Synthesis And Properties Studies Of Oligopyrrole Derivatives

Boron dipyrromethene (BODIPY) dyes have developed rapidly, asan important series of organisms dyes. They contain some outstandingproperties such as high fluorescence quantum yields and high absorptioncoefficients, good stability to light, low susceptibility to solvent polarityand pH, narrow emission spectrum band, max absorption and emissionwavelength lying on visible region and have been widely used influorescent molecular switch, laser dyes, sensitive reagents.Short oligopyrroles, such as dipyrrins, pyrrolyldipyrrin, tripyrrinsand tetrapyrroles, are versatile precursors for the synthesis ofporphyrinoids and have also found wide applications in medicinalchemistry, material science, supramolecular chemistry as anion bindingand cation coordination reagents. There is very limited number oftetrapyrroles reported to date due to their lengthy total synthesis.Reported tetrapyrroles generally prepared with limited diversity throughcondensations of bipyrroles and triethyl orthoformate under acidicconditions.We developed a stepwise and regioselective aromatic substitutionreaction of halogenated BODIPYs with pyrroles. The high efficiency inthe preparation of pyrrole substituted BODIPYs3aa-4dd is ratherremarkable, featuring with no catalyst needed and also diversity oriented.The resultant pyrrole substituted BODIPYs are interesting red andNear-Infrared (NIR) fluorescent dyes with absorption maximum up to733nm. We have characterized their structures, tested their opticalproperties and studied the dyes as potential new photosensitizers.Removal of BF2protecting group of the3-pyrrole or3,5-dipyrrolesubstituted BODIPYs provides a facial entry to a series of novelpyrrolyldipyrrin and tetrapyrroles with direct2,2’-bipyrrole linkages.7a-dhave a similar skeleton to the prodigiosine analogues, providing a fast andefficient method of synthesizing prodigiosine analogues.