Ionothermal Syntheses Research Articles

Ionothermal syntheses, crystal structures and luminescence of three three-dimensional lanthanide-1,4-benzenedicarboxylate frameworks

Ionothermal reactions of LnCl3 (Ln=Sm(1), Eu(2) and Tb(3)) with 1,4-benzenedicarboxylic acid (H2BDC) in 1-ethyl-3-methylimidazolium bromide (EMIM-Br) ionic liquid (IL) afforded three compounds, namely, {(EMIM)2[Sm2(BDC)3(H2-BDC)Cl2]}n (1) and {(EMIM)[Ln2(μ2-Cl)(BDC)3]}n (Ln=Eu(2) and Tb(3)). These compounds consist of anionic three-dimensional frameworks and extraframework charge-balancing species of imidazolium [EMIM]+ cations. Compound 1 has a 8-connected (36·418·53·6) topology based on the dinuclear samarium(III) secondary building units. Compounds Eu(2) and Tb(3) are isomorphous and are constructed from the one-dimensional rod-shaped lanthanide-carboxylate secondary building units. Each lanthanide-carboxylate rod connects to six neighboring rods through the benzene rings of BDC2− ligands to form a parallel packing of hex type topology. It is noted that the chloride ion deriving from lanthanide salt as the co-ligand is incorporated into the structures under the ionothermal reactions. Detailed photoluminescence studies showed all compounds exhibit typical lanthanide luminescent emissions and the Eu(III) and Tb(III) luminescence was efficiently sensitized by the organic ligand. Additionally, the use of an IL solvent for preparation of the lanthanide compounds can effectively prevent the coordination of water and organic solvent molecules from lanthanide centers. Thus the luminescence quenching resulting from the coordinated solvent molecules is avoided.

ChemInform Abstract: Carbon Aerogels and Monoliths: Control of Porosity and Nanoarchitecture via Sol—Gel routes

AbstractReview: 110 refs.

Carbon Aerogels and Monoliths: Control of Porosity and Nanoarchitecture via Sol–Gel routes

The synthesis of carbon aerogels by sol–gel like processes, i.e., hard templating, phase demixing, hydrothermal carbonization techniques, as well as by ionothermal syntheses are reviewed. In all these techniques, we start with a liquid reaction solution, where—controlled by experimental parameters and structure-directing additives—a porous carbon material with high conductivity, high pore volume, and high specific surface area is obtained. Many of these synthesis approaches give the resulting material in simple, rather sustainable processes, and the structures can be employed directly after isolation without further activation processes. The article will discuss also some applications, such as battery and electrode materials as well as catalyst supports.

Ionothermal syntheses and characterization of 2-D coordination polymers with 4-(1H-imidazol-1-yl) benzoic acid

4-(1H-imidazol-1-yl) benzoic acid and its coordination polymers [M(IBA)Cl] n (M = Zn (1) and Co (2)) have been synthesized. Compounds 1 and 2 were obtained under ionothermal conditions and possess a 2-D laminar [M(IBA)] n layer based on M2(CO2)2 building blocks with coordinated chloride completing tetrahedral coordination of the metal. Compound 1 exhibits two photoluminescence emission peaks at 410 and 510 nm. The low-energy emission can be attributed to ligand-centered transition and the high-energy band can be assigned to ligand-to-metal charge transfer between the aromatic systems of the organic ligands and the 4s orbitals of Zn(II). The role of the ionic liquid in ionothermal synthesis and crystallization of 1 and 2 are briefly discussed.

Lead(ii) chloride ionic liquids and organic/inorganic hybrid materials – a study of chloroplumbate(ii) speciation

A range of chloroplumbate(II) organic salts, based on the two cations, 1-ethyl-3-methylimidazolium and trihexyl(tetradecyl)phosphonium, was prepared by ionothermal synthesis. Depending on the structure of the organic cation and on the molar ratio of PbCl2 in the product, χPbCl2, the salts were room-temperature ionic liquids or crystalline organic/inorganic hybrid materials. The solids were studied using Raman spectroscopy; the crystal structure of [C2mim]{PbCl3} was determined and shown to contain 1D infinite chloroplumbate(II) strands formed by edge-sharing tetragonal pyramids of pentacoordinate (PbCl5) units. The liquids were analysed using (207)Pb NMR and Raman spectroscopies, as well as viscometry. Phase diagrams were constructed based on differential scanning calorimetry (DSC) measurements. Discrete anions: [PbCl4](2-) and [PbCl3](-), were detected in the liquid state. The trichloroplumbate(II) anion was shown to have a flexible structure due to the presence of a stereochemically-active lone pair. The relationship between the liquid phase anionic speciation and the structure of the corresponding crystalline products of ionothermal syntheses was discussed, and the data were compared with analogous tin(II) systems.

