TY - JOUR A1 - Krüger, Ralph-Peter A1 - Kricheldorf, H.R. A1 - Böhme, S. T1 - Macrocycles 16. Macrocyclic Dibutyltin Dicarboxylates by Ring-Closing Polycondensation T2 - Macromolecular chemistry and physics N2 - Various dibutyltin derivatives were polycondensed with aliphatic ,-dicarboxylic acids having chain lengths from 4 (succinic acid) to 22 carbon atoms. White crystalline products were obtained from all experiments, and the structure of the products was independent of the synthetic method. Viscosity measurements revealed low molecular weights (n 1 500 Da) in all cases. Vapor pressure osmometry (VPO) measurements and matrix-assisted laser desorption time-of-flight (MALDI-TOF) mass spectrometry proved that cyclic dimers and trimer were formed from dicarboxylic acids having 6 to 16 carbons, but mainly the monomeric cycle from docosane dioic acid. Heating to 250°C did not change the structure. Therefore, the results indicate that the macrocycles are the result of a thermodynamically controlled ring-closing polycondensation. This means that linear high-molecular weight poly(dibutyltin dicarboxylate)s cannot exist above room temperature. PB - Wiley-VCH Verl. CY - Weinheim PY - 2002 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/1796 AN - OPUS4-1796 SN - 1022-1352 SN - 1521-3935 VL - 203 IS - 2 SP - 313 EP - 318 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany