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Photochemistry of Tetraphenyldiboroxane and its Use as Photopolymerization Coinitiator,


  • This article is part of the Special Issue dedicated to the memory of Elsa Abuin.
  • This is a contribution from the USP Research Consortium for Photochemical Technology.


2-Hydroxyethyl methacrylate (HEMA) was photopolymerized in the presence of Safranine (SfH+) and tetraphenyldiboroxane (TPhB). Polymerization results are correlated with the photochemistry of TPhB and its ability to aggregate forming hydrophobic domains (critical aggregation concentration, cac, 1.2 × 10−4 M). Polymerization was not observed when the TPhB concentration was below the cac, indicating that the polymerization is initiated in the hydrophobic environment. The quenching of the triplet state of SfH+ by TPhB and the generation of the semireduced species of SfH+ suggests an electron transfer from the boron compound to the excited dye, and that the resulting boron-centered radical initiates the polymerization process.

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