FORMATION AND STRUCTURE OF ALKYL PEROXIDE COMPLEXES OF GERMANIUM(IV) PORPHYRINS FROM DIRECT REACTIONS WITH ALKYL HYDROPEROXIDES AND BY PHOTOLYSIS OF ALKYLGERMANIUM(IV) PORPHYRINS IN THE PRESENCE OF DIOXYGEN

TPPGe(OOCH2CH3)2(TPP is the dianion of tetraphenylporphyrin) which has remarkable thermal stability but is hydrolytically sensitive has been prepared by both reaction of ethyl hydroperoxide with TPPGe(OH)2and by photolysis of TPPGe(CH2CH3)2in the presence of dioxygen. The latter reaction involves successive reactions of the two ethyl groups to give TPPGe(OOCH2CH3)(CH2CH3) and TPPGe(OOCH2CH3)2and the decomposition/hydrolysis products TPPGe(O-H)(CH2CH3) and TPPGe(OH)(OOCH2CH3). X-ray diffraction studies on both TPPGe(OOCH2CH3)2and TPPGe(OCH2CH3)2confirm their similar, six-coordinate structures. The ring current shifted 1H NMR resonances of the axial ligands in these complexes are more effective than electronic spectra in monitoring reaction products. Photolysis of TPPGe(OOCH2CH3)2in toluene produces acetaldehyde and ethanol in ratios that are highly temperature dependent. At 23 °C the acetaldehyde/ethanol ratio is 0.55, while at -70 °C it is 3.5. © 1990, American Chemical Society. All rights reserved.