Recent Developments in Phosphole‐Containing Oligo‐ and Polythiophene Materials

Abstract

The introduction of phosphorus‐containing moieties into π‐conjugated thiophene materials has been found to provide materials with strongly optimized and highly tunable optoelectronic features compared to their native thiophene counterparts. 2,5‐Diaryl‐ and 2,5‐bis(heteroaryl)phospholes as well as fused tricyclic dithieno[3,2‐b:2′,3′‐d]phospholes represent two very valuable building blocks for organic electronics as their intriguing features can be altered systematically by several, in part unique, methodologies. The potential scope of these modifications has been determined by comprehensive investigations of their structure–property relationships via suitable molecular model compounds. Onseveral occasions, these observations could successfully be transposed to corresponding polymers that are often difficult to characterize independently. The same is true for the first organic light‐emitting diodes (OLEDs) based on a phosphole scaffold, whose properties could also be predicted successfully. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Comparative Study on the Structural, Optical, and Electrochemical Properties of Bithiophene‐Fused Benzo[c]phospholes

“…[1,2] In the present P,S-hybrid chromophores, the P-coordination to AuCl salt induces a bathochromic shift of the absorption and emission maxima (Dl abs = 31-52 nm and Dl em = 61-66 nm; for 7/8 versus 4/5) and a considerable decrease in emission efficiency (F F = 0.02-1.1 % for 7-9 versus F F = 0.6-17.6 % for 4-6). The oxygenation at the phosphorus atom causes more pronounced effects on the p-p* transitions, that is, the larger bathochromic shifts of absorption maxima (Dl abs = 61-83 nm for 10/11 versus 4/5) and complete suppression of emission.…”

“…The combined organic extracts were washed with brine, and dried over Na 2 SO 4 . After removal of the volatile components under reduced pressure, the residue was subjected to silica-gel column chromatography (CH 2 …”

“…[8,9] In particular, Baumgartners dithienoA C H T U N G T R E N N U N G [b,d]phospholes have proven to emit intense fluorescence covering the blueyellow region. [2,9] Quite recently, Yamaguchi and co-workers Abstract: Three types of bithiophenefused benzo[c]phospholes were successfully prepared by Ti II -mediated cyclization of the corresponding dialkynylated bithiophene derivatives as a key step. Each s 3 -phosphorus center of the benzo[c]phosphole subunits was readily transformed into s 4 -phosphorus center by Au coordination or oxygenation.…”

“…These prominent features of phosphole are beneficial for developing new classes of heterole-based p-conjugated materials for use in optoelectrochemical applications, such as organic light-emitting diodes (OLEDs), field-effect transistors (FETs), and nonlinear optical (NLO) devices. [2] In search of potential candidates for this purpose, much effort has been devoted to reveal the relationship between the structure and the fundamental properties of phospholes bearing p-conjugative substituents at the 2,5-positions (a,a'-positions). For example, RØau and co-workers systematically investigated the optical and electrochemical properties of 2,5-diarylphospholes, [3] and demonstrated the potential utility of this class of compounds as components of the emissive layer for OLEDs.…”

“…The combined organic extracts were washed with brine and dried over Na 2 SO 4 . After removal of the volatile components under reduced pressure, the residue was subjected to silica-gel column chromatography (CH 2 X-ray crystal crystallographic analysis: Single crystals were grown from CH 2 Cl 2 -MeOH (for 4 a, 5 a, 7 a, 8 a, and 9 a) or CH 2 Cl 2 -hexane (for 10 a) at room temperature. All measurements were made on a Rigaku Saturn CCD area detector with graphite monochromated Mo Ka radiation (l = 0.71069 ).…”