First principle simulation of the temperature dependent magnetic circular dichroism of a trinuclear copper complex in the presence of zero field splitting

We present a test of a recently developed density functional theory (DFT) based methodology for the calculation of magnetic circular dichroism (MCD) spectra in the presence of zero-field splitting (ZFS). The absorption and MCD spectra of the trinuclear copper complex μ(3)O ([Cu(3)(L)(μ(3)-O)](4+)), which models the native intermediate produced in the catalytic cycle of the multicopper oxidases, have been simulated from first principle within the framework of adiabatic time dependent density functional theory. The effects of the ZFS of the quartet (4)A(2) ground state on the theoretical MCD spectrum of μ(3)O have been analyzed. The simulated spectra are consistent with the experimental ones. The theoretical assignments of the MCD spectra are based on direct simulation as well as a detailed analysis of the molecular orbitals in μ(3)O. Some of the assignments differ from those given in previous studies. The ZFS effects in the presence of a strong external magnetic field (7 T) prove negligible. The change of the sign of the ZFS changes systematically the intensity of the MCD bands of the z-polarized excitations. The effect of the ZFS on the x,y-polarized excitations is not uniform.     

Synthesis and Biological Activity of Some Novel O-Phosphorylated Benzoxazole Derivatives

The phosphorylation of 2-(2′-hydroxyphenyl) benzoxazole has been accomplished with phosphorus oxychloride in a 1:1, 2:1, and 3:1 molar ratio in the presence of a base to yield O-phosphorylated benzoxazole derivatives. Their structures were confirmed by elemental analyses and IR, ¹H NMR, and ³¹P NMR spectral studies. These compounds have been screened for their insecticidal activity against Periplenata americana and were found to be quite active in this respect.     

Studies on Rare Earth Polyphosphate Glasses of the Composition [NaxM(1 − x)/2aGd(1 − x)/2aPO3]n

A fusion technique was used for the preparation of derivatives of the composition [Na _x M_{(1? x)/2a} Gd_{(1? x)/2a} PO₃] _n (where M = bivalent metal like Cu(II), Ca(II), Zn(II), Ni(II), and Mg (II); x = 1/2, 3/4, & 2/3; and a = valency of metal). Composition of these polyphosphate glasses was confirmed by their analyses for metals and phosphorus. The polymeric nature of all polyphosphate glasses was confirmed by the determination of a number average molecular weight (M _n ). The characteristic frequencies in the IR spectra are supportive of the presence of polyphosphate indicative of the polymeric nature of these derivatives. From X-ray diffraction, the amorphous nature of complex polyphosphates has been determined.     

A new method for precise determination of iron,zinc and cadmium stable isotope ratios in seawater by double-spike mass spectrometry

The study of Fe, Zn and Cd stable isotopes (δ⁵⁶Fe, δ⁶⁶Zn and δ¹¹⁴Cd) in seawater is a new field, which promises to elucidate the marine cycling of these bioactive trace metals. However, the analytical challenges posed by the low concentration of these metals in seawater has meant that previous studies have typically required large sample volumes, highly limiting data collection in the oceans. Here, we present the first simultaneous method for the determination of these three isotope systems in seawater, using Nobias PA-1 chelating resin to extract metals from seawater, purification by anion exchange chromatography, and analysis by double spike MC-ICPMS. This method is designed for use on only a single litre of seawater and has blanks of 0.3, 0.06 and <0.03 ng for Fe, Zn and Cd respectively, representing a 1–20 fold reduction in sample size and a 4–130 decrease in blank compared to previously reported methods. The procedure yields data with high precision for all three elements (typically 0.02–0.2‰; 1σ internal precision), allowing us to distinguish natural variability in the oceans, which spans 1–3‰ for all three isotope systems. Simultaneous extraction and purification of three metals makes this method ideal for high-resolution, large-scale endeavours such as the GEOTRACES program.     

Synthesis of Enol Esters from Copper(I) Carboxylates Generated from Copper(I) Trifluoromethanesulfonate Benzene Complex

A rapid method for the preparation of copper(I) carboxylates by use of copper(I) trifluoromethanesulfonate benzene complex followed by their conversion to enol esters under mild conditions is presented.     

First observation of the decay Ds+-->pn

Using e+e--->Ds*-Ds+ data collected near the peak Ds production energy, Ecm=4170 MeV, with the CLEO-c detector, we present the first observation of the decay Ds+-->pn. We measure a branching fraction B(Ds+-->pn)=(1.30+/-0.36(-0.16)+0.12)x10(-3). This is the first observation of a charmed meson decaying into a baryon-antibaryon final state.     

Study of the decays D0-->pi{-}e{+}nu{e}, D{0}-->K{-}e{+}nu{e}, D{+}-->pi{0}e{+}nu{e}, and D{+}-->K0e{+}nu{e}

By using 1.8x10{6} DDpairs, we have measured B(D{0}-->pi{-}e{+}nu{e})=0.299(11)(9)%, B(D{+}-->pi{0}e{+}nu{e})=0.373(22)(13)%, B(D{0}-->K{-}e{+}nu{e})=3.56(3)(9)%, and B(D{+}-->K{0}e{+}nu{e})=8.53(13)(23)% and have studied the q;{2} dependence of the form factors. By combining our results with recent lattice calculations, we obtain |V{cd}|=0.217(9)(4)(23) and |V{cs}|=1.015(10)(11)(106).     

Precision measurement of the mass of the hc(1P1) state of charmonium

A precision measurement of the mass of the h_{c}(1P1) state of charmonium has been made using a sample of 24.5x10;{6} psi(2S) events produced in e;{+}e;{-} annihilation at the Cornell Electron Storage Ring (CESR). The reaction used was psi(2S)-->pi;{0}h_{c}, pi;{0}-->gammagamma, h_{c}-->gammaeta_{c}, and the reaction products were detected in the CLEO-c detector. Data have been analyzed both for the inclusive reaction and for the exclusive reactions in which eta_{c} decays are reconstructed in 15 hadronic decay channels. Consistent results are obtained in the two analyses. The averaged results of the present measurements are M(h_{c})=3525.28+/-0.19(stat.)+/-0.12(syst.) MeV, and B(psi(2S)-->pi;{0}h_{c})xB(h_{c}-->gammaeta_{c})=(4.19+/-0.32+/-0.45)x10;{-4}. Using the ;{3}P_{J} centroid mass, DeltaM_{hf}(1P) identical withM(chi_{cJ})-M(h_{c})=+0.02+/-0.19+/-0.13 MeV.     

Absolute measurement of hadronic branching fractions of the Ds+ meson

The branching fractions of D(s)(+/-) meson decays serve to normalize many measurements of processes involving charm quarks. Using 298 pb(-1) of e(+)e(-) collisions recorded at a center of mass energy of 4.17 GeV, we determine absolute branching fractions for eight D(s)(+/-) decays with a double tag technique. In particular we determine the branching fraction B(D(s)(+)-->K(-)K(+}pi(+))=(5.50+/-0.23+/-0.16)%, where the uncertainties are statistical and systematic, respectively. We also provide partial branching fractions for kinematic subsets of the K(-)K(+)pi(+) decay mode.     

Synthesis,characterization, and biological activity of phosphorylated/thiophosphorylated compounds of 2‐substituted benzimidazoles

A series of phosphorylated and thiophosphorylated compounds of 2‐substituted benzimidazoles have been synthesized by the reaction of POCl₃ and PSCl₃ with 2‐substituted benzimidazoles in different molar ratios. The compounds have been characterized by elemental analyses, infrared, and ¹H NMR and ³¹P NMR spectral studies. These compounds were found to be insecticidal when tested against Periplenata americana. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:154–157, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20385