A Novel Sandwich‐type Dinuclear Complex for High‐capacity Hydrogen Storage

From density functional theory (DFT) calculations, we predicted that the sandwich‐type dinuclear organometallic compounds Cp₂Ti₂ and Cp₂Sc₂ can adsorb up to eight hydrogen molecules respectively, corresponding to a high gravimetric storage capacity of 6.7% and 6.8% (w), respectively. These sandwich‐type organometallocenes proposed in this work are favorable for reversible adsorption and desorption of hydrogen at ambient conditions.     

Synthesis and Crystal Structure of a Rare Tetra‐Yttrium‐Supported Krebs‐Type Tungstoantimonate

A rare tetra‐yttrium‐supported Krebs‐type tungstoantimonate was prepared in an acidic solution at pH 2.2 and characterized by elemental analysis and IR spectroscopy. Single‐crystal X‐ray analysis was carried out on Na₂[{Y(H₂O)₇}₄Sb₂W₂₂O₇₆]·14H₂O ( 1 ), which comprises a Krebs‐type [Sb₂W₂₂O₇₆]^14– unit supported by four yttrium ions.     

Inorganic‐organic Microporous Solid of Wells‐Dawson Type Polyoxometalate: Synthesis,Characterization, and Electrochemical Properties

An inorganic‐organic hybrid solid (H_6/5bppy)₅[P₂W₁₈O₆₂]·4.5H₂O ( 1 ) (bppy = 4‐(5‐(4‐bromophenyl)pyridin‐2‐yl)pyridine) was hydrothermally synthesized by using pre‐constructed Wells‐Dawson type salt α‐K₆P₂W₁₈O₆₂·15H₂O as inorganic moiety. The crystal structure keeps integrated and steady under the interactions together of aryl packing, hydrogen bonding and halogen bonding. X‐ray single crystal structure analysis reveals that compound 1 contains cavities with the sizes of about 6 × 8Å, in which H₂O molecules are captured. The hybrid was used as a solid bulk modifier to fabricate a three‐dimensional bulk‐modified carbon paste electrode ( 1 ‐CPE) by direct mixing. The electrochemical and electrocatalytic behavior of the 1 ‐CPE has been studied in detail. The results exhibit that the redox ability of the Wells‐Dawson polyanions can be maintained in the hybrid solid, which has a good electrocatalytic activity toward the reduction of bromate and hydrogen peroxide. A hydrodynamic voltammetric experiment was performed to characterize the electrode as an amperometric sensor for the determination of hydrogen peroxide. The 1 ‐CPE showed long‐term stability and excellent reproducibility of surface renewal.     

Cation Effect on Formation of Preyssler‐type 30‐Tungsto‐5‐phosphate: Enhanced Yield of Na‐encapsulated Derivative and Direct Synthesis of Ca‐ and Bi‐Encapsulated Derivatives

The effect of cations in a reaction mixture for the preparation of the Preyssler‐Jeannin‐Pope type 30‐tungsto‐5‐phosphate [P₅W₃₀O₁₁₀Na]^14– is investigated. Reaction of phosphate and tungstate with a P/W ratio of ca. 3.9 in an acidic aqueous solution without cations selectively leads to the Dawson‐type 18‐tungsto‐2‐phosphate, [P₂W₁₈O₆₂]^6–. Amongst all the alkali cations, only Na⁺ allows formation of the Preyssler‐type polyanion [P₅W₃₀O₁₁₀Na]^14–, with an encapsulated Na⁺ ion, and the product yield can be improved by increasing Na⁺ amount. The presence of Li⁺ ions instead results in the Dawson‐type polyanion [P₂W₁₈O₆₂]^6–, whereas K⁺, Rb⁺, and Cs⁺ selectively result in the Keggin‐type polyanion [PW₁₂O₄₀]^3–. An improved synthetic procedure for the Na⁺‐encapsulated Preyssler‐ion leading to a higher isolated yield is presented. Furthermore, addition of Ca²⁺ and Bi³⁺ compounds allows formation of the Ca²⁺‐ and Bi³⁺‐encapsulated Preyssler‐type polyanions, [P₅W₃₀O₁₁₀Ca]^13– and [P₅W₃₀O₁₁₀Bi]^12–, respectively. Furthermore, single‐crystal XRD structure of the Bi³⁺‐encapsulated Preyssler‐type polyanions, [P₅W₃₀O₁₁₀Bi]^12–, is presented for the first time.     

