Highly Proton-Conductive Zinc Metal-Organic Framework Based On Nickel(II) Porphyrinylphosphonate

The design of new solid-state proton-conducting materials is a great challenge for chemistry and materials science. Herein, a new anionic porphyrinylphosphonate-based MOF ( IPCE-1Ni ), which involves dimethylammonium (DMA) cations for charge compensation, is reported. As a result of its unique structure, IPCE-1Ni exhibits one of the highest value of the proton conductivity among reported proton-conducting MOF materials based on porphyrins (1.55×10⁻³ S cm⁻¹ at 75 °C and 80 % relative humidity).     

STRUCTURAL FEATURES OF HYDROGEN- BONDED ORGANIC FRAMEWORKS BASED ON NICKEL(II) 5,10,15,20-TETRAKIS(4- PHOSPHONATOPHENYL)PORPHYRINATE

Journal of Structural Chemistry - Two hydrogen-bonded organic frameworks of the composition [((CH3)2NH2)3.5(Ni-H4.5TPPP)]·DMF·H2O (1) and [((CH3)2NH2)4(Ni-H4TPPP)(H2O)3]·DMF·H2O...     

Erbium complexes with tetra-15-crown-5-phthalocyanine: Synthesis and spectroscopic study

Erbium mono-, bis-, and tris(phthalocyaninates) with tetra-15-crown-5-phthalocyanine (H₂R₄Pc) were synthesized and studied by spectroscopic methods. The complexes were obtained by reacting H₂R₄Pc with erbium salts in high-boiling solvents. To compare the efficiency of two approaches to the synthesis of double-decker lanthanide phthalocyaninates, bis(phthalocyaninate) [Er(R₄Pc)₂] was also obtained by a template procedure from dicyanobenzo-15-crown-5. A combination of physicochemical methods (UV and IR spectroscopy, MALDI-TOF mass spectrometry, ¹H NMR) was used for identifying the compounds and proving their individuality and structure. The photoluminescence method demonstrated that solutions of erbium bis- and tris(phthalocyaninates) in CHCl₃ are nonfluorescent in the visible range of light whereas solutions of mono(phthalocyaninate) in CHCl₃ and DMSO exhibit fluorescence with maxima at 707 and 695 nm, respectively. The oxidation of erbium mono(phthalocyaninate) leads to fluorescence quenching.     

Sorption of Strontium Ions on Potassium-Titanate Nanoparticles of Various Morphology Obtained under Hydrothermal Conditions

The results of the study of the interaction of an aqueous solution of strontium nitrate with potas-sium-titanate nanoparticles of different morphology obtained by the hydrothermal method are reported. Comparative analysis showed the advantage of nanotubes as sorbents over nanolayers and nanowires. As can be seen from the experiment conducted with nanotubes containing aluminum, an amount of strontium sorbed from the solution rises with increasing temperature: at 50°C the absorption by the tubular matrix was ≈ 0.76 × 10^?3 mol g^?1, and at 80°C that was ≈ 2.02 × 10^?3 mol g^?1. Nanotube samples doped with magnesium had the best sorption characteristics: After 5 h of keeping in a solution at 80°С, the content of strontium in them was ≈3.65 × 10^?3 mol g^?1. The results show the promise of using potassium titanate nanoparticles to extract strontium from aqueous solutions.

     

Reactions of some arenes and pyrazoles in MeCN under conditions of undivided-cell electrolysis

As exemplified for the first time by pyrazole and its 4-nitro and 3,5-dimethyl derivatives, N-arylation of pyrazoles can be performed under conditions of undivided-cell amperostatic electrolysis (Pt electrodes, MeCN) of systems containing the pyrazolate anion and (or) pyrazole, arene (benzene, 1,4-dimethoxybenzene, or xylene), and a supporting electrolyte. In the case of electrolysis involving 1,4-dimethoxybenzene as arene, N-arylation followed simultaneously three routes to form an ortho-substitution product (1,4-dimethoxy-2-(pyrazol-1-yl)benzene), an ipso-substitution product (4-methoxy-1-(pyrazol-1-yl)benzene), and an ipso-bisaddition product (1,4-dimethoxy-1,4-di(pyrazol-1-yl)cyclohexa-2,5-diene) in a total current yield of up to 50%. The acid-base properties of the pyrazoles under study affect the ratio of the N-arylation products and govern the required composition of the starting reaction mixture. In the case of a stronger base, such as 3,5-dimethylpyrazole, N-arylation with 1,4-dimethoxybenzene occurred even in the pyrazole—arene—tetraalkylammonium perchlorate system, whereas N-arylation of 4-nitropyrazole (a weaker base) proceeded only in the presence of the pyrazolate anion or another base, viz., sym-collidine. Oxidation of arene to the radical cation is the key anodic reaction. Not only the pyrazolate anion, but also highly basic pyrazole or a solvate complex of weakly basic pyrazole with collidine can serve as a nucleophilic partner in subsequent transformations of these radical cations.     

