Linear Multiselenium Interactions in Dicationic Oligomers of 1,5‐(Diselena)canes: Behavior of Se(mc) σ(m(c)c‐n(e)e) (6≤m(c)≤16) Elucidated with QTAIM Dual Functional Analysis

The intrinsic dynamic and static nature m (c) center‐n (e) electron interactions of the σ‐type σ(m (c)c‐n (e)e) were elucidated for the Se‐Se interactions in dicationic oligomers of Se(CH(2)CH(2)CH(2))(2)Se (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 (C(ii)) 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‐HB(wc) (typical‐HB with covalency) but some are pure‐CS/t‐HB(nc) (t‐HB with no covalency). The linear Se(2n) (2+) interactions in 2 (2+)–8 (2+) seem close to those without any limitations, since the nature of Se‐*‐Se inside and outside of (CH(2)CH(2)CH(2))(2) are very similar with each other. The linear Se(2n) (2+) interactions in 3 (2+)–8 (2+) are shown to be analyzed as σ(m(c)c‐n(e)e: 6≤m(c)≤16), not by the accumulated σ(3c–4e).