The effects of heteroatom substituents on structure, stability, and electronic properties of remote N‐heterocyclic germylenes (rNHGes), at DFT

Abstract

In this theoretical research, we have investigated the substituent effect of singlet (s) and triplet (t) rNHGes with the fused various aromatic rings, at (U)B3LYP/AUG‐cc‐pVTZ and (U)M06‐2X/AUG‐cc‐pVTZ. All singlet and triplet rNHGes appear as minima and every singlet germylene displays more thermodynamic stability and more kinetic stability than its corresponding triplet state. Regarding to the relationship among germylenic center (—:GeC— moiety) and the substituted NH, PH, O, and S—heteroatoms, the order of thermodynamic stability based on singlet (s)–triplet (t) energy difference (ΔΕs‐t) and kinetic stability based on band gap (ΔΕHOMO‐LUMO) for the fused rings is ortho‐pyrrole > furan > thiophene > benzene > phosphole in a “zigzag” arrangement. Except for phosphole, every ortho‐heterocycle ring in a “zigzag” arrangement stabilizes rNHGe more than para‐heterocycle ring in a “chair” arrangement. Every triplet rNHGe shows lower frequency, lower polarity, higher nucleophilicity, lower electrophilicity and lower chemical hardness than the corresponding singlet rNHGe. The resonance effect and aromaticity character of the scrutinized rNHGes appears considerably dependent on the electronegativity, size, and topology of the substituted heteroatoms in the fused rings.