Danil N. Dybtsev

Three-dimensional metal-organic framework with (3,4)-connected net, synthesized from an ionic liquid medium

A new 3D metal-organic framework with a (3,4)-connected network topology is synthesized from an ionic liquid medium; its highly symmetrical structure comprises doubly interpenetrating nets with the cubic-C3N4 topology.

Porous carbon materials with a controllable surface area synthesized from metal–organic frameworks

Carbonization of zinc containing metal-organic frameworks produces porous carbon materials with an interesting linear relationship between the Zn/C ratio of the precursors and the surface area of the resulting carbon materials.

Synthesis of phase-pure interpenetrated MOF-5 and its gas sorption properties.

For the first time, phase-pure interpenetrated MOF-5 (1) has been synthesized and its gas sorption properties have been investigated. The phase purity of the material was confirmed by both single-crystal and powder X-ray diffraction studies and TGA analysis. A systematic study revealed that controlling the pH of the reaction medium is critical to the synthesis of phase-pure 1, and the optimum apparent pH (pH*) for the formation of 1 is 4.0-4.5. At higher or lower pH*, [Zn(2)(BDC)(2)(DMF)(2)] (2) or [Zn(5)(OH)(4)(BDC)(3)] (3), respectively, was predominantly formed. The pore size distribution obtained from Ar sorption experiments at 87 K showed only one peak, at ~6.7 Å, which is consistent with the average pore size of 1 revealed by single crystal X-ray crystallography. Compared to MOF-5, 1 exhibited higher stability toward heat and moisture. Although its surface area is much smaller than that of MOF-5 due to interpenetration, 1 showed a significantly higher hydrogen capacity (both gravimetric and volumetric) than MOF-5 at 77 K and 1 atm, presumably because of its higher enthalpy of adsorption, which may correlate with its higher volumetric hydrogen uptake compared to MOF-5 at room temperature, up to 100 bar. However, at high pressures and 77 K, where the saturated H(2) uptake mostly depends on the surface area of a porous material, the total hydrogen uptake of 1 is notably lower than that of MOF-5.

Supramolecular compounds of cucurbituril with molybdenum and tungsten chalcogenide cluster aqua complexes

The review surveys the synthesis and structures of a new class of supramolecular compounds composed of the macrocyclic cavitand cucurbituril and molybdenum or tungsten chalcogenide clusters. The structural motifs of supramolecular compounds and factors influencing their formation are considered.

Methane sorption and structural characterization of the sorption sites in Zn2(bdc)2(dabco) by single crystal X-ray crystallography.

Sorption isotherms of methane in Zn(2)(bdc)(2)(dabco) are measured up to a pressure of 35 bar in the temperature range between 198-296 K. The methane sorption measurements at 296 K showed an uptake of 137 cm(3) cm(-3) at 35 bar. The enthalpy of methane adsorption for Zn(2)(bdc)(2)(dabco) estimated by the virial equation is 13.6 kJ mol(-1) at zero coverage. X-ray structure analysis of methane-adsorbed Zn(2)(bdc)(2)(dabco) by synchrotron radiation at 90 K revealed that methane molecules occupy three independent sorption sites (A, B, and C) with a stoichiometry of Zn(2)(bdc)(2)(dabco) x 6.69 CH(4), which is consistent with the results of the gas sorption measurements at 198 K. In a cavity, eight symmetry-related methane sorption sites A are located near the {Zn(2)(CO(2))(4)} paddle-wheel units, while four symmetry-related methane sorption sites B are near the center of the small windows along the a and b axes. Both A and B sites are half-occupied. Methane molecules occupying sites A are not only in van der Waals contact with the paddle-wheel units, but also interact with the phenyl rings of bdc ligands through partial pi-HC interactions. Methane molecules in B sites interact with the side of the phenyl rings through van der Waals interaction. The site C, located at the center of the cavity, is a secondary sorption site; methane molecules occupying sites C are in van der Waals contact with those in sites A and B.

Influence of [Mo6Br8F6](2-) Cluster Unit Inclusion within the Mesoporous Solid MIL-101 on Hydrogen Storage Performance

The inclusion of (TBA)(2)Mo(6)Br(8)F(6) (TBA = tetrabutylammonium) containing [Mo(6)Br(8)F(6)](2-) cluster units within the pores of the mesoporous chromium carboxylate MIL-101 (MIL stand for Materials from Institut Lavoisier) has been studied. X-ray powder diffraction, thermal analysis, elemental analysis, solid-state NMR, and infrared spectroscopy have evidenced the successful loading of the cluster. In a second step, the hydrogen sorption properties of the model cluster loaded metal organic framework (MOF) system have been analyzed and compared to those of the pure MOF sample, through a combination of adsorption isotherms (77 K, room temperature), thermal desorption spectroscopy, and calorimetry (calculated and experimental) in order to evaluate the hydrogen storage efficiency of the cluster loading.

High Proton Conductivity and Spectroscopic Investigations of Metal–Organic Framework Materials Impregnated by Strong Acids

Strong toluenesulfonic and triflic acids were incorporated into a MIL-101 chromium(III) terephthalate coordination framework, producing hybrid proton-conducting solid electrolytes. These acid@MIL hybrid materials possess stable crystalline structures that do not deteriorate during multiple measurements or prolonged heating. Particularly, the triflic-containing compound demonstrates the highest 0.08 S cm(-1) proton conductivity at 15% relative humidity and a temperature of 60 °C, exceeding any of todays commercial materials for proton-exchange membranes. The structure of the proton-conducting media, as well as the long-range proton-transfer mechanics, was unveiled, in a certain respect, by Fourier transform infrared and (1)H NMR spectroscopy investigations. The acidic media presumably constitutes large separated droplets, coexisting in the MIL nanocages. One component of proton transfer appears to be related to the facile relay (Grotthuss) mechanism through extensive hydrogen-bonding interactions within such droplets. The second component occurs during continuous reorganization of the droplets, thus ensuring long-range proton transfer along the porous structure of the material.

