Reversible, Photoinduced Activation of P4 by Low-Coordinate Main Group Compounds

• Published in: Chemistry : a European journal Vol. 20; no. 22; pp. 6739 - 6744
• Main Authors: Dube, Jonathan W., Graham, Cameron M. E., Macdonald, Charles L. B., Brown, Zachary D., Power, Philip P., Ragogna, Paul J.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 26.05.2014; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: bond activation; Chemistry; germanium; main group chemistry; reversible reactivity; white phosphorus; bond activation; white phosphorus; germanium; main group chemistry; reversible reactivity
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201402031

Two unique systems based on low‐coordinate main group elements that activate P4 are shown to quantitatively release the phosphorus cage upon short exposure to UV light. This reactivity marks the first reversible reactivity of P4, and the germanium system can be cycled 5 times without appreciable loss in activity. Theoretical calculations reveal that the LUMO is antibonding with respect to the main group element–phosphorus bonds and bonding with respect to reforming the P4 tetrahedron, providing a rationale for this unprecedented activity, and suggesting that the process is tunable based on the substituents. Rooooxanne, put on the UV light: A low‐coordinate germanium compound and a phosphenium ion are shown to quantitatively release a P4 fragment upon exposure to UV light (see figure, Mes=2,4,6‐trimethylphenyl). Theoretical work reveals the LUMO to be antibonding with respect to the main‐group‐element–phosphorus bonds and bonding for reforming the P4 tetrahedron, rationalizing this unique reactivity.