Salinity-Driven Structural and Viscosity Modulation of Confined Polar Oil Phases by Carbonated Brine Films: Novel Insights from Molecular Dynamics.

The structural and dynamic properties of fluids under confinement in a porous medium differ from their bulk properties. This study delves into the surface structuring and hydrodynamic characteristics of oil/thin film carbonated brine two-phase within a calcite channel upon salinity variation. To this end, both equilibrium and non-equilibrium molecular dynamics simulations are utilized to unveil the effect of the carboxylic acid component (benzoic acid) in a simple model oil (decane) confined between two thin films of carbonated brine on the oil-brine-calcite characteristics.

Synthesis and structure of clozapine -oxide hemi(hydro-chloride): an infinite hydrogen-bonded poly[]catenane.

The structure of the title compound, 2CHClNO·HCl or (CNO)·HCl (CHClNO), at 100 K has tetra-gonal (4/) symmetry. The dihedral angle between the benzene rings of the fused ring system of the CNO mol-ecule is 40.08 (6)° and the equivalent angle between the seven-membered ring and its pendant -oxide ring is 31.

Comparability of in situ crude oil emulsification in phase equilibrium and under porous-media-flow conditions.

Hypothesis: The emulsification of water and crude oil is typically examined and optimized in test tubes by optical means, that is, mixed under turbulent conditions and detected outside the porous medium in equilibrium. In this study, we investigate the rather complex case of crude oil emulsification by alkaline solutions to assess whether the classical phase behavior experiments are representative of the emulsification under laminar flow conditions in porous media.

Experiments: We characterized the phase equilibrium in the test tubes through X-ray attenuation in micro-X-ray computed tomography (μCT).

Coupling of CO and epoxides catalysed by novel -fused mesoionic carbene complexes of nickel(II).

We report the syntheses of two rigid mesoionic carbene (MIC) ligands with a carbazole backbone an intramolecular Finkelstein-cyclisation cascade and investigate their coordination behavior towards nickel(II) acetate. Despite the nickel(II) carbene complexes 4a,b showing only minor differences in their chemical composition, they display curious differences in their chemical properties, solubility. Furthermore, the potential of these novel MIC complexes in the coupling of carbon dioxide and epoxides as well as the differences in reactivity compared to classical NHC-derived complexes are evaluated.

Development of foam-like emulsion phases in porous media flow.

Hypothesis: While surfactant solutions mobilize residual oil under optimal conditions by lowering the water-oil interfacial tension, emulsion phases outside of the optimum tend to be immobile. How are mobility and texture of such phases related, and how can the stability of these phases be understood? Can non-optimized surfactant solutions improve displacement processes through mobility control?

Experiment: Emulsification and miscibility during surfactant flooding were investigated in microfluidics with generic oil and surfactant solutions. The salt concentration was varied in an exceptionally wide range across the optimal displacement conditions.

Remarkable Structural Diversity between Zr/Hf and Rare-Earth MOFs via Ligand Functionalization and the Discovery of Unique (4, 8)-c and (4, 12)-connected Frameworks.

Ligand modification in MOFs provides great opportunities not only for the development of functional materials with new or enhanced properties but also for the discovery of novel structures. We report here that a sulfone-functionalized tetrahedral carboxylate-based ligand is capable of directing the formation of new and fascinating MOFs when combined with Zr/Hf and rare-earth metal cations (RE) with improved gas-sorption properties. In particular, the resulting M--SO (M: Zr, Hf) materials display a new type of the augmented -a net, which is different as compared to the -a framework formed by the nonfunctionalized tetrahedral ligand.

Insight into the Bonding and Aggregation of Alkyllithiums by Experimental Charge Density Studies and Energy Decomposition Analyses.

In this Article, the organolithiums [((-)-sparteine)LiBu] (), [(ABCO)LiBu] (), and [(ABCO)(LiPr)] () are investigated by means of experimental and theoretical charge density determination to elucidate the nature of the Li-C and Li-N bonds. Furthermore, the valence shell charge concentrations (VSCCs) in the nonbonding region of the deprotonated C-atom will provide some insight on the localization of the carbanionic lone pair. Analysis of the electron density (ρ()), Laplacian (∇ρ()), and the energy decomposition (EDA) confirmed that the Li-C/N bond exhibits astonishingly similar characteristics, to reveal an increasingly polar contact with decreasing aggregate size.

