N-donor ligands (1LR/1LS and 2LR/2LS) to replace two coordinated H2O molecules of Yb(tta)3(H2O)2, respectively, two eight- and nine-coordinated YbIII enantiomeric pairs, namely, Yb(tta)31LR/Yb(tta)31LS (Yb-R-1/Yb-S-1) and [Yb(tta)32LR]·CH3CN/[Yb(tta)32LS]·CH3CN (Yb-R-2/Yb-S-2), were isolated, in which Htta = 2-thenoyltrifluoroacetone, 1LR/1LS = (-)/(+)-4,5-pinene-2,2'-bipyridine, and 2LR/2LS = (-)/(+)-2,6-bis(4',5'-pinene-2'-pyridyl)pyridine. Interestingly, they not only present distinct degrees of chirality but also show large differences in near-infrared (NIR) photoluminescence (PL), circularly polarized luminescence (CPL), and second-harmonic generation (SHG). Eight-coordinated Yb-R-1 with an asymmetric bidentate 1LR ligand has a high NIR-PL quantum yield (1.26%) and a long decay lifetime (20 µs) at room temperature, being more than two times those (0.48%, 8 µs) of nine-coordinated Yb-R-2 with a C2-symmetric tridentate 2LR ligand. In addition, Yb-R-1 displays an efficient CPL with a luminescence dissymmetry factor glum = 0.077, being 4 × Yb-R-2 (0.018). In particular, Yb-R-1 presents a strong SHG response (0.8 × KDP), which is 8 × Yb-R-2 (0.1 × KDP). More remarkably, the precursor Yb(tta)3(H2O)2 exhibits a strong third-harmonic generation (THG) response (41 × α-SiO2), while the introduction of chiral N-donors results in the switching of THG to SHG. Our interesting findings provide new insights into both the functional regulation and switching in multifunctional lanthanide molecular materials.

Effects of Counterions, Coordination Anions, and Coordination Solvent Molecules on Single-Molecule Magnetic Behaviors and Nonlinear Optical Properties of Chiral Zn2Dy Schiff Base Complexes.

By changing the counterions (ClO4- and CF3SO3-) and the coordination anions (Cl- and Br-), we investigated their influences on the structures and performances of a class of Zn2Dy chiral single-molecule magnets (SMMs), which are based on a pair of chiral Schiff bases R,R-H2LSchiff and S,S-H2LSchiff {R,R-H2LSchiff = 2-((E)-((1R,2R)-2-((E)-2-hydroxy-3-methoxybenzylideneamino)cyclohexylimino)methyl)-6-methoxyphenol and S,S-H2LSchiff = 2-((E)-((1S,2S)-2-((E)-2-hydroxy-3-methoxybenzylideneamino)cyclohexylimino)methyl)-6-methoxyphenol}. Three pairs of chiral Zn2Dy Schiff base complexes were obtained by directed synthesis, which are [DyZn2(R,R-LSchiff)Cl2(H2O)](ClO4)·0.5MeOH·0.25H2O (R-1) and [DyZn2(S,S-LSchiff)Cl2(H2O)][DyZn2(S,S-LSchiff)Cl2(MeOH)](ClO4)2·MeOH·0.5H2O (S-1), [DyZn2(R,R-LSchiff)Cl2(H2O)](CF3SO3)·0.5MeOH (R-2) and [DyZn2(S,S-LSchiff)Cl2(H2O)][DyZn2(S,S-LSchiff)Cl2(MeOH)](CF3SO3)2·MeOH (S-2), and [DyZn2(R,R-LSchiff)Br2(H2O)](CF3SO3)·0.25MeOH (R-3) and [DyZn2(S,S-LSchiff)Br2(H2O)][DyZn2(S,S-LSchiff)Br2(MeOH)](CF3SO3)2 (S-3). They all exhibit good SMM behaviors, and their magnet relaxation is regulated by not only the counterions (ClO4- and CF3SO3-) but also the coordination anions (Cl- and Br-); these anions also have important effects on the second-harmonic generation (SHG) and third harmonic generation (THG) nonlinear optical properties. Interestingly, in the S-configuration complexes, the coordination solvent molecule of the Dy3+ ion on half of the molecules is the methanol molecule instead of the water molecule. This change in the coordinating solvent molecule can also significantly affect the SMM behaviors and the SHG and THG nonlinear optical properties. Moreover, ab initio calculations were applied to rationally explain the SMM properties.

