3,3,3',3'-Tetra-methyl-6,6'-bis-[(pyridin-4-yl)meth-oxy]-1,1'-spiro-biindane -monohydrate.

The asymmetric unit in the title compound, C(33)H(34)N(2)O(2)·H(2)O, consists of a V-shaped mol-ecule and a water mol-ecule to which it is hydrogen bonded. The angle between the mean planes of the two spiro-connected indane groups is 77.06†(5)°. The two five-membered rings of the indane groups have envelope conformations with the methyl-ene atoms adjacent to the spiro C atom forming the flaps. They have deviations from the mean plane of the other four atoms in the rings of 0.374†(4) and 0.362†(4)†à . In the crystal, molecules are linked to form inversion dimers via O-H⋯N hydrogen bonds involving the pyridine N atoms and the solvent water mol-ecule. The dimers are linked into a chain along the b axis by π-π stacking inter-actions between a pyridine ring and its centrosymmetrically related ring in an adjacent dimer. The centroid-centroid distance between the planes is 3.7756†(17)†à , the perpendicular distance is 3.4478†(11)†à and the offset is 1.539†à .