Seven Ln(III) coordination polymers with two kinds of geometric coordination but the same 3D topological property: luminescence sensing and magnetic property.

Two series of seven lanthanide metal coordination polymers (Ln-CPs) formulated as {[Ln(dttpa)1.5(H2O)2]·H2O}n [Ln = La3+ (1), Ce3+ (2), Nd3+ (3), Sm3+ (4) and Eu3+ (5)] and {[Ln (dttpa)1.5(H2O)]·xH2O}n [Ln = Tb3+ (6) and Er3+ (7), x = 0.75] have been successfully constructed using Ln3+ ions and 2,5-di(1H-1,2,4-triazol-1-yl)terephthalic acid (H2dttpa) via a hydrothermal method. Their 3D structures are fully characterised by Fourier transform infrared (FT-IR) spectroscopy, X-ray single-crystal analyses, powder diffraction analyses (PXRD), elemental analyses (EAs) and thermogravimetric analyses (TGAs). All Ln-CPs display the same topological property with the point symbol of {42·84}{44·62}2{49·66}2, and crystallize in the triclinic space group P1̄. Interestingly, Eu-CP (5) effectively sensitizes the visible emission of Tb3+ and shows high selectivity and stable response with the lowest detection limit of 9.88 nM. Furthermore, Tb-CP (6) acts as a good luminescence sensor to detect nitrobenzene (NB) with a detection limit of 12.5 nM. In addition, the magnetic susceptibility measurement for Er-CP (7) further shows that compounds constructed by dttpa2- are a kind of promising functional material.

Structure, magnetic properties and spin density of two alternative Mn(II) coordination polymers based on 1,4-bis(2'-carboxyphenoxy)benzene.

Two novel manganese coordination polymers [Mn2(µ2-bcpb)(µ4-bcpb)(2,2'-bipy)2]n (1) and [Mn2(µ3-bcpb)2(2,2'-bipy)2(H2O)]n (2) (H2bcpb = 1,4-bis(2'-carboxylato phenoxy)-benzene; 2,2'-bipy = 2,2'-bipyridine), have been synthesized successfully from the same reactants. This unusual selectivity was corroborated by X-ray powder diffraction. Single crystal X-ray diffraction analysis of complex 1 reveals that neighboring Mn(II) ions are linked via two bcpb2- anions to form a dinuclear Mn(II) subunit [Mn2(µ1,1-COO)2]2+ with a Mn⋯Mn distance of 3.3758 (6) Å. And π⋯π interactions between aromatic rings of the bcpb2- and 2,2'-bipy ligands stabilize the two-dimensional extended coordination network with the unprecedented Schläfli symbols {4·62}2{42·62·82}. In the [Mn2(µ1,3-COO)2]2+ subunit of 2, two linking bcpb2- ligands subtend an interaction distance of 4.4048(6) Å. Intermolecular O-H⋯O hydrogen bonds involving oxygen atoms of carboxylic acid and coordinated water molecules connect adjacent 1D chain molecules into a 2D network. Experimental temperature-dependent magnetic susceptibility measurements and spin density analyses by DFT disclose that compounds 1 and 2 display different magnetic properties.

Design and synthesis of three new copper coordination polymers: efficient degradation of an organic dye at alkaline pH.

Three new coordination polymers (CPs) based on Cu(II), namely {[Cu6(H2L)4(4,4'-bpy)6(H2O)2]·16H2O}n(1), {[Cu(H3L)(1,4-bib)]·3H2O}n(2), and {[Cu2(H2L)2(1,4-bib)2][Cu(1,4-bib)(H2O)2]}n·4nH2O(3) (H5L = 6-(3',4'-dicarboxyphenoxy)-2,3,5-benzene tricarboxylic acid, 4,4'-bpy = 4,4'-bipyridine and 1,4-bib = 1,4-bis(1H-imidazol-1-yl)benzene) were synthesized under hydrothermal conditions and characterized. 1 adopts a three-dimensional structure and can be described with the point symbol {4·52}2{42·54·64·83·92}{5·104·12} whereas 2 shows a layered structure. 3 can be perceived as a complex salt of two coordination polymers: the cationic component [Cu(1,4-bib)(H2O)2]n2+ (3a) represents a chain polymer and the second anionic moiety [Cu2(H2L)2(1,4-bib)2]n2- (3b) corresponds to a 2D sub-structure. In the presence of H2O2, all complexes 1-3 act as efficient photocatalysts for the degradation of the dye methylene blue (MB). The effects of properties such as initial MB concentration, catalyst dosage, pH value, and H2O2 concentration on MB degradation were also investigated and analyzed in detail. Compounds 1-3 exhibit excellent structural stability during the catalytic process and can be reused at least three times. The hydroxyl radical (OH˙) and holes (h+) were confirmed as the main active species in the degradation process.

