The 2:1 adducts of (benzoylmethylene)triphenylphosphorane with fumaric and terephthalic acids

Abstract

Co-crystals of the ylide (benzoylmethylene)triphenylphosphorane (BPPY) with either fumaric acid, viz. (benzoylmethylene)triphenylphosphorane-fumaric acid (2/1), C26H21OP·0.5C4H4O 4, or terephthalic acid, viz. (benzoylmethylene)triphenylphosphorane- terephthalic acid (2/1), C26H21OP·0.5C 8H6O4, have a stoichiometric ratio of 2:1 between the ylide and the corresponding dicarboxylic acid. In both adducts, the acid component lies across a centre of inversion. In neither case is the ylide protonated by the organic acid; instead the H atoms of the non-ionized dicarboxylic acid molecules participate in the formation of strong O-H . . .O hydrogen bonds with the benzoyl O atom of the ylide species. These structures are the first reported examples of co-crystals containing non-protonated BPPY.