Structure, Reactivity and Solution Dynamics of the Sn94- Ion
| dc.contributor.advisor | Eichhorn, Bryan W | en_US |
| dc.contributor.author | Kocak, Fatma Sanem | en_US |
| dc.contributor.department | Chemistry | en_US |
| dc.contributor.publisher | Digital Repository at the University of Maryland | en_US |
| dc.contributor.publisher | University of Maryland (College Park, Md.) | en_US |
| dc.date.accessioned | 2011-07-06T05:41:27Z | |
| dc.date.available | 2011-07-06T05:41:27Z | |
| dc.date.issued | 2011 | en_US |
| dc.description.abstract | In this thesis, the nature of the Sn<sub>9</sub><super>4-</super> in solution and its reactivity with transition metal atoms and electrophiles have been studied. The Sn<sub>9</sub><super>4-</super> ion is a very strong Brønsted base that deprotonates en to form the Sn<sub>9</sub>H<super>3-</super> ion and is a potent ion sequestering agent that competes with 2,2,2-crypt for binding K<super>+</super>. The Sn<sub>9</sub>H<super>3-</super> ion has a pK<sub>a</sub> in a range of 32.2– 44 in dmso and can be reversibly interconverted to K<sub>3</sub>Sn<sub>9</sub><super>-</super> through addition of K<super>+</super> and base. Addition of K<super>+</super> to Sn<sub>9</sub>H<super>3-</super> in the absence of base gives the proposed coupled Sn<sub>9</sub>–Sn<sub>9</sub><super>6-</super> dimer. The diamagnetic Sn<sub>9</sub>H<super>3-</super> ion was mischaracterized as the Sn<sub>9</sub><super>3-</super> paramagnetic radical in numerous publications since 1983. The Sn<sub>9</sub>H<super>3-</super> ion reacts with Ni(cod)<sub>2</sub> and Pd(PPh<sub>3</sub>)<sub>4</sub> complexes and give the M@Sn<sub>9</sub>H<super>3-</super> clusters (M= Ni, Pd). The Ni@Sn<sub>9</sub>H<super>3-</super> ion reacts with (arene)M(CO)<sub>3</sub> complexes to form is the Ni@Sn<sub>9</sub>M(CO)<sub>3</sub><super>4-</super> ion. Endohedral d–10 atoms do not affect the pK<sub>a</sub>'s of the hydrido clusters, whereas coordination of M(CO)<sub>3</sub> group (M= Cr, Mo) significantly increases the acidity. The M@Sn<sub>9</sub>SnCy<sub>3</sub><super>3-</super> ions, where M= Ni and Pd, have been prepared with two different synthetic routes from Ni@Sn<sub>9</sub>H<super>3-</super> and Sn<sub>9</sub>SnCy<sub>3</sub><super>3-</super> ions, respectively. The Ni@Sn<sub>9</sub>H<super>3-</super> ion reacts with Cy<sub>3</sub>SnCl and gives the Ni@Sn<sub>9</sub>SnCy<sub>3</sub><super>3-</super> ion. The Sn<sub>9</sub>SnCy<sub>3</sub><super>3-</super> ion reacts with Pd(PPh<sub>3</sub>)<sub>4</sub> and gives the Pd@Sn<sub>9</sub>SnCy<sub>3</sub><super>3-</super> cluster. The Pd@Sn<sub>9</sub>PdSnCy<sub>3</sub><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@Sn<sub>9</sub>—SnCy<sub>3</sub><super>3-</super>. Two new fused deltahedral clusters have been prepared from Sn<sub>9</sub><super>4-</super>, Ge<sub>9</sub><super>4-</super>, Pd(PPh<sub>3</sub>)<sub>4</sub>, and Ni(cod)<sub>2</sub> precursors to give the Pd<sub>2</sub>@Sn<sub>18</sub><super>4-</super>, the largest-known deltahedral cluster to-date, and Ni@Sn<sub>8</sub>(μ–Ge)Ni@Sn<sub>8</sub><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 Sn<sub>9</sub>SnR<sub>3</sub><super>3-</super> ions (R= Cy and <super>n</super>Bu) and M@Sn<sub>9</sub>R<super>3-</super> ions (M= Ni, Pd and R= H, SnCy<sub>3</sub>) exhibit fast intramolecular exchange of the all 9-Sn atoms, while the exo-substituent groups scramble around the clusters. The Sn<sub>9</sub>–<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. | en_US |
| dc.identifier.uri | http://hdl.handle.net/1903/11470 | |
| dc.subject.pqcontrolled | Chemistry | en_US |
| dc.subject.pqcontrolled | Inorganic Chemistry | en_US |
| dc.subject.pquncontrolled | acid-base chemistry | en_US |
| dc.subject.pquncontrolled | fused deltahedral clusters | en_US |
| dc.subject.pquncontrolled | ion sequestering | en_US |
| dc.subject.pquncontrolled | Sn clusters | en_US |
| dc.subject.pquncontrolled | transition metals | en_US |
| dc.subject.pquncontrolled | Zinlt ions | en_US |
| dc.title | Structure, Reactivity and Solution Dynamics of the Sn94- Ion | en_US |
| dc.type | Dissertation | en_US |
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