Analysis of the Oxygen Passivation Effects on MAPbI3 and MAPbBr3 in Fresh and Aged Solar Cells by the Transient Photovoltage Technique.

Previous studies have revealed that for some perovskite compositions, power conversion efficiencies (PCEs) improved after storing the devices in different ambient conditions. With the aim of better understanding such improvements, we focus our attention on the carrier/ionic dynamic kinetics of fresh and aged PSCs with different perovskite compositions (MAPbI3 and MAPbBr3 ) and using spiro-OMeTAD as HTM. For that, we use transient photovoltage (TPV), a technique used to analyse the different recombination kinetics at equilibrium and at different illumination times. We observe that the aging treatment causes significant changes on the kinetics behaviour for bromide-based devices, resulting in a positive influence on the cell performance (from 3.5 % to 6.1 % PCE, in reverse scan). However, the kinetics for those iodide-based perovskite solar cells remains unchangeable (from 16.3 % to 15.0 % PCE, in reverse scan).

The dual inhibition against the activity and expression of tyrosine phosphatase PRL-3 from a rhodanine derivative.

Increasing evidences demonstrated that PRL-3 was associated with metastatic potential in a variety of cancers including CRC, gastric cancer, ovarian cancer and so on. PRL-3 knock down inhibited the development of metastasis by reducing the size of primary tumors and inhibiting the invasion and growth of cancer cells. Therefore, PRL-3 is a promising diagnostic marker and therapeutic target in tumors. So far, only several PRL-3 inhibitors have been reported. In this study, six rhodanine derivatives were synthesized and characterized. The compounds were evaluated against tyrosine phosphatase PRL-3. Among these compounds, 5-(5-chloro-2-(trifluoromethyl)benzylidene)-2-thioxothiazolidin-4-one (4) could effectively inhibit PRL-3 with IC50 value of 15.22 µM. Fluorescent assays suggested compound 4 tightly bound to tyrosine phosphatase PRL-3 with the molar ratio of 1:1, and the binding constant of 1.74 × 106 M-1. Compound 4 entered into SW-480 cells, selectively inhibited the expression of PRL-3 and increased the phosphorylation of PRL-3 substrates, and decreased the survival rate of SW-480 cells with IC50 of 6.64 µM and induced apoptosis. The results revealed that compound 4 is a dual functional inhibitor against the activity and expression of PRL-3 and a promising anti-cancer candidate targeting PRL-3.

Syntheses, crystal structures, and biological evaluations of new dinuclear platinum(ii) complexes with 1,2,4-triazole derivatives as bridging ligands.

A series of new dinuclear platinum(ii) complexes with the general formula [Pt2(µ-HL)4] (1-4), where H2L is 4-[(5-chloro-2-hydroxy-benzylidene)-amino]-3-R-1,2,4-triazole-5-thione: R = H (1), methyl (2), ethyl (3) and propyl (4), were synthesized and characterized. The X-ray crystal structures of 2, 3 and 4 reveal that the two platinum atoms form a paddlewheel core with four chelating triazole ligands as bridges, revealing a radically different structure than those of the traditional anticancer platinum(ii) complexes. These complexes show higher in vitro antiproliferative activity against human liver hepatocellular carcinoma (HepG2) and human breast adenocarcinoma (MCF7) than human lung cancer (A549) and human normal hepatocyte (HL-7702) cell lines. In particular, 3 exhibits antiproliferative activity (IC50 = 5.5 µM) against HepG2 cells comparable to that of cisplatin. Different from the traditional anticancer platinum(ii) complexes with high DNA affinity, 3 binds very weakly to DNA. Upon comparison, it exhibits potent inhibiting activity against protein tyrosine phosphatases 1B (PTP1B, IC50 = 16 µM) through possible binding to its active sites and its binding constant is 5.28 × 104 M-1. The results suggest that the antiproliferative mechanism of 3 against HepG2 cells may be different from that of cisplatin.

