Transformations of the molecular complex of hydroiodide of 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene and 5,50-dibromo-2,20-biphenol between crystal and solutions

A complex of 5,50-dibromo-2,20-biphenol with 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene hydroiodide has been studied by X-ray diffraction, FT-IR, and 1HNMR spectroscopy. In the crystal structure, the iodide anion is hydrogen-bonded to the MTBDHC cation and to two hydroxyl groups of two 5,50-dibromo-2,20-biphenol molecules. In chloroform and acetonitrile the structure of the complex assumes a new structure due to almost complete dissociation of the protonated MTBD molecule. In chloroform the MTBDHC cation is hydrogen bonded to 5,50-dibromo-2,20-biphenol whereas in acetonitrile it is free and solvated by the solvent. In both cases the 5,50-dibromo-2,20- biphenol molecule is hydrogen bonded to the iodide anion. In chloroform the iodide ion interacts strongly with the solvent. q 2005 Elsevier B.V. All rights reserved