ABSTRACT
Metal-organic 1D-coordination polymers, having unique electronic and optical properties, are expected to be a novel advanced functional material capable of fabricating smart plastics, films, and fibers. In this study, we have synthesized a novel metal-organic 1D-coordination polymer composed of a phenylene-bridged bipyrrole bearing N-alkylimino groups (BPI) and palladium(II) ion. The BPI and Pd(II) form square planar bis(bidentate) complex to form a metal coordinated π-conjugation polymer (Poly-BPI/Pd). It is stable in solutions at room temperature, and allowed measurement of its average molecular weight in SEC (M w = 106,000 and M n = 18,000, M w/M n = 5.88). It also provided a reversible multi redox profile in cyclic voltammetry, most likely originating from strong π-electronic interactions between the BPI components via Pd ion. A variety of substituent groups can be attached to the imino-nitrogens of BPI. A coordination polymer composed of a BPI derivative bearing chiral alkyl chains and Pd(II) showed strong circular dichroism (CD) in the solution due to the unidirectional chiral conformation of the BPI components in the polymer backbone.
ABSTRACT
A novel acid-responsive single trichromatic luminescent dye capable of emitting pure white light (WL) is reported. A newly designed p-phenylene-bridged bipyrrole bearing N-alkylimino groups (1 a) specifically provides WL emission upon mixing with trifluoroacetic acid (TFA) in a CH2Cl2 solution. The emission originates from the trichromatic luminescent behavior of 1 a upon protonation of the imino groups. The blue-light-emitting 1 a exhibits dramatic color changes in fluorescence to orange and green upon mono- and diprotonation, respectively, providing a wide emission band in the range of λ=400-800â nm that provide WL when the compound is in a dynamic equilibrium between the three states. The sample also exhibits low self-absorption of the emitted light and a high fluorescence quantum yield upon excitation with UV light.
