Crystal structures of 1-(4-chloro­phen­yl)-2-(di­phenyl­phosphor­yl)ethan-1-one and 1-(di­phenyl­phosphor­yl)-3,3-di­methyl­butan-2-one

The title compounds, C(20)H(16)ClO(2)P, (I), and C(18)H(21)O(2)P, (II), were synthesized via an Arbuzov reaction between an α-bromo­ketone and isopropoxydi­phenyl­phosphane. In the crystals of both compounds, mol­ecules 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 inter­actions, 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)].