Highly stable tetrathiafulvalene radical dimers in [3]catenanes.
Two [3]catenane 'molecular flasks' have been designed to create stabilized, redox-controlled tetrathiafulvalene (TTF) dimers, enabling their spectrophotometric and structural properties to be probed in detail. The mechanically interlocked framework of the [3]catenanes creates the ideal arrangement and ultrahigh local concentration for the encircled TTF units to form stable dimers associated with their discrete oxidation states. These dimerization events represent an affinity umpolung, wherein the inversion in electronic affinity replaces the traditional TTF-bipyridinium interaction, which is over-ridden by stabilizing mixed-valence (TTF)2•+ and radical-cation (TTF•+)2 states inside the 'molecular flasks.' The experimental data, collected in the solid state as well as in solution under ambient conditions, together with supporting quantum mechanical calculations, are consistent with the formation of stabilized paramagnetic mixed-valence dimers, and then diamagnetic radical-cation dimers following subsequent one-electron oxidations of the [3]catenanes.
Spruell
Jason M
JM
Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA.
Coskun
Ali
A
Friedman
Douglas C
DC
Forgan
Ross S
RS
Sarjeant
Amy A
AA
Trabolsi
Ali
A
Fahrenbach
Albert C
AC
Barin
Gokhan
G
Paxton
Walter F
WF
Dey
Sanjeev K
SK
Olson
Mark A
MA
Benítez
Diego
D
Tkatchouk
Ekaterina
E
Colvin
Michael T
MT
Carmielli
Raanan
R
Caldwell
Stuart T
ST
Rosair
Georgina M
GM
Hewage
Shanika Gunatilaka
SG
Duclairoir
Florence
F
Seymour
Jennifer L
JL
Slawin
Alexandra M Z
AM
Goddard
William A
WA
Wasielewski
Michael R
MR
Cooke
Graeme
G
Stoddart
J Fraser
JF
D043863:Catenanes / Q000737:chemistry*; D019281:Dimerization
D043863:Catenanes