Synthesis and Structural Studies on Halogen(I) Complexes

This thesis work has focused on the preparation and structural analysis of the halogen(I) complexes from mono and multivalent ligands in solution, in gas phase and in the solid state. Single crystal X-ray diffraction (SCXRD), NMR experiments, and mass spectrometry were used to identify the conformations and structures of the halogen(I) complexes. In the literature part, firstly the overview of the halogen bonding and the introduction of the three-center four-electron halogen bond are given. Later the halogen(I) complexes of aromatic and aliphatic ligands in solution and in the solid state are reviewed. The review chapter also presents the recent solid-state study of nucleophilic iodine(I) interactions.In this thesis, the results and discussion part describes the synthesis and characterization of the silver(I), iodine(I), and bromine(I) complexes of mono and di-substituted pyridine ligands. All [N···Ag···N]+ and [N···X···N]+ complexes were analyzed with ¹H-NMR and SCXRD. In addition, some of the complexes were studied by ¹H-¹⁵N-NMR HMBC spectroscopy. In the second part, silver(I) and iodine(I) complexes of 1-methyl-1H-1,2,3-triazole are synthesized and later used for the synthesis of [I(mtz)₂]PF₆*[Ag(bpy)₂]PF₆ complex (solid-state NIIs) and have been analyzed by NMR and SCXRD. The third part of the result and discussion outlines the iodine [N···X···N]+ complexes of NR₁R₂R₃ amines. This is the first example of [N···I···N]⁺ iodine(I) complex where the nitrogen of the tertiary amines acts as halogen bond acceptor, derived from their parent [N···Ag···N]⁺ complexes. Final part reports results from silver(I) complexes of tetra- and hexadentate ligands studied by using SCXRD, NMR, and mass spectrometry.Keywords: halogen bond, three-center four-electron bond, halogen(I) ions, supramolecular chemistry, nucleophilic iodine(I) interactions, NMR spectroscopy, X-ray crystallography, Mass spectrometry.