Linear Multiselenium Interactions in Dicationic Oligomers of 1,5-(Diselena)canes: Behavior of Semc σ(mc c-ne e) (6≤mc ≤16) Elucidated with QTAIM Dual Functional Analysis.

Abstract

The intrinsic dynamic and static nature m c center‐n e electron interactions of the σ‐type σ(m cc‐n ee) were elucidated for the Se‐Se interactions in dicationic oligomers of Se(CH2CH2CH2)2Se (1 (Se, Se)) [n 2+ (Se, Se): n=1–8], especially for m c≥6, where n 2+ (Se, Se: n=1–8) are abbreviated by n 2+ (n=1–8), respectively. QTAIM dual functional analysis (QTAIM‐DFA) was applied to the interactions. Perturbed structures generated using coordinates derived from the compliance constants (Cii) were employed for QTAIM‐DFA. Each Se‐*‐Se in 1 2+ and 2 2+ has the nature of CT‐TBP (trigonal bipyramidal adduct formation through CT) and Cov‐w (weak covalent), respectively, which supply the starting points of the investigations. The asterisk emphasizes the existence of a bond critical point on the interaction. All Se‐*‐Se in 3 2+ are classified by the regular closed shell (r‐CS) interactions and characterized as CT‐MC (molecular complex formation through CT), which are denoted as r‐CS/CT‐MC, except for the central interaction, of which nature is r‐CS/CT‐TBP. Most interactions in 4 2+–8 2+ are r‐CS/t‐HBwc (typical‐HB with covalency) but some are pure‐CS/t‐HBnc (t‐HB with no covalency). The linear Se2n 2+ interactions in 2 2+–8 2+ seem close to those without any limitations, since the nature of Se‐*‐Se inside and outside of (CH2CH2CH2)2 are very similar with each other. The linear Se2n 2+ interactions in 3 2+–8 2+ are shown to be analyzed as σ(mcc‐nee: 6≤mc≤16), not by the accumulated σ(3c–4e).