The first ternary Nd-MOF/GO/Fe3O4 nanocomposite exhibiting an excellent photocatalytic performance for dye degradation.

Herein, a ternary nanocomposite photocatalyst (MOF-1/GO/Fe3O4) based on a novel Nd-MOF, graphene oxide (GO), and Fe3O4 was successfully prepared. It was verified that the MOF nanoparticles and GO sheets were integrated by means of intimate interfacial contacts and a large number of Fe3O4 microspheres were uniformly loaded on the surface of GO. The ternary nanocomposite was a stable, environmentally friendly, and efficient visible-light photocatalyst, which displayed excellent photocatalytic performance in the degradation of methylene blue (MB) (∼95%) dye within 80 min under sunlight irradiation in the aqueous solution. Compared to MOF-1, the photocatalytic efficiency of the composite was improved by 90% and the excitation wavelength was moved from the ultraviolet to visible region. The enhancement of photocatalytic performance can be ascribed to the introduction of GO, which efficiently accelerated electron migration, minimized the recombination of photogenerated electron-hole pairs, and improved the optical absorption properties, leading to a synergistic facilitation of the photocatalysis process. The ternary composite demonstrated excellent stability and reusability and can be easily recovered by a magnetic field. The study would provide novel avenues for the preparation of highly efficient and environmentally stable photocatalysts for organic wastewater treatment.

First Ln-MOF as a trifunctional luminescent probe for the efficient sensing of aspartic acid, Fe3+ and DMSO.

Five 3D network Ln3+ metal-organic frameworks (Ln-MOFs) formulated as [[Ln(µ6-H2cpboda)(µ2-OH2)2]·xH2O]n [Ln3+ = La3+ (1), Nd3+ (2), Sm3+ (3), Eu3+ (4), Tb3+ (5), H2cpboda = 5,5'-((5-carboxy-1,3-phenylene)bis(oxy))diisophthalic acid] were synthesized via a hydrothermal method. They were established by single-crystal X-ray and powder diffraction analyses, elemental analysis (EA) and thermogravimetric analyses (TGAs). All the compounds are isostructural with three-dimensional structures with the point symbol of (413·62)(48·66·8) in terms of topology, and they crystallize in the monoclinic space group P21/n. Interestingly, the solid-state luminescence of complexes 4 and 5 shows intense red and green emission, respectively. Besides, the Tb-MOF (5) is a good luminescent sensor, able not only to detect aspartic acid and Fe(iii) ions with good stability, high efficiency and reversibility, but also to exhibit a rapid response and high selectivity to DMSO. To our knowledge, it is the first Ln-MOF that can act as a luminescent probe for the efficient sensing of DMSO, while the lone pair of electrons in the O of DMSO attacked the positive charge at the protonation carboxylic acid of H5cpboda. Consequently, Tb-MOF (5) is a rare and versatile fluorescent probe for aspartic acid, Fe3+ cations and DMSO, simultaneously.

Potent and selective PTP1B inhibition by a platinum(ii) complex: possible implications for a new antitumor strategy.

Showing anti-proliferation activity against MCF7 cells better than cisplatin, a platinum(ii) complex, [PtL(DMSO)Cl], was found to potently and selectively inhibit protein tyrosine phosphatase 1B (PTP1B), a putative target for anticancer agents, suggesting a new possible anticancer strategy based on platinum drugs.

A Ce(iii) complex potently inhibits the activity and expression of tyrosine phosphatase SHP-2.

