The salts of 4-(2,4,6-triphenylpyridinium-1-yl)-phenolate with selected sulfonic acids

The crystals of two new salts containing 1-(4-hydroxyphenyl)-2,4,6-triphenyl-pyridinium cations and biphenyl-4-sulfonic or 4- aminobenzenesulfonic acid counterions were determined by X-ray diffraction. 4-(2,4,6-triphenylpyridinium-1-yl)-phenolate itself is interesting because of its large negative solvatochromic effect. The salts were obtained from ethanol solution with the following chemical composition: 2C29H21NO·2C12H10O3S·C2H6O (2) and 3C29H21NO·3C6H7NO3S·3C2H6O·H2O (3) as found by crystal structure analysis. Both salts crystallize in monoclinic centrosymmetric space groups (P21=c and P21=n; respectively). The hydroxyl group of the cation serves in these structures as a donor for strong hydrogen bond. Symmetrically independent molecules form hydrogen bonds with different acceptors. In this work, some important aspects of the studied structures are discussed: an antiparralel arrangement of the molecules, relationships between various molecular geometrical parameters and acceptor/donor behaviour of the phenolate O2/OH substituent in different crystal (solvent) environments. q 2004 Elsevier B.V. All rights reserved