General guide to the exhibition halls of the American Museum of Natural History, 1930.

The synthesis and characterization of three barium coordination polymers with one-, two-, and three-dimensional (1-D, 2-D, 3-D) inorganic connectivity based on biphenyl carboxylic acid ligands are described. Employing biphenyl-3,3′,5,5′-tetracarboxylic acid (H₄BTTC) as a ligand, [Ba₂(BTTC)­(H₂O)₂]_<i>n</i> (<b>1</b>, space group = <i>Pn</i>2₁<i>a</i>, <i>a</i> = 7.059(1) Å, <i>b</i> = 12.432(2) Å, <i>c</i> = 19.090(3) Å), a coordination polymer with 1-D inorganic connectivity (I¹O²), can be synthesized. The coordinated water is strongly coordinated and removed at 270 °C. By using 4,4′-biphenyldicarboxylic acid (H₂BPDC), [Ba­(BPDC)]_<i>n</i> (<b>2</b>, space group = <i>C</i>2/<i>m</i>, <i>a</i> = 6.955(2) Å, <i>b</i> = 5.947(1) Å, <i>c</i> = 13.852 (4) Å, β = 92.399(4)°) a coordination polymer with 2-D inorganic connectivity (I²O¹) is obtained. The connection of the Ba–O bonds in each layer is topologically similar to CaF₂. Using biphenyl-3,5,5′-tricarboxylic acid (H₃BPTC) as a ligand, [Ba₃(BPTC)₂(NMF)₅⊃2NMF]_<i>n</i> (<b>3</b>, space group = <i>I</i>4̅2<i>d</i>, <i>a</i> = 25.984(3) Å, <i>c</i> = 13.999(2) Å) (NMF = <i>N</i>-methyl formamide), a structurally porous coordination polymer with rare 3-D inorganic connectivity (I³O⁰) can be synthesized. Hence, barium as a metal is extremely malleable with respect to construction of coordination polymers of different inorganic dimensionalities. <b>2</b> with I²O¹ connectivity demonstrates extraordinary thermal stability and maintains its crystallinity until decomposition at 590 °C. The luminescence behavior of <b>1</b>, <b>2</b>, and <b>3</b> at room temperature has been investigated and is predominantly intraligand based

A Family of Rare Earth Porous Coordination Polymers with Different Flexibility for CO₂/C₂H₄ and CO₂/C₂H₆ Separation

A family of new porous coordination polymers (PCPs) were prepared by the reaction of an acylamide modified ligand (H₃L) and RE­(NO)₃·​<i>x</i>H₂O (RE = Y, La, Ce, Nd, Eu, Tb, Dy, Ho, and Tm). PXRD and single-crystal X-ray analyses of them revealed that, besides the La PCP, all other rare earth members gave isomorphous structures. The two types of structural toplogies obtained, although similar, differ in their alignment of acylamide functional groups and structural flexibility. Adsorption experiments and in situ DRIFT spectra showed that rigid frameworks have the typical microporous behavior and poor selective capture of CO₂ over C₂H₄ and C₂H₆; however, the unique La-PCP with structural flexibility and close-packed acylamide groups has a high selective capture of CO₂ with respect to C₂H₆ or C₂H₄ at 273 K, especially at the ambient pressure area (0.1–1 bar)

A Family of Rare Earth Porous Coordination Polymers with Different Flexibility for CO₂/C₂H₄ and CO₂/C₂H₆ Separation

A family of new porous coordination polymers (PCPs) were prepared by the reaction of an acylamide modified ligand (H₃L) and RE­(NO)₃·​<i>x</i>H₂O (RE = Y, La, Ce, Nd, Eu, Tb, Dy, Ho, and Tm). PXRD and single-crystal X-ray analyses of them revealed that, besides the La PCP, all other rare earth members gave isomorphous structures. The two types of structural toplogies obtained, although similar, differ in their alignment of acylamide functional groups and structural flexibility. Adsorption experiments and in situ DRIFT spectra showed that rigid frameworks have the typical microporous behavior and poor selective capture of CO₂ over C₂H₄ and C₂H₆; however, the unique La-PCP with structural flexibility and close-packed acylamide groups has a high selective capture of CO₂ with respect to C₂H₆ or C₂H₄ at 273 K, especially at the ambient pressure area (0.1–1 bar)

Modular Design of Domain Assembly in Porous Coordination Polymer Crystals via Reactivity-Directed Crystallization Process

