| Transition metal pincer complexes are of great interest, and are widely used in catalysis and bond activation. In this dissertation, the development of a new type of PNP pincer complexes of group 10 and group 9 metals and their application are presented.; In chapters 2 and 3, the preparation of several new diarylamine-based PNP pincer ligands is described. The synthetic strategy is modular and allows incorporation of a variety of substituents that change the steric and the electronic properties of the ligand. The syntheses of group 10 pincer complexes were accessed by the means of N-H or N-C cleavage of the pincer ligands. The mechanistic considerations for the NC cleavage are discussed. The preparation of a new series of pincer derivatives and the investigation of their reactivity are described as well.; In chapter 4, the utility of (PNP)NiOTf as an efficient and robust catalyst for coupling of acetonitrile with aldehydes is presented. The most important advantage of this catalytic system over others is its high stability to air and moisture. Newest research revealed that (PNP)NiOTf could also be used to catalyze coupling of other alkyl nitriles with aldehydes, the Henry reaction and acetalization of aldehydes.; In chapter 5, the competition between C-H oxidative addition and C-Halide oxidative addition of halobenzenes (C6H5Cl, C6H5Br) to the iridium(I) species ((PNP)Ir) is discussed. The C-H oxidative addition product was proved to be kinetically preferred, whereas the C-Hal oxidative addition product was thermodynamically preferred. The products of the C-Cl or C-Br oxidative addition were separated from the C-H oxidative addition products by a high activation barrier and are only accessible at >100°. Of the C-H oxidative addition products of chlorobenzene, the isomer with the o-ClC6H4 ligand has the lowest energy. Meanwhile, it was found that only sp2 C-H activation products (PNP)Ir(H)(Aryl) were observed when (PNP)Ir fragment reacted with p-xylene or mesitylene. However, upon reacting the (PNP)Ir(H)(Aryl) with pyridine or PMe3 with gentle heating, the formation of (PNP)Ir(L)(H)(CH 2-Ar) was evidenced (L = Py, PMe3). |