Modulating Two Pairs of Chiral DyIII Enantiomers by Distinct ß-Diketone Ligands to Show Giant Differences in Single-Ion Magnet Performance and Nonlinear Optical Response.

Using Dy(dbm)3(H2O) and Dy(btfa)3(H2O)2 to react with enantiopure N-donors, (-)/(+)-4,5-pinenepyridyl-2-pyrazine (LR/LS), respectively, two pairs of chiral DyIII enantiomers, Dy(dbm)3LR/Dy(dbm)3LS (R-1-Dy/S-1-Dy) and Dy(btfa)3LR/Dy(btfa)3LS (R-2-Dy/S-2-Dy) were obtained, wherein one of the benzene rings of dbm- (dibenzoylmethanate) in R-1-Dy/S-1-Dy is displaced by the -CF3 group of btfa- (4,4,4-trifluoro-1-phenyl-1,3-butanedionate) in R-2-Dy/S-2-Dy. Interestingly, this substitution results not only in giant differences in their single-ion magnetic (SIM) performances but also in their completely different nonlinear optical (NLO) responses. R-1-Dy presents a large effective energy barrier (Ueff = 265.47 K) under zero applied field, being more than 4 × R-2-Dy (61.40 K). The discrepancy on their magnetic performances has been further elucidated by ab initio calculations. Meanwhile, R-1-Dy/S-1-Dy display the strongest third-harmonic generation responses (35/33 × α-SiO2) among the known lanthanide NLO-active coordination compounds (CCs). On the contrary, R-2-Dy/S-2-Dy exhibit moderate second-harmonic generation responses (0.65/0.70 × KDP). These results not only give the first example of the CCs with both SMM/SIM behavior and a THG response but also provide an efficient strategy for achieving the function regulation and switch in multifunctional CCs.

Multifunctional DyIII Enantiomeric Pairs Showing Enhanced Photoluminescences and Third-Harmonic Generation Responses through the Coordination Role of Homochiral Tridentate N,N,N-Pincer Ligands.

By utilizing Dy(hfac)3(H2O)2 to react with enantiomerically pure tridentate N,N,N-pincer ligands, namely (-)/(+)-2,6-bis(4',5'-pinene-2'-pyridyl)pyridine (LR and LS), respectively, homochiral DyIII enantiomeric pairs formulated as Dy(hfac)3LR/Dy(hfac)3LS (R-1/S-1) (hfac- = hexafluoroacetylacetonate) were achieved and structurally characterized. Meanwhile, their magnetic, photoluminescent (PL), and chiroptical properties were probed. The PL test results indicate that the precursor Dy(hfac)3(H2O)2 only shows very weak emission, while R-1 exhibits characteristic DyIII f-f transition emission bands at room temperature. Furthermore, the nonlinear optical responses of Dy(hfac)3(H2O)2, LR/LS, and R-1/S-1 were investigated in detail based on crystalline samples. The results reveal that LR and LS present the coexistence of second- and third-harmonic generation (SHG and THG) responses with more intense signals for SHG responses; and Dy(hfac)3(H2O)2 merely displays weak THG responses, while R-1 and S-1 also only exhibit THG responses. However, the THG intensities of R-1 and S-1 are more than six times larger than that of Dy(hfac)3(H2O)2 under the identical measurement conditions. These results demonstrate that introducing homochiral N,N,N-pincer ligands to replace two H2O molecules of Dy(hfac)3(H2O)2 results in significant improvements of both PL performances and THG responses of resultant R-1/S-1 enantiomers. R-1 and S-1 integrate PL, THG, and chiral optical activity in one molecule, suggesting their multifunctional merits. In particular, a convenient method is introduced to simultaneously test THG and SHG responses of molecular materials based on crystalline samples in this work.

Safety and complications of medical thoracoscopy in the management of pleural diseases.

