A new streptocyanine dye has been doped into monolithic silica gels with different porosities, characterized by nitrogen adsorption isotherms. Single-molecule tracking with a wide-field fluorescence microscope is used to determine the diffusivity of the dye in the nanoporous network of the host. The majority of molecules in the gel with wider pores (22 nm) diffuse freely with an average diffusion coefficient of D = 4.7 × 10-9 cm2 s-1. Most of those in the gel with narrower pores (3 nm) are trapped in regions ranging in size from 50 nmthe positioning accuracy of the setupup to 200 nm. Others are alternately trapped and freely diffusing with an average D = 3.5 × 10-10 cm2 s-1. The significance of the distribution of diffusion coefficients measured by single-molecule tracking is discussed. Besides traps, the wide spread of the diffusion coefficients for individual molecules in both gels reveals pronounced microscopic inhomogeneities.

We perform nonresonant surface second harmonic reflection from an isotropic layer of a chiral pentamethinium salt. The combination of gated integration and photon counting techniques allows for a very high sensitivity of our experimental setup. We measure a second harmonic optical rotation angle of 5°, as well as linear and circular dichroisms of 5% to 140%. We quantitatively compare these three experimental techniques and obtain a good agreement. The nonresonant configuration of our experiments enables us to distinguish between electric and magnetic contributions to the second order optical activity. The nonvanishing circular dichroism, as well as the nonvanishing s-polarized second harmonic signal with s-polarized fundamental beam, indicates that electric and magnetic effects are of the same order of magnitude.

In the grotz'ing field of dicoordinated

No abstract

A new highly reactive nonacarbon chain carboxonium salt 1 was synthesized. It leads, by action of various amines and hydrazone, to a new class of symmetrical nonacarbon chain streptocyanine dyes 3−5.

P‐CNAs are dinucleotide building blocks in which the torsional angles α and β of the sugar/phosphate backbone are constrained to non‐canonical values within a cyclic phosphonate structure (phostone) synthesised by diastereoselective intramolecular Arbuzov reaction. The reaction has been improved through the use of microwave activation and addition of lithium bromide.

Artemisinin and its derivatives are peroxide-containing compounds targeting P. falciparum. We review here structural analogues of bicyclic peroxides belonging to the G factors family presenting antimalarial properties. They were synthesised under Mannich type conditions, followed by an autoxidation step resulting exclusively in the peroxide. As the electron transfer from haem or free iron to the peroxide is the first step in the mode of action of artemisinin-like compounds, the redox properties of some endoperoxides were studied by electrochemistry allowing the evaluation of the reduction standard potentials. The Fe(II) induced reduction was also investigated and the reactivity of the C-centered radical intermediate formed was linked to the antimalarial activity. These bicyclic peroxides both with various hybrid molecules containing the endoperoxide framework were evaluated in vitro against Plasmodium falciparum. They exhibited moderate to good activities.

Two series of streptocyanine dyes incorporating cyclic peroxide or 4-aminoquinoline moieties are prepared and X-ray diffraction structures for three compounds are determined. All hybrid dyes show good antiplasmodial activity (0.06 to 0.66 μM) and are not or are slightly cytotoxic, except 10a.