Spectroscopic and theoretical studies of the H-bonded complex of quinuclidine with 2,6-dichloro-4-nitrophenol

The molecular structure and spectroscopic properties of the 1:1 complex of quinuclidine (Q) with 2,6-dichloro-4-nitrophenol (DCNP) have been characterized by X-ray diffraction, B3LYP/6-311++G(d,p) calculations, UV-vis, FTIR and NMR spectroscopies. In the crystals the proton from DCNP is transferred to Q and the ionic pair is linked by the N+H center dot center dot center dot O- hydrogen bond of 2.620(2) angstrom, while in the theoretically optimized structure a molecular complex is present. The band at 405 nm in the UV-vis spectra in ethanol provides the evidence of proton transfer. The calculated natural atomic charges (NBO) show the differences between neutral components Q and DCNP, and the corresponding cation Q(+)H or anion DCNP-. The potential energy distribution (PED) has been used to assign the vibrational spectra. (C) 2017 Elsevier B.V. All rights reserved.