3,3,3′,3′-Tetramethyl-6,6′-bis[(pyridin-4-yl)methoxy]-1,1′-spirobiindane monohydrate

The asymmetric unit in the title compound, C33H34N2O2·H2O, consists of a V-shaped molecule and a water molecule 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 methylene 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) Å. 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 molecule. The dimers are linked into a chain along the b axis by π–π stacking interactions between a pyridine ring and its centrosymmetrically related ring in an adjacent dimer. The centroid–centroid distance between the planes is 3.7756 (17) Å, the perpendicular distance is 3.4478 (11) Å and the offset is 1.539 Å.

The asymmetric unit in the title compound, C 33 H 34 N 2 O 2 ÁH 2 O, consists of a V-shaped molecule and a water molecule 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 methylene 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) Å . In the crystal, molecules are linked to form inversion dimers via O-HÁ Á ÁN hydrogen bonds involving the pyridine N atoms and the solvent water molecule. The dimers are linked into a chain along the b axis bystacking interactions between a pyridine ring and its centrosymmetrically related ring in an adjacent dimer. The centroidcentroid distance between the planes is 3.7756 (17) Å , the perpendicular distance is 3.4478 (11) Å and the offset is 1.539 Å .
The molecule of C 33 H 34 N 2 O 2 .H 2 O, is V-shaped, Figure 1. 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 an envelope pucker with the methylene atoms, C9 and C17, adjacent to the spiro carbon atom forming the flaps. They have deviations from mean plane of other 4 atoms in the rings of 0.374 (4) Å and 0.362 (4) Å, respectively.

Refinement
The hydrogen atoms were placed in idealized positions and allowed to ride on the relevant atoms, with C-H = 0.93 and 0.97 Å for aryl and methylene H atoms, respectively, U iso (H)=1.

Figure 1
ORTEP drawing of title compound with the atom-numbering scheme, showing 30% probability displacement ellipsoids.
(All labels of the H atoms are omitted for clarity, the dotted line represents as hydrogen bond).

Figure 2
The chain structure constructed by the dimers by the π-π stacking forces shown as dotted lines.  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.24 e Å −3 Δρ min = −0.17 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.