Monoanionic Anilidophosphine Ligand in Lanthanide Chemistry: Scope, Reactivity, and Electrochemistry.

We present the synthesis of a series of new lanthanide(III) complexes supported by a monoanionic bidentate anilidophosphine ligand (-(2-(dipropylphosphanyl)-4-methylphenyl)-2,4,6-trimethylanilide, short PN). The work comprises the characterization of a variety of heteroleptic complexes containing either one or two PN ligands as well as a study on further functionalization possibilities. The new heteroleptic complexes cover selected examples over the whole lanthanide(III) series including lanthanum, cerium, neodymium, gadolinium, terbium, dysprosium, and lutetium.

: a standalone program for the calculation of optimal weighting parameters for least-squares crystallographic refinements.

The rigorous analysis of crystallographic models, refined through the use of least-squares minimization, is founded on the expectation that the data provided have a normal distribution of residuals. Processed single-crystal diffraction data rarely exhibit this feature without a weighting scheme being applied. These schemes are designed to reflect the precision and accuracy of the measurement of observed reflection intensities.

Quantum Crystallography: Current Developments and Future Perspectives.

Crystallography and quantum mechanics have always been tightly connected because reliable quantum mechanical models are needed to determine crystal structures. Due to this natural synergy, nowadays accurate distributions of electrons in space can be obtained from diffraction and scattering experiments. In the original definition of quantum crystallography (QCr) given by Massa, Karle and Huang, direct extraction of wavefunctions or density matrices from measured intensities of reflections or, conversely, ad hoc quantum mechanical calculations to enhance the accuracy of the crystallographic refinement are implicated.

Precrystalline Aggregates Enable Control over Organic Crystallization in Solution.

Understanding and controlling organic crystallization in solution is a long-standing challenge. Herein, we show that crystallization of an aromatic amphiphile based on perylene diimide in aqueous media involves initially formed amorphous spherical aggregates that evolve into the crystalline phase. The initial appearance of the crystalline order is always confined to the spherical aggregates that are precursors for crystalline evolution.

Subsecond pore-scale displacement processes and relaxation dynamics in multiphase flow.

With recent advances at X-ray microcomputed tomography (μCT) synchrotron beam lines, it is now possible to study pore-scale flow in porous rock under dynamic flow conditions. The collection of four-dimensional data allows for the direct 3-D visualization of fluid-fluid displacement in porous rock as a function of time. However, even state-of-the-art fast-μCT scans require between one and a few seconds to complete and the much faster fluid movement occurring during that time interval is manifested as imaging artifacts in the reconstructed 3-D volume.

Lanthanide-polyphosphonate coordination polymers combining catalytic and photoluminescence properties.

A rapid, mild and high-yield microwave synthesis of 1D isotypical [Ln(H4bmt)(H5bmt)(H2O)2]·3H2O coordination polymers is presented. The La(3+)-based material is highly active as a heterogeneous catalyst in the methanolysis of styrene oxide at nearly room temperature. Eu(3+)- and Tb(3+)-doped materials are very effective UV-to-visible light converters.

Real-time 3D imaging of Haines jumps in porous media flow.

Newly developed high-speed, synchrotron-based X-ray computed microtomography enabled us to directly image pore-scale displacement events in porous rock in real time. Common approaches to modeling macroscopic fluid behavior are phenomenological, have many shortcomings, and lack consistent links to elementary pore-scale displacement processes, such as Haines jumps and snap-off. Unlike the common singular pore jump paradigm based on observations of restricted artificial capillaries, we found that Haines jumps typically cascade through 10-20 geometrically defined pores per event, accounting for 64% of the energy dissipation.

Periphery-substituted [4+6] salicylbisimine cage compounds with exceptionally high surface areas: influence of the molecular structure on nitrogen sorption properties.

The synthesis of various periphery-substituted shape-persistent cage compounds by twelve-fold condensation reactions of four triptycene triamines and six salicyldialdehydes is described, where the substituents systematically vary in bulkiness. The resulting cage compounds were studied as permanent porous material by nitrogen sorption measurements. When the material is amorphous, the steric demand of the cages exterior does not strongly influence the gas uptake, resulting in BET surface areas of approximately 700 m(2)  g(-1) for all cage compounds 3 c-e, independently of the substituents bulkiness.