Ionothermal syntheses, crystal structures and properties of three-dimensional rare earth metal–organic frameworks with 1,4-naphthalenedicarboxylic acid

Twelve isostructural rare earth metal-organic frameworks, namely, [Hmim][RE(2)Cl(1,4-NDC)(3)] (RE = La (1), Ce (2), Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), Tb (8), Dy (9), Ho (10), Er (11), Y (12), Hmim = 1-hexyl-3-methylimidazolium, 1,4-NDCH(2) = 1,4-naphthalenedicarboxylic acid), have been ionothermally synthesized and structurally characterized. The structures feature three-dimensionally anionic frameworks of [RE(2)Cl(1,4-NDC)(3)](n)(n-) with channels in which the Hmim(+) cations are located. The current results are the first ionothermal synthesis of rare earth metal-organic frameworks based on 1,4-NDCH(2) which possess a previously unknown (4,7)-connected 3-nodal network with the Schläfli symbol of (3(2)·4(2)·5(2))(3(2)·4(9)·5(2)·6(8))(2)(4(3)·6(3))(2). Luminescent and magnetic properties of some of the title compounds have been studied. Thermogravimetric analyses indicated that all these compounds were thermally stable up to ca. 250 °C.

Ionothermal Syntheses and Characterizations of New Open-Framework Metal Borophosphates

Three new open-framework metal borophosphates, [Na(6)Co(3)B(2)P(5)O(21)Cl]·H(2)O (JIS-4), K(5)Mn(2)B(2)P(5)O(19)(OH)(2) (JIS-5), (NH(4))(8)[Co(2)B(4)P(8)O(30)(OH)(4)] (JIS-6), have been prepared under ionothermal conditions using ionic liquid 1-ethyl-3-methylimidazolium ([Emim]Br) as the solvent. They are the first examples of metalloborophosphate prepared by the ionothermal method. Their structures are determined by single-crystal X-ray diffraction. The 3-D open framework of JIS-4 is made of CoO(5)Cl octahedra, CoO(5) square pyramids, and PO(4) and BO(4) tetrahedra forming 12-ring channels along the [010] direction. It is noted that JIS-4 is the first 3-D open-framework structure in the family of borophosphate with the B/P ratio of 2/5, which features a borophosphate cluster anionic partial structure. Such cluster anionic partial structures connect with MnO(6) octahedra and MnO(5) trigonal bipyramids resulting in the formation of the 2-D layer structure of JIS-5 with the same B/P ratio as JIS-4. The 2-D layer structure of JIS-6 belongs to the largest family of borophosphate with a B/P ratio of 1/2 which features a unique 1-D chain anionic partial structure. Crystal data for JIS-4, orthorhombic, Pnma, a = 14.0638(8) Å, b = 9.8813(7) Å, c = 14.0008(10) Å, V = 1945.7(2) Å(3), and Z = 2; for JIS-5, monoclinic, P2(1)/n, a = 14.4939(3) Å, b = 9.2539(3) Å, c = 14.8031(4) Å, β = 101.4600(10)°, V = 1945.88(9) Å(3), and Z = 4. For JIS-6, triclinic, P1, a = 9.6928(3) Å, b = 9.8747(3) Å, c = 10.0125(2) Å, α = 62.057(2)°, β = 82.456(2)°, γ = 76.095(2)°, V = 821.60(4) Å(3), and Z = 1.

Ionothermal syntheses and crystal structures of two cobalt(II)–carboxylate compounds with different topology

Abstract Two cobalt–carboxylate compounds, namely, {[PMIM]2[Co2(BTC)2(H2O)2]}n (1) (PMIM = 1-propyl-3-methylimidazolium and H3BTC = 1,3,5-benzenetricarboxylic acid) and [Co3(BDC)3(IM)2]n (2) (H2BDC = 1,4-benzenedicarboxylic acid and IM = imidazole) have been synthesized under ionothermal reactions. Compound 1 has a 3D anionic framework with (4.62)2(42.610.83) topology based on dinuclear cobalt(II) as a secondary building unit. The imidazolium cation [PMIM]+ of the ionic liquid acting as extraframework charge-balancing species occupies the channels of the 3D anionic framework. Complex 2 features a 3D neutral framework with (412.63) topology constructed of unusual linear trinuclear cobalt(II) as a secondary building unit. The rich ionic environments of the ionic liquid may be particularly helpful in the formation of the frameworks of 1 and 2. The roles of the ionic liquid in ionothermal syntheses and crystallizations of compounds are briefly discussed.

Structural, Transport, and Electrochemical Investigation of Novel AMSO4F (A = Na, Li; M = Fe, Co, Ni, Mn) Metal Fluorosulphates Prepared Using Low Temperature Synthesis Routes

We have recently reported a promising 3.6 V metal fluorosulphate (LiFeSO(4)F) electrode, capable of high capacity, rate capability, and cycling stability. In the current work, we extend the fluorosulphate chemistry from lithium to sodium-based systems. In this venture, we have reported the synthesis and crystal structure of NaMSO(4)F candidates for the first time. As opposed to the triclinic-based LiMSO(4)F phases, the NaMSO(4)F phases adopt a monoclinic structure. We further report the degree and possibility of forming Na(Fe(1-x)M(x))SO(4)F and (Na(1-x)Li(x))MSO(4)F (M = Fe, Co, Ni) solid-solution phases for the first time. Relying on the underlying topochemical reaction, we have successfully synthesized the NaMSO(4)F, Na(Fe(1-x)M(x))SO(4)F, and (Na(1-x)Li(x))MSO(4)F products at a low temperature of 300 degrees C using both ionothermal and solid-state syntheses. The crystal structure, thermal stability, ionic conductivity, and reactivity of these new phases toward Li and Na have been investigated. Among them, NaFeSO(4)F is the only one to present some redox activity (Fe(2+)/Fe(3+)) toward Li at 3.6 V. Additionally, this phase shows a pressed-pellet ionic conductivity of 10(-7) S x cm(-1). These findings further illustrate the richness of the fluorosulphate crystal chemistry, which has just been recently unveiled.

