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首页> 外文期刊>Chemistry: A European journal >Electronic Structure and Bonding in Neutral and Dianionic Boradiphospholes: R’BC2P2R2 (R=H, tBu, R’=H, Ph)
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Electronic Structure and Bonding in Neutral and Dianionic Boradiphospholes: R’BC2P2R2 (R=H, tBu, R’=H, Ph)

机译：中性和二价硼自由基的电子结构和键合：R'BC2P2R2（R = H，tBu，R'= H，Ph）

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摘要

Classical and non-classical isomers of both neutral and dianionic BC2P2H3 species, which are isolobal to Cp+ and Cp-, are studied at both B3LYP/6-311++GACHTUNGTRENUNG(d,p) and G3B3 levels of theory. The global minimum structure given by B3LYP/6-311++GACHTUNGTRENUNG(d,p) for BC2P2H3 is based on a vinylcyclopropenyl-type structure, whereas BC2P2H3 2- has a planar aromatic cyclopentadienyl-ion-like structure. However, at the G3B3 level, there are three low-energy isomers for BC2P2H3: 1) tricyclopentane, 2) nido and 3) vinylcyclopropenyl-type structures, all within 1.7 kcalmol-1 of each other. On the contrary, for the dianionic species the cyclic planar structure is still the minimum. In comparison to the isolobal Cp+ and HnCnP5-n+ isomers, BC2P2H3 shows a competition between p-delocalised vinylcyclopropenyl- and clustertype structures (nido and tricyclopentane). Substitution of H on C by tBu, and H on B by Ph, in BC2P2H3 increases the energy difference between the low-lying isomers, giving the lowest energy structure as a tricyclopentane type. Similar substitution in BC2P2H3 2- merely favours different positional isomers of the cyclic planar geometry, as observed in 1) isoelectronic neutral heterodiphospholes EtBu2C2P2 (E=S,Se, Te), 2) monoanionic heterophospholyl rings EtBu2C2P2 (E=P-, As-, Sb-) and 3) polyphospholyl rings anions tBu5-nCnP5-n (n=0–5). The principal factors that affect the stability of three-, four-, and five-membered ring and acyclic geometrical and positional isomers of neutral and dianionic BC2P2H3 isomers appear to be: 1) relative bond strengths, 2) availability of electrons for the empty 2p boron orbital and 3) steric effects of the tBu groups in the HBC2P2tBu2 systems.
机译：在理论上以B3LYP / 6-311 ++ GACHTUNGTRENUNG（d，p）和G3B3的水平研究了中性和二价BC2P2H3物种的经典和非经典异构体，它们与Cp +和Cp-等价。 B3LYP / 6-311 ++ GACHTUNGTRENUNG（d，p）给出的BC2P2H3的全局最小结构基于乙烯基环丙烯基型结构，而BC2P2H3 2-具有平面芳族环戊二烯基离子样结构。但是，在G3B3水平上，存在BC2P2H3的三种低能异构体：1）三环戊烷，2）氨基和3）乙烯基环丙烯基类型的结构，它们都在1.7 kcalmol-1之间。相反，对于双阴离子物质，环状平面结构仍然是最小的。与等位的Cp +和HnCnP5-n +异构体相比，BC2P2H3显示出p-离域乙烯基环丙烯基和簇型结构（nido和三环戊烷）之间的竞争。在BC2P2H3中，H被tBu取代为C，H被Ph取代为B，这增加了低位异构体之间的能量差，使三环戊烷类型的能量结构最低。在BC2P2H3 2-中类似的取代仅有利于环状平面几何结构的不同位置异构体，如1）等电中性杂二磷酸EtBu2C2P2（E = S，Se，Te），2）单阴离子杂磷酰基环EtBu2C2P2（E = P-，As- ，Sb-）和3）聚磷酰基环阴离子tBu5-nCnP5-n（n = 0-5）。影响中性和双阴离子BC2P2H3异构体的三元，四元和五元环和无环几何和位置异构体稳定性的主要因素似乎是：1）相对键强度，2）空2p的电子可用性HBC2P2tBu2系统中tBu基团的硼轨道和3）空间位阻。

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