【作者】 王芳；

【导师】 曹维良；

【作者基本信息】 北京化工大学 ， 物理化学， 2007， 硕士

【摘要】 几十年来，过渡金属配合物所具有的性质引起了广泛的关注。具有同种、异种或不同价态的双核过渡金属配合物出于其配位结构上的特点，具有区别于同类单核金属配合物的新奇性能。双金属活性中心的共存可以促进单一金属配合物所达不到的多电子氧化还原反应，而且双齿配体的存在可保持这种双合金属催化单元的整体性。本论文对桥联双金属Zn的配合物LZn（μ-X）₂ZnL（X=H，F，Cl，Br，OH，OMe，L={HC（CMeNPh）₂}）进行了结构优化，并分别采用NBO和AIM方法分析研究配合物中心四元环Zn₂H₂的电子结构、化学键结构等。研究表明桥联双金属Zn的配合物LZn（μ-X）₂ZnL（X=H，F，Cl，Br，OH，OMe，L={HC（CMeNPh）₂）)具有共同的Zn₂X₂中心四元环结构。Zn原子与配体之间属于供体-受体作用模式。以氢原子为桥联配体的配合物中，NBO和AIM分析都表明Zn-Zn原子之间存在着弱相互作用，Zn-Zn键级为0.5334。Zn-H键的键径是弯曲的。而以卤族元素为桥联配体的配合物，随着卤族元素桥联配体的原子半径的逐渐增大，Zn-Zn、Zn-X之间的距离逐渐增大，而Zn-N间距逐渐减小，配体原子有远离四元环中心、金属原子有靠近四元环中心的趋势。而Zn-X键键级逐渐减小，Zn-N键级增大，稳定化能逐渐增大，离域化程度逐渐增大。因此，桥联配体X、Zn原子的所带电荷数逐渐减小，而配体L上的N原子所带电荷数在逐渐增加。配合物中心四元环的稳定性也在逐渐减弱。对以含氧基团的配合物，随着与氧原子相连的基团的增大，Zn-O间距逐渐减小、Zn-N间距逐渐增大。中心四元环由稍稍弯折，渐趋平坦。而Zn-O键键级增加，Zn-N键键级减小，配合物的D-A稳定化能稍稍增大，电子离域程度增大。所以Zn-X键在逐渐增强，而Zn-N键在逐渐的减弱。同时中心四元环的稳定性也在逐渐的减弱。更多还原

【Abstract】 In recent several decades, there an increasing interests of the properties oftransition complexes. The novel properties of bimetallic transition complexesare different from the properties of mononuclear complex causing by thefeature of geometries. The bimetallic active center could catalyzemultielctronic reactions. And bichelating ligand could keep the catalyzingunits unitary.In the research, the geometries and the bond properties centroidfour-membered ring in the bimetallic bridged complexes LZn（μ-X）₂ZnL（X=H, F, Cl, Br, OH, OMe, L={HC（CMeNPh）₂}） are been studied.After analyzing the optimized molecular configuration and the results ofNBO and AIM, there are some rules we figures:There is a four-membered ring in the center of the complexes. Theinteraction between zinc atom and ligand is the type of donor-acceptor.The distances between two zinc atoms are close to the twice of zinccovalent radii in the hydro-bridged complexes. The bond order of zinc-zincbond is 0.5334. There is a weak interaction between two zinc atioms. As thesum of distances of bond critical points and bond-side atom are bigger than thebond length, Zn-H bond is bend.As the increasing atomic number of bridged atom in halo-bridgedcomplexes, the atomic radii of the ligand, Zn-Zn distance, Zn-X bond lengthare also increasing, while the Zn-N bond length is decreasing. Accordingly thebond order of Zn-X is decreasing, while that of Zn-N bond is increasing. Theligand atoms are prefer leaving the center of the complex, and the nitrogenatoms are getting closer to the center. The stabilization energies between donorand acceptor orbitals are getting higher, which shows the degree ofdelocalization are bigger. As the decreasing electron density of ring criticalpoints, Zn₂H₂ four-membered ring are weaker. The geometry information indicates the four-membered rings ofoxo-bridged complexes are folded. As the radical bonded to the oxygen atomsbecome bigger, the Zn-O bond length is decreasing, while Zn-N bond length isincreasing. Accordingly, the bond order of Zn-O bond is increasing while thatof Zn-N bond is decreasing. The stabilization energies between donor andacceptor orbitals are increasing slightly, which means the degree ofdelocaliztion are bigger. Because of the deceasing electron density of ringcritical point, the four-membered ring is weaker.更多还原