Investigation of aggregation motifs and structure-reactivity relationships of organolithium reagents - organolithium compounds are one of the most widely used organometallic compounds in organic and inorganic synthesis. Due to the high ionic character of the C-Li bond, these reagents find application both as nucleophiles and as Brønsted bases. By the specific use of novel ligands or unusual stoichiometries, new reactive intermediates can be found and tested in synthesis. These intermediates will be identified by single crystal X-ray structural analysis and detected by in situ-FTIR and NMR spectroscopy in solution. By combining this with a variety of quantum chemical methods, the stability, reactivity, and formation of these intermediates will be estimated.