New Ln-MOFs based on mixed organic ligands: synthesis, structure and efficient luminescence sensing of the Hg2+ ions in aqueous solutions.

In view of Hg2+ ion sensing by luminescence, a series of new, phenanthroline-decorated 3D lanthanide metal organic frameworks (Ln-MOFs) valorising an original combination of four different lanthanides and two organic ligands, i.e. thiobis(4-methylene-benzoic acid) (H2tmba) and 1,10-phenanthroline (phen), have been successfully synthesized, namely {[Ln4(tmba)6(phen)4]·m(H2O)(phen)}n [Ln = Ce, m = 3 (1); Pr, m = 1 (2); Eu, m = 3 (3); and Tb, m = 3 (4)]. Compounds 1-4 were characterised by single-crystal X-ray diffraction, elemental and thermogravimetric analyses, and powder X-ray diffraction. The luminescence properties of complexes 3 and 4 were thoroughly investigated. It is herein proved that compound 3 sensitively and selectively acts as an excellent luminescent probe for the detection of Hg2+ ions in waters, with a detection limit of 1.00 µM. As additional assets, 3 displays superb stability over a wide pH range (3-12) of the aqueous media, as well as convenient recycling after completion of the detection experiments. The rationale for the observed luminescence quenching effect of mercury might be a strong interaction arising between Hg2+ ions and the carboxylate oxygen atoms of the tmba2- ligand. The results open new perspectives for applications in environmental remediation.

Striking dual functionality of a novel Pd@Eu-MOF nanocatalyst in C(sp2)-C(sp2) bond-forming and CO2 fixation reactions.

Pd nanoparticles were immobilized on a highly porous, hydrothermally stable Eu-MOF via solution impregnation and H2 reduction to yield a novel Pd@Eu-MOF nanocatalyst. This composite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), inductively coupled plasma optical emission spectroscopy (ICP-OES), powder X-ray diffraction (PXRD) and X-ray photoelectron spectroscopy (XPS). Unprecedentedly, the Pd@Eu-MOF nanocatalyst could be applied with excellent results in two strikingly different, mechanistically distinct, reactions i.e., Suzuki-Miyaura cross-coupling and cycloaddition of CO2 to a range of epoxides. Under the best reaction conditions, 98-99% yields have been attained in both catalytic processes. Moreover, in either case the heterogeneous catalyst was easily recovered and efficiently reused for more than four cycles, indicating its high stability and reproducibility. PXRD, TEM and XPS measurements on the recycled catalyst confirmed that it maintained its original structure and morphology; no Pd NP agglomeration was observed.

Tailoring the structure, pH sensitivity and catalytic performance in Suzuki-Miyaura cross-couplings of Ln/Pd MOFs based on the 1,1'-di(p-carboxybenzyl)-2,2'-diimidazole linker.

An array of heterobimetallic Pd/Ln MOFs (1-4) with Sm, Eu, Tb, Dy as preferred metal nodes and 1,1'-di(p-carboxybenzyl)-2,2'-diimidazole (H2L) as a fairly suitable bifunctional organic linker have been synthesized, fully characterized and tested as catalysts in cross-coupling reactions. These robust MOFs, ensuring a uniform distribution of Pd, showed excellent stability in air and high catalytic activity in Suzuki-Miyaura reactions conducted in neat water, neat ethanol as well as water-ethanol mixture. Depending on the solvent, complex 1 could be effectively recycled 4-8 times without significant loss of catalytic activity. Importantly, this complex was found to be pH responsive in a reversible way, enabling convenient recovery from acidic aqueous solutions, indicating good recyclability as well as environment-friendly separation of the metal residues after the reaction.

A Yellow-Emitting Homoleptic Iridium(III) Complex Constructed from a Multifunctional Spiro Ligand for Highly Efficient Phosphorescent Organic Light-Emitting Diodes.

