Synthesis, crystal structure and Hirshfeld surface analysis of copper(I) nitrate -complex based on 1-(2,6-dimethylphenyl)-5-allylsulfanyl-1H-tetrazole

By means of the alternating current electrochemical technique and starting from copper wire electrodes in propanol solution of corresponding ligand and copper(II) nitrate, novel copper(I) -complex [Cu2(C12H14SN4)2(NO3)2] (1) has been obtained and X-ray structurally investigated: sp. gr. , a=7.352(3) Å, b=8.269(3) Å, c=12.723(4) Å, =82.08(3)0, =82.74(3)0, =88.37(3)0, V=759.9(5) Å3, Z=2, dcalc=1.625 g cm–3, (CuK)=3.502 mm–1, max=67.960, 4119 measured reflections, 1248 used reflections, 201 refined parameters, R(F2)=0.0915, S=0.95. The trigonal-pyramidal copper(I) coordination environment consists of nitrogen atom and allylic group of ligand, and of two oxygen atoms from crystallographically distinct nitrate anions. Due to a bridging function of oxygen atoms of nitrate anions, two metal-containing polyhedra are connected into {Cu2L2(NO3)2} topological units which are additionally stabilized by noncovalent interaction CuO(2). Comparatively weak hydrogen bonds C–HO exist in the crystal structure of [Cu2(C12H14SN4)2(NO3)2] (1).

Purification of Curcumin from Ternary Extract-Similar Mixtures of Curcuminoids in a Single Crystallization Step

Crystallization-based separation of curcumin from ternary mixtures of curcuminoids having compositions comparable to commercial extracts was studied experimentally. Based on solubility and supersolubility data of both, pure curcumin and curcumin in presence of the two major impurities demethoxycurcumin (DMC) and bis(demethoxy)curcumin (BDMC), seeded cooling crystallization procedures were derived using acetone, acetonitrile and 50/50 (wt/wt) mixtures of acetone/2-propanol and acetone/acetonitrile as solvents. Starting from initial curcumin contents of 67–75% in the curcuminoid mixtures single step crystallization processes provided crystalline curcumin free of BDMC at residual DMC contents of 0.6–9.9%. Curcumin at highest purity of 99.4% was obtained from a 50/50 (wt/wt) acetone/2-propanol solution in a single crystallization step. It is demonstrated that the total product yield can be significantly enhanced via addition of water, 2-propanol and acetonitrile as anti-solvents at the end of a cooling crystallization process.

Theoretical Analysis of the Intensity of Ultrasound Absorption in Aqueous Alcoholic Solutions

Ultrasound absorption in aqueous alcoholic solutions has been studied in the vicinity of their singular points. The abnormal ultrasound absorption is assumed to occur due to the formation of unstable nuclei of a new phase. A model for the time evolution of those nuclei is proposed. The model makes it possible to explain the emergence of the resonance ultrasound absorption in the vicinity of the singular point of the 2-propanol solution. The dependences of the absorption intensity on the nucleus parameters, temperature, and ultrasound frequency are analyzed. A contribution of the ultrasound radiation from the nuclei to the effective shear viscosity of the solutions is estimated. The results of theoretical calculations are compared with available experimental data.

Crystal engineering with short-chained amphiphiles: decasodium octa-n-butanesulfonate di-μ-chlorido-bis[dichloridopalladate(II)] tetrahydrate, a layered inorganic–organic hybrid material

In the course of crystal-engineering experiments, crystals of the hydrated title salt, Na10[Pd2Cl6](C4H9SO3)8·4H2O, were obtained from a water/2-propanol solution of sodium n-butanesulfonate and sodium tetrachloridopalladate(II). In the crystal, sodium n-butanesulfonate anions and water molecules are arranged in an amphiphilic inverse bilayered cationic array represented by the formula {[Na10(C4H9SO3)8(H2O)4]2+} n . Within this lamellar array: (i) a hydrophilic layer region parallel to the bc plane is established by the Na+ cations, the H2O molecules (as aqua ligands in κNa,κNa′-bridging coordination mode) and the O3S– groups of the sulfonate ions, and (ii) hydrophobic regions are present containing all the n-butyl groups in an almost parallel orientation, with the chain direction approximately perpendicular to the aforementioned hydrophilic layer. Unexpectedly, the flat centrosymmetric [Pd2Cl6]2− anion in the structure is placed between the butyl groups, within the hydrophobic regions, but due to its appropriate length primarily bonded to the hydrophilic `inorganic' layer regions above and below the hydrophobic area via Pd—Clt...Na- and Pd—Clt...H—O(H)—Na-type (Clt is terminal chloride) interactions. In addition to these hydrogen-bonding interactions, both aqua ligands are engaged in charge-supported S—O...H—O hydrogen bonds of a motif characterized by the D 4 3(9) graph-set descriptor within the hydrophilic region. The crystal structure of the title compound is the first reported for a metal n-butanesulfonate.