BACKGROUND: Medical thoracoscopy is considered an overall safe procedure, whereas numbers of studies focus on complications of diagnostic thoracoscopy and talc poudrage pleurodesis. We conduct this study to evaluate the safety of medical thoracoscopy in the management of pleural diseases and to compare complications in different therapeutic thoracoscopic procedures. METHODS: A retrospective study was performed in 1926 patients, 662 of whom underwent medical thoracoscopy for diagnosis and 1264 of whom for therapeutic interventions of pleural diseases. Data on complications were obtained from the patients, notes on computer system, laboratory and radiographic findings. Chi-square test was performed to compare categorical variables and Fisher's exact test was used for small samples. RESULTS: The mean age was 51 ± 8.4 (range 21-86) years and 1117 (58%) were males. Diagnostic procedure was taken in 662 (34.4%) patients, whereas therapeutic procedure was taken in 1264 (65.6%) patients. Malignant histology was reported in 860 (44.6%) and 986 (51.2%) revealed benign pleural diseases. Eighty patients (4.2%) were not definitely diagnosed and they were considered as unidentified pleural effusion. One patient died during the creation of artificial pneumothorax, and the causes of death were supposed as air embolism or an inhibition of phrenic motoneurons and circulatory system. Complication of lung laceration was found in six patients (0.3%) and reexpansion pulmonary edema was observed in two patients (0.1%). Higher incidence of prolonged air leak was observed in bulla electrocoagulation group, in comparison with pleurodesis group. Moreover, pain and fever were the most frequently complications in pleurodesis group and cutaneous infection in entry site was the most frequently reported complication in pleural decortication of empyema group. CONCLUSIONS: Medical thoracoscopy is generally a safe and effective method, not only in the diagnosis of undiagnosed pleural effusions, but also in the management of pleural diseases. Mastering medical thoracoscopy well, improving patient management after the procedure and attempts to reduce the occurrence of post-procedural complications are the targets that physicians are supposed to achieve in the future.

Endostatin, an angiogenesis inhibitor, ameliorates bleomycin-induced pulmonary fibrosis in rats.

BACKGROUND: Recent evidence has demonstrated the role of angiogenesis in the pathogenesis of pulmonary fibrosis. Endostatin, a proteolytic fragment of collagen XVIII, is a potent inhibitor of angiogenesis. The aim of our study was to assess whether endostatin has beneficial effects on bleomycin (BLM)-induced pulmonary fibrosis in rats. METHODS: The rats were randomly divided into five experimental groups: (A) saline only, (B) BLM only, (C) BLM plus early endostatin treatment, (D) BLM plus late endostatin treatment, and (F) BLM plus whole-course endostatin treatment. We investigated the microvascular density (MVD), inflammatory response and alveolar epithelial cell apoptosis in rat lungs in each group at different phases of disease development. RESULTS: Early endostatin administration attenuated fibrotic changes in BLM-induced pulmonary fibrosis in rats. Endostatin treatment decreased MVD by inhibiting the expression of VEGF/VEGFR-2 (Flk-1) and the activation of extracellular signal-regulated protein kinase 1/2 (ERK1/2). Endostatin treatment also decreased the number of inflammatory cells infiltrating the bronchoalveolar lavage fluid during the early inflammatory phase of BLM-induced pulmonary fibrosis. In addition, the levels of tumour necrosis factor-α (TNF-α) and transforming growth factor ß1 (TGF-ß1) were reduced by endostatin treatment. Furthermore, endostatin decreased alveolar type II cell apoptosis and had an epithelium-protective effect. These might be the mechanism underlying the preventive effect of endostatin on pulmonary fibrosis. CONCLUSIONS: Our findings suggest that endostatin treatment inhibits the increased MVD, inflammation and alveolar epithelial cell apoptosis, consequently ameliorating BLM-induced pulmonary fibrosis in rats.

Two pairs of chiral YbIII enantiomers presenting distinct NIR luminescence and circularly polarized luminescence performances with giant differences in second-harmonic generation responses.

By introducing enantiomerically pure mono-bidentate N-donor ligands (LR/LS) into Yb(btfa)3(H2O)2 and Yb(dbm)3(H2O), respectively, two pairs of chiral YbIII enantiomers, namely Yb(btfa)3LR/Yb(btfa)3LS (D-1/L-1) and [Yb(dbm)3LR]·[Yb(dbm)3(C2H5OH)]/[Yb(dbm)3LS]·[Yb(dbm)3(C2H5OH)] (D-2/L-2) were isolated, where btfa- = 3-benzoyl-1,1,1-trifluoroacetonate, dbm- = dibenzoylmethanate, and LR/LS = (-)/(+)-4,5-pinenepyridyl-2-pyrazine. D-1/L-1 possess mononuclear structures in which the YbIII ions are eight-coordinated, while D-2/L-2 show cocrystal structures containing Yb(dbm)3(LR/LS) and Yb(dbm)3(C2H5OH) moieties in which the two YbIII ions are eight and seven-coordinated, respectively. They not only feature different molecular structures but also present distinct linear and nonlinear optical performances. Chiral mononuclear D-1 has better near infrared photo-luminescence (NIR-PL) and circularly polarized luminescence (CPL) performances than chiral cocrystal D-2. More remarkably, D-1/L-1 show large second-harmonic generation (SHG) responses (up to 1.25/1.28 × KDP) 18/16 times those of D-2/L-2 (0.07/0.08 × KDP). In addition, D-2/L-2 represent the first examples of lanthanide cocrystal complexes with NIR-PL, NIR-CPL and SHG properties.

