TY - JOUR
T1 - Comparison of linear and cross-conjugation from rates of vinylheptafulvene ring-closure
AU - Fjelbye, Kasper
AU - Christensen, Trine Nørgaard
AU - Jevric, Martyn
AU - Broman, Søren Lindbæk
AU - Petersen, Anne Ugleholdt
AU - Kadziola, Anders
AU - Nielsen, Mogens Brøndsted
PY - 2014/10/29
Y1 - 2014/10/29
N2 - The concept of cross-conjugation has in recent years attracted increasing interest in materials science as well as in the field of molecular electronics as a means to tune the optical properties and molecular conductance of nanoscale devices. In this paper we show how the rate of an electrocyclic reaction, the conversion of vinylheptafulvene (VHF) into dihydroazulene (DHA), is influenced by an electron-withdrawing p-nitrophenyl group separated from the VHF by either cross-conjugated or linearly π-conjugated bridging units. A selection of DHA/VHF molecules with ethyne, 1,1-and 1,2-diethynylethene, and 1,3-butadiyne bridges was prepared by metal-catalyzed coupling reactions. The effect of the different conjugated spacers on the kinetics of the conversion of VHF into DHA was examined by UV/Vis absorption spectroscopy by monitoring the decay of the VHF absorption. The cross-conjugated diethynylethene spacer was found to increase the half-life of the VHF relative to the linearly conjugated spacers.
AB - The concept of cross-conjugation has in recent years attracted increasing interest in materials science as well as in the field of molecular electronics as a means to tune the optical properties and molecular conductance of nanoscale devices. In this paper we show how the rate of an electrocyclic reaction, the conversion of vinylheptafulvene (VHF) into dihydroazulene (DHA), is influenced by an electron-withdrawing p-nitrophenyl group separated from the VHF by either cross-conjugated or linearly π-conjugated bridging units. A selection of DHA/VHF molecules with ethyne, 1,1-and 1,2-diethynylethene, and 1,3-butadiyne bridges was prepared by metal-catalyzed coupling reactions. The effect of the different conjugated spacers on the kinetics of the conversion of VHF into DHA was examined by UV/Vis absorption spectroscopy by monitoring the decay of the VHF absorption. The cross-conjugated diethynylethene spacer was found to increase the half-life of the VHF relative to the linearly conjugated spacers.
U2 - 10.1002/ejoc.201403117
DO - 10.1002/ejoc.201403117
M3 - Journal article
SN - 1434-193X
VL - 2014
SP - 7859
EP - 7864
JO - European Journal of Organic Chemistry
JF - European Journal of Organic Chemistry
IS - 35
ER -