Crystal and molecular structure of the ethanol solvate of 2-[bis(diphenylphosphoryl)methyl]phenol

Crystal and molecular structure of the ethanol solvate of 2-bis(diphenylphosphoryl)methyl]phenol, C₃₁H₂₆O₃P₂·3/4 C₂H₅OH (I), was determined by X-ray diffraction analysis. Crystals I are monoclinic: a=11.896(3), b=17.207(3), c=28.421(6) Å, β=90.75(2)°, Z=8, space group P2₁/c. The structure of I was solved by direct methods and refined anisotropically by large-block least-squares analysis to R=0.066 (CAD-4 automatic diffractometer, λMoK_α radiation, 3650 independent reflections with I≥3σ). The crystal structure of I contains two independent molecules, Ia and Ib, of the basic substance and two independent solvate molecules of ethanol. The P atoms in molecules Ia and Ib have distorted tetrahedral environments; the average bond lengths are: P=O 1.476(3), P-C(sp³)=1.833(4) and P-C(Ar)=1.809(4) Å. Molecule Ia has an approximate symmetry plane C_s. The conformation of molecule Ib differs from that of Ia in rotation of one diphenylphosphoryl substituent around the P-C(sp³) bond by an angle of ≈34°. In molecule Ia, the O=P-C-P=O fragment has the form of a chela with two nearly parallel P=O bonds. In the crystal structure of I there are O-H...O=P intermolecular H-bonds; in molecules Ia and Ib there is an intramolecular H-bond of C-H...OH type.