Preparation of cationic chlorophyll-a derivative linked with poly(4-vinylpyridine) by using a Barluenga reagent and physical properties of the polymeric conjugates

A chlorophyll- a (Chl- a ) derivative possessing the C3-vinyl group, methyl pyropheophorbide- a was conjugated to poly(4-vinylpyridine) (P4VP) through a C3 1 –N + bond by a well-established oxidative addition reaction using a Barluenga reagent. Because of the decreased solubility of the Chl–P4VP + conjugate with an increase in the cationic pyridinium content, the maximum incorporation of methyl pyropheophorbide- a was limited to 14 mol% for the pyridyl units. The optical properties of the conjugates were specifically dependent on the additive chlorin π-system. Intramolecular fluorescence quenching of the photoexcited Chl moiety was observed in the individual polymeric conjugates.