Synthesis and characterization of P2N3 : An aromatic ion composed of phosphorus and nitrogen

See allHide authors and affiliations

Science  29 May 2015:
Vol. 348, Issue 6238, pp. 1001-1004
DOI: 10.1126/science.aab0204

An aromatic phosphorus and nitrogen ring

In chemistry, the term “aromatic” denotes the energy stabilization associated with electrons being shared among atoms in a ring. Benzene is the best-known aromatic compound, although numerous related hydrocarbons also manifest the property. Velian and Cummins now report a rare instance of an inorganic aromatic compound: a negatively charged pentagonal ring composed of three nitrogen and two phosphorus atoms.

Science, this issue p. 1001


Aromaticity is predominantly associated with carbon-rich compounds but can also occur in all-inorganic ones. We report the synthesis of the diphosphatriazolate anion, a rare example of a planar aromatic inorganic species. Treatment of azide (N3) in tetrahydrofuran solution with P2A2 (A = C14H10), a source of P2, produced P2N3, which we isolated as its [Na-kryptofix-221]+ salt in 22% yield and characterized by single-crystal x-ray diffraction. Salts [Na-kryptofix-221] [P2N3] and [Na-kryptofix-221] [P215NN2] were analyzed by infrared and Raman spectroscopy, 15N and 31P nuclear magnetic resonance spectroscopy, and mass spectrometry. The formation of the P2N3 anion was investigated using density functional theory, and its aromatic character was confirmed by NICS (nucleus-independent chemical shift) and QTAIM (quantum theory of atoms in molecules) methods.

View Full Text