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Reversible Insertion of CO_(2)into a Bis(formazanate)Magnesium Complex

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CCS chemistry 2023年第6期5卷 1277-1284页

作者： Da Jin Xiaofei Sun Alexander Hinz Peter W.Roesky institute for inorganic chemistry Karlsruhe Institute of Technology76131 Karlsruhe

The capture,storage,and release of CO_(2)is one of the most pressing issues in chemistry.Herein,we designed bis(formazanate)magnesium complexes as precursors,which were synthesized by straightforward transamination between the neutral formazan[PhNNC(4-tBuPh)NNHPh](LH)and[Mg{N(SiMe_(3))_(2)}_(2)].Depending on the solvent,either the homoleptic complex[L_(2)Mg]or the thf-coordinated complex[L_(2)Mg(thf)]was isolated.Reaction of the solvent-free complex[L_(2)Mg]with CO_(2)led to stoichiometric insertion into one of the four Mg–Nbonds with concomitant rearrangement of the ligand scaffold which adopts a trinuclear cagelike structure.The insertion reaction is reversible depending on thermolysis or treatment with tetrahydrofuran,which is corroborated by density functional theory calculations.This showcases the first example of reversible uptake of CO_(2)by an s-block coordination compound.

关键词： reversibility CO_(2)activation formazanate magnesium s-block chemistry

Forging a Cage into a Chain:Stepwise Transformation of P_(4) by Silylenes to a Si_(3)P_(4) Motif

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CCS chemistry 2022年第6期4卷 1843-1849页

作者： Xiaofei Sun Alexander Hinz Peter W.Roesky Institute of Inorganic Chemistry Karlsruhe Institute of Technology(KIT)76131 Karlsruhe

We have discovered a route to access the longest low-valent molecular silaphospha-chain,a sevenmembered chain structure that incorporates three silicon and four phosphorus atoms by stepwise activation of white phosphorus(P_(4))using two different silylene precursors.The chain species was formed via a highly reactive polyphosphide intermediate.The isolation of a stable analogue of this reaction intermediate was achieved by stepwise reaction with mono and bis(silylenes).Due to the rigidity of the ferrocenediyl framework of the bis(silylene),the isomerization process of the chain structure was hampered.Theoretical studies such as natural bond orbital and atoms in molecules analyses of the seven-membered chain species indicated some degree of delocalization of the double bond system.

关键词： phosphorus P_(4)activation silylene silicon main group synthesis

Nitric oxide(NO) decomposition on catalysts, containing oxides of lanthanum and cerium, supported on γ-alumina

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Journal of Rare Earths 2019年第2期37卷 151-159页

作者： D.Stoyanova P.Georgieva I.Avramova K.Aleksieva D.Marinova D.Mehandjiev institute of General and inorganic chemistry-BAS institute of Catalysis-BAS

The present work was devoted to study the catalytic activity of lanthanum and cerium oxides separately,deposited on g-alumina in the reaction of decomposition of nitric oxide. The catalyst samples were prepared by the method of impregnation of g-Al_2 O_3 using solutions, containing nitrates of lanthanum and cerium. The prepared samples were calcined for 4 h at temperature 650℃ in an oven in air atmosphere. The catalysts were characterized by: chemical analysis by inductively coupled plasma atomic emission spectrometry(ICP-AES), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM) combined with energy-dispersive X-ray spectroscopy(EDS), electron paramagnetic resonance(EPR) and infrared(IR) spectroscopy, as well as measurement of the specific surface area. The results show that the catalysts based on lanthanum oxide and cerium oxide deposited on alumina display high catalytic activity over 60% conversion degree with respect to decomposition of nitric oxide in the absence of reducing agent. In the presence of reducer the activity reaches 90% conversion degree.

关键词： Rare earths Catalysts Catalytic activity Decomposition of nitric oxide

Dual-radical-based molecular anisotropy and synergy effect of semi-conductivity and valence tautomerization in a photoswitchable coordination polymer

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National Science Review 2023年第6期10卷 200-214页

作者： Jing-Wei Dai Yu-Qin Li Zhao-Yang Li Hai-Tao Zhang Carmen Herrmann Shohei Kumagai Marko Damjanovi? Markus Enders Hiroyuki Nojiri Masakazu Morimoto Norihisa Hoshino Tomoyuki Akutagawa Masahiro Yamashita State Key Laboratory of Medicinal Chemical Biology Nankai University School of Materials Science and Engineering Nankai University institute of inorganic and Applied chemistry University of Hamburg Department of chemistry Graduate School of Science Tohoku University Institute of Inorganic Chemistry University of Heidelberg institute for Materials Research Tohoku University Department of chemistry Rikkyo University institute of Multidisciplinary Research for Advanced Materials (IMRAM) Tohoku University

