1,10-PHENANTHROLIN-1-IUM CHLORIDE BIS(1,10-PHENANTHROLINE) SOLVATE AT143 K

The crystal and molecular structure of the title compound, C12H9N2+.Cl -.2C(12)H(8)N(2), has been determined at 143 K. It consists of three p henanthroline units and one Cl- ion. One of the phenanthroline molecul es is protonated at an N atom. In agreement with other authors, the pr otonated phenanthroline forms a hydrogen bond to another phenanthrolin e molecule. The third phenanthroline is not involved in any hydrogen b ond at all. The C-N-C angle at the protonated N atom is significantly larger than the corresponding angle at the non-protonated N atom. Comp aring the structure of the title compound with four similar structures , it was found that the angle between the phenanthroline molecules for ming the hydrogen bond correlates with the distance between the two N atoms: with an increasing angle between the aromatic ring systems, the N ... N distance decreases. For the Cl- ion, six contacts less than 3 Angstrom to H atoms (bound to C atoms) are observed.