An Organic‐Inorganic Hybrid Based on Keggin‐Type Polyoxometalate and Hypoxanthine: Synthesis,Structure, Stability,and Electrochemistry Properties

The organic‐inorganic hybrid H₅[Ag₂(hyp)₂]₂[BW₁₂O₄₀] · 9H₂O ( 1 ) (hpy = hypoxanthine), based on Keggin‐type polyoxometalate and hypoxanthine, was prepared by hydrothermal synthesis and characterized by single‐crystal and powder X‐ray diffraction, IR spectroscopy, elemental analysis, and thermogravimetry. The title compound has a two‐dimensional layer structure constructed by Keggin‐type [BW₁₂O₄₀]^5– anion, silver, and the biomolecule hyp. In addition, compound 1 exhibited excellent stability and superior activity in the electro‐catalytic oxidation of glucose.     

Synthesis,Structure and Magnetic Properties of a Novel N‐Benzenesulfonyl‐L‐glutamic Acid‐bridged Manganese(II) Polymer with Double‐Chain Structure

First N‐benzenesulfonyl‐L‐glutamic acid‐bridged manganese(II) coordination polymer [Mn(bipy)(bs‐glu)]_n (bs‐glu = N‐benzenesulfonyl‐L‐glutamic acid dianion, bipy = 2, 2′‐bipyridine) has been synthesized and characterized structurally and magnetically. It crystallizes in the orthorhombic space group P2₁2₁2₁. The γ‐carboxyl group coordinates to the Mn^II atom in a chelating mode, while the α‐carboxyl group coordinates in a bidentate‐bridging mode. The complex displays a one‐dimensional double‐chain polymer. Magnetic measurements show that there are weak antiferromagnetic interactions between the adjacent Mn^II ions in the compound.     

Two Extended 5‐Methyltetrazolate‐Based Magnetic Complexes: Synthesis,Structure, and Magnetic Properties

Two 5‐methyl‐tetrazolate (mtz^–)‐based paramagnetic metal coordination polymers, {[Cu₂(H₂O)₂(mtz)(μ₃‐OH)(nip)] · H₂O}_n ( 1 ) and [Cu(H₂O)(mtz)₂]_n ( 2 ), were obtained in the presence and absence of aromatic 5‐nitroisophathalate (nip^2–) coligand by varying the preparation methods. Structural determinations reveal that 1 is a three‐dimensional (3D) framework with corner‐sharing triangular ribbons infinitely extended by ditopic nip^2– connectors. In contrast, 2 is a coplanar (4,4) layer constructed from square‐pyramidal Cu^II ions and μ‐N1,N4‐mtz^– linkers, which is further assembled into a 3D supramolecular network by interlayer hydrogen‐bonding interactions. Magnetically, spin‐frustrated antiferromagnetic ordering is observed in the 3D framework of 1 and canted antiferromagnetic behavior with a slight spin‐flop transition is presented in 2 , which are structurally resulting from the locally Δ‐ribbon in 1 and asymmetric magnetic superexchange mediated by the μ‐N1,N4‐mtz^– bridge of 2 .     

Fabrication,Characterization, and Application of ‘Sandwich‐Type’ Electrode Based on Single‐Walled Carbon Nanotubes and Room Temperature Ionic Liquid

The much‐enhanced electrochemical responses of potassium ferricyanide and methylene blue (MB) were firstly explored at the glassy carbon electrode modified with single‐walled carbon nanotubes (SWNT/GCE), indicating the distinct electrochemical activity of SWNTs towards electroactive molecules. A hydrophobic room temperature ionic liquid (RTIL), 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMIMPF₆), was used as electrode modification material, which presented wide electrochemical windows, proton permeation and selective extraction ability. In consideration with the advantages of SWNTs and RTIL in detecting target molecules (TMs), a novel strategy of ‘sandwich–type’ electrode was established with TMs confined by RTIL between the SWNT/GCE and the RTIL membrane. The strategy was used for electrochemical detection of ascorbic acid (AA) and dopamine (DA), and detection limits of 400 and 80 fmol could be obtained, respectively. The selective detection of DA in the presence of high amount of AA could also be realized. This protocol presented many attractive advantages towards voltammetric detection of TMs, such as low sample demand, low cost, high sensitivity, and good stability.     

