Synthesis and Structure of Tetra-1,3-Diketonyl Ligands Based on Tetrathia- And Calix[4]arene

This work presents the development of methods for the synthesis of tetra-1,3-diketones on a 1,3-alternate calix[4]arene platform containing alkyl substituents at the lower rim of the macrocycle. It was intended to obtain compounds with butyl and dodecyl substituents. It was supposed that long alkyl chains in the obtained compounds would improve the further solubility of their lanthanide complexes in low-polarity organic media. Alkyl substituents were introduced onto the macrocycle by interaction of alkyl tosylate with the cesium salt of calix[4]arene in DMFA. As a result of the reaction, the calixarene macrocycle change the cone conformation to the 1,3-alternate position. The obtained tetra-alkyl derivative has been chloromethylated by using methyl chloromethyl ether as chloromethylating agent and tin tetrachloride as a catalyst. 1,3-diketone groups were incorporated into the macrocyclic backbone by the addition of sodium salt of acetylacetone to the tetra-chloromethyl derivatives of calix[4]arene in the presence of sodium iodide. The work also included the task of developing a method for the synthesis of bis-1,3-diketone calix[4]arene. For the obtaining the bis-chloromethyl derivative, the initial calix[4]arene was selectively brominated by pairwise insertion of alkyl groups onto the lower rim of the macrocycle. The introduction of the last two alkyl groups was also accompanied by conformation change of the calixarene platform. The chloromethylation reaction and attaching of 1,3-diketone fragments were carried out similarly to preparation of tetra-1,3-diketone derivatives of calix[4]arene. The structure of the obtained compounds was established by a complex of physicochemical methods. Spectral analysis techniques such as NMR, IR spectroscopy, elemental analysis and high resolution MALDI-TOF mass spectrometry were used in this work.