Radiation Effects on Polyacetylenes Having Substituents

Photochromism of dithienylethene single crystals having anthracene substituents.

Three dithienylethene derivatives having anthracene substituents (connected at 1-, 2- and 9-positions) were prepared. Although these three derivatives exhibit photochromic reactivity in solution, only one of the derivatives (connected at 2-position) undergoes the photochromic reaction in the crystalline phase. X-Ray crystallographic analysis and DFT calculation revealed that conformation of the...

Selective recognition of endocrine disruptors by fluorogenic gamma-cyclodextrin having pyrene-tosyl substituents on hetero rims.

dithiophene Diimides: Effects of Substituents

Naphtho[2,3-b:6,7-b1]dithiophene-4,5,9,10-tetracarboxylic diimide (NDTI) is a promising electron-deficient building block for n-type organic conductors, and the performance of NDTI-based field-effect transistors (FETs) is largely dependent on the substituents that alter the supramolecular organization in the solid state and, in turn, the intermolecular orbital overlap. For this reason, the rati...

Effects of ethynyl substituents on the electronic structure of cyclobutadiene.

The effects of ethynyl substitution on the electronic structure of cyclobutadiene are investigated in this work. Ethynyl substituted cyclobutadienes may be involved in Bergman cyclization reactions and are possible intermediates in the formation of fullerenes and graphitic sheets. Prediction of the electronic structure of cyclobutadiene is challenging for single-reference ab initio methods beca...

Rotational barriers of biphenyls having heavy heteroatoms as ortho-substituents: experimental and theoretical determination of steric effects.

The free energies of activation for the aryl-aryl rotation of 17 biphenyl derivatives, bearing a heavy heteroatom (S, Se, Te, P, Si, Sn) as ortho substituent, have been measured by variable temperature NMR. These numbers, so called B values, represent a meaningful measure of the steric hindrance exerted by the selected substituents. DFT computations match quite satisfactorily the experimental b...