Hydrogen-Bonded Di(hydroperoxy)alkane Adducts of the Type CyP=O·(HOO)CHR (R = Alkyl).

Five representatives of a novel type of di(hydroperoxy)alkane adducts of phosphine oxides have been synthesized and fully characterized, including their solubility in organic solvents. The phosphine oxide CyPO () has been used in combination with the corresponding aldehydes to create the adducts CyPO·(HOO)CHCH (), CyPO·(HOO)CHCHCH (), CyPO·(HOO)CH(CH)CH (), CyPO·(HOO)CH(CH)CH (), and CyPO·(HOO)CH(CH)CH (). All adducts crystallize easily and contain the peroxide and phosphine oxide hydrogen-bonded in 1:1 ratios. The single crystal X-ray structures of - and their unique features are discussed. The P NMR spectra of the adducts - show downfield-shifted signals as compared to CyPO. In the IR spectra, the ν(P=O) wavenumbers of the adducts have smaller values than the neat phosphine oxide. All spectroscopic results of - show that the P=O bond is weakened by hydrogen-bonding to the di(hydroperoxy)alkane moieties. Adduct selectively oxidizes PPh to OPPh within minutes, and nonanal is reformed in the process. The easy synthesis, handling, and administration of these stable, solid, and soluble peroxides with well-defined composition will have a positive impact on synthetic chemistry.