Formation of the H-bonds in 1 and 2 shifts the electronic density along the molecular backbone of the dye and this effect leads to hindering rotation of the rhodanine moiety around the C=C bond of the central conjugated system
to achieve the stable isomer form intrinsic of the dyes 1a and 2a.
As shown in figure 2, this creates a conjugated system
via the two aromatic rings, known as a quinone imide.
This is due to the much larger molecule number density in the solid film than that in the solution, especially to the much larger delocalized [pi]-electrons conjugated system
formed in the film.
For the aromatic substituted oxazole to form a conjugated system
, all the structural components must be coplanar.
Band (c) in the range of 630-650 nm is as-sociated with bipolaron transition (np) in the large p conjugated system
of the polymer chain .
X-ray analysis reveals that the atoms of C(1) to C(8), N(1) and N(2) form a planar and N2, C3, C2, C1 and N1 atoms can form a conjugated system
. The structure in solution is in agreement with the solid-state structure.
On the other hand, since the discovery of the ultra-fast and ultra-efficient photo induced electron transfer between [pi]-conjugated systems and fullerene derivatives [13-14], a considerable interest for hetero-junction solar cells based on interpenetrating networks of conjugated systems
and C60 derivatives have been generated .
Porphyrins are conjugated systems
because they contain alternating single and double bonds.
Since then, researchers have showed that electron correlation effects play a key role in correctly describing the linear and nonlinear optical properties of conjugated systems
Although he continues his interest in unusual conjugated systems
, his major emphasis in recent years has been on the synthesis and study of molecules that imitate enzymatic reactions.
Topics include optical microscopy and spectroscopy of single molecules, optical properties of single conjugated polymer chains (polydiacetylenes), morphology-correlated photophysics in organic semiconductor thin films by confocal laser microscopy and spectroscopy, spectroscopy of long-lived photoexcitations in pi- conjugated systems
, charge transport in disordered organic semiconductors, probing organic semiconductors with terahertz pulses, macroscopic polarization and exciton properties for strong exciton polaritons in anisotropic crystals, sub-5 fs spectroscopy of polydiacetylene, and ultrafast optoelectronic probing of excited states in low-dimensional carbon-based pi-conjugated materials.