TY - JOUR
T1 - Preorientation of olefins toward a single photodimer
T2 - Cucurbituril-mediated photodimerization of protonated azastilbenes in water
AU - Maddipatla, Murthy V.S.N.
AU - Kaanumalle, Lakshmi S.
AU - Natarajan, Arunkumar
AU - Pattabiraman, Mahesh
AU - Ramamurthy, V.
PY - 2007/7/3
Y1 - 2007/7/3
N2 - With the view to establishing the generality of cucurbit[8]uril as a template, the photodimerization of hydrochloride salts of eight azastilbenes has been investigated in an aqueous medium. Whereas in solution upon excitation all of these olefins yield products of geometric isomerization, cyclization, and hydration, in the presence of cucurbit[8]uril the predominant product is that of dimerization. Such a change in product distribution is attributed to the localization of the olefins by the host cucurbit[8]uril. Most importantly, instead of a mixture of dimers, predominantly a single dimer was obtained in each case. The nature of the dimer that was formed could be rationalized on the basis of the principles of "best fit" and "minimization of electrostatic repulsion". The superior ability of cucurbit[8]uril compared to micelles to act as a templating agent is attributed to its ability to provide a reaction cavity that is tight and time-independent.
AB - With the view to establishing the generality of cucurbit[8]uril as a template, the photodimerization of hydrochloride salts of eight azastilbenes has been investigated in an aqueous medium. Whereas in solution upon excitation all of these olefins yield products of geometric isomerization, cyclization, and hydration, in the presence of cucurbit[8]uril the predominant product is that of dimerization. Such a change in product distribution is attributed to the localization of the olefins by the host cucurbit[8]uril. Most importantly, instead of a mixture of dimers, predominantly a single dimer was obtained in each case. The nature of the dimer that was formed could be rationalized on the basis of the principles of "best fit" and "minimization of electrostatic repulsion". The superior ability of cucurbit[8]uril compared to micelles to act as a templating agent is attributed to its ability to provide a reaction cavity that is tight and time-independent.
UR - http://www.scopus.com/inward/record.url?scp=34547164452&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34547164452&partnerID=8YFLogxK
U2 - 10.1021/la700803k
DO - 10.1021/la700803k
M3 - Article
C2 - 17539667
AN - SCOPUS:34547164452
VL - 23
SP - 7545
EP - 7554
JO - Langmuir
JF - Langmuir
SN - 0743-7463
IS - 14
ER -