| Sumario: | Chapter I contains synthetic, structural and reactivity studies on Pt(II) complexes bearing the bulky dimethylterphenylphosphines PMe2ArXyl2 (L1), PMe2ArDipp2 (L2) or PMe2ArTipp2 (L3) (see page 13 for the structural formulae of these phosphines). It comprises two main sections. The first is dedicated to compounds of the xylyl substituted terphenylphosphine (L1). Despite the bulkiness of this ligand, bis(phosphine) Pt(II) complexes could be synthesised. Since the ligand contains -C-H bonds, cyclometallation reactions could be achieved to form seven-membered platinacycles. Kinetic studies on the cyclometallation reaction were also developed. Two different Pt(II) precursors were used in this section, namely cis-[PtCl2(COD)] and cis-[PtMe2(SMe2)2]. The newly prepared complexes included bis(chloride) and bis(methyl) derivatives with different molecular geometry, i.e. trans-[PtCl2(PMe2ArXyl2)2] and cis-[PtMe2(PMe2ArXyl2)2], as well as some cyclometallated complexes. The protonation reactions of some of these platinum organometallics were investigated by variable temperature NMR spectroscopy. The second section of Chapter I describes a variety of Pt(II) complexes of ligands L2 and L3. These ligands are able to stabilize low-coordinated species that feature formally a 14-electron count. In order to counterbalance the metal coordinative and electronic unsaturation, these compounds feature a relatively weak Pt···Carene interaction with the ipso carbon atom of a flanking aryl ring of the terphenyl group of the phosphine.
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