An oligomeric gold(III) compound containing dicarbanionic chelating 4,4'-di-tert-butylbiphenyl was prepared via transmetallation using the corresponding organotin(IV) compound. The reactivity of the chloro-bridged oligomer with various species including neutral N-, P-, and C-donor ligands as well as monoanionic S- and Se-ligands was investigated. Some of the products were characterised by X-ray crystallography. The photophysical properties of two derivatives were studied.
A Sonogashira coupling reaction led to star‐shaped 1,3,5‐tris({5‐[7‐(thiophen‐2‐yl)benzo[c][1,2,5]thiadiazol‐4‐yl]thiophen‐2‐yl}ethynyl)benzene derivatives. The star‐shaped molecules were optically analyzed, and – depending on their substitution pattern – they displayed bathochromically shifted absorptions, which were compared to their nonlinked arm precursors. The materials displayed a highly interesting morphology in bulk when blended with [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM). One derivative formed columnar structures and revealed prospective use in photodiodes.
Matrix-assisted laser desorption ionization (MALDI) is a very powerful and widely used mass spectrometric technique to ionize high molecular weight compounds. The most commonly used dried droplet (DD) technique can lead to a concentration distribution of the analyte on the target and is therefore often not suitable for reproducible analyses. We developed a new solvent-free deposition technique, called compressed sample (CS), to prevent the distribution of the analytes caused by the crystallization of the compounds. The CS technique presented in this work allows the quantitative analysis of synthetic polymers such as derivatized maltosides with correlation coefficients of 0.999 and peptides up to 3500 Da with correlation coefficients of at least 0.982 without the use of stable-isotope-labeled standards.
A recently developed solvent-free compressed-sample technique for matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) analysis allows the reproducible analysis of synthetic polymers and peptides up to 3,500 Da. In this work, we present an improvement in resolution, an increase in intensity and a decrease of the variation coefficient, as illustrated by the analysis of PEG 2000 and MALDI imaging experiments. These advantages were achieved by homogenization of the electrical field, which was disturbed by the drills in the original MALDI target. In order to homogenize the electrical field, a new target with smaller drills was developed, metal powder was added to the matrix/analyte mixture and a round laser raster was used. Furthermore, a ball mill was implemented for the sample preparation to replace the extremely user-dependent grinding in a mortar. The new conditions were successfully applied to the quantification of several peptides of higher molecular weight and gave higher precision than had previously been achieved with the compressed-sample technique.
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