Novak, Julia Anne (1989) The quintet state of a partially localized, hydrocarbon tetraradical: cyclobutane as a general ferromagnetic coupling unit. Master's thesis, California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:04022010-085334137
The partially localized tetraradical 22 has been generated at temperatures of 77 K and below in 2-methyltetrahydrofuran and poly(methylmethacrylate) matrices, and directly observed by EPR spectroscopy. The evolution of the EPR spectrum resulting from prolonged photolysis of the bisdiazene precursor 20 indicates a two-photon process, wherein a triplet spectrum (assigned unambiguously to the monoazobiradical) gradually gives way to a quintet spectrum, ascribed to the target tetraradical. The observed quintet state is tentatively identified as the ground state of the tetraradical, based on design considerations, the fact that the quintet spectrum is intense at temperatures as low as 3.8 K, and preliminary Curie Law studies. The thermal stability of 22 (indefinitely stable in the dark at 77 K) is an unexpected attribute of this molecule; no other cyclobutanediyl studied thus far has exhibited similar sturdiness at temperatures above ca. 60 K. Two synthetic routes to the prerequisite bisfulvene 15 are discussed.
|Item Type:||Thesis (Master's thesis)|
|Degree Grantor:||California Institute of Technology|
|Division:||Chemistry and Chemical Engineering|
|Thesis Availability:||Restricted to Caltech community only|
|Defense Date:||30 May 1989|
|Default Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||16 Apr 2010 22:34|
|Last Modified:||26 Dec 2012 03:24|
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