PNNL

Abstract

The recent successful synthesis of P2N3–, a planar all-inorganic aromatic molecule, represents a breakthrough in inorganic chemistry, because, like its isolobal counterparts C5H5– and cyclo-P5–, P2N3– has potential to serve as a new ligand for transition metals and a building block in solid-state molecular architectures. In light of its importance, we report here a negative ion photoelectron spectroscopy (NIPES) and ab initio study of P2N3–, to investigate the electronic structures of P2N3– and its neutral P2N3• radical. The adiabatic detachment energy of P2N3– (electron affinity of P2N3•) was determined to be 3.765 ± 0.010 eV, indicating high stability for the P2N3– anion. Ab initio electronic structure calculations reveal five low-lying electronic states in the neutral P2N3• radical. Calculation of the Franck-Condon factors (FCFs) for each anion-to-neutral electronic transition and comparison of the resulting simulated NIPE spectrum with the vibrational structure in the observed spectrum allows the first four excited states of P2N3• to be determined to lie 6.2, 6.7, 11.5, and 22.8 kcal/mol above the ground state of the radical, which is found to be a 6-electron, 2A1, state.