Synthesis and structural characterization of two rotationally flexible bis(benzoxaphosphole)s

Abstract

Two bis(benzoxaphosphole)s, 2,2′-diphenyl-7,7′-bibenzo[d][1,3]benzoxaphosphole (1) and 1,1′-bis(2-benzo[d][1,3]oxaphosphole)ferrocene (2) have been prepared and fully characterized, including structural characterization by single crystal X-ray diffraction methods. Compound 1 has flexibility about the connecting CC bond as evaluated by DFT calculations. The structure of 2 adopts a configuration in the solid state whereby the two BOP units are held in close proximity, presumably due to π-stacking interactions. Under UV irradiation compound 1 is blue fluorescent with a quantum yield of 18% in THF. Compound 2, however, displays no significant emission, which is attributed to ferrocene’s excited state quenching ability.