Resorcinol ninhydrin complex: 1,5,9-trihydroxy-8-oxatetracyclo[7.7.0.02,7.010,15]hexadeca-2,4,6,10(15),11,13-hexaen-16-one

In the title compound, C15H10O5, the cyclopentanone (r.m.s. deviation = 0.049 Å) and oxolane (r.m.s. deviation = 0.048 Å) rings make a dihedral angle of 67.91 (4)°. An intramolecular O—H⋯O hydrogen bond is observed. In the crystal, molecules associate via O—H⋯O hydrogen bonds, forming a three-dimensional network.


D-HÁ
The X-ray study confirmed the molecular structure and atomic connectivity for (I), as illustrated in Fig. 1.
The molecular structure is influenced by an intramolecular O-H···O hydrogen bonds. In the molecular packing, O-H···O hydrogen bonds involving atoms O3 and O4 link inversion-related molecules to form R 2 2 (16) graph-set dimer.
( Fig. 2 and Table 1). In addition to this atoms, O2 and C11 form a R 2 2 (10) graph-set motif in the unit cell with the help of intermolecular hydrogen bonds (Fig.3). A C(8) chain motif is formed in the unit cell with the help of O-H···O hydrogen bonds involving atoms O4 and O3 which results the helical shape arrangement along bc plane of the unit cell ( Fig. 4).

Experimental
A mixture of ninhydrin and resorcinol in molar ratio 1:1 were dissolved in dilute acetic medium and stirred well using a temperature controlled magnetic stirrer to yield a homogeneous mixture of solution. Then the solution was allowed to evaporate at room temperature, which yielded a crystalline adduct. Single crystals were grown by slow evaporation from ethanol.

Refinement
All H atoms were located from a difference Fourier map and refined isotropically.       where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.31 e Å −3 Δρ min = −0.28 e Å −3 Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.