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.

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.

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.

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, 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.

Effects of Leached Amylose and Amylopectin in Rice Cooking Liquidon Texture and Structure of Cooked Rice

ABSTRACT Effects of leached amylose (AM) and amylopectin (AP) on textural and morphological properties of cooked rice were investigated separately by replacing cooking liquid with AM and AP separated from pouring cooking liquid. The pouring of cooking water reduced the hardness (from 28.45 to 19.42N) and stickiness (from 1.74 to 1.19N·s) significantly. However, the addition of AM and AP enhanced the hardness (27.63N) and stickiness (1.71N·s).Scanning electron microscopy show that the leached short-chain AM entered the surface hollows in the cooked rice after water evaporation. Meanwhile, the Long-chain AM cross-linked to formed a three-dimensional network structures, which covered on the filled hollows. This distribution led to a harder texture of cooked rice. The leached AP absorbed water and swelledto form masses. Atthe gelatinization temperature,theAPmassesagglomeratedtoformafilmlayer,whichcoveredtheunevenstructure, the thicker and smoother film contributed to the sticky texture.