Four new Ce(iii) complexes 1-4 with tridentate NNO-donor Schiff base ligands have been designed and successfully synthesized. These complexes were characterized by elemental analysis, IR, and ESI-MS, with formulas of [Ce(HL1)2(NO3)3]·2CH3OH (1), [Ce(L2)2(NO3)]·3H2O (2), [Ce(HL3)(L3)(NO3)Br]·H2O (3) and [Ce(L4)2(NO3)]·3H2O (4), in which ligands HL1-HL4 are respectively N'-[(1E)-pyridin-2-ylmethylidene]pyrazine-2-carbohydrazide (HL1), 2-(1-(salicyloylhydrazono)ethyl)pyrazine (HL2), N'-[(1E)-pyridin-2-ylmethylidene]pyridine-2-carbohydrazide (HL3) and 2-(1-(salicyloylhydrazono)ethyl) pyridine (HL4). X-ray single crystal diffraction analysis indicates that complex 1 crystallizes in the monoclinic system with the space group C2/c and the structure of complex 1 consists of a monomeric Ce(iii) species with a Ce(iii) moiety bonded to two tridentate Schiff base ligands, three nitrates and solvents. These complexes effectively inhibit the enzyme activities of PTPs (SHP-1, SHP-2, TCPTP and PTP1B), among which complex 3 shows the most potent inhibition of SHP-2 with the lowest IC50 value of 0.61 µM and displays obvious selectivity towards SHP-2. Its inhibition potency against SHP-2 was approximately 17, 4, and 5 fold higher than that against SHP-1, TCPTP and PTP1B, respectively. Further study discloses that complex 3 inhibits SHP-2 in a competitive manner. Fluorescence measurements indicate that complex 3 tightly binds to SHP-2 with a molar ratio of 1 : 1 and a binding constant of 5.45 × 105 M-1. Western blot experiments show that complex 3 promotes the phosphorylation of the SHP-2 substrate by the combination of the inhibition of the activity and expression of SHP-2. Moreover, complex 3 decreases the survival rate of A549 cells to 35.12% at 100 µM and induces apoptosis with an apoptosis rate of 12.06% at 50 µM. All these results suggest that complex 3 is a potential bi-functional inhibitor of the activity and expression of tyrosine phosphatase SHP-2.

Three new ZnII coordination polymers constructed from a semi-rigid tricarboxylic acid: structural changes caused by flexibility and luminescence sensing for hexavalent chromate anions.

Coordination polymers (CPs) with specific structures and functional luminescence have been widely designed as sensors for detecting small molecules and ions. In this study, with or without the help of an N-donor auxiliary linker, three new ZnII CPs, namely, three-dimensional (3D) poly[[pentaaquabis[µ3-5-(4-carboxybenzyloxy)isophthalato]bis[µ6-5-(4-carboxylatobenzyloxy)isophthalato]di-µ3-hydroxido-hexazinc(II)] trihydrate], {[Zn6(C16H10O7)2(C16H9O7)2(OH)2(H2O)5]·3H2O}n or {[Zn6(µ3-HL)2(µ6-L)2(µ3-OH)2(H2O)5]·3H2O}n, (I), one-dimensional (1D) catena-poly[[[aqua(1,10-phenanthroline)zinc(II)]-µ2-5-(4-carboxybenzyloxy)isophthalato] dihydrate], {[Zn(C16H10O7)(C12H8N2)(H2O)]·2H2O}n or {[Zn(µ2-HL)(phen)(H2O)]·2H2O}n (phen is 1,10-phenanthroline), (II), and 3D poly[diaquatetrakis(4,4'-bipyridine)bis[µ6-5-(4-carboxylatobenzyloxy)isophthalato]di-µ3-formato-di-µ3-hydroxido-pentazinc(II)], [Zn5(C16H9O7)2(HCOO)2(OH)2(C10H8N2)4(H2O)2]n or [Zn5(µ4-L)2(bpy)4(µ2-OH)2(µ3-HCOO)2(H2O)2]n (bpy is 4,4'-bipyridine), (III), have been constructed from the semi-rigid tricarboxylic acid 5-(4-carboxybenzyloxy)isophthalic acid (H3L) under hydrothermal conditions. CP (I) exhibits a twofold interpenetrated 3D+3D→3D skeleton with a 3,5-conn topology constructed from triangular trinuclear [Zn3(COO)4(µ3-OH)] clusters, in which the H3L ligand adopts three different coordination modes. CP (II) exhibits a 1D infinite chain and stacking that gives a 3D structure mediated by hydrogen bonds and weak interactions. CP (III) is an interesting 3D 3,4,8-conn network including linear tetranuclear [Zn4(µ2-OH)2(HCOO)2(COO)2] clusters with a new {4·62}2{4·64·8}{46·619·83} topological symbol. The influences of the flexible -CH2-O- linker of the H3L ligand and subtle environmental factors, such as solvent, pH value and auxiliary ligands, on the formation of the final structures are also discussed. The solid-state fluorescence spectra of CPs (I)-(III) were recorded at room temperature and all show better fluorescence performances than H3L. In particular, (II) can act as a potential multifunctional fluorescent material for sensing hexavalent chromium ions in aqueous solution with high stability, selectivity and sensitivity. Under ultraviolet light of 365 nm from a UV lamp, a signal response of fluorescence from turning on to off can be observed with the naked eye. It was found that the detection for hexavalent chromium (i.e. Cr2O72-) by (II) has a high selectivity [KSV = 1.61 × 104 M-1 and limit of detection (LOD) = 0.434 µM] in aqueous solution. Quenching mechanisms were also studied in detail.

