Complex Open-Framework Germanate Built by 8‑Coordinated Ge₁₀ Clusters

A novel open-framework germanate |(C₅H₁₄­N₂)₂­(C₅H₁₂­N₂)_0.5(H₂O)_2.5|[Ge_12.5O₂₆(OH)₂] with three-dimensional 10- and 11-ring channels, denoted as SU-67, has been synthesized under hydrothermal conditions using 2-methylpiperazine (MPP) as the structure-directing agent (SDA). The synthesis is intimately related to that of JLG-5, a tubular germanate built from Ge₇ clusters. The influences of synthesis parameters are discussed. A strong influence of the hydrofluoric acid quantity on the resulting cluster building units can be concluded. The framework of SU-67 is based on an elaborate topological pattern of connected Ge₁₀ clusters forming intersecting 10- and 11-ring channels and has a low framework density (12.4 Ge atoms per 1000 ų). We have discovered that the topology of SU-67 is a new 8-connected <b>nce-8-</b><i><b>I</b></i><b>4</b>_<b>1</b><b>/</b><i><b>acd</b></i> net. Strong hydrogen bonding among the organic SDAs, water molecules, and Ge₁₀ clusters resulted in helical networks in SU-67

Complex Open-Framework Germanate Built by 8‑Coordinated Ge₁₀ Clusters

A novel open-framework germanate |(C₅H₁₄­N₂)₂­(C₅H₁₂­N₂)_0.5(H₂O)_2.5|[Ge_12.5O₂₆(OH)₂] with three-dimensional 10- and 11-ring channels, denoted as SU-67, has been synthesized under hydrothermal conditions using 2-methylpiperazine (MPP) as the structure-directing agent (SDA). The synthesis is intimately related to that of JLG-5, a tubular germanate built from Ge₇ clusters. The influences of synthesis parameters are discussed. A strong influence of the hydrofluoric acid quantity on the resulting cluster building units can be concluded. The framework of SU-67 is based on an elaborate topological pattern of connected Ge₁₀ clusters forming intersecting 10- and 11-ring channels and has a low framework density (12.4 Ge atoms per 1000 ų). We have discovered that the topology of SU-67 is a new 8-connected <b>nce-8-</b><i><b>I</b></i><b>4</b>_<b>1</b><b>/</b><i><b>acd</b></i> net. Strong hydrogen bonding among the organic SDAs, water molecules, and Ge₁₀ clusters resulted in helical networks in SU-67

A Family of Flexible Lanthanide Bipyridinedicarboxylate Metal–Organic Frameworks Showing Reversible Single-Crystal to Single-Crystal Transformations

A family of flexible lanthanide metal–organic frameworks, [Ln₂(bpydc)₃(H₂O)₃]·nDMF (denoted as SUMOF-6-Ln; Ln = Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Er, H₂bpydc =2,2′-bipyridine-5,5′-dicarboxylic acid), was synthesized and characterized. SUMOF-6-Ln has a monoclinic space group <i>P</i>2₁<i>/c</i>. The three-dimensional framework contains chains of LnO_<i>n</i> (<i>n</i> = 7–8) polyhedra connected through the bpydc linkers forming 1D rhombic channels along the <i>c</i>-axis. SUMOF-6-Ln showed reversible breathing phenomenon upon desorption/adsorption of the solvent, with up to 27% changes of the unit cell dimensions and 23% changes of the unit cell volume. Single crystal X-ray diffraction (XRD) revealed that the desolvation and resolvation of SUMOF-6-Ln occurred via single-crystal to single-crystal transformations. The thermal behavior of SUMOF-6-Sm was also examined. SUMOF-6-Eu and SUMOF-6-Tb showed solid-state luminescent properties

A Family of Flexible Lanthanide Bipyridinedicarboxylate Metal–Organic Frameworks Showing Reversible Single-Crystal to Single-Crystal Transformations

A family of flexible lanthanide metal–organic frameworks, [Ln₂(bpydc)₃(H₂O)₃]·nDMF (denoted as SUMOF-6-Ln; Ln = Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Er, H₂bpydc =2,2′-bipyridine-5,5′-dicarboxylic acid), was synthesized and characterized. SUMOF-6-Ln has a monoclinic space group <i>P</i>2₁<i>/c</i>. The three-dimensional framework contains chains of LnO_<i>n</i> (<i>n</i> = 7–8) polyhedra connected through the bpydc linkers forming 1D rhombic channels along the <i>c</i>-axis. SUMOF-6-Ln showed reversible breathing phenomenon upon desorption/adsorption of the solvent, with up to 27% changes of the unit cell dimensions and 23% changes of the unit cell volume. Single crystal X-ray diffraction (XRD) revealed that the desolvation and resolvation of SUMOF-6-Ln occurred via single-crystal to single-crystal transformations. The thermal behavior of SUMOF-6-Sm was also examined. SUMOF-6-Eu and SUMOF-6-Tb showed solid-state luminescent properties

Hydrothermal Synthesis of 1‑Butanol from Ethanol Catalyzed with Commercial Cobalt Powder

We reported a highly efficient conversion of ethanol to 1-butanol under hydrothermal conditions with commercial cobalt (Co) metal powder as a recyclable and inexpensive catalyst. The possible reaction pathways were explored. Moreover, it has been found that sodium bicarbonate is better than sodium hydroxide for the Guerbet reaction because the former led to less corrosion of reaction vessels and blocked the oxidation of the ethanol to acetic acid

Three-Dimensional Open-Framework Germanate Built from a Novel Ge₁₃ Cluster and Containing Two Types of Chiral Layers

A new open-framework germanate [Ge₁₅O₃₀(OH)₄]·2­(H₂tren), denoted SU-69, was synthesized under hydrothermal conditions with tris­(2-aminoethyl)-amine (tren) as a structure directing agent (SDA). SU-69 crystallizes in a monoclinic space group (<i>C</i>2/<i>c</i>, No. 15) with <i>a</i> = 20.2656(7) Å, <i>b</i> = 11.6250(4) Å, <i>c</i> = 18.5602(10) Å, and β = 90.528(4)°. The framework of SU-69 is built from a novel Ge₁₃O₂₇(OH)₂ (Ge₁₃) cluster with two additional GeO₃(OH) tetrahedra. Two types of chiral 3,6-net building layers are found in the framework, which alternately stack and connect to form a three-dimensional achiral framework with a two-dimensional 10 × 12-ring channel system. The SDA molecules interact with the framework via H-bonds. The thermal stability of as-synthesized SU-69 has also been investigated

Novel Cigarlike TiO₂ Nanofibers: Fabrication, Improved Mechanical, and Electrochemical Performances

By coupling the self-assembly of polystyrene-block-poly­(ethylene oxide) (PS-b-PEO) containing titanium precursors with the electrospinning technique, novel cigarlike nanofibers with an outer-shell and inner-continuous-pore structure and resultant fabrics were fabricated. Different from typical porous metal oxides, the prepared high-surface-area nonwoven fabrics show excellent mechanical properties. Not only are these fabrics self-supporting over a large area, but they can also be cut using scissors, which is important for large-scale applications. Furthermore, as electrode materials in Li-ion batteries, these fabrics exhibit much higher charge/discharge capacity and cycle stability compared with the commercially available nanosized TiO₂ (P25). The improved mechanical and electrochemical performances are attributed to the presence of an outer-shell, inner-bicontinuous structures (including continuous TiO₂ frame and continuous nanopores) and hierarchical pores from the cigarlike nanofibers