COLLECTIVE H+, LI+, AND NA+ MOTIONS AND CATION POLARIZABILITIES OF THE CATION-BONDED SYSTEMS WITHIN 1,11,12,13,14-PENTAHYDROXYPENTACENE SALTS - A FTIR STUDY

1,11,12,13, 14-Pentahydroxypentacene (PHP) and its pentakis(tetrabutylammonium) salts were synthesized. The corresponding 2:1 complex of PHP with HAuCl4 as well as the complexes of pentakis (tetrabutylammonium) salts with four Li+ or four Na+ cations were obtained, respectively. PHP formed a dimer if one HAuCl4 molecule was present per two PHP molecules. In this dimer a cyclic hydrogen-bonded chain with 10 hydrogen bonds is present, and the excess proton fluctuates between all O-atoms of this cyclic chain. The fluctuation of all protons in the cyclic structure causes large proton polarizability due to collective proton motion, as indicated by an intense continuum in the infrared spectra. In the far infrared spectra of the tetra Li+ and tetra Na+ salts, respectively, continua are also observed, indicating Li+ and Na+ polarizability due to collective cation motion involving the four cation bonds. The relationship between the mass of the cations and the region in which the infrared continua are observed as well as the influence of the type of cation and the integrated absorbance of the continua and the cation polarizability are discussed.