Understanding optoelectronic properties of cyano-terminated oligothiophenes in the context of intramolecular charge transfer.

In this paper we have prepared a new series of oligothiophenes capped with hexyl groups and a variety of strong acceptors, mainly cyanovinyl moieties. An exhaustive analysis of the absorption, photophysical, electrochemical, solid state, nonlinear optical and vibrational properties has been presented guided by theoretical calculations. The investigation is centered on the efficiency of the intramolecular charge transfer (i.

Comparison of thiophene-pyrrole oligomers with oligothiophenes: a joint experimental and theoretical investigation of their structural and spectroscopic properties.

We have prepared a new series of mixed thiophene-pyrrole oligomers to investigate the electronic benefits arising from the combination of these two heterocycles. The oligomers are functionalized with several hexyl and aryl groups to improve both processability and chemical robustness. An analysis of their spectroscopic (absorption and emission), photophysical, electrochemical, solid state, and vibrational properties is performed in combination with quantum-chemical calculations.

Inefficient crystal packing in chiral [Ru(phen)(3)](PF(6))(2) enables oxygen molecule quenching of the solid-state MLCT emission.

The molecular oxygen quenching of the solid-state emission from pure crystals of Delta-Ru(phen)(3)(PF(6))(2), Lambda-Ru(phen)(3)(PF(6))(2), and racemic Ru(phen)(3)(PF(6))(2) (phen = 1,10-phenanthroline) was studied by emission spectroscopy. Crystals of the pure enantiomers exhibit significant and nearly identical emission-intensity quenching [0.36(2) and 0.

Concurrent sensing of benzene and oxygen by a crystalline salt of tris(5,6-dimethyl-1,10-phenanthroline)ruthenium(II).

The complex [Ru(5,6-Me2Phen)3]tfpb2 has been examined as a solid-state benzene and oxygen sensor. The crystalline solid undergoes a reversible vapochromic shift of the emission lambda max to higher energy in the presence of benzene. Additionally, in the presence of oxygen the solid exhibits linear Stern-Volmer quenching behavior.

Reduced band gap dithieno[3,2-b:2',3'-d]pyrroles: new n-type organic materials via unexpected reactivity.

Direct addition of tetracyanoethylene to N-(p-hexylphenyl)dithieno[3,2-b:2',3'-d]pyrrole yields not only the aromatic mono- and bis-tricyanovinyl-substituted products but also a quinoidal product with dicyanomethylene groups. The analogous reaction with dithieno[3,2-b:2',3'-d]thiophene yields exclusively the aromatic mono-tricyanovinyl product. The aromatic and quinoidal products possess red-shifted absorptions, increased electron affinities, and favorable pi-stacking motifs in comparison to the unsubstituted oligomers.

Reverse selectivity in m-CPBA oxidation of oligothiophenes to sulfones.

Oligothiophene sulfones of up to six rings can be conveniently prepared by the direct oxidation of butyl-substituted thiophene oligomers with m-CPBA in dichloromethane. Reverse selectivity of oxidized rings is observed relative to previously reported systems without beta-substitution. The selectivity in the trimer and hexamer is confirmed with single-crystal X-ray structure data.

Selective low-temperature syntheses of facial and meridional tris-cyclometalated iridium(III) complexes.

We have developed a selective low-temperature synthesis of fac and mer tris-cyclometalated Ir(III) complexes. The chloro-bridged dimers [Ir(CwedgeN)2Cl]2 (CwedgeN = cyclometalating ligand) are cleaved in coordinating solvents like acetonitrile to give neutral Ir(CwedgeN)2(NCCH3)Cl species which in turn are reacted with AgPF6 to give hexafluorophosphate salts of the bis-acetonitrile species [Ir(CwedgeN)2(NCCH3)2]PF6 for CwedgeN = 2,2'-thienylpyridine (thpy) and 2-phenylpyridine (ppy). These bis-acetonitrile complexes are excellent starting materials for the synthesis of tris-Ir(III) complexes.