Metallophilic (metal-metal) interactions are weak interactions between closed-shell (d10, s2) or pseudo-closed-shell (d8) metal cations. This type of interaction is generally believed to be responsible for various intriguing structures, luminescence, catalysis and magnetism. To gain a better understanding of metallophilic interactions, both experimental and computational investigations have been carried out in this thesis. Chapter 1 gave an up-to-date literature review on the definition, significance, and methods of estimating metallophilic interactions. The disputed nature and strength of metallophilic interactions encouraged us to further understand them. Chapter 2 focused on aurophilic interactions between AuI cations. Aurophilic interactions were observed in the solid state, but not well expressed in solution. Further experimental and computational results suggested that the strength of aurophilic interactions were weaker than electrostatic interactions. The nature of aurophilic interactions arose from orbital interactions rather than dispersion. Chapter 3 presented the study of metallophilic interactions between group 10 metal centres, including PtII-PtII, PdII-PdII and NiII-NiII. A series of cyclometalated square-planar metal complexes with different metals or substituents were prepared. PtII-PtII interactions were found to be stronger than PdII-PdII and NiII-NiII interactions. The dimerization constants of the Pt-containing complexes increased in line with increasing electron-withdrawing ability. Chapter 4 investigated the solvent-induced and thermally dependent colour changes of the Pt-containing complexes synthesised in chapter 3. Metallophilic interactions were proposed to be important in influencing the luminescence properties.

L’objectif de ce travail fut la synthèse de ligands fonctionnels de type N,N'-diphosphanyl-NHC (NHC = carbènes N-hétérocycliques) et l’étude de leur chimie de coordination. La synthèse du nouveau ligand tridentate, stable et rigide, N,N'-diphosphanyl-imidazol-2-ylidene a permis des études expérimentales et théoriques et l’accès à des complexes mono-, di-, tri-, penta-, et hexanucléaires des métaux du groupe 11 (Cu, Ag et Au) originaux et aux propriétés structurales uniques. Les complexes mono- et dinucléaires avec un ou deux atomes de phosphore libres ont permis d’accéder à des complexes hétérotrinucléaires à interactions d10-d10 qui sont luminescents. La transmétallation partielle ou totale des complexes homotrinucléaires de Cu ou d’Ag avec des réactifs contenant du Pd(0) ont conduit à des complexes hétérotrinucléaires à interactions d10-d10. En plus de son comportement pontant, ce ligand peut se agir en chélate dans des complexes du palladium et du chrome. Dans le cas du Cr(III), ils montrent une activité catalytique en oligomérisation de l’éthylène supérieure à celle des complexes du Cr(II) et conduisent principalement à des oligomères. / The purpose of this work was the synthesis of N,N'-diphosphanyl-functionalized NHC ligands andtheir coordination chemistry. The novel stable and rigid tridentate N,N'-diphosphanyl-imidazol-2-ylidene was synthesized and experimental and computational information on its stability weregained. It served as a unique platform for the synthesis of novel mono-, di-, tri-, penta-, hexanuclear complexes with the coinage metals (Cu, Ag and Au), exhibiting rare structural features. The mono- and dinuclear complexes with one or two dangling P-donors provided rational access to heterotrinuclear complexes. All these coinage metal complexes have short metal-metalseparations, indicating the presence of d10-d10 interactions, and display excellent luminescentproperties. Partial or complete transmetallation of the homotrinuclear Cu or Ag complexes withPd(0) precursors led to hetero-trinuclear complexes with d10-d10 interactions. In addition to itsbridging behavior, this ligand also showed its chelating behavior in Pd or Cr(III) complexes. Thelatter displayed superior performance in ethylene oligomerization than the Cr(II) complexes andgave mostly oligomers.