Autoionization of homogeneous nickel(II) diphosphane hydrogenation catalysts. An NMR study and crystal structures of [Ni(o-MeO-dppe)I2] and [Ni(o-MeO-dppe)I2](PF6)2

The synthesis of a number of nickel(II) complexes containing the didentate phosphane ligand 1,2-bis(di(o-methoxyphenyl)phosphino)ethane (o-MeO-dppe) is reported. Two types of complexes have been synthesized, i.e., the mono(chelate) complex (1) of the general formula [Ni(o-MeO-dppe)X2] (where X = Cl, Br or I) and the bis(chelate) complex (2) of the general formula [Ni(o-MeO-dppe)2]Y2 (where Y = PF6 or trifluoroacetate (TFA)). These complexes have been characterized using electronic absorption and NMR spectroscopy. The structures of the mono(chelate) complex [Ni(o-MeO-dppe)I2] (1c) and of the bis(chelate) complex [Ni(o-MeO-dppe)2](PF6)2 (2e) have been determined by X-ray crystallography. [Ni(o-MeO-dppe)I2] crystallizes in the monoclinic space group P2(1)/c with Z = 4, a = 12.1309(1) A, b = 16.5759(3) A, c = 17.6474(2) A, beta = 119.3250(10) degrees. [Ni(o-MeO-dppe)2](PF6)2 crystallizes in the monoclinic space group C2/c with Z = 4, a = 22.5326(3) A, b = 13.6794(2) A, c = 21.7134(3) A, beta = 107.1745(7) degrees. In both structures the nickel ion is in a square-planar geometry with a NiP2I2 and NiP4 chromophore, respectively. Using 1H and 31P[1H] NMR spectroscopy the behavior of the complexes in various solvents has been studied. It appears that in solution these nickel complexes are involved in an autoionization equilibrium: 2[Ni(o-MeO-dppe)X2] <==>[Ni(o-MeO-dppe)2](2+) + ["NiX(4)"](2-). The ionized complex (3) consists of a cationic unit in which a nickel atom is surrounded by two didentate phosphane ligands, and an anionic unit that stoichiometrically consists of a nickel atom and four anions. The position of the autoionization equilibrium is highly dependent on the anion and the solvent used. In a polar solvent in combination with weakly coordinating anions only the ionized complex is observed, whereas in an apolar solvent in combination with coordinating anions only the mono(chelate) complex occurs. A comparison of the behavior of o-MeO-dppe with its unsubstituted analogue dppe in combination with nickel(II) acetate using 31P[1H] NMR spectroscopy shows that the latter is more readily oxidized.     

Mathematical modeling of the distribution of a finely dispersed admixture in a turbulent tube-jet flow

An attempt to numerically model the specific characteristics of the distribution of small solid particles in a turbulent tube-jet flow is presented. The numerical results are compared with experimental data. Tallin. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 2, pp. 76–86, March–April, 1998. The theoretical part of the work was supported financially by the Government of Estonia and the International Science Foundation (grant LK 6100).     

Quantitation of l-alpha-acetylmethadol and its metabolites in human serum by capillary gas-liquid chromatography and nitrogen detection

A procedure is described for the simultaneous measurement of l-alpha-acetylmethadol and its two pharmacologically active metabolites: noracetylmethadol and dinoracetylmethadol. In the method an intramolecular conversion reaction of the two metabolites to their amide configuration is utilized. The reaction is performed while the metabolites are still in the serum. Following solvent extraction the samples are analyzed by capillary gas-liquid chromatography coupled with nitrogen detection. Quantitation is achieved by internal standardization. The lower limit of sensitivity is 5 ng/ml in serum. Absolute sensitivity is 0.1 ng for all three compounds. The advantages over other procedures are: speed due to the single extraction step; increased recovery of noracetylmethadol and dinoracetylmethadol due to decreased polarity of the amides; greater stability of the metabolites in the amide configuration; better chromatographic quantitation and separation because detector response for the amides is greater than it is for the original configuration of the metabolites and the area of the chromatographic tracing is free of interfering substances.     

Health benefits of pistachios consumption

The health benefits of nuts, mainly in relation to the improvement of dysmetabolic conditions such as obesity, type 2 diabetes mellitus and the related cardiovascular diseases, have been widely demonstrated. Compared to other nuts, pistachios have a lower fat and caloric content, and contain the highest levels of unsaturated fatty acids, potassium, γ-tocopherol, phytosterols and xanthophyll carotenoids, all substances that are well known for their antioxidant and anti-inflammatory actions. This variety of nutrients contributes to the growing body of evidence that the consumption of pistachios improves health, leading to a greater potential of healthy antioxidant and anti-inflammatory activity, glycemic control, and endothelial function. The present review examines the nutrients and phytochemicals present in pistachios as well as the potential health benefits of including pistachios in a diet.     

Synthesis,thermal, spectral,antimicrobial and cytotoxicity profile of the Schiff bases bearing pyrazolone moiety and their Cu(II) complexes

Journal of Thermal Analysis and Calorimetry - A series of Schiff bases resulted in the [1?+?1] condensation of 8-alkyl-2-hydroxy-tricyclo[7.3.1.02.7]-tridecan-13-one with the...     

TUD-1: synthesis and application of a versatile catalyst, carrier, material…

The three-dimensional sponge-like mesoporous material TUD-1 is straightforward to prepare. Its synthesis can readily be modified to introduce metals into the framework of TUD-1, imparting many different catalytic activities. M-TUD-1 catalysts have proven to be very active, unlimited by diffusion and very stable. By combining two metals into one TUD-1 catalyst, synergy between Lewis and Br?nsted acid sites could be induced; incorporation of zeolites similarly gave rise to synergy. In addition to successful applications in redox-, acid- and photo-catalysis TUD-1 proved to be an excellent carrier material for catalysts, enabling new applications. TUD-1 was used as a contrast agent and drug delivery system, indicating that this material is but at the beginning of its potential applications.     

Three-dimensional photoacoustic imaging of blood vessels in tissue

We applied photoacoustics as a tissue tomography technique for the detection of blood concentrations, e.g., angiogenesis around tumors. We imaged blood vessels in highly scattering samples, using 532-nm light, to depths of ~1 cm . The samples were real tissue (chicken breast) or 10% dilutions of Intralipid-10%. The blood flowed through nylon capillaries. Polyvinylidene difluoride (PVdF) piezoelectric detectors were used in a surface-scanning mode. We demonstrate the sensitivity of the technique by photoacoustic detection of single red blood cells upon a glass plate. Lateral resolution is limited by the detector diameter (200 microm). The depth resolution is ~10 microm.