Structural diversity, magnetic property, or luminescence sensing of Co(ii) and Cd(ii) coordination polymers derived from designed 3,3'-((5-carboxy-1,3-phenylene)bis(oxy))dibenzoic acid.

Five novel coordination polymers (CPs), formulated as {[Co3(µ4-cpboda)2(µ1,1-OH2)2(2,2-bipy)2]·1.5DMF·2H2O}n (1), {[Co3(µ3-cpboda)2(4,4'-bpy)3(H2O)2]·4H2O}n (2), {[Co(µ2-H2cpboda)2(1,4-bib)3(H2O)2]·H2O·DMF·1.5HCOOH}n (3), [Cd(µ3-Hcpboda)(1,4-bib)]n (4), and {[Cd3(µ4-cpboda)2(µ1,1-OH2)2(phen)2]·2DMF·1.5H2O}n (5) (H3cpboda = 3,3'-((5-carboxy-1,3-phenylene)bis(oxy))dibenzoic acid, 2,2-bipy = 2,2-bipyridine, 4,4'-bpy = 4,4'-bipyridine, 1,4-bib = 1,4-di(1H-imidazol-1-yl)benzene, phen = 1,10-phenanthroline) have been synthesized under solvothermal conditions and characterized by elemental analyses (EAs), single-crystal X-ray diffraction analyses, X-ray powder diffraction analyses (PXRD), FT-IR spectra, and thermogravimetric analyses (TGAs). The structural analyses reveal that these complexes have four 2D coordinate polymers and one 3D framework, in which metal ions are in octahedral coordination geometries in 1-3 and 5, but seven-coordinated disordered pentagonal bipyramids in 4. Complexes 1 and 5 represent linear trinuclear [M3(µ1,1-OH2)2(µ1,3-COO)4] SBUs in 1 (M = Co(ii)) and in 5 (M = Cd(ii)) based on a 3,4,6-connected net with a point symbol (32·4)2(32·83·9)2(34·42·82·94·103) net, complex 2 exhibiting a (3-c)2(4-c)(4-c)2 3D structure with the (52·6·82·9)2(52·62·92)(52·6)2 topology and complexes 3 and 4 having a novel 2D framework with the point symbol of (44·62). Magnetization analyses disclose the antiferromagnetic (AF) behaviors between Co(ii) ions in complexes 1 & 3 and S = 3/2 (Co2+) spin Heisenberg chains with alternating magnetic sequences (F/F/AF)n in 2. Fluorescence measurements indicate that 4 and 5 are promising luminescence sensors for the detection of CrO42- and Cr2O72- anions in aqueous solution.

Cadmium(II) three-dimensional coordination polymers constructed from 1,3,5-tris(4-carboxyphenoxy)benzene: synthesis, crystal structure, fluorescence and I2 sorption characterization.

