Triphenyl phosphite ozonide explained

Triphenyl phosphite ozonide (TPPO) is a chemical compound with the formula PO₃(C₆H₅O)₃ that is used to generate singlet oxygen.^{[1] [2]}

When TPPO is mixed with amines, the ozonide breaks down into singlet oxygen and leaves behind triphenyl phosphite. Pyridine is the only known amine that can effectively cause the breakdown of TPPO while not quenching any of the produced oxygen.

Synthesis

Triphenyl phosphite ozonide is created by bubbling dry ozone through dichloromethane with triphenyl phosphite being added dropwise at -78 °C. If triphenyl phosphite is added in excess in the synthesis, TPPO can be reduced to triphenyl phosphite oxide, PO(C₆H₅O)_3, and oxygen gas.^[3]

Notes and References

1. Pryor . William A. . Govindan . C. K. . November 1981 . Decomposition of triphenyl phosphite ozonide in the presence of spin traps . The Journal of Organic Chemistry . en . 46 . 23 . 4679–4682 . 10.1021/jo00336a010 . 0022-3263.
2. Bartlett . Paul D. . Mendenhall . G. David . Durham . Dana L. . October 1980 . Controlled generation of singlet oxygen at low temperatures from triphenyl phosphite ozonide . The Journal of Organic Chemistry . en . 45 . 22 . 4269–4271 . 10.1021/jo01310a001 . 0022-3263.
3. Mendenhall . G. David . Priddy . Duane B. . 1999-08-01 . A Reexamination of the Ozone−Triphenyl Phosphite System. The Origin of Triphenyl Phosphate at Low Temperatures . The Journal of Organic Chemistry . en . 64 . 16 . 5783–5786 . 10.1021/jo982339y . 0022-3263.