Organic radicals are widely used as linkers or ligands to synthesize molecular magnetic materials.However,studies regarding the molecular anisotropies of radical-based magnetic materials and their multifunctionalities are rare.Herein,a photoisomerizable diarylethene ligand was used to form{[CoⅢ(3,5-DTSQ·-)(3,5-DTCat2-)]2(6F-DAE-py2)}·3CH3CN·H2O(o-1·3CH3CN·H2O,6F-DAE-py2=1,2-bis(2-methyl-5-(4-pyridyl)-3-thienyl)perfluorocyclopentene),a valence-tautomeric(VT) coordination polymer.We directly observed dual radicals for a single crystal using high-field/-frequency(～13.3 T and～360 GHz) electron paramagnetic resonance(EPR) spectroscopy along the c-axis,which was further confirmed by angle-dependent Q-band EPR spectroscopy.Moreover,a conductive anomaly close to the VT transition temperature was observed only when probes were attached at the ab plane of the single crystal,indicative of synergy between valence tautomerism and conductivity.Structural anisotropy studies and density functional theory(DFT) calculations revealed that this synergy is due to electron transfer associated with valence tautomerism.This study presents the first example of dual-radical-based molecular anisotropy and charge-transfer-induced conductive anisotropy in a photoswitchable coordination polymer.

关键词： valence tautomerization charge transfer photo switching diradical coordination polymer

Nucleation of methane hydrate and ice in emulsions of water in crude oils and decane under non-isothermal conditions

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Chinese Journal of Chemical Engineering 2019年第3期27卷 668-676页

作者： Andrey S. Stoporev Lidiya I. Svarovskaya Larisa A. Strelets Lubov’ K. Altunina Galina V. Villevald Tamara D. Karpova Tatyana V. Rodionova Andrey Yu. Manakov Nikolaev Institute of Inorganic Chemistry SB RAS Novosibirsk State University institute of Petroleum chemistry

Achievable supercooling for the formation of methane hydrate from water emulsions was studied in seven different crude oils and in decane. The experiments were performed under constant rate cooling from + 20 to-15 °C and a pressure of methane of 12 MPa. It was demonstrated that the shapes and positions of the resulting survival curves depend on the density, viscosity and dispersive power of oil samples used in the experiments, as well as on the degree of oil oxidation. In addition, results of the experiments on ice freezing under the same emulsions are presented. The results obtained in the work allowed us to discuss the possibility and features of primary and secondary nucleation of the hydrate and ice in the systems under consideration.

关键词： Methane hydrate Crude oil Oil dispersive system Nucleation

Impact of lanthanum on the modification of HfO_2 films structure

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Journal of Rare Earths 2015年第8期33卷 857-862页

作者： T.P.Smirnova L.V.Yakovkina V.O.Borisov Nikolaev Institute of Inorganic Chemistry SB RAS

LaxHf1-xOy thin films with various concentrations of La, homogeneous and nonhomogeneous distributions of elements throughout the films thickness was purposefully grown by CVD. The composition of the films and their chemical structures were characterized throughout the films thickness by X-ray photoelectron spectroscopy （XPS） and energy-dispersive X-ray spectrometry （EDXA）. A full picture of the film crystallinity was provided by the combination of grazing incidence X-ray diffraction （GIXRD） synchrotron radiation （SR） and high resolution transmission electron microscopy （HR TEM）. It was shown that La acted as ＂molar volume modulator＂ and stabilized the nonequilibrium at T≤1300 ℃ cubic phases. The samples with La content in range of 7 at.%〈CLa〈22 at.% were materials with fluorite-type （Fm-3m） structure. The pyroehlore phase formation was observed at -18 at.% La content. The correlation between the La-doped content and the films microstructure was revealed.

关键词： Hf1-xLaxOy films solid solutions X-ray diffraction microstructure rare earths

[Y(dbm)_(3)(H_(2)O)]:Synthesis,thermal behavior and spin-coating precursor for Y_(2)O_(3)layer formation

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Journal of Rare Earths 2017年第12期35卷 1248-1254页

作者： Elaheh Pousaneh Andrea Preuβ Khaybar Assim Julian Noll Alexander Jakob Tobias Rüffer Heinrich Lang Technische Universitat Chemnitz Faculty of Natural SciencesInstitute of ChemistryInorganic Chemistry

