在Cl→M（r）和M（r）→Cl两个方向电场作用下,采用密度泛函UBP86方法研究了线性杂金属串配合物[CuCuM（npa）4Cl]＋（1：M=Pt,2：M=Pd,3：M=Ni）的几何和电子结构的变化规律.总体上,电场作用下高电势端原子的自旋密度减小而低电势端原子的自旋密度增大,原子的负电荷向高电势方向移动,分子能量下降,偶极矩呈线性变化;前线轨道分布呈规律性变化,随电场增大前线占据轨道能升高的显著性次序为πnb〉σ＊〉δ＊M（r）—N（r）,这使前线占据轨道能级易交错.在Cl→M（r）电场作用下,自旋密度由Cu向杂金属M离域,Cu的正电荷向M转移;分子能量下降更显著;Cu—Cu和Cu—M键缩短,前线轨道能隙减小,利于金属链的电子传输.而M（r）→Cl电场则使Cu—Cu,Cu—M键增长,但对分子能量及金属原子的电荷密度和自旋密度的影响不明显,当增大至一定电场强度后金属原子的自旋密度保持不变,两个方向电场作用下自旋密度的变化呈明显的非对称性.故1～3可能具有分子整流器的潜在应用.%The geometrical and electronic structures of heterometal string complexes [CuCuM（npa）4Cl]＋（1： M=Pt,2： M= Pd,3： M=Ni） were investigated theoretically by density functional theory UBP86 method with incorporating the external electric field along the metal chain in Cl→M（r） and M（r）→Cl two directions.In general,under the electric field,the spin densities of the high potential end decrease while that of the low potential end increase,and the negative charge transfers to the high potential end.When the electric field enhances,the molecular energy decreases and the dipole moment increases linearly.With the increase of the electric field,the spatial distribution of frontier orbitals changes regularly,and the energies of frontier occupied orbitals increase in the sensitive order of πnb〉σ＊〉δ＊M（r）—N（r）,which leads to the frontier occupied orbital level crossing.When the Cl→M（r） electric field is applied,the spin densities delocalize from Cu to M（r）,and the positive charge transfers from Cu to M（r）.Moreover,the molecular energy decreases more sensitively.Also in the Cl→M（r） electric field,the contractions of Cu—Cu and Cu—M（r） distances and the decrease of the frontier orbital energy gap are beneficial to the electron transport of the metal string complexes.However,under the M（r）→Cl electric field,the distances of Cu—Cu and Cu—M increase.The effect of M（r）→Cl electric field on the molecular energy,spin density and charge density of metal atoms are less obvious than that of Cl→M（r） electric field.When the electric field increases to some extent,the spin densities of the metal atoms remain stable values,and the changes of them are obviously asymmetric in Cl→M（r） and M（r）→Cl directions.Therefore,1～3 may have the potential application of molecular rectifier.
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