Two three-dimensional (3D) CdII coordination polymers, namely poly[[di-µ-aqua-diaquabis{µ5-4,4',4''-[benzene-1,3,5-triyltris(oxy)]tribenzoato}tricadmium(II)] dihydrate], {[Cd3(C27H15O9)2(H2O)4]·2H2O}n, (I), and poly[[aqua{µ6-4,4',4''-[benzene-1,3,5-triyltris(oxy)]tribenzoato}(µ-formato)[µ-1,1'-(1,4-phenylene)bis(1H-imidazole)]dicadmium(II)] dihydrate], {[Cd2(C27H15O9)(C12H10N4)(HCOO)(H2O)]·2H2O}n, (II), have been hydrothermally synthesized from the reaction system containing Cd(NO3)2·4H2O and the flexible tripodal ligand 1,3,5-tris(4-carboxyphenoxy)benzene (H3tcpb) via tuning of the auxiliary ligand. Both complexes have been characterized by single-crystal X-ray diffraction analysis, elemental analysis, IR spectra, powder X-ray diffraction and thermogravimetric analysis. Complex (I) is a 3D framework constructed from trinuclear structural units and tcpb3- ligands in a µ5-coordination mode. The central CdII atom of the trinuclear unit is located on a crystallographic inversion centre and adopts an octahedral geometry. The metal atoms are bridged by four syn-syn carboxylate groups and two µ2-water molecules to form trinuclear [Cd3(COO)4(µ2-H2O)2] secondary building units (SBUs). These SBUs are incorporated into clusters by bridging carboxylate groups to produce pillars along the c axis. The one-dimensional inorganic pillars are connected by tcpb3- linkers in a µ5-coordination mode, thus forming a 3D network; its topology corresponds to the point symbol (42.62.82)(44.62)2(45.66.84)2. In contrast to (I), complex (II) is characterized by a 3D framework based on dinuclear cadmium SBUs, i.e. [Cd2(COO)3]. The two symmetry-independent CdII ions display different coordinated geometries, namely octahedral [CdN2O4] and monocapped octahedral [CdO7]. The dinuclear SBUs are incorporated into clusters by bridging formate groups to produce pillars along the c axis. These pillars are further bridged either by tcpb3- ligands into sheets or by 1,4-bis(imidazol-1-yl)benzene ligands into undulating layers, and finally these two-dimensional surfaces interweave, forming a 3D structure with the point symbol (4.62)(47.614). Compound (II) exhibits reversible I2 uptake of 56.8 mg g-1 with apparent changes in the visible colour and the UV-Vis and fluorescence spectra, and therefore may be regarded as a potential reagent for the capture and release of I2.

A two-dimensional cadmium(II) coordination polymer constructed from 4-carboxy-1-(4-carboxylatobenzyl)-2-propyl-1H-imidazole-5-carboxylate and 1-(4-carboxylatobenzyl)-2-propyl-1H-imidazole-4-carboxylate ligands.

Crystals of poly[[aqua[µ3-4-carboxy-1-(4-carboxylatobenzyl)-2-propyl-1H-imidazole-5-carboxylato-κ5O1O1':N3,O4:O5][µ4-1-(4-carboxylatobenzyl)-2-propyl-1H-imidazole-4-carboxylato-κ7N3,O4:O4,O4':O1,O1':O1]cadmium(II)] monohydrate], {[Cd2(C15H14N2O4)(C16H14N2O6)(H2O)]·H2O}n or {[Cd2(Hcpimda)(cpima)(H2O)]·H2O}n, (I), were obtained from 1-(4-carboxybenzyl)-2-propyl-1H-imidazole-4,5-dicarboxylic acid (H3cpimda) and cadmium(II) chloride under hydrothermal conditions. The structure indicates that in-situ decarboxylation of H3cpimda occurred during the synthesis process. The asymmetric unit consists of two Cd2+ centres, one 4-carboxy-1-(4-carboxylatobenzyl)-2-propyl-1H-imidazole-5-carboxylate (Hcpimda2-) anion, one 1-(4-carboxylatobenzyl)-2-propyl-1H-imidazole-4-carboxylate (cpima2-) anion, one coordinated water molecule and one lattice water molecule. One Cd2+ centre, i.e. Cd1, is hexacoordinated and displays a slightly distorted octahedral CdN2O4 geometry. The other Cd centre, i.e. Cd2, is coordinated by seven O atoms originating from one Hcpimda2- ligand and three cpima2- ligands. This Cd2+ centre can be described as having a distorted capped octahedral coordination geometry. Two carboxylate groups of the benzoate moieties of two cpima2- ligands bridge between Cd2 centres to generate [Cd2O2] units, which are further linked by two cpima2- ligands to produce one-dimensional (1D) infinite chains based around large 26-membered rings. Meanwhile, adjacent Cd1 centres are linked by Hcpimda2- ligands to generate 1D zigzag chains. The two types of chains are linked through a µ2-η2 bidentate bridging mode from an O atom of an imidazole carboxylate unit of cpima2- to give a two-dimensional (2D) coordination polymer. The simplified 2D net structure can be described as a 3,6-coordinated net which has a (43)2(46.66.83) topology. Furthermore, the FT-IR spectroscopic properties, photoluminescence properties, powder X-ray diffraction (PXRD) pattern and thermogravimetric behaviour of the polymer have been investigated.

