2-(4-tert-Butyl-phen-yl)-1H-imidazo[4,5-f][1,10]phenanthroline sesquihydrate.

In the title compound, C(23)H(20)N(4)·1.5H(2)O, the mean planes of the imidazo[4,5-f][1,10]phenanthroline system and the benzene ring make a dihedral angle of 21.76 (2)°. One water O atom lies on a twofold rotation axis. The organic mol-ecules and water mol-ecules are linked via N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds. Weak inter-molecular C-H⋯N hydrogen bonds and π-π stacking inter-actions between inversion-related phenanthroline rings complete the three-dimensional hydrogen-bonding network in the crystal structure. The stacking distance is short at 3.513 (2) Å and the perpendicular distance between the rings is 3.355 Å. The three methyl groups are disordered over two positions, with a site-occupancy ratio of 0.875 (14):0.125 (14).