Theoretical investigation of the role of pi-pi interactions for the stability of phenylene ethynylene aggregates

M. PICKHOLZ; S. STAFSTROM

CHEMICAL PHYSICS

elsevier

Lugar: LAUSSANE; Año: 2001 vol. 270 p. 245 - 251

0301-0104

A theoretical investigation of phenylene ethynylene macrocycles and oligomers aggregation was carried out. Two types of stacked supramolecular organization were investigated at the MP2 level: the intermolecular aggregation of macrocycles and the intramolecular conformational ordering of long oligomers. For the neutral monomer and ortho- and meta-macrocycles bound states of pi-pi stacked pairs were found, having binding energies of similar to -0.061, -0.378 and -0.81 eV, respectively. The relative stability between ortho- and teta-phenylene ethynylene chains and helices as function of the oligomer length n, in gas phase was also studied. The results show that pi-pi interactions stabilize the helical structures for long oligomers.