Polyvinyl-locked versus free quaterthiophene: effect of spatial constraints on the electronic properties of n-hexylquaterthiophene.
A soluble, low-weight fraction of poly(alpha-vinyl,omega-n-hexyl-quaterthiophene), PT4Hex, having n-hexylquaterthiophenes as side-chain groups, is prepared by free-radical polymerization of alpha-vinyl,omega-n-hexyl-quaterthiophene and the corresponding properties compared to those of free di-n-hexylquaterthiophene (T4Hex). Optical analysis (absorption and emission) and X-ray diffraction data indicate that in the polyvinyl-locked architecture the quaterthiophene pendants adopt a cofacial arrangement with a mutual distance close enough for pi-pi orbitals to overlap ( approximately 4 A). As a consequence of the close chain packing, a shift of the reduction potential of about 0.5 V toward less negative values with respect to free T4Hex, is found for PT4Hex films. Due to its enhanced electron affinity, PT4Hex displays an electron-acceptor behavior when blended with alkylated and silylated quaterthiophenes acting as donors.
Istituto per la Sintesi Organica e la Fotoreattività, CNR-ISOF via Gobetti 101, 40129 Bologna, Italy. mmelucci@isof.cnr.it
Manuela
M
Melucci
Massimo
M
Zambianchi
Alberto
A
Zanelli
Nadia
N
Camaioni
Massimo
M
Gazzano
Alessandro
A
Bongini
Giovanna
G
Barbarella
D002627:Chemistry, Physical / Q000379:methods*; D004563:Electrochemistry / Q000379:methods*; D004581:Electronics; D004583:Electrons; D008956:Models, Chemical; D008968:Molecular Conformation; D015394:Molecular Structure; D011108:Polymers / Q000737:chemistry; D011145:Polyvinyls / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013053:Spectrophotometry / Q000379:methods; D013876:Thiophenes / Q000737:chemistry*; D014961:X-Ray Diffraction / Q000379:methods
D011108:Polymers; D011145:Polyvinyls; D012997:Solvents; D013876:Thiophenes