权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Binding interactions between transition metal cations and organic molecules

过渡金属阳离子与有机分子之间的结合相互作用

基本信息

批准号：
13640540
负责人：
MISHIMA Masaaki
金额：
$ 2.24万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

To elucidate the intrinsic nature of interaction between transition metal cation and organic molecule structural effects on the binding energy was investigated. The free energy changes for the reaction CuL_2^+ = Cu^+ + 2L were obtained in the gas phase for a series of acetophenones and pyridines by measuring ligand exchange equilibria using a FT-ICR mass spectrometer. For comparison lithium cation basicities in which electrostatic interaction plays a important role were also determined for acetophenone series in this sudy.Analysis of substituent effects on gas-phase basicity toward Cu cation, GB(Cu), showed that the effect of para-π-donor substituents on the GB(Cu) of acetophenone is reduced by 29% than that of GB(H) while that of GB(Li) is reduced by 37%. The magnitude of substituent effects on GB(Cu) is smaller than the corresponding GB(H) by 38% but is larger than the GB(Li). The similar results were observed for the pyridine bases. These results suggest that the positive charge developed at the carbonyl oxygen atom in the Cu-complex ion is larger than that of Li-complex ion.Reaction of Cu and Li cations with a series of MeO(CH_2)_nOMe that has two binding sites was studied in the gas phase. Cu cation gave a 1 : 1 adduct ion when n is larger than 4. The GB(Cu) increased with n, i.e., 10 kcal/mol from n=4 to n=9. On the other hand, although a 1 : 1 adduct ion with Li cation was observed when n=2, the change of GB(Li) is much smaller than the GB(Cu). This result suggests that the linearity of the O-Cu-O bond is an important factor to determine the GB(Cu), being in consistent with the optimized geometries obtained by DFT calculations.These facts suggests that the nature of O-Cu and N-Cu bonds are controlled by covalent interactions in addition to electrostatic interactions.

为了阐明过渡金属阳离子和有机分子之间相互作用的内在本质，研究了结构对结合能的影响。通过使用 FT-ICR 质谱仪测量配体交换平衡，获得了一系列苯乙酮和吡啶在气相中反应 CuL_2^+ = Cu^+ + 2L 的自由能变化。为了比较，本研究还测定了苯乙酮系列中静电相互作用起重要作用的锂阳离子碱度。取代基对铜阳离子 GB(Cu) 气相碱度的影响分析表明，对位 π 供体取代基对苯乙酮 GB(Cu) 的影响比 GB(H) 降低了 29%，而对位π-供体取代基对苯乙酮 GB(Cu) 的影响比 GB(H) 降低了 29%。 GB(Li) 降低 37%。取代基对GB(Cu)的影响幅度比相应的GB(H)小38%，但比GB(Li)大。对于吡啶碱也观察到类似的结果。这些结果表明，Cu络合离子中的羰基氧原子上产生的正电荷大于Li络合离子的正电荷。研究了Cu和Li阳离子与一系列具有两个结合位点的MeO(CH_2)_nOMe的气相反应。当n大于4时，Cu阳离子产生1:1加合离子。GB(Cu)随着n的增加而增加，即从n=4到n=9增加10 kcal/mol。另一方面，虽然当n=2时观察到与Li阳离子的1:1加合离子，但GB(Li)的变化比GB(Cu)小得多。这一结果表明O-Cu-O键的线性是决定GB(Cu)的重要因素，与DFT计算得到的优化几何结构一致。这些事实表明O-Cu和N-Cu键的性质除了静电相互作用之外还受到共价相互作用的控制。