Herein, a series of tin and oxidovanadium complexes, as well as a hexanuclear manganese cluster, supported by the bidentate, dianionic perfluoropinacolate (pinF) ligand, {(O(C(CF3)2)2}2−, are reported. While six-coordinate SnIV-pinF complexes (2.1−2.3) were found to be spectroscopically similar to SnO2 (cassiterite), four-coordinate SnII-pinF complexes (2.4−2.5) possess low 119Sn NMR chemical shifts and remarkably high quadrupolar splitting. Additionally, the Sn(II) complexes are unusually unreactive towards both Lewis acids and bases. Computational analysis suggests that this lack of reactivity with Lewis acids arises from the energetic inaccessibility of the HOMO (5s), and the lack of reactivity with Lewis bases is due to donation into the LUMO (5px) by fluorine atoms on the ligand. Furthermore, monomeric and dimeric {VIV=O}- and {VV=O}-pinF complexes (3.1−3.4) were synthesized and characterized, including (Me4N)2[V2(O)2(μ-O)2(pinF)2] (3.3a). Complex 3.3a was found to catalyze the oxidation of several benzyl alcohols at room-temperature under ambient conditions, reproducing reactivity known for VOx surfaces and demonstrating the thermodynamically challenging selective oxidation of alcohols to aldehydes/ketones. Finally, a hexanuclear manganese cluster, {MnIII4MnIV2(pinF)6(OK(THF))4(OH)4}, abbreviated {Mn6} (4.1) which contains four-fold axial symmetry, and its oxidized analog {MnIII3MnIV3(pinF)6(OK(THF))4(OH)4}[PF6] (4.2), were prepared and characterized. High-field EPR measurements of 4.1 confirm a high spin magnetic ground state of ST = 11, corroborating the oxidation state assignments of the manganese centers. While EPR and CTM data suggest the possibility of slow magnetic relaxation for 4.1, field-dependent SQUID magnetometry reveals a lack of magnetic hysteresis, precluding the SMM behavior hypothesized for 4.1.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/41984 |
| Date | 02 February 2021 |
| Creators | Elinburg, Jessica Kelly |
| Contributors | Doerrer, Linda H. |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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