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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Structural Effect on the Stability of Acetophenone—B(OMe)_2Complexes in the Gas Phase.The Nature of the Bond between the Boron Cation and Neutral Molecules
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Structural Effect on the Stability of Acetophenone—B(OMe)_2Complexes in the Gas Phase.The Nature of the Bond between the Boron Cation and Neutral Molecules

机译：苯乙酮-B（OMe）_2配合物在气相中的稳定性对结构的影响。硼阳离子与中性分子之间键的性质

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摘要

The free energy changes (ΔG, boron cation basicity; BCB) for the reaction [(Me0)_2B]L~+= (Me0)_2B~++ L(L = acetophenones) were determined in the gas phase by measuring ligand exchange equilibria using anFT-ICR mass spectrometer. On the basis of the correlation analysis by the Yukawa-Tsuno equation, ΔG =ρ(σ°+r~+ΔσR), the substituent effect on ΔBCB of acetophenone was characterized by a ρvalue (in kJmol~(-σ~(-1)unit) of -43.2 and anr~+value 0.89. Both the ρandr~+values were found to be similar thecorresponding values for protonation, indicating that the bond between (MeO)_2B~+and the oxygen atom ofthe carbonyl group has a high covalent character similar to the H~+ —0=C bond. This conclusion was consistentwith the geometrical features and the charge distribution calculated at DFT-B3LYP/6-311+G(d,p) level oftheory. A comparison with the results for a series of Lewis cation basicity of the acetophenone system showedthat the r~+value decreases in the order of H~+= (Me0)_2B~+> Me_3Si~+> 3Ge~+> Cu~+> Li~+. This decreasingorder is related to increasing ionic (ion-dipole interaction) nature of the bonding interaction between Lewiscations and the carbonyl oxygen atom. This was also supported by the theoretical calculations.
机译：通过测量配体交换平衡，确定气相中[[Me0] _2B] L〜+ =（Me0）_2B〜++ L（L =苯乙酮）反应的自由能变化（ΔG，硼阳离子碱度; BCB）使用FT-ICR质谱仪。在通过Yukawa-Tsuno方程ΔG=ρ（σ°+ r〜+ΔσR）进行相关分析的基础上，用ρ值（kJmol〜（-σ〜（-1） ））的值-43.2和anr〜+值0.89。发现ρandr〜+值都与质子化的相应值相似，表明（MeO）_2B〜+与羰基氧原子之间的键高类似于H〜+ -0 = C键的共价特性，这一结论与在理论上DFT-B3LYP / 6-311 + G（d，p）水平计算的几何特征和电荷分布是一致的。苯乙酮系统的一系列Lewis阳离子碱度表明r〜+值按H〜+ =（Me0）_2B〜+> Me_3Si〜+> 3Ge〜+> Cu〜+> Li〜+的顺序降低。与路易斯阳离子和羰基氧原子之间键合相互作用的离子（离子-偶极子相互作用）性质增加有关，这也得到了理论计算的支持ns。

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