【作者】 韦永勤；

【导师】 义祥辉；

【作者基本信息】 广西师范大学 ， 无机化学， 2002， 硕士

【摘要】 含立方体核[阻郎（1l 3-Q）。广（Q‘S、Sc）的原子簇化合物具有特殊的荧光性质，几乎每一种含立方体核IRc‘(L1 3-Q刘’t-（Q‘S、Se）的原子簇化合物都有光致发光现象。阻c‘（Ll，·S）8X6广（X=Cl、n，、 1）无论在固态还是在溶液中都能发出强烈的红色磷光。本研究用HF方法对Re6（u 3-S）8X6广（X=CI、Br、1）进行了结构优化，采用已优化的结构，用单电子激发组态相互作用方法（CIS）对三个离子的分子轨道和激发态进行计算。从电子结构内部很好地解释了[Rc‘（1l 3-S）8X6广（X=CI、Br、1）的电子吸收光谱，并阐明了它们的磷光发生的机理。这对于具有立方体核[1k‘（1Jj-Q）。广（Q‘S、Sc）的原子簇化合物的光化学研究有一定的指导意义。 计算表明，在阻c‘（皿J·S）8X6广（X=CI、m、 1）的前线分子轨道中，重金属原子所占的百分数都很大（约80％）。这使得三个原子簇离子吸收光子从单重基态跃至单重激发态后，处于激发能级上的电子由于重金属原子的强烈的自旋-轨道耦合作用而发生自旋转变，单重激发态变为三重激发态，然后以辐射跃迁的形式回到单重基态。这是三个原子簇离子产生磷光的主要原因。此外，电子激发态和电子基态较低的振动能级是阻c6（皿，—S）8X6广（X=CI、Br、 1）产生磷光的另一个重要原因。 作为比较，用密度泛函理论中的B3LYP／CEP-4G方法对Re₂（edt）₄进行结构优化和自然键轨道计算，并用CIS方法计算Re₂（edt）₄的分子轨道和激发态。从理论上解释了Re-Re之间不存在明显的三重键，并且很好地解释了分子Re₂（edt）₄的电子吸收光谱。更多还原

【Abstract】 The atomic cluster compounds with cubic core [Re6(u 3-Q)g]2+(Q=S Se) have special fluorescence. Nearly all of atomic cluster compounds with cubic core [Re& (n 3-Q)8]2+(Q=S Se) have luminescent behavior. |Re6(H 3-S)8X6]4-(X=CK Br,I ) show strong red emission,either in solid state or in soluble state. In this studies,geometry optimizations for [Re&( " 3-S)gX6j4-(X=CK Br> I) were carried out with HF method. On the basis of optimizated geometries .molecular orbitals and excited states of the three ions were caculated with single excitation configuration interactions (CIS) method.The electronic absorbsion spectra and the mechanism of phosphorescence of [Re&( u 3-S)gX6J4-(X=Cl Br I ) were explained very well,which,in some extent,is favor to the photochemical investigation of atomic cluster compounds with cubic core [Re6(P3-Q)8]2+(Q=S,Se).It is showed that the frontier orbitals of [Re6( u3-S)8X6]4-(X=Cl Br I) are heavy metal rhenium based (the percentage of rhenium in the frontier orbitals is about 80%). Thus,aiter the three cluster ions absorb photon and singlet groud state is turned into singlet excited state.the electron in excited energy level can change its direction because of the spin-orbit coupling of heavy metal rhenium,which converts singlet excited state into triplet excited state.And then,the cluster ions return to singlet groud state by means of radiate transiton. This is essential reason why [Re&( u 3-S)8X6]4-(X==Cl Br I ) have vivid red emission. The low oscillatory energy levels both in ground state and in excited state of [Re&( u3-S)8X6]4- (X=Cl Br I ) is another important reason.By comparison,geometry optimization and natural bond orbital analysis for Re2 (edt)4 were carried out with B3LYP method. Molecular orbitals and excited states for Re2(edt)4 were calculated with CIS method . The results show that there is not obvious triplet metal-metal bond between two Re atoms in Re2 (edt)4 and that the electronic absorption spectra of Re2(edt)4 was explained very well by theoretical calculation results.更多还原