Cyclopentadienyl Late-transition-metal Complexes Promoted C-H Bond Activation Reactions

In this dissertation, the stoichiometric and catalytic C-H bond activation reactions of several series of cyclopentadienyl late-transition-metal complexes were studied. They are helpful for us to further understand the mechanism of C-H bond activation and promote their applications in organic synthesis.A highly efficient rhodium-catalyzed cascade oxidative annulation leading to naphtho[1,8-bc]pyran derivatives has been developed. These reactions proceeded by sequential cleavage of C(sp2)-H/C(sp3)-H and C(sp2)-H/O-H bonds. Moreover, these reactions are highly regioselective with unsymmetrical alkynes. The further experiments indicated that the cascade reaction is a stepwise process, wherein the1-naphthol acts as an intermediate. Most of the naphtho[1,8-bc]pyran products exhibit intense fluorescence in the solid state.Photochemical C-H bond activation and subsequent aerobic oxidation reactions of benzene with (η5-C5Me5)Ir(CO)2afforded a mononuclear iridium complex, three dinuclear iridium complexes, and a novel hexanuclear iridium cluster. The reactivities of some obtained iridium complexes were studied and their formation mechanisms were analyzed.Iodo-bridged polymeric iridium complexes{(C5Me4)(CH2)n(C5Me4)(IrI2)2}m (n=2-4) were synthesized and used as the starting material to synthesize a series of dinuclear iridium complexes. Specially, the reactions of these iodo-bridged polymeric iridium complexes with several nitrogen ligands afforded cyclometallated dinuclear iridium complexes via C(sp2)-H bond activation. Moreover, these iodo-bridged polymeric iridium complexes and derivative phosphine-coordinated dinuclear iridium complexes could serve as efficient catalysts in the selective amine cross-coupling reaction.The reactions of a series of indenylphosphines derivatives with Ru3(CO)12were studied and trinuclear and tetranuclear clusters were obtained via C-H bond and C-P bond activation. The position of methyl substituents on the indenyl ring strongly affects the mode of C-H and C-P bond activation. Moreover, an intramolecular C(sp3)-H bond activated product was isolated, which represents a rare example of C(sp3)-H bond activation by ruthenium clusters with assistance from coordinated phosphorus atom.