Light-assisted synthesis of metal oxide hierarchical structures and their catalytic applications

Short reaction times and morphology control in the synthesis of inorganic materials under nonthermal conditions remain a challenge. Herein we report a rapid, self-templating, and nonthermal method based on ultraviolet light to prepare metal oxide hierarchical structures. With this method, the morphology of the metal oxides was controlled readily without using templates.     

Conductance of tetraalkylammonium salts in propylene carbonate at 25°C

Conductance measurements of 12 quaternary ammonium salts in propylene carbonate (PC) have been made at 25°C. The cations were either tetramethylammonium, tetraethylammonium, or tetra-n-butylammonium, and the concentrations of salt varied from about 2×10^–4 to 5×10^–3 M. The data were analyzed by the equation of Pitts. The results showed that the benzoate, nitrobenzoate, and pentachlorophenolate salts are completely dissociated. The nitrophenolate, chlorophenolate, methylsulfonate, and nitrate salts are only slightly associated (K _A from 2.5 to 6.5), while the acetate, phenylacetate, and nitrophenolate salts display somewhat more extensive association, with ionpair association constants from 17 to 45. Limiting molar conductances for the anions were derived. The factors affecting ionic mobilities in this dipolar aprotic solvent are discussed.On leave 1973–1975 from the University of Gdask, Poland.     

A configuration-interaction study of the polarizability derivatives of carbon monoxide

The components of the dipole polarizability and of the dipole-quadrupole polarizability A of the carbon monoxide molecule have been calculated as a function of the internuclear distance using both SCF and CI wavefunctions. The resulting values of , A and then derivatives should be the most accurate ab initio estimates available for these quantities. A comparison of the SCF and CI results shows significant differences in the values obtained.     

Pseudopolymorphic Clathrate Structures Formed by an Alicyclic Dialcohol Inclusion Host

Dialcohol host 2,7-dimethyltricyclo[4.3.1.0^3,8]undecane-syn-2,syn-7-diol 1 can form either ellipsoidal clathrate or helical tubulate inclusion compounds where only dispersion forces operate between the hosts and guests. The former (tetragonal space group I4₁/acd), built from two interpenetrating sublattices containing both diol enantiomers, encloses the guests in rugby ball-shaped cavities. The latter (trigonal space group P3₁21 or P3₂21), containing only one diol enantiomer, traps the guests within parallel tubes. Which inclusion type is produced is determined by the guest size and shape and, hence, control is possible over these structures. At room temperature, cyclohexane gives the tetragonal structure, but fluorocyclohexane yields the trigonal structure. Chloroform produces both pseudopolymorphs: the tetragonal form at higher and the trigonal form at lower temperatures. Powder and single-crystal structural X-ray data are reported for these clathrate compounds.     

Ruthenium‐Containing Linear Helicates and Mesocates with Tuneable p53‐Selective Cytotoxicity in Colorectal Cancer Cells

The ligands L¹ and L² both form separable dinuclear double‐stranded helicate and mesocate complexes with Ru^II. In contrast to clinically approved platinates, the helicate isomer of [Ru₂( L¹ )₂]⁴⁺ was preferentially cytotoxic to isogenic cells (HCT116 p53^?/?), which lack the critical tumour suppressor gene. The mesocate isomer shows the reverse selectivity, with the achiral isomer being preferentially cytotoxic towards HCT116 p53^+/+. Other structurally similar Ru^II‐containing dinuclear complexes showed very little cytotoxic activity. This study demonstrates that alterations in ligand or isomer can have profound effects on cytotoxicity towards cancer cells of different p53 status and suggests that selectivity can be “tuned” to either genotype. In the search for compounds that can target difficult‐to‐treat tumours that lack the p53 tumour suppressor gene, [Ru₂( L¹ )₂]⁴⁺ is a promising compound for further development.     

Bis(2,3‐di­methyl­quinoxalinium) tribromo­cuprate(I)

The title compound, (C₁₀H₁₁N₂)₂[CuBr₃], contains layers of planar monoprotonated cations. Isolated trigonal–planar [CuBr₃]^2? anions are hydrogen bonded to cations in adjacent layers, providing three‐dimensional stability to the crystal structure.     

(±)-1-Tetralone-3-carboxyl­ic acid and (±)-1-tetralone-2-acetic acid: hydrogen bonding in two γ-keto acids

The crystal structure of (±)-4-oxo-1,2,3,4-tetra­hydro­naph­thalene-2-carboxylic acid (C₁₁H₁₀O₃) involves projection of the carboxyl group nearly orthogonal to the aromatic plane and hydrogen bonding of the acid groups by centrosymmetric pairing across the a edge and the center of the chosen cell [O⃛O = 2.705 (2) Å]. Intermolecular C—H⃛O=C close contacts to translationally related mol­ecules are found for both the ketone (2.55 Å) and the acid (2.67 Å). In (±)-1-oxo-1,2,3,4-tetra­hydro­naph­thalene-2-acetic acid (C₁₂H₁₂O₃), the aggregation involves centrosymmetric carboxyl dimers mutually hydrogen bonded across the bc face and the a edge of the chosen cell [O⃛O = 2.674 (2) Å]. A 2.60 Å close C—H⃛O=C contact is found to the carboxyl group of centrosymmetrically related mol­ecule.