A pair of ionic 1D Cu(II) chain enantiomers simultaneously displaying large second- and third-harmonic generation responses.

By employing enantiomerically pure mono-bidentate N-donors (LR/LS) as chiral bridging ligands to react with Cu(ClO4)2(H2O)6 in CH3CN-DMF mixed solvent, respectively, a pair of ionic one-dimensional (1D) Cu(II) chain enantiomers formulated as {[CuLR(CH3CN)(DMF)H2O](ClO4)2}n/{[CuLS(CH3CN)(DMF)H2O](ClO4)2}n (D-1/L-1) were isolated and structurally characterized, where LR/LS = (-)/(+)-4,5-pinenepyridyl-2-pyrazine. They crystallize in the noncentrosymmetric (NCS) P212121 space group of an orthorhombic system due to the introduction of chiral LR/LS, and the ClO4- groups as counteranions reside in crystal lattices, thus leading to charge separation with large dipole moments in their molecular structures. Based on crystal samples, investigation on their nonlinear optical (NLO) behaviors showed that D-1 and L-1 display simultaneously much larger second- and third-harmonic generation (SHG and THG) responses than their analogues based on the same chiral N-donors (LR/LS) and Cu(NO3)2(H2O)3 with NO3- acting as the coordination group to bind Cu(II) ions. The SHG intensities of D-1/L-1 are 0.62/0.60 × KDP (KH2PO4), and THG intensities of D-1/L-1 are 238/228 × α-SiO2. Our finding indicates that coordination polymers (CPs) with charge separation and NCS structures, i.e., ionic CPs with NCS arrangements are the ideal NLO crystalline materials for the simultaneous observation of large SHG and THG responses, thus providing a new approach to obtain NLO-active CP crystalline materials with high-performance SHG and THG responses.

Two temperature-induced 1D CuII chain enantiomeric pairs showing different magnetic properties and nonlinear optical responses.

At different reaction temperatures, using Cu(NO3)2·3H2O to react with enantiomerically pure N-donor ligands (LS/LR), respectively, two pairs of chiral one-dimensional (1D) CuII chain enantiomers formulated as [Cu(µ2-NO3)(NO3)(LS)]n/[Cu(µ2-NO3)(NO3)(LR)]n (S-1-Cu/R-1-Cu, formed at 40 °C with an NO3- group as a sole bridging ligand) and [Cu(µ2-LS)(NO3)2]n/[Cu(µ2-LR)(NO3)2]n (S-2-Cu/R-2-Cu, formed at 25 °C with LS or LR as a bridging ligand) were prepared, where LS/LR = (+)/(-)-4,5-pinenepyridyl-2-pyrazine. Interestingly, such a disparity in bridging ligands leads not only to their distinct structural features but also to their completely different magnetic couplings together with a large difference in their nonlinear optical responses. S-1-Cu with a 1D helical structure shows weak ferromagnetic coupling between CuII ions, while S-2-Cu with a 1D stairway-like structure presents weak antiferromagnetic coupling. In particular, they simultaneously possess both second- and third-harmonic generation (SHG and THG) responses in one molecule with large strength differences. More remarkably, S-1-Cu exhibits a very large THG response (162 × α-SiO2), which is 22.5 times that of S-2-Cu, and the SHG strength of S-1-Cu is more than 3 times that of S-2-Cu. This work demonstrates that reaction temperature has a great impact on the self-assembled structures of coordination polymers and subsequently results in their large performance differences.

Modulation of homochiral Dy(III) complexes: single-molecule magnets with ferroelectric properties.