Irreversible solvent-assisted structural transformation in 3D metal-organic frameworks: Structural modification and enhanced iodine-adsorption properties.

In this work, we demonstrate a solvent-assisted structural transformation between two 3D metal-organic frameworks (MOFs) ([Zn4(α-bptc)2(H2O)3]n (1) → {[Zn2(α-bptc)(H2O)4]·(pra)}n (2)) (α-H4bptc = 2,3,3',4'-biphenyl tetra-carboxylic acid and pra = pyridin-2-amine) at room temperature by immersing complex 1 in a mother solution. The structural transformation involves not only solvent exchange but also the cleavage and formation of coordination bonds, which is confirmed by infrared spectroscopy, single-crystal X-ray diffraction analysis, powder X-ray diffraction patterns, and thermogravimetric analysis. Structural analyses revealed that significant modifications occurred during the transformation including the changes in lattice parameters, unit cell volume, space group, coordination number, secondary building units, and topological type. In the case of drastic structural transitions, significant changes in properties were also observed. Complex 2 displayed the interesting uptake and release of iodine with the changes in visible color, UV and fluorescence spectra, and fully reversible I2 uptake of 8.5 mg g-1, which further suggested about its future application as iodine absorbing material.

Aspartate aminotransferase is potently inhibited by copper complexes: Exploring copper complex-binding proteome.

Recent researches indicated that a copper complex-binding proteome that potently interacted with copper complexes and then influenced cellular metabolism might exist in organism. In order to explore the copper complex-binding proteome, a copper chelating ion-immobilized affinity chromatography (Cu-IMAC) column and mass spectrometry were used to separate and identify putative Cu-binding proteins in primary rat hepatocytes. A total of 97 putative Cu-binding proteins were isolated and identified. Five higher abundance proteins, aspartate aminotransferase (AST), malate dehydrogenase (MDH), catalase (CAT), calreticulin (CRT) and albumin (Alb) were further purified using a SP-, and (or) Q-Sepharose Fast Flow column. The interaction between the purified proteins and selected 11 copper complexes and CuCl2 was investigated. The enzymes inhibition tests demonstrated that AST was potently inhibited by copper complexes while MDH and CAT were weakly inhibited. Schiff-based copper complexes 6 and 7 potently inhibited AST with the IC50 value of 3.6 and 7.2µM, respectively and exhibited better selectivity over MDH and CAT. Fluorescence titration results showed the two complexes tightly bound to AST with binding constant of 3.89×106 and 3.73×106M-1, respectively and a stoichiometry ratio of 1:1. Copper complex 6 was able to enter into HepG2 cells and further inhibit intracellular AST activity.

A dioxidovanadium (V) complex of NNO-donor Schiff base as a selective inhibitor of protein tyrosine phosphatase 1B: Synthesis, characterization, and biological activities.

A new dioxidovanadium (V) complex, VO2(HPPCH) (1) (H2PPCH = N'-picolinoylpyridin-1-ium-2-carbohydrazonate) has been synthesized and characterized by elemental analysis, IR, X-ray diffraction analysis and electrospray ionization mass spectra. Complex 1 crystallized in the monoclinic system with space group P21/c. It potently inhibited PTP1B with IC50 of 0.13 µM, about 7, 15 and 125-fold stronger against PTP1B than over TCPTP, SHP-1 and SHP-2, displaying obvious selectivity against PTP1B. Western blotting analysis indicated that complex 1 effectively increased the phosphorylation of PTP1B substrates, especially the phosphorylation of IR/IGF 1R and IRS-1. It exhibited lower cytotoxicity than positive control VOSO4. These results make complex 1 a promising candidate for novel anti-diabetic drug development.

Spectroscopic and molecular docking studies on the interaction of human serum albumin with copper(II) complexes.