To suppress concentration quenching and to improve charge-carrier injection/transport in the emission layer (EML) of phosphorescent organic light-emitting diodes (PhOLEDs), a facial homoleptic iridium(III) complex emitter with amorphous characteristics was designed and prepared in one step from a multifunctional spiro ligand containing spiro[fluorene-9,9'-xanthene] (SFX) unit. Single-crystal X-ray analysis of the resulting fac-Ir(SFXpy)3 complex revealed an enlarged Ir···Ir distance and negligible intermolecular π-π interactions between the spiro ligands. The emitter exhibits yellow emission and almost equal energy levels compared to the commercial phosphor iridium(III) bis(4-phenylthieno[3,2-c]pyridinato-N,C2')acetylacetonate (PO-01). Dry-processed devices using a common host, 4,4'-bis(N-carbazolyl)-1,1'-biphenyl, and the fac-Ir(SFXpy)3 emitter at a doping concentration of 15 wt % exhibited a peak performance of 46.2 cd A-1, 36.3 lm W-1, and 12.1% for the current efficiency (CE), power efficiency (PE), and external quantum efficiency (EQE), respectively. Compared to control devices using PO-01 as the dopant, the fac-Ir(SFXpy)3-based devices remained superior in the doping range between 8 and 15 wt %. The current densities went up with increasing doping concentration at the same driving voltage, while the roll-offs remain relatively low even at high doping levels. The superior performance of the new emitter-based devices was ascribed to key roles of the spiro ligand for suppressing aggregation and assisting charge-carrier injection/transport. Benefiting from the amorphous stability of the emitter, the wet-processed device also exhibited respectful CE, PE, and EQE of 32.2 cd A-1, 22.1 lm W-1, and 11.3%, respectively, while the EQE roll-off was as low as 1.7% at the luminance of 1000 cd m-2. The three-dimensional geometry and binary-conjugation features render SFX the ideal multifunctional module for suppressing concentration quenching, facilitating charge-carrier injection/transport, and improving the amorphous stability of iridium(III)-based phosphorescent emitters.

pH Dependent synthesis of two isomeric dinuclear Cerium(II) complexes: Structures, DNA interactions, cytotoxic activity and apoptotic study.

Two isomeric dinuclear Cerium(II) complexes 1 and 2, formulated as Ce2(phen)2(NO3)2(L)4 [L=phenylacetic acid, phen=1,10-phenanthroline] was synthesized under solvothermal conditions at different pH values. The two complexes were characterized by elemental analysis, IR and single crystal X-ray diffraction. Complexes 1 and 2 were studied the binding with DNA and against cytotoxic activity. Fluorescence analysis indicated that the two complexes can bind to DNA. The changes with different gradient concentration of DNA added into the complexes in absorption spectra show a strongπ-stacking interaction between the complexes and DNA base pairs. The Cerium(II) complexes showed good cytotoxic activity against cancer cell lines, being 2 the most potent complex. Apoptotic studies of the two novel dinuclear complexes showed significant inhibitory rate on cancer cell growth line KB.

The synergistic effect of cobalt on a Pd/Co catalyzed Suzuki-Miyaura cross-coupling in water.

This work introduces the new trimetallic complex CoPd2(HBPDC)2Cl4·(H2O)4(H2BPDC = 2,2'-bipyridine-4,4'-dicarboxylic acid) as a highly efficient and more cost-effective catalyst for a Suzuki-Miyaura reaction proceeding in water, without additives and under aerobic conditions. Catalytic studies revealed a synergistic Co-Pd cooperativity, fostered by ligation through H2BPDC, and accounting for the superior performance of the heterobimetallic complex vs. its Co-free counterpart.

Novel mononuclear Pt2+ and Pd2+ complexes containing (2,3-f)pyrazino(1,10)phenanthroline-2,3-dicarboxylic acid as a multi-donor ligand. Synthesis, structure, interaction with DNA, in vitro cytotoxicity, and apoptosis.

New cytotoxic, mononuclear Pt and Pd coordination complexes featuring the planar, multi-donor ligand (2,3-f)pyrazino(1,10)phenanthroline-2,3-dicarboxylic acid (H2PPDA) have been synthesized under hydrothermal conditions (in water, at high temperature and pressure) and fully characterized. The complexes were proven to be isostructural by applying the single-crystal X-ray diffraction technique. UV-Vis and fluorescence spectroscopy investigations on their interaction with fish sperm DNA revealed a considerable binding capacity while gel electrophoresis provided evidence in favor of cleavage of pBR322 plasmid DNA. The newly synthesized complexes manifested significant in vitro cytotoxic activity against two different human cancer cell lines, the KB and JEKO cells, with cell death mainly caused by apoptosis.