Ionothermal syntheses of two coordination polymers constructed from 5-sulfoisophthalic acid ligands with 1-n-butyl-3-methylimidazolium tetrafluoroborate ionic liquid as solvent

Abstract Two coordination polymers, namely, [Co(IM)6][Co2(SIP)3] (1) (IM = imidazole, H3SIP = 5-sulfoisophthalic acid) and [BMIM]2[Cd2(SIP)3] (2) (BMIM = 1-n-butyl-3-methylimidazolium) were synthesized in ionothermal reactions by using ionic liquid 1-n-butyl-3-methylimidazolium tetrafluoroborate as solvent. Single-crystal X-ray analyses revealed that 1 has an anionic 1D polymeric chain charge balanced by an uncommon [Co(IM)6]2+ cation. Complex 2 features an anionic 2D layer containing unique tetranuclear [Cd4(CO2)6(SO3)2] cluster wherein the four Cd atoms are co-planar. The imidazolium cation [BMIM]+ of the ionic liquid acting as charge compensating agent intercalated into the [Cd2(SIP)2]2n− interlayers in structure 2. The rich ionic environments of the ionic liquid may be particularly helpful in the formation of the anionic frameworks of 1 and 2.

Ionothermal syntheses of three transition-metal-containing polyoxotungstate hybrids exhibiting the photocatalytic and electrocatalytic properties

Employing the ionothermal synthesis approach, three new transition-metal-containing polyoxotungstate hybrids: [Dmim] 2Na 3[SiW 11O 39Fe(H 2O)]·H 2O (Dmim=1,3-Dimethylimidazole) ( 1), [Emim] 9Na 8[(SiW 9O 34) 3{Fe 3(μ 2-OH) 2(μ 3-O)} 3(WO 4)]·0.5H 2O(Emim=1-Ethyl-3-meth-ylimidazole) ( 2) and [Dmim]2[HMim]Na 6[(AsW 9O 33) 2{Mn III(H 2O)} 3]·3H 2O (Dmim=1,3-Dimethylimidazole; Mim=1-Methylimidazole) ( 3) have been synthesized in 1-ethyl-3-methyl imidazolium bromide ([Emim]Br) ionic liquids (ILs). Compound 1 possesses a 3-D open framework constructed from the mono-iron III-substituted α-Keggin-type anion and the organic cations [Dmim]+ through the hydrogen bond interactions. Compound 2 contains a [{Fe III 3(μ 2-OH) 2(μ 3-O)} 3(μ 4-WO 4)] cluster surrounded by three [SiW 9O 34] 10− ligands, eight sodium cations and nine dissociative [Emim] + cations around the polyoxoanion. The polyoxoanion of 3 consists of a high-valent trinuclear-manganese (III)-substituted sandwiching polyoxoanion based on the [α-AsW 9O 33] 9− units. All the compounds are characterized by elemental analyses, IR, UV–vis spectra, TG-DTA and XRD analyses. The XPS and EPR spectra of Mn III in 3 were studied. The photocatalytic and electrocatalytic properties, as well as the stabilities of 1– 3 were also investigated.

Ionothermal Syntheses of Six Three-Dimensional Zinc Metal−Organic Frameworks with 1-Alkyl-3-methylimidazolium Bromide Ionic Liquids as Solvents

We have performed ionothermal reactions between Zn(NO3)2 and H3BTC in 1-alkyl-3-methylimidazolium bromide ionic liquids with the alkyl group varying from ethyl to amyl. Six 3-D metal-organic frameworks (MOFs), including two isomeric compounds [Zn3(BTC)2(H2O)2] x 2H2O (1 and 2) (H3BTC = 1,3,5-benzenetricarboxylate acid), [EMI][Zn(BTC)] (3) (E = ethyl, MI = 3-methylimidazolium), [PMI][Zn(BTC)](4) (P = propyl), [BMI]2[Zn4(BTC)3(OH)(H2O)3] (5) (B = butyl), and [AMI][Zn2(BTC)(OH)Br] (6) (A = amyl), have been synthesized and structurally characterized. Compounds 1 and 2 are isomeric compounds, in which the coordination modes of Zn atoms and the BTC3- ligands are considerably different. Compounds 3-6 crystallize with the corresponding ionic liquid cations incorporated in the frameworks. Their crystal structures show various features including various coordination geometries of Zn2+ and various bridging modes of the BTC3- ligands. The incorporated cations appear to have strong interactions with the frameworks.