 In order to investigate structure-property relationships of phosphole containing organic p-conjugated oligomers, derivatives of 1-phenyl-2,5-biaryl phospholes were synthesized using biarylbutadienes as precursors, and steady-state photophysical characterizations of the compounds were performed. Spectroscopic data shows that annulation of the butadiene moiety with a phosphorous atom increases the p-conjugation, causing bathochromic shifts in the absorption/emission maxima. Oxidation at the phosphorous by oxygen or sulfur also results in a bathochromic shift in the absorption/emission maxima. In addition, introduction of a heavy atom such as sulfur promotes intersystem crossing to the triplet excited state resulting in phosphorescence. To explore the electronic effects of the aryl groups, p-flurophenyl , p-methoxyphenyl, and 2-thienyl analogues were investigated. Spectroscopic analyses show bathochromic shifts in the absorption/emission maxima in case of p-methoxyphenyl and thienyl derivatives, while no such shifts are seen in the case of the p-fluorophenyl analogue. Absorption/emission maxima proved to be relatively independent of solvent, while quantum efficiencies are shown to be highly dependent on solvent polarity.

Effects of annulations and oxidation on photophysical properties of phosphole containing oligomers and their precursors

248th National Meeting (2014)

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