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

A complex of 5,5′-dibromo-2,2′-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 MTBDH+ cation and to two hydroxyl groups of two 5,5′-dibromo-2,2′-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 MTBDH+ cation is hydrogen bonded to 5,5′-dibromo-2,2′-biphenol whereas in acetonitrile it is free and solvated by the solvent. In both cases the 5,5′-dibromo-2,2′-biphenol molecule is hydrogen bonded to the iodide anion. In chloroform the iodide ion interacts strongly with the solvent.