Synthesis and Characterization of Dicyanovinyl-Substituted Thienylpyrroles as New Nonlinear Optical Chromophores

[structure: see text] New dicyanovinyl-substituted 1-(alkyl)aryl-2-(2'-thienyl)pyrroles 2 were synthesized and characterized. The solvatochromic behavior of the synthesized compounds was investigated. All the derivatives showed reversible oxidation and reduction on the CV time scale. The hyperpolarizabilities (beta) of compounds 2 were measured using hyper-Rayleigh scattering. The results are among the highest beta values reported for donor-acceptor-substituted thienylpyrroles.

Direct Synthesis of Bipyrroles Using Phenyliodine Bis(trifluoroacetate) with Bromotrimethylsilane

[reaction: see text] The hypervalent iodine(III) reagent, phenyliodine bis(trifluoroacetate) (PIFA), mediates the unprecedented, oxidative coupling reaction of pyrroles to give alpha-linked bipyrroles selectively in the presence of bromotrimethylsilane. This straightforward synthesis could provide 2,3'-bipyrrole by the choice of a N-substituent of pyrrole. Mechanistic consideration of the present reaction is also described.

Synthesis of 2,2‘-Bipyrroles and 2,2‘-Thienylpyrroles from Donor−Acceptor Cyclopropanes and 2-Cyanoheteroles

[reaction: see text] Two new series of 2,2'-bipyrroles and 2,2'-thienylpyrroles have been prepared by trimethylsilyl trifluoromethanesulfonate (TMSOTf)-mediated reaction of donor-acceptor cyclopropanes with 2-cyanopyrroles and 2-cyanothiophene, respectively. This method opens the door toward a wide variety of unsymmetrical bipyrroles and thienylpyrroles.