Structures and stabilities of XCCY2+ dications (X, Y = O, S and NH), doubly charged isoelectronic analogues of cyanogen

✍ Scribed by Ming Wah Wong

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 460 KB
• Volume: 30
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/jms.1190300811

✦ Synopsis

Abstract

Consistent with experimental observations, high‐level ab initio calculations, at the G2(MP2) level of theory, predict that the XCCY^2+^ (X, Y = O, S and NH) dications are remarkably stable species in the gas phase. OCCS^2+^, SCCS^2+^, HNCCO^2+^, HNCCS^2+^ and HNCCNH^2+^ are calculated to be thermodynamically stable species, whereas OCCO^2+^ is predicted to lie in a deep potential well, separated from exothermic CC cleavage by a large barrier. All the doubly charged species are calculated to have a linear skeleton. Despite the inherent strong Coulombic repulsion, these species are characterized by short CX or CY triple bonds. Vertical and adiabatic ionization energies of the XCCY^+·^ monocations and the heats of formation of the resulting dications are reported. There are remarkable changes in the structures and stability ordering of isomers on going from the XCCY neutrals to the XCCY^+·^ monocations and to the XCCY^2+^ dications. The rationalization of these results is discussed.