Tuning Thiophene with Phosphorus: Synthesis and Electronic Properties of Benzobisthiaphospholes

• Published in: Chemistry : a European journal 2014-06, Vol.20 (25), p.7746-7751
• Main Authors: Qiu, Yunyan, Worch, Joshua C., Chirdon, Danielle N., Kaur, Aman, Maurer, Andrew B., Amsterdam, Samuel, Collins, Christopher R., Pintauer, Tomislav, Yaron, David, Bernhard, Stefan, Noonan, Kevin J. T.
• Format: Article
• Language: English
• Subjects: Calomel electrode; Chemistry; Chlorides; Diffraction; Electrochemistry; fused-ring systems; heterocycles; Mathematical analysis; Modulation; n-type acceptors; organic electronics; Phosphorus; phosphorus heterocycles; Reduction; Tuning; X-rays
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201402561

1,4‐Dimercapto‐2,5‐diphosphinobenzene and 3,6‐bis(hexyloxy)‐1,4‐dimercapto‐2,5‐diphosphinobenzene were synthesized and combined with various acid chlorides to obtain a series of benzobisthiaphospholes. Electrochemical and photophysical properties of the substituted benzobisthiaphospholes have been evaluated, and the observed reductions are more facile than the related benzothiaphospholes and 2,6‐diphenylbenzobisthiazole. A benzobisthiaphosphole with C6H4‐p‐CN substituents was reduced at E1/2=−1.08 V (vs. saturated calomel electrode (SCE)). X‐ray diffraction data for several of these phosphorus heterocycles has been obtained, and DFT calculations at the B3LYP level have been performed. Fused‐ring systems: Energetic tuning of conjugated building blocks can be achieved by atomic modulation of aromatic architectures. A phosphorus mimic of benzodithiophene and benzobisthiazole has been synthesized and structurally characterized (see figure). The UV/Vis spectrum of the phosphorus heterocycle is significantly redshifted compared to its organic counterparts. The redox properties of the benzobisthiaphospholes have been probed and revealed reversible reductions in THF.