Homochiral Dy(III) complexes: by changing the ligand-to-metal ratio, enantiomeric pairs of a Dy(III) complex of different nuclearity could be obtained. The mono- and dinuclear complexes exhibit characteristics of single-molecule magnets and different slow magnetic relaxation processes. In addition, the dinuclear complexes exhibit ferroelectric behavior, thus representing the first chiral polynuclear lanthanide-based single-molecule magnets with ferroelectric properties.

Two homochiral EuIII and SmIII enantiomeric pairs showing circularly polarized luminescence, photoluminescence and triboluminescence.

Two homochiral EuIII and SmIII tris(ß-diketonate) enantiomeric pairs, based on fluorinated ß-diketone (Hbtfa) and enantiopure asymmetric N,N'-donor ligands (LR and LS), Λ-Eu(btfa)3LR (R-1-Eu)/Δ-Eu(btfa)3LS (S-1-Eu) and Λ-Sm(btfa)3LR (R-2-Sm)/Δ-Sm(btfa)3LS (S-2-Sm) (btfa- = 4,4,4-trifluoro-1-phenyl-1,3-butanedionate and LR/LS = (-)/(+)-4,5-pineno-2,2'-bipyridine) were synthesized. The electronic circular dichroism (ECD) spectra confirmed their enantiomeric nature. R-1-Eu/S-1-Eu and R-2-Sm/S-2-Sm exhibit intense characteristic emissions of EuIII (red) and SmIII (orange-red) ions both in the solid state and in DCM with long lifetimes and high luminescence quantum yields. For example, the overall quantum yields reach up to 61% and 53% along with very high sensitization efficiency values of 82 and 79 for R-1-Eu in the solid state and in DCM, respectively. Notably, the corresponding values are determined to be 6.5% (solid state) and 3.1% (DCM) for R-2-Sm, which are among the highest quantum yields for rare SmIII tris(ß-diketonate) luminescent complexes reported to date. Furthermore, R-1-Eu and R-2-Sm show a strong triboluminescence (TL) phenomenon visible with the naked eye in daylight. Moreover, R-1-Eu/S-1-Eu and R-2-Sm/S-2-Sm show circularly polarized luminescence (CPL) properties. Particularly, the luminescence dissymmetry factors (glum) for R-2-Sm/S-2-Sm are larger than those for R-1-Eu/S-1-Eu despite the fact that SmIII complexes usually show poorer emission than EuIII homologues, which is very rare in the reported EuIII and SmIII CPL-active complexes.

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.

A pair of 2D chiral Ag(i) enantiomers with dual chiral elements: syntheses, structures, and photoluminescent and chiroptical properties.

In this work, two new enantiopure bis-monodentate N-donor chiral ligands, namely (-)/(+)-2-(4'-pyridyl)-4,5-pinene-pyridine (L R /L S ), have been designed and synthesized. Using L R and L S as bridging ligands to react with AgClO4, a pair of novel 2D chiral Ag(i) enantiomers formulated as [Ag2(L R )2(ClO4)2] n (R-1) and [Ag2(L S )2(ClO4)2] n (S-1) were isolated and characterized. In R-1 and S-1, each Ag(i) ion is bonded by two N atoms from two different chiral L R or L S ligands, leading to the formation of 1D right- or left-handed -L-Ag(i)-L- helical chains. Moreover, two adjacent helical chains are further doubly linked by two monodentate ClO4 - anions through weak Ag-O contacts to form 2D network structures, in which dual chiral elements, i.e., center chirality and helical chirality coexist. Interestingly, each free ligand L R /L S and R-1/S-1 enantiomers show very different ECD spectra in the solid state and in solution, which are correlated to the intermolecular interactions and molecular structures in each state, respectively. Notably, as a representative, R-1 exhibits intense room temperature photoluminescence both in the solid state and in solution with different emission features and mechanisms, while it also shows more intense emission than that of free ligand L R . In particular, R-1 and S-1 represent the first examples of 2D Ag(i) chiral coordination polymers (CCPs) supported by ClO4 - anions, possessing dual chiral elements.

Tris(dibenzoyl-methanido-κO,O')[(6S,8S)-(+)-7,7-dimethyl-3-(2-pyrid-yl)-5,6,7,8-tetra-hydro-6,8-methano-isoquinoline-κN,N']gadolinium(III).

