New Solvatochromic Dyes of the 5-Dimethylamino-5′nitro-2,2′-bithiophene Type

Abstract

The first serious competitor to the known solvatochromic pyridiniumphenolate betaines has been uncovered with the 5-dimethylamino-5'-nitro-2,2'-bithiophene 1 a (X=Z=S, Y=CH, R=CH(3)), which has the added benefit of being notably sensitive to solvent in acidic media. By simple heterocyclization further compounds of the general type 1 have been synthesized, and their suitability as solvent indicators was investigated. In this way a new record was set with the selenophene analogue of 1 a.

Use of Stable Amine-Capped Polyynes in the Regioselective Synthesis of Push–Pull Thiophenes

“…Substituted push–pull 2-aminothiophenes exhibit excellent properties for optoelectronic applications and play an important role in NLO (nonlinear optics) materials . Compounds with 2-aminothiophene moiety exhibit also strong anti-AR (androgen receptor) potency, are used as fluorescence biomarkers or play an important role as fluorescent dyes. , For instance, DTM-2 and BAP-2 (Figure ) are used for in vivo fluorescence imaging of β-amyloid (Aβ) plaques that is expected to be a new method for detecting Alzheimer’s disease. , Substituted 2-amino-5-phenylethynylthiophenes or 2-amino-5-phenylthiophenes (G and H in Figure ) have also an influence on A 1 adenosine receptor . The approach presented so far to obtain these compounds was different from that shown in this work, so we believe, we have added a valuable contribution to the synthesis of such thiophenes with high application potential.…”

Raman and Theoretical Study of the Solvent Effects on the Sizable Intramolecular Charge Transfer in the Push−Pull 5-(Dimethylamino)-5‘-nitro-2,2‘-bithiophene

“…The UV−vis absorption maximum, λ max , of Me 2 N-T 2 -NO 2 largely redshifts, as a function of the solvent polarity, from ∼466 nm in aliphatic solvents such as n -pentane or n -hexane to ∼577 nm in formamide. The dye was used as a suitable probe for the determination of solvent polarity 13b and has been recently shown to be the dye with the greatest solvent sensitivity among a family of donor−acceptor substituted 2,2‘-bithiophenes . The effective electronic interaction between the ending groups is evident not only in the marked solvatochromism but also in the large values measured for the hyperpolarizability β …”

Chromophore-derivatized semifluorinated polymers for colorimetric and turn-on fluorescent anion detection

“…Conjugated semifluorinated polymers that exhibit similar optical responses to F − in polar aprotic solvent (dimethylacetamide) are proposed to act by such a mechanism [68]. It is also well known that oligothiophenecontaining materials often display strong solvatochromism, so anion-induced changes in the polarity of the environment about the chromophore could be responsible for the observed optical changes [65][66][67][68][69]. Efforts to further probe the response mechanism by 1 H NMR spectroscopy were unsuccessful due to low chromophore loading and overlap of chromophore resonances with polymerderived resonances [70].…”