Synthesis and Crystal Structure of Bis-(N,N′-dibenzylethane-1,2-diamine) cobalt(II) acetate

Abstract  

Bis-(N,N′-dibenzylethane-1,2-diamine) cobalt(II) acetate has been synthesized and the crystal structure determined. The compound crystallizes in the space group P2₁/c, a = 8.3212(6) ?, b = 11.8774(8) ?, c = 17.3643(12) ?, β = 98.1850(10)°, V = 1698.7(2) ?³, Z = 2. The complex occupies a crystallographic inversion center. The cobalt is in a distorted octahedral environment likely due to steric influences of the acetate groups.     

Study of the broad-band saturable absorption of indocyanine green J-aggregates in polymeric films using 10-fs laser pulses

Thin films of indocyanine green J-aggregates in polymers have been prepared and their saturable absorption properties studied in a high intensity regime using a unique ultrashort pulse Ti:sapphire laser (10 fs) with a very broad bandwidth (over 200 nm at -20 dB). The samples showed a surprisingly high stability to irradiation, strong absorption bleaching, and wavelength dependent differential absorption spectra. PACS 42.70 Jk; 42.65.-k; 78.66.Qu     

Reductive Catenation of Phosphine Antimony Complexes

Reactions of triarylphosphines with fluoroantimony(III) triflates give phosphine antimony(III) complexes, which undergo spontaneous reductive elimination of fluorophosphonium cations. The resulting phosphine antimony(I) complexes catenate to give the first examples of cationic antimony bicyclic compounds, [(R₃P)₄Sb₆]⁴⁺, featuring a bicyclo[3.1.0]hexastibine framework stabilized by four phosphine ligands. The unprecedented 14‐electron redox process illustrates the generality of the reductive catenation method.     

Recent advances in anion recognition

By linkage of 1,5-naphthalenedisulfonate (1,5-NDS) anion fluorophore, 3D cucurbit[7]uril (CB[7]) framework has been constructed. The maximum solid-state fluorescence wavelength of the CB[7] framework exhibits blue-shift from 406 to 340 nm in comparison with that of 1,5-NDS, which was ascribed to increased excited energy from 0.10 to 0.13 eV according to theoretical calculations.     

Structure, solution chemistry, antiproliferative actions and protein binding properties of non-conventional platinum(II) compounds with sulfur and phosphorus donors

Twelve Pt(II) complexes with cis-PtP(2)S(2) pharmacophores (where P(2) refers to two monodentate or one bidentate phosphane ligand and S(2) is a dithiolato ligand) were prepared, characterized and evaluated as potential antiproliferative agents. The various compounds were first studied from the structural point of view; afterward, their solubility properties as well as their solution behaviour were analyzed in detail. Antiproliferative properties were specifically evaluated against A2780 human ovarian carcinoma cells, either resistant or sensitive to cisplatin. For comparison purposes similar studies were carried out on four parent cis-dichloro bisphosphane Pt(II)complexes. On the whole, the cis-PtP(2)S(2) compounds displayed significant antiproliferative properties while the cis-PtP(2)Cl(2) (cis-dichloro bisphosphane Pt(II)) compounds revealed quite poor biological performances. To gain further insight into the molecular mechanisms of these bisphosphane Pt(II) compounds, the reactions of selected complexes against the model protein cytochrome c were investigated by ESI-MS and their adduct formation explored. A relevant reactivity with cyt c was obtained only for cis-PtP(2)Cl(2) compounds, whereas cis-PtP(2)S(2) compounds turned out to be nearly unreactive. The obtained results are interpreted and discussed in the frame of the current knowledge of anticancer platinum compounds and their structure-activity-relationships. The observation of appreciable antiproliferative effects for the relatively inert cis-PtP(2)S(2) compounds strongly suggests that these compounds will undergo specific activation within the cellular environment.     

Sub- and superluminal velocity of supercontinuum pulses propagating in scattering media

The XFROG technique has been applied to measuring temporal shifts of supercontinuum pulses propagating in scattering media consisting of spherical beads. Negative (subluminal) and positive (superluminal) changes in the group velocity have been measured. This behaviour can be explained in terms of spectral scattering losses and is directly related to the complex time formulation used in other phenomena where tunnelling times are used to describe the velocity changes. A numerical simulation of the XFROG measurement is consistent with the experimental results. PACS 42.25.Dd; 42.25.Fx; 42.65.Re     

Phase-resolved laser Raman scattering and laser Doppler velocimetry applied to periodic instabilities in a gas turbine model combustor

The understanding of periodic flame instabilities belongs to the major challenges in modern combustion research and technology and is of special importance for lean premixed gas turbine combustion. This paper presents experimental investigations in a gas turbine model combustor using laser diagnostic techniques. A partially premixed CH₄/air flame operated at a thermal power of 10 kW at atmospheric pressure and an overall equivalence ratio of 0.75, which exhibited thermoacoustic oscillations at a frequency of 290 Hz, was investigated. Phase-locked laser Raman scattering was applied in order to determine the major species concentrations, temperature, and mixture fraction. In addition, laser Doppler velocimetry (LDV) was used separately for the measurement of the axial and radial velocity components. The measurements revealed pronounced phase-dependent variations of the velocity and the temperature, species, and mixture fraction distributions. The combined Raman and LDV results also enabled the determination of molecular species fluxes which showed that the fuel and air supply rates both varied during an oscillation cycle by ±33% but with a phase shift of 80 between them. The correlations between temperature and mixture fraction revealed strong deviations from equilibrium composition and temperature, and their phase-dependent changes reflected the transport and mixing processes near the nozzle. The emphasis of the paper lies on the demonstration of the potential of phase-locked laser Raman scattering for the study of phenomena of periodic flame instabilities. PACS 33.20; 39.30; 47.27; 47.70; 82.33; 82.40     

The freeze-shut of a convectively cooled parallel plate channel subjected to laminar internal liquid flow

The paper presents an approximative solution for the time dependent development of the ice layers at the cooled walls inside a parallel plate channel. The upper and the lower wall of the channel are cooled by an uniform external convection. By assuming a constant pressure drop across the channel, the freeze-shut of the planar channel could be calculated approximately. It was found out that the origin of the freezing fronts moves upstream during the ice layer growth. Furthermore a simple criterion is presented to predict whether a given system will lead to blockade.