Thiophene-fused phospholes

The phosphole ring can be fused to a number of other cyclic structures. The most widely found are the dibenzo- and dithieno-derivatives 9 and 10. It is noteworthy that these compounds display few properties associated with phospholes. Instead, they behave as diarylphosphines due to the presence of the highly aromatic fused benzene or thiophene rings. 

Incorporation of other heteroatoms to phosphole-containing heteroarenes also leads to interesting molecular properties. One common example is the incorporation of thiophene units (Figure 12.10). These phospholes have high photoluminescence quantum yields due to their limited degrees of freedom from the rigid, fused ring system. Like many of the compounds discussed herein, these... 

---