Kinetics of formation of the host-guest complex of a viologen with cucurbit[7]uril.
Host-guest complexation between the dicationic viologen 1-tri(ethylene glycol)-1'-methyl-m-xylyl-4,4'-bipyridinium and cucurbit[7]uril (CB7) was studied at pH = 4.5 in water. The stability constants of the mono- and bis-CB7 adducts were determined at 25 °C by UV-vis spectroscopy. Stopped-flow kinetic experiments were performed to measure the formation and dissociation rate constants of the monoadduct: k(1) = (6.01 ± 0.03) × 10(6) M(-1)s(-1) and k(-1) = 52.7 ± 0.4 s(-1), respectively. Possible mechanisms of complexation are discussed in view of the kinetic results.
Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA.
József
J
Kalmár
Shawna B
SB
Ellis
Michael T
MT
Ashby
Ronald L
RL
Halterman
D001952:Bridged-Ring Compounds / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D007700:Kinetics; D008958:Models, Molecular; D015394:Molecular Structure; D014755:Viologens / Q000737:chemistry*; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils
D001952:Bridged-Ring Compounds; D007093:Imidazoles; D014755:Viologens; C456276:cucurbit(7)uril; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils