Stability of BN and its ions, from BN3+ to BN2?: AN ab initioMRD-CI study

Abstract

mThe stabilities of BN and its ions, from BN3+ to BN2-, were investigated by ab initio methods. Theory predicts the ground state of BN to be X3n, with a'Z + lying about 0.03 eV higher. Photodetachment of BN-and photoionization of BN are proposed as alternative routes to optical spectroscopy for identifying the ground state of BN. The electronic spectra of BN-and BN+ exhibit features similar to those observed for the isoelectronic C, ions. BN-and BN+ have low infrared intensities, whereas BN(X3H) is practically infrared-inactive. Fourteen electronic states of BN2+ and three of BN3+ are metastable, an uncommonly large number for multiply charged cations from the first row. Both high-energy ions might be characterized experimentally by the calculated ionization potentials and kinetic energy releases. In the gas phase, the dianion BN2-autodetaches spontaneously into BN-+ e-, but it could be stabilized, eg., in Li,BN crystals. 0 1995 John Wiley & Sons, Inc.

Fundamental Thermochemical Properties of Ammonia Borane and Dehydrogenated Derivatives (BNHn, n = 0−6)

“…19 Grein and co-workers have reported the electron affinity and ionization potential of BN from multireference configuration interaction (MR-CI) calculations with a 6s5p3d1f valence basis set. 20 Kirwan and Roberts estimated the B-H and N-H BDEs for BH 3 NH 3 from MP3/6-31G** calculations. 21 Apart from these results, a consistent set of other basic thermochemical parameters of the BNH n compounds such as ionization energies, electron affinities, basicities, and acidities are not known.…”

Theoretical Studies on Dications and Trications of FH, ClH, and BrH. Properties of the Bound 15Σ- States. Electron-Spin g-Factors and Fine/Hyperfine Constants of the Metastable X3Σ- States of ClH2+ and BrH2+

“…Similar arguments were presented recently 3c,20c for ClH 2+ and BrH 2+ , where the reported potential curves reproduce well the literature data (IPs, R e 's, ω e 's, Franck−Condon factors, tunneling lifetimes). The semiempirical procedure used in both studies 3c,20c combines together, and substantially improves, semiquantitative arguments previously advanced in the literature about the stability of dications. − , It should be noted, however, that most of the properties studied here (fine and hyperfine structure, nuclear quadrupole couplings, etc.) lie beyond the capabilities of the semiempirical approach applied to ClH 2+ /BrH 2+ . 3c,20c …”

“…For a metastable state, the larger Δ E el ( R e ) the deeper the potential well. As discussed in several papers on multiply charged AB n + ions (Be 2 2+ , B 2 2+ , BN 2+ , Al 2 3+ , and BN 3+ ), the Δ E el (R) function associated with a metastable state looks like a regular bound potential curve, and the same applies to present XH 2+ 's (as shown for FH 2+ and ClH 2+ in ref ).…”

A conformational transition in the adenylyl cyclase catalytic site yields different binding modes for ribosyl-modified and unmodified nucleotide inhibitors

“…A ligand binding mode close to these cations thus corresponds to sufficient proximity to the receptor's partner anions to register a 'favorable' van der Waals interaction, which is plausible since van der Waals interactions generally have a longer-range influence than electrostatics, as has been reported elsewhere for metastable ion-ion attractions. 20 2.1.2. Nucleotide base binding site.…”