title: Probing the electronic stability of multiply charged anions: sulfonated pyrene tri- and tetraanions.
abstract: The strong intramolecular Coulomb repulsion in multiply charged anions (MCAs) creates a potential barrier that provides dynamic stability to MCAs and allows electronically metastable species to be observed. The 1-hydroxy-3,6,8-pyrene-trisulfonate {[Py(OH)(SO(3))(3)](3-) or HPTS(3-)} was recently observed as a long-lived metastable MCA with a large negative electron binding energy of -0.66 eV. Here we use Penning trap mass spectrometry to monitor the spontaneous decay of HPTS(3-) --> HPTS(*2-) + e(-) and have determined the half-life of HPTS(3-) to be 0.1 s. To explore the limit of electronic metastability, we tried to make the related quadruply charged pyrene-1,3,6,8-tetrasulfonate {[Py(SO(3))(4)](4-)}. However, only its decay product, the triply charged radical anion [Py(SO(3))(4)](*3-), as well as the triply charged ion-pairs [Py(SO(3))(4)H](3-) and [Py(SO(3))(4)Na](3-), was observed, suggesting that the tremendous intramolecular Coulomb repulsion makes the [Py(SO(3))(4)](4-) anion extremely short-lived. Photoelectron spectroscopy data showed that [Py(SO(3))(4)](*3-) is an electronically stable species with electron binding energies of +0.5 eV, whereas [Py(SO(3))(4)H](3-) and [Py(SO(3))(4)Na](3-) possess electron binding energies of 0.0 and -0.1 eV, respectively. Ab initio calculations confirmed the stability of these triply charged species and further predicted a large negative electron binding energy (-2.78 eV) for [Py(SO(3))(4)](4-), consistent with its short lifetime.
authors: Department of Physics, Washington State University, 2710 University Drive, Richland, Washington 99354, USA.
authors: Xue-Bin
authors: XB
authors: Wang
authors: Alina P
authors: AP
authors: Sergeeva
authors: Xiao-Peng
authors: XP
authors: Xing
authors: Maria
authors: M
authors: Massaouti
authors: Tatjana
authors: T
authors: Karpuschkin
authors: Oliver
authors: O
authors: Hampe
authors: Alexander I
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authors: Boldyrev
authors: Manfred M
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authors: Wang