Four three-dimensional lanthanide coordination polymer constructed from benzene-1,4-dioxydiacetic acid

Four crystalline lanthanide(III) three-dimensional (3D) coordination polymers {[La(BDOA)_1.5(H₂O)] · H₂O}_n (1), {[Nd(BDOA)_1.5(H₂O)] · H₂O}_n (2), [Tm(BDOA)_1.5(H₂O)]_n (3), [Yb(BDOA)_1.5(H₂O)]_n (4) were obtained under hydrothermal conditions and characterized by elemental analysis, IR, as well as single-crystal X-ray diffraction. Compounds 1 and 2 crystallize in the monoclinic system, space group P2₁/c, they are isostructural and exhibit the same 3²¹.4⁵⁷.5¹³ topological network constructed from different coordination modes of two BDOA ligands, whereas isostructural 3 and 4 crystallizes in the triclinic system, space group , it holds 3⁹.4²⁰.5⁷ topological architecture based on another two different coordination modes BDOA ligands. Moreover, a computational method is applied to evaluate the potential porosity of complex 1.     

A 2D [Fe-bistetrazole] coordination polymer exhibiting spin-crossover properties

The reaction of 1,3-bis(tetrazol-1-yl)-2-propanol (btzpol) with Fe(BF₄)₂ · 6H₂O in acetonitrile yields the remarkable 2D coordination polymer [Fe^II(btzpol)_1.8(btzpol-OBF₃)_1.2](BF₄)_0.8 · (H₂O)_0.8(CH₃CN) (1). This compound has been structurally characterized using an X-ray single-crystal synchrotron radiation source. The iron(II) centers are bridged by means of double btzpol bridges along the c direction, and by single btzpol bridges along the b direction. The reaction of part of the ligand with the counterion has forced the compound to crystallize in this extended two dimensional structure. The compound shows spin-transition properties, both induced by temperature and light, with T_1/2 = 112 K and T(LIESST) = 46 K, respectively. The relaxation of the metastable high-spin state created by irradiation is exponential, following an Arrhenius type behavior at high temperature, and dominated by a temperature independent tunneling process at lower temperatures.     

Self-assembly of two fluorescent supramolecular frameworks constructed from unsymmetrical benzene tricarboxylate and bipyridine

Two new supramolecular compounds, [Ag(4,4′-bipy)]_n [Ag(HBTC)]_n (1) and [Cu(H₂BTC)(2,2′-bipy)] (2) (HBTC/H₂BTC = 1,2,4-benzenetricarboxylate, 4,4′-bipy/2,2′-bipy = 4,4′/2,2′-bipyridine), have been synthesized and characterized by elemental analyses, IR spectra, ultraviolet-visible diffuse reflection integral spectra (UV-Vis DRIS), fluorescent spectra, thermogravimetric analysis and single crystal X-ray diffraction analysis. It is noteworthy that there were two kinds of one-dimensional stairs-chain including cationic [Ag(4,4′-bipy)]_n chain and anionic [Ag(HBTC)]_n chain in 1. Furthermore, a two-dimensional double layer supramolecular framework was constructed through coordination bonds, hydrogen bonds, π-π stacking interactions and Ag?O weak coordinative interactions. The one-dimensional supramolecular chain of 2 was built from combining mononuclear [Cu(H₂BTC)(2,2′-bipy)] by inter- and intra-molecular hydrogen bonding interactions. Additionally, the two complexes exhibit intense blue or olivine luminescence at room temperature.     

Radiolarian skeleton: Morphology of spines,internal framework,and primary sphere

The morphology and evolution of the internal framework, primary inner sphere, and various spines of radiolarian skeletons are considered. A new scheme of successive stages of spine formation is offered. The convergent similarity of radiolarian spines and sponge spicules are discussed.     