The synthesis,structure and thermal behavior of [Y（dbm）3（H2 O）]（3）（dbm = 1,3-diphenyl-1,3-propandionate） and its use as a spin-coating precursor for Y2 O3 deposition is reported. Complex 3 was prepared by the reaction of [Y（NO3）3·6 H2 O]（1） with 3 equiv of Hdbm（2） in presence of NaOH. The molecular structure of 3 in the solid-state was determined by single X-ray crystal diffraction. Both C1 symmetric crystallographically independent species of 3 possess a YO7 coordination setup with minor deviation from an ideal capped octahedron coordination geometry（∧ enantiomer）. Complex 3 forms a1 D chain, due to intermolecular hydrogen bonds between the coordinated H2 O molecule and the 0 atom of the dbm ligand, respectively. The thermal decomposition behavior of 3 was investigated by thermogravimetric studies in the temperature range of 40-800 ℃ and 40-1300 ℃ under an oxygen and argon atmosphere, respectively. Powder X-ray diffraction（PXRD） measurements of the residues confirmed the formation of Y2 O3. Complex 3 was applied as a spin-coating precursor for yttrium oxide film formation on either Si wafers with a continuous 100 nm thick SiO2 film, or with a native oxide layer.The as-deposited Y2 O3 layers are smooth, conformal, dense and transparent and are of a thickness of 27 and 30 nm, respectively.

关键词： Yttrium β-Diketonate Yttrium oxide Spin-coating Solid-state structure Vapor pressure

Succinate-bonded pullulan: An efficient and reusable super-sorbent for cadmium-uptake from spiked high-hardness groundwater

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Journal of Environmental Sciences 2015年第11期27卷 51-58页

作者： Azhar Abbas Muhammad Ajaz Hussain Muhammad Amin Muhammad Sher Muhammad Nawaz Tahir Wolfgang Tremel Department of chemistry University of Sargodha institute of inorganic and Analytical chemistry Johannes Guttenberg University

Chemically modified pullulan was evaluated for its sorption efficiency and selectivity to remove cadmium（Cd） from spiked high-hardness groundwater（GW）. Pullulan esterified with succinic anhydride using dimethylaminopyridine showed a fairly high degree of substitution value as confirmed by1 H NMR spectroscopy. Pullulan succinate（Pull-Suc） was converted into the sodium salt（Pull-Suc-Na）. The effect of contact time（5–200 min） and p H（2–8） on Cd-uptake by the sorbent（Pull-Suc-Na） was investigated. The sorbent showed more than 90% Cd-removal in first 15 min from distilled water（DW） and GW solution,respectively. Comparison of Pull-Suc-Na with other polysaccharidal sorbents suggested its high efficiency（DW 476.2 mg/g and GW 454.5 mg/g） and selectivity for the removal of Cd by an ion exchange mechanism, which is further supported by the negative Gibbs free energy values calculated from Langmuir isotherms. A Langmuir isotherm kinetic model provided the best fit for the sorption of Cd using Pull-Suc-Na. The sorbent showed a negligible decrease in Cd-uptake over three regeneration cycles. The thermal stability testing of the sorbents indicated that Pull-Suc-Na（sorbent） is more stable than Pull-Suc.

关键词： Adsorption Cadmium Modified pullulan Succinylation Thermal stability

Crystal-to-crystal transformation from the triclinic to the cubic crystal system by partial desolvation

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Frontiers of Chemical Science and Engineering 2018年第3期12卷 433-439页

作者： Qianqian Guo Irmgard Kalf Ulli Englert Institute of Inorganic Chemistry RWTH Aachen University Aachen Germany

Diffusion reaction of the labile building block Mg（acacCN）2 （acacCN= 3-cyanoacetylacetonate） with silver salts leads to a series of solvated Mg/Ag bimetallic coordination polymers with composition [Mg（acacCN）aAg].solvent. Despite their common stoichiometry, the topology of these polymers depends on the solvent of crystallization. The two-dimensional coordination compound [Mg（acacCN）aAg]-4CHCl3 in space group P]- is obtained as platelet-shaped crystals from a mixture of methanol and chloroform. When kept in the reaction mixture, these thin plates within one week convert to isometric tetrahedral crystals of the 3D network [Mg（acacCN）3Ag]. 2CHC13 in the cubic space group/9213. The transformation reaction proceeds via dissolution and recrystallization. The co-crystallized solvent molecules play an important role for stabilizing the target structure： They subtend Cl...Cl contacts and interact via non- classical C-H.-. O hydrogen bonds with the coordination framework. In the new cubic coordination network, both Mg（II） and Ag（I） adopt octahedral coordination, with unprecedented face-sharing by bridging O atoms of three acetylacetonato moieties. Prolonged standing of [Mg（acacCN）3Ag]-2CHCl3 in the reaction medium leads to further degradation, under formation of [Ag（acacCN）].

关键词： ditopic ligand substituted acetylacetone desolvation diffraction