The Syntheses, Structures, Fluorescence Properties and Biological Activity of two Novel Zinc(II) Complexes Controlled by the Tripodal Imidazole Ligand.

Two new zinc complexes, namely Zn(L(1))ClCH2NO(1) and {Zn(L(2))CH2NO}n▪N(CH3)3▪ClO4(2) (L(1) = 3,5-di(1H-imidazol-1-yl)pyridine L(2) = 1,3,5-tris(1-imidazolyl) benzene), have been synthesized, and characterized by IR spectra, elemental analysis, and a single crystal X-ray diffraction. Fluorescence spectroscopy indicated that two complexes presented strong DNA binding affinity constants to fish sperm DNA (FS-DNA). Gel electrophoresis assay demonstrated the ability of the complex to cleave the HL-60 DNA. Apoptotic study showed the complex exhibited significant cancer cell(KB) inhibitory rate.

Synthesis, structure and properties of 2D lanthanide coordination polymers based on N-heterocyclic arylpolycarboxylate ligands.

The reaction of 3-(2,4-dicarboxyphenyl)-2,6-pyridinedicarboxylic acid (H4dppd) with rare earth nitrates under hydrothermal conditions generated a series of new two-dimensional (2D) coordination polymers, namely {[La(Hdppd)(H2O)2·(H2O)2]n (1), [Ln2(Hdppd)2(H2O)4·(H2O)3]n [Ln = Sm (2), Eu (3)] and [Ln(Hdppd)(H2O)3·H2O]n [Ln = Gd (4), Tb (5), Dy (6), Ho (7), Er (8)] [Hdppd = 3-(2,4-dicarboxyphenyl)-2,6-pyridinedicarboxylic trivalent anion]}. The complexes were characterized by X-ray single-crystal diffraction, infrared spectroscopy, elemental analysis and thermogravimetric analysis. Luminescence spectroscopy of 3 and 5 showed bright red and green luminescences due to the 4f(n)-4f(n) transitions in Eu(3+) and Tb(3+) respectively, although the luminescence lifetime is shortened by non-radiative decay due to the presence of coordinating water molecules. The magnetic properties of 2-8 were measured and discussed. Compound 6 exhibits frequency dependent out-of-phase signals, and ferromagnetic coupling exists in 8.

Solvent-regulated assemblies of 1D lanthanide coordination polymers with the tricarboxylate ligand.

Solvothermal reactions of the tricarboxylic acid ligand, biphenyl-3,3',5-tricarboxylic acid (H3bpta), and rare earth nitrate (Ln(NO3)3·6H2O) in the presence of KOH or DMF produced eight 1D linear coordination polymers, namely, [La(bpta)(H2O)5·(H2O)3]n (), [Pr(bpta)(H2O)5·(H2O)2.5]n (), [Nd(bpta)(H2O)5·(H2O)1.75]n (), [Sm(bpta)(H2O)5·(H2O)0.5]n () and [Ln(bpta)(DMF)(H2O)3·(H2O)]n [Ln = Eu (), Gd (), Tb (), Dy ()]. The 1D chain further assembles into a 3D supramolecular network structure through hydrogen bonds and π-π stacking among chains. Complexes and display the typical emission spectra for lanthanide-centred luminescence. The optical properties of were analysed in detail and coincide well with the structural properties. The influence of temperature on the luminescence lifetime of has been studied and different non-radiative decay paths have been discussed. The magnetic properties show that and exhibit strong spin-orbit coupling, while weak antiferromagnetic coupling exists in .

Synthesis, characterization, interaction with DNA and cytotoxicity of Pd(II) and Pt(II) complexes containing pyridine carboxylic acid ligands.

Four metal complexes [Pd(L(1))Cl(2)·2H(2)O] (1), [Pt(L(1))Cl(2)·2H(2)O] (2), [Pd(L(2))Cl(2)·H(2)O] (3) and [Pt(L(2))Cl(2)·H(2)O] (4) (L(1) = 2,2'-bipyridyl-5,5'-dicarboxylic acid, L(2) = 2,2'-bipyridyl-4,4'-dicarboxylic acid) have been synthesized under hydrothermal conditions and fully characterized by IR and (1)H-NMR spectra, elemental analysis, and X-ray single crystal diffraction analysis. Interactions of these complexes with fish sperm DNA (FS-DNA) were investigated using UV-Vis absorption and fluorescence spectroscopic methods. Further insight was brought by quantum chemistry calculations by means of G03 package and taking B3LYP functional Lanl2dz Gen basis set. Agarose gel electrophoresis run on pBR322 plasmid DNA gave proof that all four complexes exhibit efficient DNA cleavage. Complexes 1-4 manifested cytotoxic specificity and a significant cancer cell inhibitory rate. Independent apoptosis tests under the light microscope, performed on hematoxylin-eosin stained HeLa cells, evidenced morphological changes induced by all the complexes.

