Kocak, Fatma SanemIn this thesis, the nature of the Sn₉<super>4-</super> in solution and its reactivity with transition metal atoms and electrophiles have been studied. The Sn₉<super>4-</super> ion is a very strong Brønsted base that deprotonates en to form the Sn₉H<super>3-</super> ion and is a potent ion sequestering agent that competes with 2,2,2-crypt for binding K<super>+</super>. The Sn₉H<super>3-</super> ion has a pK_a in a range of 32.2&ndash; 44 in dmso and can be reversibly interconverted to K₃Sn₉<super>-</super> through addition of K<super>+</super> and base. Addition of K<super>+</super> to Sn₉H<super>3-</super> in the absence of base gives the proposed coupled Sn₉&ndash;Sn₉<super>6-</super> dimer. The diamagnetic Sn₉H<super>3-</super> ion was mischaracterized as the Sn₉<super>3-</super> paramagnetic radical in numerous publications since 1983. The Sn₉H<super>3-</super> ion reacts with Ni(cod)₂ and Pd(PPh₃)₄ complexes and give the M@Sn₉H<super>3-</super> clusters (M= Ni, Pd). The Ni@Sn₉H<super>3-</super> ion reacts with (arene)M(CO)₃ complexes to form is the Ni@Sn₉M(CO)₃<super>4-</super> ion. Endohedral d&ndash;10 atoms do not affect the pK_a's of the hydrido clusters, whereas coordination of M(CO)₃ group (M= Cr, Mo) significantly increases the acidity. The M@Sn₉SnCy₃<super>3-</super> ions, where M= Ni and Pd, have been prepared with two different synthetic routes from Ni@Sn₉H<super>3-</super> and Sn₉SnCy₃<super>3-</super> ions, respectively. The Ni@Sn₉H<super>3-</super> ion reacts with Cy₃SnCl and gives the Ni@Sn₉SnCy₃<super>3-</super> ion. The Sn₉SnCy₃<super>3-</super> ion reacts with Pd(PPh₃)₄ and gives the Pd@Sn₉SnCy₃<super>3-</super> cluster. The Pd@Sn₉PdSnCy₃<super>3-</super> ion has been prepared from a new type of reaction, where the Pd metal is oxidatively inserted into the exo-bond of Pd@Sn₉&mdash;SnCy₃<super>3-</super>. Two new fused deltahedral clusters have been prepared from Sn₉<super>4-</super>, Ge₉<super>4-</super>, Pd(PPh₃)₄, and Ni(cod)₂ precursors to give the Pd₂@Sn₁₈<super>4-</super>, the largest-known deltahedral cluster to-date, and Ni@Sn₈(&mu;&ndash;Ge)Ni@Sn₈<super>4-</super>, the first example of an endohedral heteroatom cluster. <super>119</super>Sn, <super>1</super>H, <super>13</super>C NMR studies show these clusters to be highly dynamic. The Sn₉SnR₃<super>3-</super> ions (R= Cy and <super>n</super>Bu) and M@Sn₉R<super>3-</super> ions (M= Ni, Pd and R= H, SnCy₃) exhibit fast intramolecular exchange of the all 9-Sn atoms, while the exo-substituent groups scramble around the clusters. The Sn₉&ndash;<super>i</super>Pr<super>3-</super> ion has non-mobile alkyl substituent, which removes the exo-bonded Sn atom from exchanging with the remaining 8-Sn atoms of the cluster.DissertationChemistryInorganic Chemistryacid-base chemistryfused deltahedral clustersion sequesteringSn clusterstransition metalsZinlt ions