Del Angel Cruz Daniel, Ferreras Katherine N, Harville Taylor, Schoendorff George, Gordon Mark S
Department of Chemistry and Ames National Laboratory, Iowa State University, Ames, Iowa, 50011, USA.
Department of Chemistry, University of South Dakota, Vermillion, South Dakota, 57069, USA.
Phys Chem Chem Phys. 2024 Aug 14;26(32):21395-21406. doi: 10.1039/d4cp01800a.
The bonding structures of COLi and CSLi are studied by means of oriented quasi-atomic orbitals (QUAOs) to assess the possibility of these molecules being planar hexacoordinated carbon (phC) systems. CHLi and CO are employed as reference molecules. It is found that the introduction of Li ions into the molecular environment of carbonate has a greater effect on the orbital structure of the O atoms than it does on the C atom. Partial charges computed from QUAO populations imply repulsion between the positively charged C and Li atoms in COLi. Upon the transition from COLi to CSLi, the analysis reveals that the substitution of O atoms by S atoms inverts the polarity of the carbon-chalcogen σ bond. This is linked to the difference in s- and p-fractions of the QUAOs of C and S, as element electronegativities do not explain the observed polarity of the CSσ bond. Partial charges indicate that the larger electron population on the C atom in CSLi makes C-Li attraction possible. Upon comparison with the C-Li bond in methyllithium, it is found that the C-Li covalent interactions in COLi and CSLi have about 14% and 6% of the strength of the C-Li covalent interaction in CHLi, respectively. Consequently, it is concluded that only CSLi may be considered to be a phC system.
通过定向准原子轨道（QUAO）研究了COLi和CSLi的键合结构，以评估这些分子成为平面六配位碳（phC）体系的可能性。以CHLi和CO作为参考分子。研究发现，将锂离子引入碳酸根的分子环境中，对O原子轨道结构的影响比对C原子的影响更大。根据QUAO布居计算得到的部分电荷表明，COLi中带正电的C和Li原子之间存在排斥作用。从COLi到CSLi的转变过程中，分析表明用S原子取代O原子会使碳-硫属元素σ键的极性反转。这与C和S的QUAO中s成分和p成分的差异有关，因为元素电负性无法解释观察到的CSσ键的极性。部分电荷表明，CSLi中C原子上较大的电子布居使得C-Li吸引成为可能。与甲基锂中的C-Li键相比，发现COLi和CSLi中C-Li共价相互作用的强度分别约为CHLi中C-Li共价相互作用强度的14%和6%。因此，得出结论，只有CSLi可被认为是phC体系。
