Rotational spectroscopy of the benzofuran–water complex: Conformations and preferred noncovalent interactions

[Display omitted] •The rotational spectrum of the benzofuran···H2O complex was measured and assigned.•Two different conformations stabilized by OH···O and O···HC hydrogen bonds or two OH···π hydrogen bonds were detected.•The OH···O and CH···O stabilized conformer is mainly stabilized by electrostatic interactions whereas dispersion interactions is significant in the stabilization of OH···π linked conformation. We investigated the non-covalent interactions occurring between benzofuran and water. The weakly-bound complex was produced using a supersonic jet expansion and was subsequently characterized utilizing high-resolution Fourier transform microwave spectroscopy. Through the analysis of the rotational spectrum, we were able to confirm the detection of two distinct conformations within the complex. The most stable conformation demonstrates a structure that is almost coplanar. This structure involves one hydrogen atom from a water molecule interacting with the oxygen atom of benzofuran, thus forming an Ow–Hw···O hydrogen bond. Concurrently, the oxygen atom serves as a proton acceptor, forming an Ow···HC hydrogen bond with one hydrogen atom of the phenyl ring. The secondary conformation positions the two OH bonds such that they are oriented towards the face of benzofuran, resulting in the formation of two Ow–Hw···π hydrogen bonds. The non-covalent bonding topology of the first conformation bears resemblance to the corresponding furan-water complex, while the second conformation aligns with the benzofuran-hydrogen sulfide complex. The strength and the nature of these hydrogen bonding interactions is delineated by the application of natural bond orbital theory, energy decomposition, and electronic density analysis methodologies.