Thinking in structure-activity relationships -: a way forward towards sustainable chemistry

Thinking in structure-activity relationships (T-SAR) is presented as an approach to a systematic collection and networking of knowledge and hypotheses regarding chemical structures. T-SAR can be accompanied by quantitative correlation studies commonly referred to as quantitative structure-activity relationships (QSAR) or linear free energy relationships (LFER). Some important limitations of these quantitative approaches are illustrated using the examples of biopartitioning and equilibrium partitioning in general. A systematic scheme for the qualitative analysis of a structural formula in seventeen steps is shown, covering stereo chemistry, molecular interaction potentials, and reactivity. As an example for the application of T-SAR, contributions to the molecular design of ionic liquids are described.