Synthesis and crystal structure of a 1 : 2 adduct of aquatrifluoroboron and triphenylphosphine oxide

A crystalline 1 : 2 adduct of aquatrifluoroboron and triphenylphosphine oxide 1/2[BF3(H2O)] . Ph3PO (1) is synthesized and studied by X-ray diffraction analysis. The crystals are orthorhombic, space group Fdd2, a = 32.283 Angstrom, b = 20.162 Angstrom, c = 10.191 Angstrom, Z = 16. The structure is solved by the direct method and refined by a full-matrix least-squares method in the anisotropic approximation to R = 0.054 against 2528 independent reflections (CAD4 automated diffractometer, lambdaMoK(alpha)). A Ph3PO molecule has a normal structure. A [BF3(H2O)] molecule is randomly disordered relative to axis 2; populations of positions of all its atoms are 0.5. The boron atom has a distorted tetrahedral coordination with a donor-acceptor B-O(w) bond. In crystal, strong hydrogen bonds of the P=O...H-O-H...O=P type are formed between the H2O molecule and two Ph3PO molecules.