The effects of halogen substituents on structure, stability, and electronic properties of bicyclo[1.1.1]pentanylene at density functional theory

Abstract

AbstractIn a quest to identify novel bicyclic carbenes, the effects of halogen substituents on the stability and reactivity of singlet (s) and triplet (t) forms of carbenes with one, two, and three carbenic centers (1‐15) are compared and contrasted, at B3LYP/6‐311++G** level of theory. All carbene scrutinized turn out as minima for showing no negative force constant on their energy surfaces. The highest stability (ΔEs‐t) and band gap (ΔEHOMO–LUMO) belongs to carbene 11 (37.36 and 133.45 kcal/mol, respectively) with three carbenic centers. Such higher stabilization attributed to three coordinate covalent bonds with their carbenic centers. The nucleophilicity (N) for each series (1‐5, 6‐10, and 11‐15) appears inverse correlation with our results of chemical potential (μ) values. Also, the N of the carbenic center is decreased due to the higher electronegativity of substituted halogens. In addition, the electrostatic potential (ESP) maps qualitatively confirm the relative N for our bicyclic carbenes.The aim of the present work was to assess the effects of halogen substituents on the stability (ΔEs‐t), ΔΕHOMO–LUMO, N, electrophilicity (ω), and proton affinity (ΔEPA). Finally, our investigation introduces carbene 1s with high stability (ΔEs‐t = 30.38 kcal/mol), N (3.438 eV), and negative ΔEPA (−244.94 kcal/mol) that can be applied as accumulated multidentate ligands.