On the track of novel triel-stabilised silylaminoiminoborenes.

Borenes and boranes: Silylaminoiminoborenes, such as depicted, were isolated after treatment of halogen triels with silylaminofluoroboranes. In addition, novel aryl- and silyl-substituted diaminofluoroboranes were also prepared in order to substantiate this reaction route.Reactions between the halogen triels AlClMe(2), AlBr(3), GaCl(3) and the silylaminofluoroboranes (Me(3)Si)(2)NB(F)NRSiMe(3) (R=SiMe(3), CMe(3)) afforded the silylaminoiminoborenes, which were isolated as the triel adducts, such as Me(3)Si(Cl(3)Ga)NBNRSiMe(3) (6).

Catalytic Abilities of [(C6F5)2BR] (R=NC4H4 and NC4H8) deduced from experimental and theoretical charge-density investigations.

Marginal difference, huge impact: The topological analyses of the electron-density distributions obtained from experiment (see figure) and quantum-chemical calculations in the two title compounds can consistently explain marginal changes in bonding and rationalize different catalytic abilities. The electronic structures of the compounds bis(pentafluorophenyl)(N-pyrrolyl)borane (1) and bis(pentafluorophenyl)(N-pyrrolidinyl)borane (2) were investigated by low-temperature high-resolution X-ray diffraction experiments and subsequent multipole refinements. Additionally, DFT calculations were performed.

Carbanion or amide? First charge density study of parent 2-picolyllithium.

The negative charge originating from deprotonation of the methyl group is distributed over the 2-picolyl ring. Bonding properties derived from the electron density distribution support the enamide character of picolyllithium (PicLi; the picture shows the deformation density of [2-PicLi x PicH](2)), but electrophilic attack occurs at the deprotonated C atom. This reactivity is rationalized by the electrostatic potential, which guides electrophiles towards the nucleophilic C atom.

Preparation and structural characterization of molecular Al-O-Sn(II) and Al-O-Sn(IV) compounds.

Reaction of the organoaluminum hydroxide LAl(Me)OH (1) with different stoichiometric ratios of the homoleptic Sn(II) amide, Sn[N(SiMe(3))(2)](2), produced the bimetallic and trimetallic oxygen bridged aluminum-tin compounds LAl(Me)(mu-O)Sn[N(SiMe(3))(2)] (2) and [LAl(Me)(mu-O)](2)Sn (3), respectively. The former compound exhibits an Al-O-Sn(II)-N core and the latter an Al-O-Sn(II)-O-Al skeleton. In addition, we obtained the [LAl(Me)(mu-O)SnPh(3)] (5) with Al-O-Sn(IV) core by the reaction of [L(Me)Al-O-Mg(THF)(2)N(SiMe(3))(2)] (4) with Ph(3)SnOH in a 1:1 molar ratio.

Structure/reactivity studies on an alpha-lithiated benzylsilane: chemical interpretation of experimental charge density.

Modern organic synthesis (e.g., of natural products) is virtually impossible without employment of enantiomerically enriched compounds.

Bis(bismuth)toluene inverted-sandwich complex supported by aminetris(phenoxide) ligands.

The reaction of bismuth amides or alkoxides with phenolic ligand precursors yields Bi complexes of aminetris(phenoxide)s, one of which was characterized by X-ray crystallography, revealing monomeric Bi units of the tetradentate NO3 ligand further associated via a symmetrical toluene bridge into a bis(bismuth)toluene inverted-sandwich complex. Synthesis of the analogous Sb complex suggests a markedly different geometric and electronic environment at the metal center, as evidenced by the solid-state molecular structure. Density functional theory calculations of the sandwich bismuth arene complex indicate the presence of a weak sigma*-2pi interaction.

Detection, isolation and partial characterization of an immunostimulating glycoprotein from Rhodococcus fascians.

In a search for novel immunostimulating substances we detected that culture supernatants of the gram-positive phytopathogenic bacterium, Rhodococcus fascians, were able to induce cytokine release (TNF(alpha)) from mouse peritoneal macrophages. Monoclonal antibodies were generated against the active principle, and were employed for its isolation and partial characterization as a high molecular (MW>100 kDa) glycoprotein. In addition, methods practicable for its biotechnological preparation and several ELISA variants for its determination were developed.