电子定域策略在实现平面四配位结构中的适用性:氮与碳的对比研究

Adaptability of Electron-Localization Strategy for Achieving Planar Tetraco-ordination:Nitrogen versus Carbon

本文通过对含有平面四配位氮团簇NLi_(3)E^(+)(E=N,P,As)和它们的平面四配位碳等电子体CLi_(3)E(E=N,P,As)进行详细地对比,研究了电子定域策略在设计含平面四配位氮团簇时的适应性.结果表明,NLi_(3)E^(+)团簇具有类似于CLi_(3)E的平面结构,且其平面性都是由一个定域的π键决定的.然而,与CLi_(3)E相比,NLi_(3)E^(+)明显具有更高的电子结构稳定性、热力学稳定性和动力学稳定性,这可以从更宽的HOMO-LUMO能隙(4.58~4.68 eV vs.2.10~2.74 eV)在CCSD(T)/aug-cc-pVTZ水平下较低的能量和DFT水平下的分子动力学模拟中表现出的更好刚性得到验证.结果表明,电子定域策略可能更适合设计中心原子为较高电负性且更倾向于形成定域键的平面多配位分子.在这些团簇中,NLi_(3)E^(+)的稳定性最好,更适合进行气相合成及后续的质谱选择和光谱表征.

A case study has been performed on the adaptability of electron-localization strategy in designing clusters with planar tetracoordinate nitrogen(ptN)through the detailed comparison between ptN clusters NLi_(3)E^(+)(E=N,P,As)and their planar tetracoordinate carbon(ptC)counterparts CLi_(3)E(E=N,P,As).The results revealed that NLi_(3)E^(+)clusters possessed similar planar geometries to CLi_(3)E,which are both determined by the existence of a localized π bond.Nevertheless,NLi_(3)E^(+)clusters possess the obviously higher electronic,thermodynamic,and dynamic stabilities than CLi_(3)E clusters,as reflected by wider HOMO-LUMO gaps(4.58-4.68 eV versus 2.10–2.74 eV),the overall lower-lying positions on potential energy surfaces verified at the CCSD(T)/aug-cc-pVTZ level,and better rigidity during the molecular dynamic simulations at the PBE/DZVP level.Therefore,our results suggest that electron-localization strategy may be more suitable for designing the clusters,whose central atom possesses relatively higher electronegativity and more favours the localized bond.Due to the good stability,the cationic NLi_(3)E^(+)clusters designed in this work may be suitable for gas phase generation,mass-selection,and spectroscopic characterization.