Hydrothermal synthesis, crystal structure and properties of Ni(II)-4f complexes based on 1H-benzimidazole-5,6-dicarboxylic acid.

Nine novel heterometallic coordination polymers [Ln(2)Ni(Hbidc)(2)(SO(4))(2)(H(2)O)(8)](n) (Ln = Pr (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6), Ho (7), Er (8), Yb (9), H(3)bidc = 1H-benzimidazole-5,6-dicarboxylic acid) have been synthesized under hydrothermal conditions and characterized by elemental analysis, FT-IR, TG analysis and single crystal X-ray diffraction. X-ray analysis revealed that all complexes present almost identical three-dimensional (3D) structures with PtS-type topology. Complexes 1-7 are all isomorphous, and the structure variation of polymers 8 and 9 is induced by the lanthanide contraction effect. In additional, the luminescence properties of complexes 2, 3 and 5-7, and the magnetic properties of complexes 4 and 6-8 were investigated.

Solvothermal synthesis, crystal structure, and properties of lanthanide-organic frameworks based on thiophene-2,5-dicarboxylic acid.

A series of lanthanide-organic framework coordination polymers, {[La(2)(TDC)(2)(NO(3))(H(2)O)(4)](OH)·5H(2)O}(n) (1) and [Ln(TDC)(NO(3))(H(2)O)](n) (TDC = thiophene- 2, 5- dicarboxylic acid; Ln = Nd(2), Sm(3), Eu(4), Gd(5), Tb(6), Dy(7), Ho(8), Er(9), Yb(10)) have been synthesized by solvothermal reaction and characterized by elemental analysis, FT-IR, TG analysis, single-crystal X-ray diffraction and power X-ray diffraction. The single-crystal X-ray diffraction analysis results show that 1 displays a 3-D porous framework with (3,7)-connected {4(10).6(11)}{4(3)} topology. The compounds 2-10 crystallized in the same P2(1)/c space group and exhibits a (3,6)-connected {4.6(2)}(2){4(2).6(10).8(3)} topology, Right-handed and left-handed helical chains coexist in the 2-D layer structure. The luminescence properties of 2-10 and the magnetic properties of 5,7,8,9 were investigated.

Study on the sonodynamic activity and mechanism of promethazine hydrochloride by multi-spectroscopic techniques.

In this paper, the bovine serum albumin (BSA) was selected as a target molecule, the sonodynamic damage to protein in the presence of promethazine hydrochloride (PMT) and its mechanism were studied by the means of absorption, fluorescence and circular dichroism (CD) spectra. The results of hyperchromic effect of absorption spectra and quenching of intrinsic fluorescence spectra indicate that the ultrasound-induced BSA molecules damage is enhanced by PMT. The damage degree of BSA molecules increases with the increase of ultrasonic irradiation time and PMT concentration. The results of synchronous fluorescence, three-dimensional fluorescence and CD spectra confirmed that the synergistic effects of ultrasound and PMT induced the damage of BSA molecules. The results of oxidation-extraction photometry with several reactive oxygen species (ROS) scavengers indicate that the damage of BSA molecules could be mainly due to the generation of ROS and both (1)O(2) and OH are the important mediators of the ultrasound-induced BSA molecules damage in the presence of PMT.

Spectroscopic investigation on the synergistic effects of ultrasound and dioxopromethazine hydrochloride on protein.

