Distinct Difference in the Geometries of NCCL^- Anions (L = N₂, CO, CS): A Balance Between π Conjugation and Steric Repulsion.

ABSTRACT: NCCL^- anions (L = N₂, CO and CS) exhibit notable geometric differences: NCCNN^- favors a bent structure, whereas NCCCO^- and NCCCS^- prefer linear configurations. Here, we investigate the origin of their geometric differences using the conventional density functional theory (DFT) and block-localized wave function (BLW) method. Computations reveal that the bent structure is preferred for all species at the BLW state in which the in-plane π_// back-donation from NCC^- to ligands is disabled. For NCCNN^-, enforcing linearity leads to a gain in the π_// electron delocalization (conjugation) stability, but it is insufficient to offset the steric penalty. Differently, NCCCO^- and NCCCS^-

SUBMITTER: Wei J 

PROVIDER: S-EPMC12606702 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature