The synthesis and coordination chemistry of N-heterocyclic thione (NHT) and selone (NHSe) ligands containing a saturated pyrimidine ring and bulky aromatic substituents on the nitrogen atoms is described in this thesis. To further understand the effect that the saturated pyrimidine ring has on the Lewis basicity of the ligands, particularly relative to analogous ligands based on five-membered rings, several closed-shell (d10) metal complexes have been synthesized and fully characterized. For example, mercury(II) complexes (SpymArE)HgX2, copper(I) compounds (SpymArE)CuX, and gold(I) derivatives (SpymArE)AuX (E = S, Se; Ar = 2,6-xylyl, mesityl, 2,6-diisopropyl phenyl; X = Cl, Br, I) have been isolated and fully characterized. In addition hypervalent iodine adducts (SpymArE)I2 have also been isolated and structurally characterized. The molecular structures of most of these species have been determined by X-ray crystallography and are compared with those of their corresponding five-membered ring analogues and other related compounds.
