Crystallographic and Computational Studies of Non-Covalent Interactions of Molecular Clips with a Series of Small Solvent Molecules

Abstract

Molecular clips hold the potential of self-association and the ability to form host–guest complexes. Here we describe the synthesis of a 1,2-dimethoxyphenyl terminated glycoluril molecular clip (2) that binds with smaller solvent molecules by π⋯H–C and C=O⋯H–O non-covalent interactions. We obtained single crystals of 2 and 2 + CH2Cl2, CH3OH, CH3CN, and DMF solvents complexed within the clip. These solvents always form two π⋯H–C interactions between the aromatic rings in the clip, and CH3OH formed an additional C=O⋯H–O hydrogen bond with the glycoluril carbonyl group. Based on single crystal data we found that π⋯H–C interactions of 2 + CH2Cl2 are stronger than 2 + CH3CN and 2 + DMF, due to the presence of stronger electron withdrawing groups in CH2Cl2, which lead to a decrease in dihedral angle of two glycoluril aromatic planes. We also investigated the non-covalent interaction energies of these solvent molecules with 2 using computational methods. Several solvent adducts of a glycoluril derivative have been isolated and characterized by single crystal X-ray diffraction, revealing two common pi⋯H–C non-covalent bonds within the molecular clip.