Charge-Transfer Salts of 6,6-Dicyanopentafulvenes: From Topology to Charge Separation in Solution.
Chemistry
; 24(51): 13616-13623, 2018 Sep 12.
Article
en En
| MEDLINE
| ID: mdl-30094881
ABSTRACT
6,6-Dicyanopentafulvene derivatives and metallocenes with redox potentials appropriate for forming their radical anions form highly persistent donor-acceptor salts. The charge-transfer salts of 2,3,4,5-tetraphenyl-6,6-dicyanofulvene with cobaltocene (1â
Cp2 Co) and 2,3,4,5-tetrakis(triisopropylsilyl)-6,6-dicyanofulvene with decamethylferrocene (2â
Fc*) have been prepared. The X-ray structures of the two salts, formed as black plates, were obtained and are discussed herein. Compared with neutral dicyanopentafulvenes, the chromophores in the metallocene salts show substantial changes in bond lengths and torsional angles in the solid state. EPR, NMR, and optical spectroscopy, as well as superconducting quantum interference device (SQUID) measurements, reveal that charge-separation in the crystalline states and in frozen and fluid solutions depends on subtle differences of redox potentials, geometry, and on ion pairing. Whereas 1â
Cp2 Co reveals paramagnetic character in the crystalline state and in solution, compound 2â
Fc* shows a delicate balance between para- and diamagnetism, depending on the temperature and solvent characteristics.
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1
Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
Chemistry
Asunto de la revista:
QUIMICA
Año:
2018
Tipo del documento:
Article
País de afiliación:
Suiza