Dopant-induced modifications and non-covalent interactions in diamondoids: a theoretical investigation of N-doped diamondoid complexes with transition metal cations
摘要
Nitrogen-doped diamondoids have emerged as promising nanoscale ligands due to their tunable electronic structures and the presence of lone electron pairs capable of forming non-covalent complexes with metal centers. This study presents a detailed computational investigation of complexes formed between N-doped diamondoids (adamantane, diamantane, and triamantane) and first-row transition metal cations (Fe+/2+, Co+/2+, Ni+/2+, Cu + /2+ , and Zn+/2+). Geometry optimizations were performed using DFT at the ωB97XD/6–311+ +G(d,p) level, and interaction energies were calculated employing high-level ab initio quantum chemical methods, such as DLPNO-MP2, DLPNO-CCSD, and DLPNO-CCSD(T), using the aug-cc-pVTZ basis set with BSSE and relativistic corrections. All complexes exhibit strong non-covalent binding driven by the lone pair on the nitrogen dopant, with interaction energies ranging from − 58 to − 76 kcal/mol for monovalent and − 159 to − 266 kcal/mol for divalent metal cations. The interaction strength increases with the size of the diamondoid core, revealing the critical role of molecular surface area in stabilizing metal coordination. Spin state preferences were found to be metal-dependent and critical for accurate energetic predictions. Relativistic corrections were found to be essential for almost all complexes, significantly affecting binding energy predictions. The study also suggests the presence of cooperativity effects, where the structural and electronic features of the diamondoid ligands enhance lone pair–metal binding beyond additive contributions. These results position N-doped diamondoids as promising nanoscale ligands for the construction of spin-sensitive, catalytically active, and electronically tunable nanomaterials, offering insights into future applications in molecular electronics, sensing, and supramolecular design.