4,5-propylenedithio-1,3-dithiole-2-thione and 4,5-propylenedithio-1,3-dithiol-2-one.

4,5-Propylenedithio-1,3-dithiole-2-thione, C(6)H(6)S(5), (I), crystallizes in the centrosymmetric space group P2(1)/c. The molecular packing is characterized by pairs of S.S intermolecular contacts between neighbouring molecules, which may account for the rather high thermal stability of the crystal.

Trivalent boron as an acceptor in donor-pi-acceptor-type compounds for single- and two-photon excited fluorescence.

The synthesis, structure, and fluorescence properties of a series of new donor-pi-acceptor (D-pi-A) type compounds, with a trivalent boron, protected by two mesityl groups, as acceptor, and with various typical donors and different pi-conjugated bridges, are reported. All these stable organoboron compounds show intense single-photon excited fluorescence (SPEF) and two-photon excited fluorescence (TPEF) in a wide spectral range from blue to green, with the spectral peak position of the SPEF being basically the same as that of the TPEF. The remarkably strong Cbond;B(mesityl)(2) bonding, and the well-conjugated pi-system, shown in X-ray crystal structures of two compounds, indicate some charge transfer features of the ground state.

[A kinetic model of chlorine decay reacting with organics in water distribution systems].

A combined first and second-order model was developed to describe the bulk decay of chlorine in water distribution systems. The parameters of model were determined by deriving the best fit with a lot of experimental data. The complex relationships between bulk decay and the temperature, the initial chlorine concentration and TOC were quantificationally described in the model.

N-ethylpyridinium bis(2-thioxo-1,3-dithiole-4,5-dithiolato)nickelate.

The title compound, (C(7)H(10)N)[Ni(C(3)S(5))(2)] or (Etpy)[Ni(dmit)(2)] (where Etpy is the N-ethylpyridinium cation, C(7)H(10)N(+), and dmit is the 2-thioxo-1,3-dithiole-4,5-dithiolate dianion, C(3)S(5)(2-)), crystallizes in the P-1 space group with two molecules in the asymmetric unit. The [Ni(dmit)(2)](-) monoanion has a planar D(2h) conformation, with the central Ni atom and the four coordinated S atoms forming an NiS(4) square plane. The six-membered ring of the Etpy cation also shows good planarity, as expected.

Trivalent boron as acceptor in D-pi-A chromophores: synthesis, structure and fluorescence following single- and two-photon excitation.

A series of new donor-pi-acceptor type compounds with trivalent boron as acceptor which show strong two-photon excited up-conversion fluorescence have been synthesized and one crystal structure described.

2'-Hydroxy-4"-dimethylaminochalcone.

The title compound, 3-[4-(dimethylamino)phenyl]-1-(2-hydroxyphenyl)prop-2-en-1-one, C(17)H(17)NO(2), is a chalcone derivative substituted by 2'-hydroxyl and 4"-dimethylamino groups. The crystal structure indicates that the aniline and hydroxyphenyl groups are nearly coplanar, with a dihedral angle of 10.32 (16) degrees between their phenyl rings.

Tetra-n-butylammonium bis(2-thioxo-1,3-dithiole-4,5-dithiolato-kappa2S4,S5)nickelate(III).

The crystal structure of the title compound, (C(16)H(36)N)[Ni(C(3)S(5))(2)], is isomorphous with that of the corresponding Pt complex but different from the structures reported for compounds of the same chemical composition, and so provides a new crystalline phase of this complex. The nickel complex anion has good planarity and lies on a crystallographic inversion centre. There is disorder in the two terminal C atoms of two of the butyl chains of the tetra-n-butylammonium cation, the N atom of which is located on a twofold axis.

Two-color excitation system for fluorescence detection in DNA sequencing by capillary array electrophoresis.

Two computer-controlled galvanometer scanners are adapted for two-dimensional step scanning across a 96-capillary array for laser-induced fluorescence detection. 488 nm and 514 nm laser lines from the same Ar(+) laser were alternately coupled for two-color excitation in each capillary. The signal at a single photomultiplier tube is temporally sorted to distinguish among the capillaries and the excitation wavelengths.

One-step concentration of analytes based on dynamic change in pH in capillary zone electrophoresis.

A novel strategy for one-step concentration of analytes during capillary electrophoresis (CE) is presented. A short platinum wire was inserted into the 75-microm-i.d.