DOCKING PREFERENCE AND GEOMETRY OF 1-NAPHTHOL COMPLEXES REVEALED BY ROTATIONAL SPECTROSCOPY

We examine the interplay of docking preference on 1-naphthol in van der Waals complexes with simple molecules. The advantage of 1-naphthol is that it allows for two main docking sites, the first on the conjugated $\pi$-system of the fused rings, and the second on the hydrogen bond donor site at the hydroxyl group. Initial complexes studied include furan, dimethylfuran, and thiophene. These three systems follow a similar structure of a heterocyclic, five-membered ring containing a chalcogen as the heteroatom, setting up a common structural motif to benchmark quantum chemical methods with experimental results. Later measurements were extended to benzene and carbon monoxide. Current progress on the ethylene and acetylene complexes will also be discussed. We compare these results with recent literature reports of the dissociation energies and computational studies, where available. The spectra for all the reported systems were recorded using a broadband microwave spectrometer in the 2-8 GHz frequency range in a cold, supersonic jet. From the spectroscopic constants of those complexes, an effective geometry has been determined for each. As is often the case in such systems, more than one docking site can be observed in the supersonic expansion, which is indeed true for the furan complex. A combination of experiment and quantum chemical calculations are used to determine the relative abundances of each furan docking site observed in the expansion