Synthesis,Surface Activity,and Antifogging Property of Triethanolamine Monolaurate Ester

Triethanolamine monolaurate ester was synthesized by lauric acid and triethanolamine (TEA) with a molar ratio around 1:1 and the esterification process was investigated and optimized. The esterification product of lauric acid with TEA was characterized by infrared spectra and nuclear magnetic resonance. The surface tension (γ_CMC) at the critical micelle concentration (CMC) was determined, and the antifogging properties of triethanolamine laurate ester on low-density polyethylene (LDPE) films were also measured. The results indicated that the yield of triethanolamine monolaurate ester was more than 69% under optimized esterification condition, the CMC value and γ_CMC of esterification product was 0.91 μg/mL and 22.1 mN/m in aqueous solution at 25 ^oC, respectively. The first-drop time and ten-drop time was 257 and 86 s, respectively, and the antifogging duration of triethanolamine laurate ester on the surface of LDPE film at 60 ^oC was more than 150 h.     

Synthesis,Structures, and Magnetic Properties of Zigzag Tetranuclear Lanthanide Complexes

Five isostructural tetranuclear lanthanide complexes with the general formula [Ln₄(teaH₂)₂(teaH)₂(NO₃)₆] · 2CH₃OH [Ln³⁺ = Dy³⁺ ( 1 ), Tb³⁺ ( 2 ), Ho³⁺ ( 3 ), Er³⁺ ( 4 ), and Gd³⁺ ( 5 )] were successfully synthesized by the reaction of various lanthanide nitrate and triethanolamine (teaH₃) ligand. Single crystal X-ray analyses reveal the eight-coordinate Ln³⁺ centers adopt a slightly distorted triangular dodecahedron geometry and nine-coordinate Ln³⁺ ions own an approximately capped square antiprism environment in similar zigzag Ln4 core. Magnetic studies demonstrate the presence of anitferromagnetic interactions between Ln³⁺ centers without obvious SMM behavior.     

Novel 1D Copper(II) Helical Chain Formed by Weak Coordination‐driven Self‐assembly: Synthesis,Structure, and Magnetic Property

A novel 1D copper(II) helical chain is constructed through the connection of tetranuclear copper(II) units [Cu₄(L)(Py)₄] (H₈L=N,N′‐(BINOL‐3,3′‐dicarboxyl)‐disalicylhydrazide, where BINOL is 1,1′‐binaphthalenyl‐2,2′‐diol, py=pyridine) by weak coordination‐driven self‐assembly, and characterized by IR, single crystal X‐ray diffraction, thermogravimetric analysis, and X‐ray power diffraction analysis. Interestingly, the helical chains are packed in an alternating left‐(M) and right‐handed (P) chirality, the orientation of the helices was determined by the axial chirality of the ligand. The complex shows antiferromagnetic interactions between the copper centers.     

Three 3‐Amino‐1, 2, 4‐Triazole‐Based Magnetic Complexes Incorporated with Different Carboxylate‐Containing Coligands: Synthesis,Structures, and Magnetic Properties

Three 3‐amino‐1, 2, 4‐triazole (atz)‐based paramagnetic complexes, [Mn(atz)(pa)]_n ( 1 ), {[Mn(atz)_1.5(hip)] · H₂O}_n ( 2 ), and [Mn(H₂O)₂(atz)₂(nb)₂] ( 3 ) (H₂pa = o‐phthalic acid, H₂hip = 5‐hydroxylisophthalic acid, and Hnb = p‐nitrobenzoic acid) were prepared by introducing different carboxylate‐containing aromatic coligands, and structurally and magnetically characterized. Helical Mn^II‐atz and bent Mn^II‐pa^2– chains are crosslinked by sharing the same metal sites to generate a honeycomb‐shaped framework of 1 . The undulated Mn^II‐atz layers constructed from 22‐member metallomacrocycles are periodically supported by ditopic hip^2– ligands to lead to a pillared‐layer structure of 2 . In contrast, complex 3 is a centrosymmetric mononuclear entity, which is assembled into a three‐dimensional supramolecular network by abundant hydrogen‐bonding interactions. The structural difference of 1 – 3 is significantly due to the combinations of the flexible coordination modes adopted by the mixed atz and carboxylate groups. Weak and comparable antiferromagnetic couplings are observed in the nearest neighbors of 1 – 3 , which are cooperatively transmitted either by short carboxylate and/or atz heterobridges or by weak non‐covalent interactions.     

