Phospholes photophysical properties

It is noteworthy that the P atoms of these phosphole oligomers retain the versatile reactivity observed with monophospholes [7]. In particular, biphosphole 9 exhibits a rich coordination chemistry, which allows for the preparation of a variety of neutral and cationic transition metal complexes (Scheme 4.5) [18a,b, 22]. These have been used as precursors for homogeneous catalysts [22] however, their photophysical properties have not been studied. 

As is illustrated in Section 3.15.12.4 the use of phospholes as building blocks of extended 7t-conjugated materials is an area of considerable interest due to the ease with which the photophysical properties of the various materials may be tuned at the molecular level by exploiting the now well-established reactivity and synthetic flexibility of these P-containing heterocycles. Representative NMR data are presented for a number of compounds in Table 18. 

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