In the title compound, [Gd(C(15)H(11)O(2))(3)(C(17)H(18)N(2))], the Gd(III) atom is coordinated by six O atoms from three ß-diketonate ligands and two N atoms from a chiral ligand L(S),(S)-(+)-7,7-dimethyl-3-(2-pyrid-yl)-5,6,7,8-tetra-hydro-6,8-methano-iso-quinoline, in a coordination geometry best described as distorted square-anti-prismatic.

Evans-Showell-type polyoxometalate-based metal-organic complexes with novel 3D structures constructed from flexible bis-pyrazine-bis-amide ligands and copper metals: syntheses, structures, and fluorescence and catalytic properties.

Two new Evans-Showell-type polyoxometalate (POM)-based metal-organic complexes, namely {Cu3(L1)1.5(H2O)5[Co2Mo10H4O38]}·5H2O (1), {[Cu(L2)0.5(H2O)2]2[Co2Mo10H4O38]}·6H2O (2) (L1 = N,N'-bis(2-pyrazinecarboxamide)-1,4-butane, L2 = N,N'-bis(2-pyrazinecarboxamide)-1,6-hexane), were successfully synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). In complex 1, the adjacent [Co2Mo10H4O38]6- polyoxoanions are linked by CuII ions to form a 1D Cu-[Co2Mo10H4O38]6- inorganic chain, which is further linked by ligand L1 and [Co2Mo10H4O38]6- polyoxoanions, forming a 3D metal-organic framework. In complex 2, the adjacent [Co2Mo10H4O38]6- polyoxoanions link the CuII ions to generate a 2D Cu-[Co2Mo10H4O38]6- inorganic layer, which is further connected with bidentate ligands L2 to obtain a 3D metal-organic framework. The structural diversities of compounds 1 and 2 showed that the spacer lengths of the flexible bis-pyrazine-bis-amide ligands play important roles in tuning the structures of the title complexes. Compounds 1 and 2 represent the first examples of 3D frameworks based on the Evans-Showell-type polyoxoanions and Cu-bis-pyrazine-bis-amide coordination complexes. Moreover, the ligand L1 was first successfully introduced into the POM system. The electrochemical and fluorescence properties of compounds 1 and 2 were discussed. As heterogeneous catalysts, compounds 1 and 2 have good catalytic activity for the oxidation of benzyl alcohol. Moreover, compound 2 has higher catalytic performance with 100% conversion and 98.0% selectivity for benzoic acid at 10 h. The difference in their catalytic performance may be mainly due to the difference of their structures. The catalysts can be recovered and reused without displaying any significant loss of activity.

Syntheses, structures and catalytic properties of Evans-Showell-type polyoxometalate-based 3D metal-organic complexes constructed from the semi-rigid bis(pyridylformyl)piperazine ligand and transition metals.

Herein, two novel Evans-Showell-type polyoxometalate (POM)-based metal-organic complexes, namely, {[Cu(L)(H2O)3][Cu(L)0.5(H2O)][Cu(L)0.5(H2O)4][Co2Mo10H4O38]}·5H2O (1) and [(H2L)0.5]2{[Zn(L)0.5(H2O)4]2[Co2Mo10H4O38]}·2H2O (2) (L = N,N'-bis(3-pyridinecarboxamide)-piperazine), were hydrothermally synthesized using a semi-rigid bis-pyridyl-bis-amide ligand and structurally characterized via single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). The single-crystal X-ray diffraction analysis shows that complex 1 is a 3D Evans-Showell-type POM-based metal-organic network. In complex 1, the 1D infinite double chain structure constructed from {{Cu[Co2Mo10H4O38]}4-L} units and the µ4-bridging L ligand are linked by quadrate Cu2L2 loops to form a 2D layer, which is further connected by µ2-bridging L ligands, forming a 3D (2,3,4)-connected metal-organic framework. Complex 2 displays 3D supramolecular networks based on 1D {[Co2Mo10H4O38]-Zn-L}n infinite chains, which are constructed from Evans-Showell-type polyoxoanions and µ2-bridging 3-bpfp ligands (via ligation of pyridyl nitrogen atoms). The different coordination modes of the POM polyanions, bis(pyridylformyl)piperazine ligands and ratios play key roles in the construction of the title complexes. Significantly, the ligand L shows a µ4-bridging coordination mode in complex 1, which is observed for the first time in a POM system. Compounds 1 and 2 represent the first examples of metal-organic complexes based on Evans-Showell-type polyoxoanion and transition metal-bis-pyrazine-bis-amide coordination complexes. The fluorescence properties of the title complexes are reported herein. In addition, the title complexes act as heterogeneous Lewis acid catalysts for the oxidation of benzyl alcohol, and can also be recovered and reused without any significant loss in activity. Significantly, compound 1 with a 3D metal-organic framework showed higher catalytic performance with 99.4% conversion and 98.8% selectivity for benzoic acid at 10 h than compound 2 with 3D supramolecular networks.

