5), and [Pb(NNO) 2 ] (6), have been prepared by the reaction of Pb(NO 3 ) 2 with isonicotinic acid N-oxide (HINO), or nicotinic acid N-oxide (HNNO), and characterized by elemental analysis, IR, and singlecrystal X-ray diffraction. Compound 1, consisting of a one-dimensional (1D) infinite chain, is a three-dimensional (3D) supramolecular framework with a 1D rectanglar channel in which free water molecules locate. The structure of 2 consists of 1D chains built by two parallel INO ligands bridging a pair of rhombic-planar [Pb 2 O 2 ] units, which is further extended into a 2D supramolecular layer via hypervalent interactions and interlayer π-π interactions. Compound 3 consists of a two-dimensional (2D) inorganic layer containing 16-membered rings, which are further linked through µ-INO to generate a unique 3D open framework. In compound 4, the selfassembly based on 2D motifs with side arms leads to the formation of a new type of polythreaded network, which contains 1D channels with guests molecules along the b-axis. In compound 5, NNO ligands in three kinds of coordination modes link to three unique lead centers to generate two kinds of Pb-O chains which are bridged by NNO to give a 2D network. Compound 6 is a 2D layer structure and in the intralayer regions parallel left-and right-handed helical chains exist. In addition, compounds 1, 2, 3, and 6 exhibit strong phosphorescent emissions in the solid state at room temperature. The results of theoretical calculations show that the absorptions of these complexes derive mainly from ligand to ligand charge transfer (LLCT) transitions.

Six coordination polymers constructed from three structurally related ligands, 1,2-bis[2-(2-pyridyl)imidazol-1-ylmethyl]benzene (L1), 1,3-bis[2-(2-pyridyl)imidazol-1-ylmethyl]benzene (L2), and 1,4-bis[2-(2-pyridyl)imidazol-1-ylmethyl]benzene (L3) have been synthesized: [Zn2(ODPT)(L1)0.5(H2O)]·3H2O (1), [Zn2(ODPT)(L2)(H2O)2]·3H2O (2), [Zn2(ODPT)L3(H2O)]·6H2O (3), [Cd2(ODPT)(L1)0.5(H2O)]·4H2O (4), [Cd(H2ODPT)(L2)]·2H2O (5), and [Cd1.5(HODPT)(L3)0.5] (6), where H4ODPT is 4,4′-oxidiphthalic acid. Their structures have been determined by single crystal X-ray diffraction analyses. All compounds are also characterized by elemental analyses, IR spectra, and thermogravimetric (TG) analyses. Compound 1 exhibits a two-dimensional (2D) layer structure with tetra-nuclear zinc clusters as building units, and intermolecular π···π stacking interactions link these sheets to a three-dimensional (3D) supramolecular structure. Compound 2 shows infinite chains and is extended into a 2D supramolecular sheet by intermolecular hydrogen bonds. The structure of 3 is built by L3 ligands connecting ODPT-Zn double-chains to a 3D network with a (42·6·102·12)(42·6)(102·12) topology. Compound 4 is isostructural with compound 1. In 5, partly deprotonated H2ODPT2− anions link the L2-Cd 24-membered rings to generate an infinite chain that extends into a 2D supramolecular sheet by intermolecular π···π stacking interactions. In 6, L3 ligands and the ether O atoms of HODPT3− anions link Cd−O chains formed by phthalic groups into a 3D network. In addition, the luminescent properties of these compounds are discussed.

It is a promising strategy to prepare composite photocatalysts based on MOFs and semiconductors for enhancing photocatalytic reduction of carbon dioxide (CO2). A family of binary composite photocatalysts (CdS@UiO-66-NH2) with...

Developing a low-cost and effective proton-conductive electrolyte to meet the requirements of the large-scale manufacturing of proton exchange membrane (PEM) fuel cells is of great significance in progressing towards the upcoming “hydrogen economy” society. Herein, utilizing the one-pot acylation polymeric combination of acyl chloride and amine precursors, a polyamide with in-built -SO3H moieties (PA-PhSO3H) was facilely synthesized. Characterization shows that it possesses a porous feature and a high stability at the practical operating conditions of PEM fuel cells. Investigations of electrochemical impedance spectroscopy (EIS) measurements revealed that the fabricated PA-PhSO3H displays a proton conductivity of up to 8.85 × 10−2 S·cm−1 at 353 K under 98% relative humidity (RH), which is more than two orders of magnitude higher than that of its -SO3H-free analogue, PA-Ph (6.30 × 10−4 S·cm−1), under the same conditions. Therefore, matrix-mixed membranes were fabricated by mixing with polyacrylonitrile (PAN) in different ratios, and the EIS analyses revealed that its proton conductivity can reach up to 4.90 × 10−2 S·cm−1 at 353 K and a 98% relative humidity (RH) when the weight ratio of PA-PhSO3H:PAN is 3:1 (labeled as PA-PhSO3H-PAN (3:1)), the value of which is even comparable with those of commercial-available electrolytes being used in PEM fuel cells. Additionally, continuous tests showed that PA-PhSO3H-PAN (3:1) possesses a long-life reusability. This work demonstrates, using the simple acylation reaction with the sulfonated module as precursor, that low-cost and highly effective proton-conductive electrolytes for PEM fuel cells can be facilely achieved.

No abstract