Ph2POH

Ph2POH, commonly referred to as diphenylphosphinous acid, is an organophosphorus compound with the formula Ph2POH. It features a phosphorus atom bonded to two phenyl groups and a hydroxyl substituent, giving a trivalent phosphorus center. The P–OH unit allows hydrogen bonding and provides a handle for further transformations, while the lone pair on phosphorus confers Lewis basic character.

In terms of structure and reactivity, Ph2POH is typically described as a phosphinous acid derivative (phosphorus in a relatively low oxidation state). The molecule can act as a soft Lewis base at phosphorus and can engage in coordination to transition metals as a ligand. The P–OH group can participate in acid–base chemistry, and the compound can undergo condensation with alcohols or other nucleophiles to form phosphinite esters (Ph2P–OR) or related derivatives. Oxidation of Ph2POH under appropriate conditions affords higher-oxidation-state phosphorus species such as phosphinic acids (Ph2P(O)OH) and related oxide derivatives.

Applications and significance in chemistry are primarily synthetic and methodological. Ph2POH and its derivatives serve as building blocks in organophosphorus chemistry, including the development of ligands for catalysis and as precursors to more complex phosphorus-containing reagents. The chemistry of Ph2POH often complements studies of phosphorus(III) chemistry, ligand design, and transformations that exploit the reactivity of P–OH and Ph2P moieties. Handling is typically performed under standard inert or dry conditions due to the reactive nature of phosphinous acids and their tendency to undergo further transformation.

See also: phosphinous acids, phosphinic acids, phosphine oxides, phosphinite esters.