Structure and Magnetic Properties of Two Lanthanide 1,4‐Phenylenediacetate Compounds

The reactions of Ln(NO₃)₃ with 1,4‐phenylenediacetic acid (H₂PDA) under hydrothermal conditions produced two isostructural lanthanide coordination polymers with the empirical formula [Ln₂(PDA)₃(H₂O)] · 2H₂O [Ln = Nd ( 1 ), Sm ( 2 )]. Single‐crystal X‐ray diffraction analyses revealed that both contain one‐dimensionalmetal carboxylato chains, which are further connected by the–CH₂C₆H₄CH₂– spacers of PDA^2– ligands to yield a three‐dimensional metal‐organic framework. Magnetic susceptibilities of 1 and 2 were measured. The experimental χ_mT value of both compounds decreases continuously with decreasing temperature over the whole temperature range. The best least‐squares fit of the experimental data of 1 to a theoretical equation in the temperature range of 70–300 K gives the zero‐field splitting parameter Δ = 2.21 cm^–1 and the magnetic interaction between the Nd^III ions 2zJ′ = –1.97 cm^–1, which indicates the presence of antiferromagnetic interaction between the Nd^III ions. The experimental χ_mT value of 2 at 2 K is much smaller than the expected value for two free Sm^III ions (⁶H_5/2, g = 2/7) in the ground state, indicating that an antiferromagnetic interaction possibly exists between Sm^III ions at low temperature. Fitting the magnetic data of 2 above 110 K based on an equation deduced from the Sm^III ion in a monomeric system with free‐ion approximation gave a spin‐orbit coupling parameter λ = 192(2) cm^–1     

A 3D Polyoxometalate‐Based Framework Constructed from Ag/trz Metal‐Organic Ribbons and P2W18 Polyoxoanions: Synthesis,Structure and Electrochemical Properties

A Wells‐Dawson Polyoxometalate‐based hybrid, Ag₉(trz)₃(Htrz)₄ (H₂O)(P₂W₁₈O₆₂)·3H₂O ( 1 ) (Htrz = 1,2,4‐1H‐triazole) was hydrothermally synthesized through using trz ligand and silver nitrate in the presence of [P₂W₁₈O₆₂]^6– polyoxoanion. In the 3D framework structure of compound 1 , two kinds of wave‐like Ag/trz chains originated from trz ligands and silver cations are aggregated in a “2+1” mode by {Ag₂/trz} linkages to result in a 1D Ag/trz metal‐organic ribbon, which is further extended into a 3D framework structure by [P₂W₁₈O₆₂]^6– polyoxoanions through Ag‐O covalent bonds. Additionally, the electrochemical properties of compound 1 have also been investigated.     

具有三维交叉孔道的新型亚磷酸锌的合成与结构

本文报道了一种新型三维亚磷酸锌[HO(CH₂)₂NH₃]₂•[Zn₃(HPO₃)₄]的合成和晶体结构。在它的结构中，ZnO₄和HPO₃严格按照顶点连接的方式交替相连。骨架结构存在两个沿着不同方向无限延伸的由ZnO₄和HPO₃组成的四元环链，在[0 1 0]、[0 4 15]和[0 -4 15]三个方向形成了三个交叉8元环孔道，有机胺阳离子起着平衡电荷和稳定骨架的结构。它的晶体数据为：[HO(CH₂)₂NH₃]₂•[Zn₃(HPO₃)₄],M=640.21, 正交晶系, Fdd2空间群, a=2.8528, b=0.8426, c=1.6159nm, Z=8, V=3.884nm³, R₁=0.0219, wR₂=0.0544。     

Synthesis,Structure, and Spectroscopic Properties of Octa(iso‐pentoxy)phthalocyaninatometal Complexes