企业生物多样性信息披露: 调查、分析与建议

近年来我国每年发布《企业社会责任报告》近2,000份, 有相当比例包含生物多样性内容。但长期以来, 披露内容的实质性与可信度严重不足, 亟需引导、规范和审核。本文探讨建立我国企业生物多样性信息公开透明机制, 旨在解决两个主要问题: 一是风险规避, 二是资源调动。本文根据《生物多样性公约》相关规定, 首先梳理企业生物多样性信息披露国内外进展, 指出存在内容碎片化, 科学指标缺失, 结果难以比较, 投入产出、同业及历史数据缺乏比对分析等不足。其次, 采用5个生物多样性指标, 进一步对《企业社会责任报告评估指数》研究发现: 不同行业差异化明显、金融机构催化作用凸显、重视纳入制度战略框架、报告内容同质化严重、定性描述多于定量分析、货币化核算方法缺失、资金投入信息披露保守、未经第三方独立审核等特点。最后, 提出提高企业透明度的4项建议: (1)加强顶层设计纳入, (2)改进环境政策指引, (3)优化金融激励措施, (4)强化公司能力建设。这将为政府和金融部门量化生态影响, 管控投资风险, 实施扩大生物多样性融资决策提供支持。     

AuPd–MnOx/MOF–Graphene: An Efficient Catalyst for Hydrogen Production from Formic Acid at Room Temperature

The safe and efficient storage and release of hydrogen are widely recognized as the main challenges for the establishment of a fuel‐cell‐based hydrogen economy. Formic acid (FA) has great potential as a safe and convenient source of hydrogen for fuel cells. Despite tremendous efforts, the development of heterogeneous catalysts with high activity and relatively low cost remains a major challenge. The synthesis of AuPd–MnO_x nanocomposite immobilized on ZIF‐8–reduced‐graphene‐oxide (ZIF‐8–rGO) bi‐support by a wet‐chemical method is reported here. Interestingly, the resultant AuPd–MnO_x/ZIF‐8–rGO shows excellent catalytic activity for the generation of hydrogen from FA, and the initial turnover frequency (TOF) reaches a highest value of 382.1 mol H₂ mol catalyst^?1 h^?1 without any additive at 298 K. This good performance of AuPd–MnO_x/ZIF‐8–rGO results from the modified electronic structure of Pd in the AuPd–MnO_x/ZIF‐8–rGO composite, the small size and high dispersion of the AuPd–MnO_x nanocomposite, and also the strong metal‐support interaction between the AuPd–MnO_x and ZIF‐8–rGO bi‐support.     

Reversible Multivalent (Monovalent,Divalent, Trivalent) Ion Insertion in Open Framework Materials

The reversible electrochemical insertion of multivalent ions into materials has promising applications in many fields, including batteries, seawater desalination, element purification, and wastewater treatment. However, finding materials that allow for the insertion of multivalent ions with fast kinetics and stable cycling has proven difficult because of strong electrostatic interactions between the highly charged insertion ions and atoms in the host framework. Here, an open framework nanomaterial, copper hexacyanoferrate, in the Prussian Blue family is presented that allows for the reversible insertion of a wide variety of monovalent, divalent, and trivalent ions (such as Rb⁺, Pb²⁺, Al³⁺, and Y³⁺) in aqueous solution beyond that achieved in previous studies. Electrochemical measurements demonstrate the unprecedented kinetics of multivalent ion insertion associated with this material. Synchrotron X‐ray diffraction experiments point toward a novel vacancy‐mediated ion insertion mechanism that reduces electrostatic repulsion and helps to facilitate the observed rapid ion insertion. The results suggest a new approach to multi­valent ion insertion that may help to advance the understanding of this complex phenomenon.     

GASP: software for geometric simulations of flexibility in polyhedral and molecular framework structures

Template-based geometric simulation is a specialised method for modelling flexible framework structures made up of rigid units using a simplified, localised physical model. The strengths of the method are its ability to handle large all-atom structural models rapidly and at minimal computational expense, and to provide insights into the links between local bonding and steric geometry and global flexibility. We review the implementation of geometric simulation in the ‘GASP’ software, and its application to the study of materials including zeolites, perovskites and metal–organic frameworks. The latest version (5) of GASP has significant improvements and extensions, in particular an improved algorithm for relaxation of atomic positions, and the capacity to handle both polyhedral and molecular structural units. GASP is freely available to researchers.