Synthesis and studies of CuHg(NCX)4 (X = S,Se) and their complexes and application of the softness parameter in the elucidation of their structure

Complexes of CuHg(NCS)₄, CuHg(NCS)₂ (NCSe)₂ and CuHg(NCSe)₄ with tetrahydrofuran, dioxane, pyridine, 2-aminopyridine, nicotinamide, bipyridine and phenanthroline have been prepared and comparative studies made. Bipyridine and phenanthroline form cationic—anionic [CuL₃]²⁺ [Hg(SCN)₄]^2? (L = bipy, phen) complexes with CuHg(NCS)₄ and dinuclear bridged complexes with CuHg(NCSe)₄ and CuHg(NCS)₂ (NCSe)₂. For other ligands the nature of the complexes is binuclear or polynuclear. The comparative stability of the -XCN- bridge (X = S, Se) is CuHg(NCSe)₄ > CuHg(NCS)₂ (NCSe)₂ > CuHg(NCS)₄.     

A general microcantilever surface modification method using a multilayer for biospecific recognition

The key to microcantilever surface modification technology is to selectively modify one side of a microcantilever surface with molecular recognition layers. In this paper, we report a general microcantilever modification method using a multilayer film.     

Simultaneous densitometric determination of artemisinin, artemisinic acid and arteannuin-B in Artemisia annua using reversed-phase thin layer chromatography

A rapid and simple RP-TLC method for simultaneous quantification of pharmacologically important sesquiterpene artemisinin (AM) together with its precursors arteannuin-B (AB) and artemisinic acid (AA) in the inflorescence part of Artemisia annua plant has been developed. The RP-TLC of sesquiterpenes was performed on RP-18 F254 S thin-layer chromatographic plates by developing in mobile phase, containing 0.2% TFA in water/ACN (35:65, v/v). The densitometric determination of AM, AB and AA was carried out after derivatization with anisaldehyde reagent at 426 nm in absorption-reflectance mode.     

Electron spin resonance spectra of some phosphonyl radicals and related species

The isotropic ESR spectra of a number of phosphonyl radicals (X₂$\text{P}$O), the dimethylphosphinyl radical, and the phosphoranyl radical (MeO)₃$\text{P}$OBu-t, are described, and accurate values of the phosphorus hyperfine splittings and g-factors are reported. For X₂$\text{P}$O, the value of a(P) increases and the g-factor decreases as the electronegativity of X increases. There is a linear relationship between a(P) for X₂$\text{P}$O and ¹J(PH) for X₂P(O)H, but the same relationship does not hold for Me₂P- and Me₂PH. The spectrum of the di-n-hexylphosphonyl radical shows coupling to two pairs of α-methylene protons, and this non-equivalence is attributed to the pyramidal structure of the phosphonyl radical.     

Using IMAP technology to identify kinase inhibitors: comparison with a substrate depletion approach and analysis of the nature of false positives

IMAP is a fluorescence polarisation-based assay method which can be applied to the measurement of protein kinase activity. Using a model serine/threonine kinase we found that IMAP generated a good assay window (Z' > 0.8), was very tolerant of DMSO, and was flexible with respect to sample processing (stopped reactions were stable over a period of several days). Using a set of six low molecular weight inhibitors of the kinase, we found a good correlation between IMAP and scintillation proximity assay (SPA) potency data. IMAP, which measures product accumulation, was compared in an HTS setting with a substrate depletion method (luminescence-based measurement of ATP concentration). There was a reasonable (approximately 50%) overlap in primary hits from a 17,000 compound set, but more apparent false positives were generated from the IMAP method. We followed up the compounds that showed activity in the IMAP method but not in the luminescence assay. Approximately 10% of these compounds displayed intrinsic fluorescence, suggesting that they were false actives by virtue of intrinsic spectroscopic properties. Compound activity by competition of phosphopeptide binding to IMAP beads can occur with high concentrations of chelating compounds, but did not occur with any of the false actives, suggesting that this form of interference is rare.     

Pressure dependence of the compressibility of alkali halides

The parameterC ₁=[(1/K _T )/P] _T , which describes the pressure variation of the compressibility, has been examined correlating the thermodynamical and interatomic potential approaches employing fewer approximations than has been usual heretofore. General expressions have been derived forC ₁ by including the thermal correction terms, which have generally been ignored in previous studies concerning thermal properties of ionic crystals. The parameterC ₁ has also been related to the Grüneisen parameter, , using a relation given earlier. The applicability of the derived equations is investigated and discussed for alkali halides employing few realistic potential forms. A good general accord is found with the available experimental data, which exhibits an essential improvement over other theoretical determinations.     

Equilibrium theory of two-dimensional simple liquids

Using the Wigner-Kirkwood expansion and bare Lennard-Jones (LJ) (12-6) potential, an effectiveLJ potential is derived, which includes the quantum effects through the expressions of the effective diameter∂(T, λ) and well-depth (T, λ). We use theWCA perturbation theory to calculate the free energy and pressure for theLJ and effectiveLJ potentials. Simple analytic expressions are given for the reference system and the first order correction calculated. The results are quite good at high density. The quantum effects on the free energy and pressure are also discussed.     

Vaporization thermodynamics of thorium tetrafluoride

The thermal decomposition kinetics of Pr₂(SO₄)₃ to Pr₂O₂SO₄ have been studied by isothermal weight change determination. The reaction was found to obey a linear law up to α = 0.5; beyond α = 0.5 it could be described as a phase-boundary controlled process. A dependence of the activation energy upon the sample weight was observed. The changes in surface area and density which occur during the decomposition are also given.