The solution conformation of triarylmethyl radicals.
J Magn Reson
; 172(2): 254-67, 2005 Feb.
Article
en En
| MEDLINE
| ID: mdl-15649753
ABSTRACT
Hyperfine coupling tensors to 1H, 2H, and natural abundance 13C were measured using X-band pulsed electron nuclear double resonance (ENDOR) spectroscopy for two triarylmethyl (trityl) radicals used in electron paramagnetic resonance imaging and oximetry methyl tris(8-carboxy-2,2,6,6-tetramethyl-benzo[1,2d4,5-d']bis(1,3)dithiol-4-yl) and methyl tris(8-carboxy-2,2,6,6-tetramethyl(-d3)-benzo[1,2d4,5-d']bis(1,3)dithiol-4-yl). Quantum chemical calculations using density functional theory predict a structure that reproduces the experimentally determined hyperfine tensors. The radicals are propeller-shaped with the three aryl rings nearly mutually orthogonal. The central carbon atom carrying most of the unpaired electron spin density is surrounded by the sulfur atoms in the radical and is completely shielded from solvent. This structure explains features of the electron spin relaxation of these radicals and suggests ways in which the radicals can be chemically modified to improve their characteristics for imaging and oximetry.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Compuestos de Tritilo
/
Espectroscopía de Resonancia por Spin del Electrón
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
J Magn Reson
Asunto de la revista:
DIAGNOSTICO POR IMAGEM
Año:
2005
Tipo del documento:
Article
País de afiliación:
Estados Unidos