Crystal structures of 1-(4-chloro-phen-yl)-2-(di-phenyl-phosphor-yl)ethan-1-one and 1-(di-phenyl-phosphor-yl)-3,3-di-methyl-butan-2-one.

The title compounds, C20H16ClO2P, (I), and C18H21O2P, (II), were synthesized via an Arbuzov reaction between an α-bromo-ketone and isopropoxydi-phenyl-phosphane. In the crystals of both compounds, mol-ecules are linked via bifurcated C-H⋯(O,O) hydrogen bonds, forming chains propagating along [100] for (I) and along [010] for (II). The chains are linked via C-H⋯π inter-actions, leading to the formation of sheets lying parallel to (010) for (I) and (001) for (II). The absolute structure of compound (II) was determined by resonant scattering [Flack parameter = 0.088 (14)].