Bis-(S-benzylthiuronium) chloranilate supramolecular crystal structure: Preparation and characterization
(EN)
Stergiou, D. V.
(EN)
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας
(EL)
Stergiou, D. V.
(EN)
A novel supramolecular structure, [C8H11N2S](2)center dot(C6Cl2O4), based on hydrogen bonding of the organic S-benzylthiuronium (SBT) cation and the chloranilate dianion, is presented. Chloranilic acid or 2,5-dichlro-3.6-dihydroxy-1,4-benzoquinone, is a strong quinoidal diphenic acid (pK(1) = 1.09 and pK(2) = 2.42), with molecular formula C6Cl2O4H2 (H(2)CA). The CA-dianions and the aromatic rings of the SBT-cation; form columns along the c-axis giving an ordered pattern of dianions surrounded by densely populated areas of SBT-cations. Each CA-dianion forms eight hydrogen bonds with the amine protons of six SBT-cations, through its oxygen atoms. In this way, an extended H-bond network, containing infinite chains of alternative R-4(2)(8) and R-2(2)(9) cyclic patterns, is obtained. The whole arrangement leads to a C2/c space group crystal structure, with unit cell dimensions a = 15.109 angstrom, b = 11.606 angstrom, and c = 14.390 angstrom and with unit cell angles of alpha = gamma = 90 degrees, and beta = 97.01 degrees, and average density of 1.43 g/cm(3). Dissolution of the crystalline material in DMSO leads to the formation of associated organic ions or charge-transfer complexes as evidenced from the bathochromic shift of the absorption band of chloranilic acid from 420 to 520 nm.
(EN)