The bovine serum albumin (BSA) was selected as a target molecule, the sonodynamic damage to protein in the presence of dioxopromethazine hydrochloride (DPZ) and its mechanism were studied by means of absorption and fluorescence spectra. The results of hyperchromic effect of absorption spectra and quenching of intrinsic fluorescence spectra indicated that the synergistic effects of ultrasound and DPZ could induce the damage of BSA molecules. The damage degree of BSA molecules increased with the increase of ultrasonic irradiation time and DPZ concentration. The results of synchronous fluorescence and three-dimensional fluorescence spectra further confirmed that the synergistic effects of ultrasound and DPZ induced the damage of BSA molecules. The results of oxidation-extraction photometry with several reactive oxygen species (ROS) scavengers indicated that the damage of BSA molecules could be mainly due to the generation of ROS, in which both (1)O(2) and ·OH were the important mediators of the ultrasound-inducing BSA molecules damage in the presence of DPZ.

Hydrothermal synthesis, crystal structure and properties of Ag(I)-4f compounds based on 1H-benzimidazole-5,6-dicarboxylic acid.

Seven novel heterometallic coordination polymers [CeAg(Hbidc)(2)(H(2)O)(2)] (1) and [LnAg(Hbidc)(2)]·3(H(2)O)[Ln = Sm (2), Gd (3), Tb (4), Dy (5), Ho (6), Er (7), H(3)bidc = 1H-benzimidazole-5,6-dicarboxylic acid] have been synthesized under hydrothermal conditions and characterized by elemental analysis, FT-IR, TG analysis, and single crystal X-ray diffraction. X-Ray analysis revealed that the seven complexes present two different types of three-dimensional (3D) structures. Complex 1 crystallized in an orthorhombic manner having a Pna2(1) space group, consisting of a 3D framework with a 1D heterometallic chain. Polymers 2-7 are isostructural and crystallized in an orthorhombic fashion having a Pccn space group existing of a two-fold interpenetrating 3D framework. The luminescence properties and the magnetic properties of all polymers were investigated.

FT Raman--a valuable tool for surveying kinetics in RCM of functionalized dienes.

In this article the suitability of FT Raman spectroscopy for monitoring kinetics of ring-closing metathesis promoted by the Grubbs' 1st generation precatalyst was demonstrated for the first time. Reactions at room temperature and under low catalyst loadings were carried out on a series of representative diene substrates. The time evolution of the characteristic Raman stretching vibrations unequivocally described the reaction progress allowing for precise calculation of the substrate conversion and of the yield in the expected cyclic product, based on the corresponding peak heights. The responsive Raman technique demonstrated clean RCM pathways for diethyl diallylmalonate and diallyl ether whereas a minor olefinic side-product was detected in the case of diallyl phthalate. The study provides essential underpinnings for future utilization of Raman spectroscopy, concurrently with NMR or supplementing it, for the evaluation of RCM reactions.

Potassium aqua-terbium(III) oxalate sulfate.

Single crystals of KTb(C(2)O(4))(SO(4))(H(2)O), potassium aqua-terbium(III) oxalate sulfate, were obtained under hydro-thermal conditions. In the crystal structure, the Tb(III) atom is coordinated by four O atoms from two oxalate anions, three O atoms from three sulfate anions and one O atom from a water mol-ecule within a TbO(8) distorted square antiprismatic coordination. The potassium and terbium(III) atoms are bridged by the oxalate and sulfate groups, forming a three-dimensional structure. The coordination mode of the oxalate has not yet been reported. O-H⋯O hydrogen bonding between the water molecules and the oxygen atoms of oxalate and sulfate anions is also observed.

A novel binuclear palladium complex with benzothiazole-2-thiolate: synthesis, crystal structure and interaction with DNA.

The novel Pd(II) complex, [Pd(2)(micro-bzta)(4)].1.5DMSO (where bzta=benzothiazole-2-thiolate) has been synthesized and structurally characterized by element analysis, IR and single-crystal X-ray diffractometry. In the binuclear complex, two palladium(II) are bridged by four deprotonated benzothiazole-2-thialate in a head to tail disposition and the distance of the two Pd(II) is 2.747 A. Three-dimensional structure of the complex was constructed though S...S (3.339 A) weak interaction and pi...pi stack. The binding of the title complex with fish sperm DNA (FS-DNA) has been investigated by absorption and fluorescence spectra. The results indicate that the complex bind to FS-DNA in an intercalative mode and the intrinsic binding constant K of the title complex with FS-DNA is about 1.2 x 10(4)M(-1). Gel electrophoresis assay demonstrates the ability of the complex to cleave the pUC19 plasmid DNA.