Coumarin Derivatives: The Influence of Cycloalkyl Groups at the C-3 Position on Intermolecular Interactions—Synthesis, Structure and Spectroscopy

Abstract

In this study, we explore the synthesis and solid-state characterization of four coumarin-3-carboxylic acid esters, each modified at the C-3 position with different cycloalkyl groups: cyclohexyl, menthyl, and iso-pulegyl. We conducted a detailed analysis of these compounds utilizing a variety of techniques such as a single-crystal X-ray diffraction, nuclear magnetic resonance (NMR), and Fourier-transform infrared (FTIR) spectroscopy. Additionally, we calculated the dipole moments for these molecules. Our findings include a thorough structural assessment, highlighting the role of noncovalent interactions through Full Interaction Maps and Hirshfeld surface analysis. This study reveals the critical influence of the weak C-H…O hydrogen bonds in determining the solid-state architecture of these esters, whereas π-π stacking interactions appear to be negligible among the studied derivatives.

Keywords

• coumarin ester
• conformation of molecules
• dipole moment
• intermolecular contacts
• crystal packing