Abstract
Abstract This thesis, which is divided into three parts, aims on the studies of some new di-metal complexes. The first part is concerned with di-molybdenum multiply bonded complexes. The second part is the studies of di-manganese complexes. The third part is about di-zinc and di-cadmium complexes. The wonderful result of di-molybdenum multiply bonded complexes has been published on ‘Journal of the American Chemical Society’.* *. Tsai, Y.-C.; Lin, Y.-M.; Yu, J.-S. K.; Hwang, J.-K. J. Am. Chem. Soc. 2006, 128, 13980-13981. In the first part of di-molybdenum multiply bonded complexes, the reaction between the dimeric dilithio salts of {Me2Si[NLi(Dipp)]2}2 (1)、{PhB[NLi(Dipp)]2}2 (4) with monomeric MoCl3(THF)3, form triply bonded di-molybdenum complexes syn-1,2-Mo2Cl2[□-□2-Me2Si (NDipp)2]2 (2) and syn-1,2-Mo2Cl2[□-□2-PhB(NDipp)2]2 (5). Both of them were ethane-like eclipsed syn conformation. Reduction of (2) by Na/Hg afforded the new type of four coordinate di-molybdenum quadruply bonded complexes Mo2[□-□2-Me2Si(NDipp)2]2 (3). Raman spectroscopy and UV spectroscopy were used to probe the Mo-Mo quadruple bond. We are also using DFT computation to support the bonding of a quadruple bond. There is no other hydride bridged, it’s new type of low coordinate di-molybdenum complexes. When the Mo2Cl6(THF)3 reacts with tBuP(NDipp)2(□-Li)2(ether)2 (7), we get di-molybdenum quadruply bonded complexes {(□-Li)(THF)} {Mo2(□-Cl)Cl2[□-□2-P(NDipp)2]2} (8) directly, because the ligand lose tert-butyl radical to reduce Mo3+ to Mo2+. Di-molybdenum quadruply bonded complexes {Li(THF)4}{Mo2(□-Cl)Cl2[□-□2-C(NDipp)2]2} (10), the structure like (8), also can be prepared by reacting fresh Mo2+ with {Li[□2-CH(NDipp)2](OEt2)2} (9). If the starting material content DME, the reaction between [MoCl3DME] and (1)•DME will get triply bonded di-molybdenum complexes syn-1,2-Mo2(OMe)2[□-□2-SiMe2(NDipp)2]2 (11), different from (2). The compound (11) has two coordinate methoxy groups. According the reaction condition and the result of compound (3), we spouse it has a transition state like (3), which might reduce DME to ethylene, and afforded the corresponding (11). The second part is the studies of di-manganese complexes. Reaction of (1) with MnCl2 will get two complexes, one is dinuclear complex Mn2[□-□2-SiMe2(NDipp)2]2 (12), the other is mononuclear complex {Li(THF)4}{Mn[□2-SiMe2(NDipp)2]2} (13). When the reduction of (12) by one equivalent KC8, the corresponding reduced product [K(□6-18-crown-6)(THF)2][Mn2(□-□2-SiMe2(NDipp)2)](THF)2 (14) is formed. The structure of (14) has been changed and formed di-manganese bond, which is different from (12). If more KC8 were used for the reaction of (12) reduction, we get a product content two potassium, [K2{Mn[□2-SiMe2 (NDipp)2]}2] (15). The structure of (15) is also changed, it formed di-manganese bond, and the bridging ligand turned to chelating position. A series of di-manganese complexes (12), (14) and (15) were all anti ferromagnetic compounds, which have 4, 5 and 4 unpaired electron at room temperature, and have interesting change on structure. The third part of this thesis was about di-zinc and di-cadmium complexes. Di-zinc complex Zn2[□-□2-SiMe2(NDipp)2]2 (16) was produced form ZnBr2 react with (1). The result of di-zinc complex reduction was very similar with the result of di-manganese, by the reduction of excess KC8, we can get di-zinc bonded complexes {K(□6-18-crown-6)(THF)2}2{{Zn[□2-SiMe2(NDipp)2]}2} (17) or [K2{Zn[□2-SiMe2 (NDipp)2]}2] (18). The (17) and (18) were very similar on main structure, the difference is just on the position of potassium cat ion, and the bridging ligand turned to chelating position. Unfortunately, we can not get the product reduce by one equivalent electron, so we need to depend on the electronic structure computation, to explain the reaction mechanism. In the research of di-cadmium complexes, the CdCl2 react with (1) which formed light yellow compound (19). The synthesis of (19) were using the same pathway as zinc, so we propose the structure of it should be di-cadmium complexes Cd2[□-□2-SiMe2(NDipp)2]2 (19). And reduction of (19) by excess KC8 formed colorless cadmium (II) complexes K2Cd[□2-SiMe2(NDipp)2]2 (20), which might produce by the self-reduction of di-cadmium intermediate.