A series of octa‐substituted metal phthalocyanines [MPc(OC₅H₁₁)₈] (M = Co, Ni, Cu, Zn, Pc = phthalocyaninato, (OC₅H₁₁)₈ = iso‐pentoxy) were obtained from condensation of iso‐pentoxy phthalonitrile in the presence of DBU in n‐pentanol. The compounds were characterized using elemental analysis, IR, and UV/Vis spectra. The crystal structures of all compounds except M = Zn were determined by X‐ray diffraction methods. It was found that the distortion of Pc skeleton come of not only the intra‐molecular steric congestion of bulky substituents, but also the slipped overlaps of the closest molecules. The relations of some bond lengths of the Pc's skeleton to the substituents and central metal atom, as well as the spectroscopic properties are discussed.     

Three Novel 1‐H‐Benzimidazole‐5‐Carboxylate‐Based Nickel(II)/Cobalt(II) Coordination Polymers: Synthesis,Crystal Structures,Luminescent, and Magnetic Properties

Three 1H‐benzimidazole‐5‐carboxylate (Hbic^–)‐based coordination polymers, {[Ni(H₂O)(Hbic)₂] · 2H₂O}_n ( 1 ), {[Ni(H₂O)₂(Hbic)₂] · 3H₂O}_n ( 2 ), and {[Co₂(H₂O)₄(Hbic)₄] · 4DMF · 3H₂O}_n ( 3 ) were obtained by reactions of the ligand H₂bic and Ni^II or Co^II salts in the presence of different structure directing molecules. They were structurally characterized by single‐crystal X‐ray diffraction, IR spectra, elemental analysis, thermal stability, luminescent, and magnetic measurements. Structural analysis suggests that the three polymers exhibit a 2D (4, 4) layer for 1 and 1D linear double chains for both 2 and 3 due to the variable binding modes and the specific spatial orientation of the Hbic^– ligand towards the different paramagnetic metal ions, which were further aggregated into different 3D supramolecular architectures by popular hydrogen‐bonding interactions. Weak and comparable antiferromagnetic couplings mediating by Hbic^– bridge are observed between the neighboring spin carriers for 2 and 3 , respectively. Additionally, complexes 1 – 3 also display different luminescence emissions at room temperature due to the ligand‐to‐metal charge transfer.     

A New Organic‐Inorganic Charge‐transfer Salt [C15H17N4]4[Mo8O26] — Synthesis,Properties and Crystal Structure

A new organic donor 3‐amino‐6‐dimethylamino‐2‐methyl‐phenazine was introduced to charge‐transfer complex with polyoxometalate. The complex [C₁₅H₁₇N₄]₄[Mo₈O₂₆] ( 1 ) was synthesized by hydrothermal reaction of neutral red chloride (3‐amino‐6‐dimethylamino‐2‐methyl‐phenazine hydrochloride) and (NH₄)₆[Mo₇O₂₄] · 4H₂O and was characterized by EPR, element analysis and single crystal x‐ray diffraction.     

Syntheses,Structures and Spectroscopic Characterization of Extended Waugh‐Type Polyoxometalates with Metal Ions as Linkers

Two extended Waugh‐type polyoxometalates compounds, (NH₄)₄Na₂[MnMo₉O₃₂]·6H₂O ( 1 ) and (NH₄)₂Na₂[{Cu(H₂O)₄}(MnMo₉O₃₂)]·5H₂O ( 2 ) have been synthesized and characterized. Both of the left‐handed and right‐handed [MnMo₉O₃₂]^6? polyanions enantiomers can be observed in compounds 1 and 2 . In compound 1 , the homochiral [MnMo₉O₃₂]^6? polyanions enantiomers are linked by sodium ions to form two kinds of alternately arranged 2D polymeric sheets, which are further stacked into a 3D framework. In compound 2 , the homochiral [MnMo₉O₃₂]^6? polyanions enantiomers are linked by [(H₂O)₂Cu(μ₂‐H₂O)₂Na(H₂O)₂]³⁺ bimetal aggregates to form two kinds of alternately arranged zigzag chains, which are further weaved into a 2D polymeric sheet by sodium ions. In addition, the influence of the synthesis conditions has also been studied.