The typical crystal structures of a few representative α-aryl-α-hydroxyphosphonates

The crystal structures of seven α-aryl-α-hy­droxy­phospho­nates synthesized by the Pudovik reaction of substituted benzaldehydes and dialkyl phosphites, namely dimethyl [(hy­droxy)(phenyl)m­eth­yl]phospho­nate, C9H13O4P, dimethyl [(3,4-di­meth­oxy­phen­yl)(hy­droxy)­meth­yl]phospho­nate, C11H17O6P, dimethyl (1-hy­droxy-1-phenyl­eth­yl)phospho­nate, C10H15O4P, dimethyl [1-hy­droxy-1-(4-nitro­phen­yl)eth­yl]phospho­nate, C10H14NO6P, dibenzyl [hy­droxy(2-nitro­phen­yl)meth­yl]phospho­nate, C21H20NO6P, dibenzyl [(3-chloro­phen­yl)(hy­droxy)meth­yl]phospho­nate, C21H20ClO4P, and dibenzyl [hy­droxy(4-methyl­phen­yl)meth­yl]phospho­nate, C22H23O4P, were studied to gain a better understanding of the organization in this type of mol­ecule in the solid state. The crystals obtained for this series of compounds show a balance between C—OH⋯O=P chain-linked packing and the dimeric types of hydrogen-bond bridges of inter­molecular pairs of such functions. The description is based on primary graph-set descriptors. Using graph-set descriptors one level deeper (i.e. secondary graph sets of the C—H⋯O type) revealed a similarity in the graph-set descriptors, suggesting a fine inter­play of substituent- and shape-dependent effects on strong–weak inter­actions. It seems that the formation of chains or dimers is governed not only by the presence of a tertiary Cα atom, but also by the nature and crowding of the ortho substituents of the α-aryl group.