Enhanced single-ion magnetic and ferroelectric properties of mononuclear Dy(iii) enantiomeric pairs through the coordination role of chiral ligands.

The structures and properties of two mononuclear Dy(iii) enantiomeric pairs were dramatically controlled by crystallization temperature; the enantiomeric pair with coordinated chiral N,N'-donor ligands exhibits enhanced single-ion magnetic, ferroelectric and chiroptical properties with respect to the other one with protonated chiral N,N'-donor ligands.

A pair of dinuclear Re(I) enantiomers: synthesis, crystal structures, chiroptical and ferroelectric properties.

The reaction of enantiomeric bis-bidentate bridging ligands (+)/(-)-2,5-bis(4,5-pinene-2-pyridyl)pyrazine (L(S)/L(R)) with [Re(CO)5Cl] yielded a pair of dinuclear Re(I) enantiomers formulated as [Re2(L(S)/L(R))(CO)6Cl2]·4CH2Cl2 (R-1 and S-1, the isomers containing the respective L(R) and L(S) ligands). They were characterized by elemental analyses, IR spectra and X-ray crystallography. Circular dichroism spectra verified their chiroptical activities and enantiomeric nature. The measurements of second harmonic generation (SHG) and ferroelectric properties showed that R-1 displays a nonlinear optical (NLO) activity and ferroelectricity with a remnant polarization (P(r)) of 1.6 µC cm(-2) under an applied field of 7.3 kV cm(-1) at room temperature. R-1 and S-1 represent the first example of polynuclear Re(i) complexes with ferroelectric properties. Notably, the P(r) value is much larger than that of the reported mononuclear chiral Re(I) analogue. In particular, unlike mononuclear Re(i) complexes of the type [Re(CO)3(N^N)(X)] (N^N = diimine and X = halide), which usually exhibit an intense emission in the visible range, R-1 and S-1 do not show any detectable emission at any temperature range and the reason for the nonluminescence of R-1 and S-1 was further elucidated in this work. Moreover, our research results also elucidated that Re nuclearity has a great influence on not only the emitting properties but also on ferroelectric behavior.

Anion-controlled self-assembly of two NLO-active dinuclear and molecular square Cu(II) enantiomeric pairs: from antiferromagnetic to ferromagnetic coupling.

Two second-order nonlinear optically (NLO)-active dinuclear and square Cu(II) enantiomeric pairs were obtained via the self-assemblies of enantiopure linear bis-bidentate ligands with different copper(II) salts under the identical reaction conditions. Their magnetic properties are switched from antiferromagnetic to ferromagnetic coupling.

Simultaneous blockage of epidermal growth factor receptor and cyclooxygenase-2 in a human xenotransplanted lung cancer model.

The effects of erlotinib combined with celecoxib in a lung cancer xenograft model were here explored with a focus on possible mechanisms. A xenotransplanted lung cancer model was established in nude mice using the human lung cancer cell A549 cell line and animals demonstrating tumour growth were randomly divided into four groups: control, erlotinib, celecoxib and combined (erotinib and celecoxib). The tumor major axis and short diameter were measured twice a week and after 40 days tissues were collected for immunohistochemical analyses of Bcl-2 and Bax positive cells and Western-blotting analyses for the epidermal growth factor recepto (EGFR), P-EGFR, and cyclooxygenase-2 (COX-2). Tumor size in the combined group was smaller than in the others (p<0.01) and the percentage of Bcl-2 positive cells was fewer in most cases (p<0.01), while that of Bax positive cells was greater than in the erlotinib and celecoxib groups (P>0.05). Western blotting showed decreased expression of P-EGFR and COX-2 with both erlotinib and celecoxib treatments, but most pronouncedly in the combined group (P<0.05). Simultaneous blockage of the EGFR and COX-2 signal pathways exerted stronger growth effects in our human xenotransplanted lung cancer model than inhibition of either pathway alone. The anti-tumor effects were accompanied by synergetic inhibition of tumor cell apoptosis, activation of p-EGFR and expression of COX-2.