Structural diversity in hybrid vanadium(IV) oxyfluorides based on a common building block

There are only limited reports on vanadium(IV) oxyfluorides (VOFs) with extended crystal structures. Here we expand and enrich the list of existing VOFs with a series of 14 new materials "VOF-n (n = 1-14)" prepared using ionothermal and solvothermal synthesis methods. All of these materials arise from the condensation of a dimeric structural motif. These VOFs can be classified into three groups depending on their key structural features; layer structures: VOF-1 "[HN2C7H6][V2O2F5]", VOF-2 "[HN2C4H4][V2O2F5]", VOF-3 "[HN2C3H4][V2O2F5]" and VOF-4 "V-2(N2C4H4)O2F4", ladder like structures: VOF-5 "[NH4(HN2C3H4)][V2O2F6]", VOF-6 "[K(HN2C3H4)][V2O2F6]", VOF-7 "[HNH2CH2CH3][VOF3]", VOF-8 "[HN2C7H6][VOF3]", VOF-9 "[H2N2C4H6][V2O2F6]", VOF-10 "beta-RbVOF3", VOF-11 "alpha-KVOF3", VOF-12 "beta-KVOF3", VOF-13 "[H-2(NH2)(2)(CH2)(2)][V2O2F6]", and a chain structure: VOF-14 "[H2N2C6H12][V2O2F7]". The crystal structures of VOF-n are presented, and their synthetic and structural relationships are discussed.PostprintPeer reviewe

Synthesis and Characterization of a Novel Hydroquinone Sulfonate-Based Redox Active Ionic Liquid

Introducing redox-active moieties into an ionic liquid (IL) structure is an exciting and attractive approach that has received increasing interest over recent years for a various range of energy applications. The so-called redox-active ionic liquids (RAILs) provide a highly versatile platform to potentially create multifunctional electroactive materials. Ionic liquids are molten salts consisting of ionic species, often having a melting point lower than 100 °C. Such liquids are obtained by combining a bulky asymmetric organic cation and a small anion. Here, we report on the synthesis of a novel RAIL, namely 1-butyl-3-methylimidazolium hydroquinone sulfonate ((BMIM)(HQS)). (BMIM)(HQS) was synthesized in a two-step procedure, starting by the quaternization of methylimidazole using butylchloride to produce 1-butyl-3-methylimidazolium chloride ((BMIM)(Cl)), and followed by the anion exchange reaction, where the chloride anion is exchanged with hydroquinone sulfonate. The resulting product was characterized by 1H NMR, 13C NMR, FT-IR spectroscopy, themogravimetric analysis, and differential scanning calorimetry, and shows a high stability up to 340 °C. Its electrochemical behavior was investigated using cyclic voltammetry at different temperatures and its viscosity analysis was also performed at variable temperatures. The electrochemical response of the presented RAIL was found to be temperature dependent and diffusion controlled. Overall, our results demonstrated that (BMIM)(mix of HQS and HSQ) is redox active and possesses high stability and low volatility, leading to the employment of this RAIL without any additional supporting electrolyte or additives

(p,q) ミニマル チョウゲン リロン ニ オケル ゲンバ ギョウレツ モケイ オヨビ D ブレーン ニ カンスル ケンキュウ

京都大学0048新制・課程博士博士(理学)甲第13577号理博第3235号新制||理||1478(附属図書館)UT51-2008-C495京都大学大学院理学研究科物理学・宇宙物理学専攻(主査)准教授 福間 将文, 教授 川合 光, 教授 植松 恒夫学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDA

Ionic liquids and deep eutectic mixtures as new solvents for the synthesis of vanadium fluorides and oxyfluorides

An exploratory study of the synthesis of vanadium (oxy)fluorides (VOFs) using ionic liquids (ILs) and deep eutectic mixtures (DESs) as a solvent yielded 10 different materials. The previously reported chain type: (NH4)(2)VF5 (1), (NH4)(2)VOF4 (2), NH4VO3 (3) and (H2NH2(CH2)(2)NH2)VF5 (9) have been successfully produced for the first time using ILs as the reaction media. The monomeric (HNH2CH3)(2)VOF4(H2O) (4), the dimer (HNH2CH3)(4)V2O2F8 (5) and the 1D chains (HNH2CH3)(2)VF5 (6), (H2O)(2)VF3 (7), alpha-(H2NH2(CH2)(2)NH2)VOF4 (8) and beta-(H2NH2(CH2)(2)NH2) VOF4 (10) are novel materials. Template control has also been achieved by the selective choice of ILs or the appropriate deep eutectic mixture, where the expected template is delivered to the reaction by the partial breakdown of the urea derivative portion of the DES.</p

An ionothermally prepared S=1/2 vanadium oxyfluoride kagome lattice

Frustrated magnetic lattices offer the possibility of many exotic ground states that are of great fundamental importance. Of particular significance is the hunt for frustrated spin-1/2 networks as candidates for quantum spin liquids, which would have exciting and unusual magnetic properties at low temperatures. The few reported candidate materials have all been based on d9 ions. Here, we report the ionothermal synthesis of [NH4]2[C7H14N][V7O6F18], an inorganic-organic hybrid solid that contains a S = 1/2 kagome network of d1 V4+ ions. The compound exhibits a high degree of magnetic frustration, with significant antiferromagnetic interactions but no long-range magnetic order or spin-freezing above 2 K, and appears to be an excellent candidate for realizing a quantum spin liquid ground state in a spin-1/2 kagome network.PreprintPostprintPeer reviewe