Two osazone based ligands, butane-2,3-dione bis(2'-pyridylhydrazone) (BDBPH) and hexane-3,4-dione bis(2'-pyridylhydrazone) (HDBPH), were synthesized out of the 2:1M Schiff base condensation of 2-hydrazino pyridine respectively with 2,3-butanedione and 3,4-hexanedione. The X-ray crystal structures of both the ligands have been determined. The copper(II) complex of HDBPH has also been synthesized and structurally characterized. HDBPH and its copper(II) complex have thoroughly been characterized through various spectroscopic and analytical techniques. The X-ray crystal structure of the copper complex of HDBPH shows that it is a monomeric Cu(II) complex having 'N4O2' co-ordination chromophore. Interaction of human serum albumin (HSA) with these ligands and their monomeric copper(II) complexes have been studied by various spectroscopic means. The experimental findings show that the ligands as well as their copper complexes are good HSA binders. Molecular docking investigations have also been done to unravel the mode of binding of the species with HSA.

Synthesis, structure, DFT calculations, electrochemistry, fluorescence, DNA binding and molecular docking aspects of a novel oxime based ligand and its palladium(II) complex.

A novel oxime based ligand, phenyl-(pyridine-2-yl-hydrazono)-acetaldehyde oxime (LH), and its palladium(II) complex (1) have been synthesised and spectroscopically characterised. The ligand crystallizes in the monoclinic space group (P21/c). The X-ray crystal structure of the ligand shows that it forms a hydrogen bonded helical network. The ligand has been characterised by C, H and N microanalyses, (1)H and (13)C NMR, ESI-MS, FT-IR and UV-Vis spectral measurements. Geometry optimizations at the level of DFT show that the Pd(II) centre is nested in a square-planar 'N3Cl' coordination chromophore. The diamagnetic palladium complex has been characterised by C, H and N microanalyses, FAB-MS, FT-IR, UV-Vis spectra and molar electrical conductivity measurements. The observed electronic spectrum of 1 correlates with our theoretical findings as evaluated through TD-DFT. 1 displays quasi-reversible Pd(II)/Pd(III) and Pd(III)/Pd(IV) redox couples in its CV in acetonitrile. 1 is nine-fold more emissive with respect to the binding ligand. Biophysical studies have been carried out to show the DNA binding aspects of both the ligand and complex. The binding constants for the ligand and complex were found to be 3.93×10(4) and 1.38×10(3)M(-1) respectively. To have an insight into the mode of binding of LH and 1 with CT DNA a hydrodynamic study was also undertaken. The mode of binding has also been substantiated through molecular docking. A promising groove binding efficacy has been revealed for the ligand.

A new family of 1D, 2D and 3D frameworks aggregated from Ni5, Ni4 and Ni7 building units: synthesis, structure, and magnetism.

Three new Ni(ii)-clusters based on a Y-shaped ligand (biphenyl-3,4',5-tricarboxylate, H3BPT), [Ni5(HBPT)4(OH)2(H2O)12]n (), [Ni4(BPT)2(OH)2(H2O)6]n·4nH2O (), and [Ni7(BPT)2(1,4-bib)2(OH)6(HCO2)2]n·3nH2O () (1,4-bib = 1,4-bi(1H-imidazol-1-yl)benzene), have been synthesized under solvothermal conditions. They were studied by infrared spectroscopy (IR), single crystal X-ray diffraction, thermogravimetric analysis (TGA), and magnetochemistry. The complexes contain low nuclear Ni-clusters as building units (BUs). Structurally, in , the cluster BUs of [Ni5(µ3-OH)2](8+) can be viewed as two reverse triangles sharing a common vertex, which are connected by the partially deprotonated µ2-η(1):η(1)-HBPT(2-) forming 1D chains. The BUs of [Ni4(µ3-OH)2](6+) clusters in can be considered as two reverse triangles sharing a common edge and extended by deprotonated µ6-η(1):η(1):η(1):η(1):η(2)-BPT(3-) constructing a 2D framework. The 3D framework of complex consists of a [Ni7(µ3-OH)4(R-COO)7(HCO2)3] cluster BUs with fully deprotonated µ5-η(1):η(1):η(1):η(1):η(1):η(1)-BPT(3-) and 1,4-bib ligands. In addition, TGA reveals that the complexes are stable in the range of 293-548 K. Magnetostructural analyses indicate ferromagnetic coupling of J1 = 1.85(3) and J2 = 2.25(4) cm(-1) in and J = 5.76(6) cm(-1) in , whereas magnetic parameters J1 = -2.64(3), J2 = -23.22(19) and J3 = 12.02(5) cm(-1) indicate an alternating magnetic chain (AF/F) in .