Thermal behavior of samarium binuclear pivalate and tris-pivalate

Kinetic analysis of the thermolysis of samarium pivalate [Sm₂(μ₂-OOCCMe₃)₄(OOCCMe₃)₂(HOOCCMe₃)₆] · HOOCCMe₃ (1) was carried out (the input data were differential scanning calorimetry (DSC) and thermogravimetry data), and a mathematic model of the process was developed that allowed us to optimize (by calculation) the conditions for formation of {Sm(OOCCMe₃)₃} _n (2) samarium tris-pivalate via thermal decomposition of complex 1. The results of the thermal study of samarium and gadolinium tris-pivalates in the temperature range of −50…+50°C are reported. Specific anomalies were found in the DSC curves and heat capacity versus temperature curves in the temperature range of 0–50°C.     

Application of New Efficient Hoveyda–Grubbs Catalysts Comprising an N→Ru Coordinate Bond in a Six-Membered Ring for the Synthesis of Natural Product-Like Cyclopenta[b]furo[2,3-c]pyrroles

The ring rearrangement metathesis (RRM) of a trans-cis diastereomer mixture of methyl 3-allyl-3a,6-epoxyisoindole-7-carboxylates derived from cheap, accessible and renewable furan-based precursors in the presence of a new class of Hoveyda–Grubbs-type catalysts, comprising an N→Ru coordinate bond in a six-membered ring, results in the difficult-to-obtain natural product-like cyclopenta[b]furo[2,3-c]pyrroles. In this process, only one diastereomer with a trans-arrangement of the 3-allyl fragment relative to the 3a,6-epoxy bridge enters into the rearrangement, while the cis-isomers polymerize almost completely under the same conditions. The tested catalysts are active in the temperature range from 60 to 120 °C at a concentration of 0.5 mol % and provide better yields of the target tricycles compared to the most popular commercially available second-generation Hoveyda–Grubbs catalyst. The diastereoselectivity of the intramolecular Diels–Alder reaction furan (IMDAF) reaction between starting 1-(furan-2-yl)but-3-en-1-amines and maleic anhydride, leading to 3a,6-epoxyisoindole-7-carboxylates, was studied as well.     

Features of sol–gel synthesis of new functional materials based on complex oxides with tunnel structure

A new method of sol–gel synthesis has been proposed for fabrication of functional materials with ramsdellite and hollandite types of crystal structure in the following oxide systems: Me₂O–Me′₂O₃–Me″O₂ (Me = Li, K; Me′ = Ga, Cr, Fe, In; Me″ = Ti, Sn). The formation of titanates with ramsdellite-type structure is shown to achieve at the temperature range of 250–650 °C, when gel combustion occurs. This allows fabrication of materials with high specific surface area. The ramsdellite phases and stannate hollandites are shown to form in the temperature range of 1,100–1,150 °C. Thus our method gives the possibility to reduce the thermo-temporal parameters of synthesis for this class of materials.     

Sulfoethylated polyethylenimine: synthesis in gel and sorption properties

Using the gel synthesis approach of polymer-analogous transformations, N-sulfoethylation of polyethylenimine was carried out by treating the polymer with sodium vinyl sulfonate. The compositions and structures of the products were characterized by elemental analysis, FT-IR spectroscopy, and ¹H NMR spectroscopy. At pH 3.0–4.5 sulfoethylated polyethylenimine can selectively extract Ag^I and Cu^II from an ammonia—acetate buffer solution in the presence of a series of transition and alkaline-earth metals. At pH > 6.5 the sorbent can be used for the group extraction of a number of transition metal ions. The structural feature of the obtained derivative eliminates the selectivity of sorption of Ag^I ions compared to Cu^II ions, which has previously been revealed for the sulfoethylated derivatives of chitosan and polyaminostyrene.