Synthesis, crystal structures, luminescent and thermal properties of two new metal–organic coordination polymers based on zinc(II) carboxylates

Two new metal–organic coordination polymers, [NH2(CH3)2]2[Zn3(bdc)4]·DMF·H2O (1) (H2bdc = 1,4-benzenedicarboxylic acid) and [NH2(CH3)2]2[Zn3(bpdc)4]·5DMF (2) (H2bpdc = 4,4′-biphenyldicarboxylic acid), were synthesized by heating a DMF solution of Zn(NO3)2·6H2O, [NH2(CH3)2]Cl and organic carboxylic acids. Single-crystal X-ray structure analysis reveals that these compounds have 3D anionic framework structures built from zinc(II) carboxylate layers linked by carboxylate anions. Compounds 1 and 2 were characterized by IR, TGA and XRPD, and their luminescent properties were also investigated.

Supramolecular assemblies of [Mo3Se4Clx(H2O)9−x](4−x)+ with cucurbituril; complementarity control through the variation of x

Abstract From solutions of seleno bridged triangular cluster Mo3Se4(aq)4+ in HCl, crystalline adducts with cucurbituril (Cuc, C36H36N24O12) of different composition, depending on HCl concentration, were isolated. From 2 M HCl, a monosubstituted cationic cluster crystallizes as {[Mo3Se4Cl(H2O)8]2(C36H36N24O12)}Cl6·16H2O (1). Increase in HCl concentration to 6 M gives a pentasubstituted anionic species, (H3O)2[Mo3Se4Cl5(H2O)4]2(C36H36N24O12)·15H2O (2). The crystal structures of 1 and 2 were determined by X-ray crystallography. Each portal of Cuc in 1 is covered with cluster cations [Mo3Se4Cl(H2O)8]3+ like a ‘lid’ on a ‘barrel’. Six water molecules in the trans position to the core μ2-Se form complementary hydrogen bonds with oxygen atoms of Cuc (O⋯O, 2.713–3.067 A). In 2 the complementarity is lost and the main structure building factor is short Se⋯Se interactions (Se⋯Se, 2.96–3.43 A) between two adjacent anionic clusters. Stereochemistry of halide substitution in the triangular clusters M3Q4 is analyzed.

Coordination of Phenylsulfinate PhSO2— to Mo3MS44+ Clusters (M = Ni, Pd)

Reaction of heterometal cuboidal clusters [Mo3(MCl)S4(H2O)9]3+ (M = Ni, Pd) with PhSO2Na in aqueous HCl leads to the substitution at Ni or Pd to give the [Mo3(M(PhSO2))(H2O)9—xClx](3—x)+species, isolated as supramolecular adducts with cucurbituril (Cuc) [Mo3(Ni(PhSO2))S4Cl1.17(H2O)7.83][Mo3(Ni(PhSO2))S4Cl2.22(H2O)6.78]Cl2.61 · Cuc · 15H2O (1) and [Mo3(Pd(PhSO2))S4Cl1.12(H2O)7.88][Mo3(Pd(PhSO2))S4Cl2.29(H2O)6.71]Cl2.59 · Cuc · 11H2O (2), respectively. Crystal structure of 1 and 2 was determined, revealing that the PhSO2 is coordinated via its sulfur atom (Ni — S 2.182 A, Pd — S 2.305 A). The structure of these isostructural compounds is built from triple aggregates {(cluster)(Cuc)(cluster)} united into zigzag chains via hydrogen bonds between coordinated PhSO2 and H2O ligands. Die Koordination von Phenylsulfinat PhSO2— an Mo3MS44+ Cluster (M = Ni, Pd). Die Reaktion von kubanartigen Clustern [Mo3(MCl)S4(H2O)9]3+ (M = Ni, Pd) mit PhSO2Na in Salzsaure fuhrt zum Ligandenaustausch an Ni oder Pd. Dabei entstehen die Komplexe [Mo3(M(PhSO2))(H2O)9—xClx](3—x)+, die sich als Supramolekularaddukte mit Kukurbituril (Cuc), [Mo3S4Ni(PhSO2)Cl1.17(H2O)7.83][Mo3S4Ni(PhSO2)Cl2.22(H2O)6.78]Cl2.61 · Cuc · 15H2O (1), [Mo3(Pd(PhSO2))S4Cl1.12(H2O)7.88][Mo3(Pd(PhSO2))Cl2.29(H2O)6.71]Cl2.59 · Cuc · 11H2O (2) isolieren lassen. Die Kristallstrukturen der isostrukturellen Komplexe 1 und 2 wurden bestimmt. Der Ligand PhSO2— ist durch das Schwefelatom koordiniert (Ni — S 2.175 A, Pd — S 2.305 A). Die Struktur zeigt, dass zwei Cluster- und ein Kukurbirurilmolekul Addukte vom Typ {(Cluster)(Kukurbituril)(Cluster)} bilden, die sich weiter durch Wasserstoffbrucken zwischen PhSO2 und koordiniertem H2O zu Zickzackketten verknupfen.