Attia Amr A A, Lupan Alexandru, King R Bruce
Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, ClujNapoca RO-400028, Romania.
Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States.
J Phys Chem A. 2023 Jul 20;127(28):5887-5898. doi: 10.1021/acs.jpca.3c02944. Epub 2023 Jul 11.
The structures and energetics of the neutral BHFe() ( = 4, 3) and the dianions [BHFe(CO)] ( = 6-14) have been investigated by density functional theory. The low-energy structures of the tricarbonyl dianions [BHFe(CO)] are all found to have deltahedral structures in accordance with their 2+2 skeletal electrons. The low-energy structures of the neutral tricarbonyls BHFe(CO) ( = 6-14) with only 2 skeletal electrons are based on capped (-1)-vertex deltahedra ( = 6, 7, 8) or deltahedra with a degree 6 vertex for the iron atom. The 8- and 9-vertex deltahedra are also found in low-energy BHFe(CO) structures relating to the nondegeneracy of their frontier molecular orbitals. Carbonyl migration occurs in most of the low-energy structures of the tetracarbonyls BHFe(CO). Thus, migration of a carbonyl group from an iron atom to a boron atom gives BH(BCO)(μ-H)Fe(CO) structures with a BCO vertex and a hydrogen atom bridging a B-B deltahedral edge. In other low-energy BHFe(CO) structures, a carbonyl group is inserted into the central -vertex FeB deltahedron to give a BH(CO)Fe(CO) structure with a central (+1)-vertex FeCB deltahedron that can be an deltahedron or a μ-BH face-capped -vertex FeCB deltahedron. Other low-energy BHFe(CO) structures include BHFe(CO)(μ-CO) structures with two of the carbonyl groups bridging FeB faces ( = 6, 7, 10) or Fe-B edges ( = 12) or structures in which a BH ligand ( = 6, 7, 10, 12) is bonded to an Fe(CO) unit with exclusively terminal carbonyl groups through B-H-Fe bridges.
通过密度泛函理论研究了中性BHFe（）（ = 4, 3）和双负离子[BHFe(CO)]（ = 6 - 14）的结构和能量。发现三羰基双负离子[BHFe(CO)]的低能结构均具有符合其2 + 2骨架电子数的三角面多面体结构。中性三羰基化合物BHFe(CO)（ = 6 - 14）仅有2个骨架电子，其低能结构基于盖帽的（ - 1）顶点三角面多面体（ = 6, 7, 8）或铁原子具有6度顶点的三角面多面体。在与前沿分子轨道非简并性相关的低能BHFe(CO)结构中也发现了8顶点和9顶点的三角面多面体。羰基迁移发生在大多数四羰基化合物BHFe(CO)的低能结构中。因此，一个羰基基团从铁原子迁移到硼原子会产生具有BCO顶点和一个氢原子桥连B - B三角面棱边的BH(BCO)(μ - H)Fe(CO)结构。在其他低能BHFe(CO)结构中，一个羰基基团插入到中心 - 顶点FeB三角面多面体中，形成具有中心（ + 1）顶点FeCB三角面多面体的BH(CO)Fe(CO)结构，该三角面多面体可以是三角面多面体或μ - BH面盖帽的 - 顶点FeCB三角面多面体。其他低能BHFe(CO)结构包括两个羰基基团桥连FeB面（ = 6, 7, 10）或Fe - B棱边（ = 12）的BHFe(CO)(μ - CO)结构，或者其中BH配体（ = 6, 7, 10, 12）通过B - H - Fe桥连与仅具有端基羰基的Fe(CO)单元相连的结构。
