The complexation of 2,4-dinitrophenol with basic drugs: Acid + base = salt

Different drugs containing a basic nitrogen atom were crystallised with 2,4-dinitrophenol to study the mode of complexation in search of an antidote to 2,4-dinitrophenol poisoning. The protonated forms of quininium, quinidinium and trazodonium form N–H···O hydrogen bonds to the deprotonated O atom of the 2,4-dinitrophenolate anion, whereas haloperidolium forms a bifurcated N–H···(O,O) hydrogen bond to the deprotonated O atom of 2,4-dinitrophenol and an O atom of the adjacent nitro group. Hydrogen-bonded chains occur in the quininium, quinidinium and haloperidolium crystal structures, whereas the trazodonium structure consists of ion pairs. These results are discussed with a view to lowering the toxicity of 2,4-dinitrophenol in the body in the case of an overdose.