Enhancing Hydrogen Generation Through Nanoconfinement of Sensitizers and Catalysts in a Homogeneous Supramolecular Organic Framework.

Enrichment of molecular photosensitizers and catalysts in a confined nanospace is conducive for photocatalytic reactions due to improved photoexcited electron transfer from photosensitizers to catalysts. Herein, the self-assembly of a highly stable 3D supramolecular organic framework from a rigid bipyridine-derived tetrahedral monomer and cucurbit[8]uril in water, and its efficient and simultaneous intake of both [Ru(bpy)3 ]2+ -based photosensitizers and various polyoxometalates, that can take place at very low loading, are reported. The enrichment substantially increases the apparent concentration of both photosensitizer and catalyst in the interior of the framework, which leads to a recyclable, homogeneous, visible light-driven photocatalytic system with 110-fold increase of the turnover number for the hydrogen evolution reaction

Biochemical and Structural Properties of Cyanases from Arabidopsis thaliana and Oryza sativa

Cyanate is toxic to all organisms. Cyanase converts cyanate to CO2 and NH3 in a bicarbonate-dependent reaction. The biophysical functions and biochemical characteristics of plant cyanases are poorly studied, although it has been investigated in a variety of proteobacteria, cyanobacteria and fungi. In this study, we characterised plant cyanases from Arabidopsis thaliana and Oryza sativa (AtCYN and OsCYN). Prokaryotic-expressed AtCYN and OsCYN both showed cyanase activity in vitro. Temperature had a similar influence on the activity of both cyanases, but pH had a differential impact on AtCYN and OsCYN activity. Homology modelling provided models of monomers of AtCYN and OsCYN, and a coimmunoprecipitation assay and gel filtration indicated that AtCYN and OsCYN formed homodecamers. The analysis of single-residue mutants of AtCYN indicated that the conserved catalytic residues also contributed to the stability of the homodecamer. KCNO treatment inhibited Arabidopsis germination and early seedling growth. Plants containing AtCYN or OsCYN exhibited resistance to KCNO stress, which demonstrated that one role of cyanases in plants is detoxification. Transcription level of AtCYN was higher in the flower than in other organs of Arabidopsis. AtCYN transcription was not significantly affected by KCNO treatment in Arabidopsis, but was induced by salt stress. This research broadens our knowledge on plant detoxification of cyanate via cyanase

Water-Soluble Flexible Organic Frameworks That Include and Deliver Proteins.

Four water-soluble hydrazone-based three-dimensional (3D) flexible organic frameworks FOF-1-4 have been synthesized from a semirigid tetracationic tetraaldehyde and four flexible dihydrazides. 1H NMR spectroscopy indicated the quantitative formation of FOF-1-4 in D2O, while dynamic light scattering experiments revealed that, depending on the concentration, these porous frameworks display hydrodynamic diameters ranging from 50 to 120 nm. The porosity of the frameworks is confirmed by ethanol vapor adsorption experiments of the solid samples as well as the high loading capacity for a 2.3 nm porphyrin guest in water. The new water-soluble frameworks exhibit low cytotoxicity and form inherent pores with diameters of 5.3 or 6.7 nm, allowing rapid inclusion of proteins such as bovine serum albumin and green and orange fluorescent proteins, and efficient delivery of the proteins into normal and cancer cells. Flow cytometric analysis reveals percentages of the delivered cells up to 99.8%

Poly[[tetraaqua­bis(μ3-1H-benzimidazole-5,6-dicarboxyl­ato)dicobalt(II)] trihydrate]

The title complex, {[Co2(C9H4N2O4)2(H2O)4]·3H2O}n, was synthesized hydro­thermally. The unique CoII ion is coordin­ated in a distorted octa­hedral coordination environment by two water mol­ecules and three symmetry-related 1H-benzimid­azole-5,6-dicarboxyl­ate (Hbidc) ligands. The Hbidc ligands coordinate via a bis-chelating and mono-chelating carboxyl­ate group and by an imidazole group N atom, bridging the CoII ions and forming an extended two-dimensional structure in the ab plane. In the crystal structure, inter­molecular N—H⋯O and O—H⋯O hydrogen bonds connect complex and solvent water mol­ecules, forming a three-dimensional supermolecular network. One of the solvent water mol­ecules lies on a twofold rotation axis

catena-Poly[diaqua­tris(μ3-biphenyl-2,2-dicarboxyl­ato)disamarium(III)]

The title compound, [Sm2(C14H8O4)3(H2O)2]n, is composed of one-dimensional chains and is isostructural with previously reported compounds [Wang et al. (2003 ▶). Eur. J. Inorg. Chem. pp. 1355–1360]. The asymmetric unit contains two Sm atoms, each of which lies on a crystallographic twofold axis. Both crystallographically independent Sm atoms are coordinated by eight O atoms in a distorted dodeca­hedral arrangement. The polymeric chains run along [001]. Adjacent chains are connected through π–π inter­actions [centroid–centroid distance = 3.450 (2) Å], forming a two-dimensional supra­molecular network

Poly[[tetra­aqua­bis[μ4-2,2′-(p-phenyl­ene­di­oxy)diacetato][μ2-2,2′-(p-phenyl­ene­di­oxy)diacetato]dierbium(III)] hexa­hydrate]

The asymmetric unit of the title compound, [Er2(C10H8O6)3(H2O)4]·6H2O, comprises one Er3+ ion, one and a half 2,2′-(p-phenyl­enedi­oxy)diacetate (hqda) ligands, two coordinated water mol­ecules and three uncoordinated water mol­ecules. The Er3+ ion is nine-coordinated by seven O atoms from hqda ligands and two O atoms from water mol­ecules. In the title compound, there are two types of crystallographically independent ligands: one with an inversion center in the middle of the ligand is chelating on both ends of the ligand towards each one Er center; the other hqda ligands are bridging-chelating on one side, and bridging on the other end of the ligand. Two adjacent Er3+ ions are thus chelated and bridged by –COO groups from hqda ligands in three coordination modes (briding–chelating, bridging and chelating). These building blocks are linked by OOC—CH2O—C6H4—OCH2—COO spacers, forming two-dimensional neutral layers. Adjacent layers are linked by O—H⋯O hydrogen-bonding inter­actions, forming a three-dimensional supermolecular network