Solution and Solid-State Studies of Doubly Trimethylene-Bridged Tetraalkyl p-Phenylenediamine Diradical Dication Conformations
X-ray crystallographic structures are reported for 1(Me){sup 2+}(SbCl{sub 6}{sup -}){sub 2} {center_dot} 2CH{sub 3}CN, 2(Et){sup 2+}(SbF{sub 6}{sup -}){sub 2} {center_dot} 2CH{sub 3}CN {center_dot} 2CH{sub 2}Cl{sub 2}, and 1(iPr){sup 2+}(SbF{sub 6}{sup -}){sub 2}, which also contained unresolved solvent and is in a completely different conformation than the methyl- and ethyl-substituted compounds. A quite different structure of 1(Me){sup 2+}(SbF{sub 6}{sup -}){sub 2} than that previously published was obtained upon crystallizing it from a mixture rich in monocation. It does not contain close intramolecular PD{sup +},PD{sup +} contacts but has close intermolecular ones. Low temperature NMR spectra of 1(Me){sup 2+} and 1(Et){sup 2+} in 2:1 CD{sub 3}OD/CD{sub 3}CN showed that both contain three conformations of all-gauche NCCC unit material with close intramolecular PD{sup +},PD{sup +} contacts. In addition to the both PD{sup +} ring syn and anti material that had been seen in the crystal structure of 1(Me){sup 2+}(SbF{sub 6}{sup -}){sub 2} {center_dot} 2CH{sub 3}CN published previously, an unsymmetrical conformation having one PD{sup +} ring syn and the other anti (abbreviated uns) was seen, and the relative amounts of these conformations were significantly different for 1(Me){sup 2+} and 1(Et){sup 2+}. Calculations that correctly obtain the relative amounts of both the methyl- and ethyl-substituted material as well as changes in the optical spectra between 1(Me){sup 2+} and 1(Et){sup 2+}, which contains much less of the uns conformation, are reported.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 983574
- Report Number(s):
- BNL-93749-2010-JA; JACSAT; R&D Project: NC-001; KC020401H; TRN: US201014%%696
- Journal Information:
- Journal of the American Chemical Society, Vol. 132, Issue 17; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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