Novel Self-Assembled Metallo-Homopolymers and Metallo-alt-copolymer Containing Terpyridyl Zinc(II) Moieties

Abstract

A series of novel terpyridyl Zn(II))-based metallo-polymers, including metallo-homopolymers and metallo-alt-copolymer, containing carbazole pendants attached to the C-9 position of fluorene by long alkyl spacers were constructed by self-assembled reaction. The integrated ratios of 1H NMR reveal a facile result to distinguish the differences between metallo-homopolymers and copolymers. To further investigate these polymers, UV−vis and PL spectral titration experiments were also carried out by varying the molar ratios of zinc(II) ions to monomers. The photophysical properties of these polymers exhibited blue PL emissions (around 420 nm) with quantum yields of 11−23% (in DMF) and the PL results revealed that the formation of excimers were suppressed by the incorporation of carbazole pendant groups. In addition, the EL results showed green EL emissions (around 550 nm) with turn-on voltages of 6.0−6.5 V, maximum efficiencies of 0.85−1.1 cd A-1 (at 100 mA cm-2), and maximum luminances of 1704−2819 cd/m2 (around 15 V), correspondingly.

π‐Conjugated Donor and Donor–Acceptor Metallo‐Polymers

“…Such a behavior might be attributed to a HOMO that is located mainly at the electron-rich central chromophore and a LUMO localized on the electrondeficient metal-coordinated terpyridine moieties. [14,22] Comparing the absorption spectra of the Zn II metallopolymers, a bathochromic shift was obvious when changing from solution to films. The absorption spectra of the pure ligand 1 (l abs ¼ 368 nm) and the corresponding zinc polymer Zn1 (l abs ¼ 369 nm) did not show any conjugation effect, even when measuring at higher p-Conjugated Donor and Donor-Acceptor .…”

“…In addition, a ruthenium complex incorporated into a polymer will influence the optical as well as the electronic properties of the polymer due to its characteristic metal-to-ligand charge transfer (MLCT) transition around 500 nm, thus extending the absorption range of the material. The usage of Zn II ions leads to metallo-polymers being potential interesting light-emitting materials in OLEDs; [14,15,[21][22][23] moreover, also Ir-containing polymers are of special interest for this purpose. [24][25][26] In recent years, p-conjugated polymer semiconductors with donor-acceptor (D-A) architectures have attracted considerable attention, since their electro-optical properties make them promising candidates for potential applications in the fields of organic electronics.…”

π‐Conjugated 2,2′:6′,2″‐Bis(terpyridines): Systematical Tuning of the Optical Properties by Variation of the Linkage between the Terpyridines and the π‐Conjugated System

“…[3][4][5][6][7][8][9][10][11][12][13] 2,2Ј:6Ј,2ЈЈ-Terpyridines bearing well-defined π-conjugated substituents at the 4Ј-position are known to exhibit attractive electronic and optical properties. [6,8,10,[14][15][16][17][18][19][20][21][22][23][24][25] When two 2,2Ј:6Ј,2ЈЈ-terpyridine units are introduced at either end of a rigid conjugated spacer, the resulting ditopic bis(terpyridine) ligand enables the synthesis of metallo-supramolecular polymers by coordination with different metal ions. Several publications dealing with the synthesis and characterization of such conjugated terpyrid-ine derivatives were fully characterized by 1 H and 13 C NMR spectroscopy, UV/Vis absorption and emission measurements as well as MALDI-TOF MS.…”

“…[6,15,17,26,27] To enable the preparation of metallo-polymers exhibiting absorption over a wide range of the visible spectrum, we aimed to tune the band gap of our systems in an easy and systematic manner. The exchange of a phenyl moiety of the conjugated substituent by, for example, an anthracene or fluorene, enables the variation of the absorption of the derived terpyridyl system over a range of more than 100 nm.…”

Novel Molecular Building Blocks Based on the Boradiazaindacene Chromophore: Applications in Fluorescent Metallosupramolecular Coordination Polymers

“…[7][8][9][10][11][12] The degree of polymerization in such polymers is primarily controlled by the concentration of the building blocks in solution and the strength of interaction between the ligand and the metal ion. The dynamic nature of the equilibria governing the extent of polymerization provides enormous potential in manipulating the macroscopic properties of these polymers, whether in solution or in other phases.…”