The mesoscale design of domain assembly is crucial for controlling the bulk properties of solids. Herein, we propose a modular design of domain assembly in porous coordination polymer crystals via exquisite control of the kinetics of the crystal formation process. Employing precursors of comparable chemical reactivity affords the preparation of homogeneous solid-solution type crystals. Employing precursors of distinct chemical reactivity affords the preparation of heterogeneous phase separated crystals. We have utilized this reactivity-directed crystallization process for the facile synthesis of mesoscale architecture which are either solid-solution or phase-separated type crystals. This approach can be also adapted to ternary phase-separated type crystals from one-pot reaction. Phase-separated type frameworks possess unique gas adsorption properties that are not observed in single-phasic compounds. The results shed light on the importance of crystal formation kinetics for control of mesoscale domains in order to create porous solids with unique cooperative functionality

Modular Design of Domain Assembly in Porous Coordination Polymer Crystals via Reactivity-Directed Crystallization Process

The mesoscale design of domain assembly is crucial for controlling the bulk properties of solids. Herein, we propose a modular design of domain assembly in porous coordination polymer crystals via exquisite control of the kinetics of the crystal formation process. Employing precursors of comparable chemical reactivity affords the preparation of homogeneous solid-solution type crystals. Employing precursors of distinct chemical reactivity affords the preparation of heterogeneous phase separated crystals. We have utilized this reactivity-directed crystallization process for the facile synthesis of mesoscale architecture which are either solid-solution or phase-separated type crystals. This approach can be also adapted to ternary phase-separated type crystals from one-pot reaction. Phase-separated type frameworks possess unique gas adsorption properties that are not observed in single-phasic compounds. The results shed light on the importance of crystal formation kinetics for control of mesoscale domains in order to create porous solids with unique cooperative functionality

Visible–Near-Infrared-Light-Driven Oxygen Evolution Reaction with Noble-Metal-Free WO₂–WO₃ Hybrid Nanorods

Understanding and manipulating the one half-reaction of photoinduced hole-oxidation to oxygen are of fundamental importance to design and develop an efficient water-splitting process. To date, extensive studies on oxygen evolution from water splitting have focused on visible-light harvesting. However, capturing low-energy photons for oxygen evolution, such as near-infrared (NIR) light, is challenging and not well-understood. This report presents new insights into photocatalytic water oxidation using visible and NIR light. WO₂–WO₃ hybrid nanorods were in situ fabricated using a wet-chemistry route. The presence of metallic WO₂ strengthens light absorption and promotes the charge-carrier separation of WO₃. The efficiency of the oxygen evolution reaction over noble-metal-free WO₂–WO₃ hybrids was found to be significantly promoted. More importantly, NIR light (≥700 nm) can be effectively trapped to cause the photocatalytic water oxidation reaction. The oxygen evolution rates are even up to around 220 (λ = 700 nm) and 200 (λ = 800 nm) mmol g^–1 h^–1. These results demonstrate that the WO₂–WO₃ material is highly active for water oxidation with low-energy photons and opens new opportunities for multichannel solar energy conversion

Two-Dimensional C/TiO₂ Heterogeneous Hybrid for Noble-Metal-Free Hydrogen Evolution

Developing catalysts to improve excitonic charge-carrier transfer and separation properties is critical for solar energy conversion through photochemical catalysis. Layer staking of two-dimensional (2-D) materials has opened up opportunities to engineer heteromaterials for strong interlayer excitonic transition. However, scalable fabrication of heteromaterials with seamless and clean interfaces remains challenging. Here, we report an in situ growth strategy for synthesizing a 2-D C/TiO₂ heterogeneous hybrid. Layered structure of TiO₂ and chemically bonded Ti–C between graphitic carbon and TiO₂ generate synergetic effects, promoting interfacial charge transfer and separation, leading to more electrons participating in photoreduction for hydrogen evolution. The Ti–C bond as reactive sites, such as platinum behavior, makes it an interesting potential substitue for noble metals in hydrogen evolution. In the absence of noble metals, the C/TiO₂ hybrid exhibits a significant enhancement of hydrogen evolution from water splitting using solar light, ∼3.046 mmol h^–1 g^–1. The facile and scalable fabrication of 2-D heterogeneous hybrid with enhanced interfacial charge transfer and separation provides perspectives for the creation of 2-D heteromaterials in optoelectronics and solar-light-harvesting applications

A Crystalline Porous Coordination Polymer Decorated with Nitroxyl Radicals Catalyzes Aerobic Oxidation of Alcohols

A porous coordination polymer (PCP) has been synthesized employing an organic ligand in which a stable free radical, isoindoline nitroxide, is incorporated. The crystalline PCP possesses one-dimensional channels decorated with the nitroxyl catalytic sites. When O₂ gas or air was used as the oxidant, this PCP was verified to be an efficient, recyclable, and widely applicable catalyst for selective oxidation of various alcohols to the corresponding aldehydes or ketones