Terpyridine polymers

In order to quantify the transition metal ion concentration, Jones et al. [107] developed a highly sensitive fluorescent chemosensor in the form of dialkoxy-phenyleneethynylene-thiophene copolymers 68/69. The PAEs were functionalized on the thiophene unit with terpyridine (68), and included 2,2 -bipyridine (69) as a Lewis acid receptor. The terpyridine polymers [108] were found to respond quantitatively to transition metal ions at concentrations as low as 4x10 M (NP, Hg, Cr ", and Co " ). The additionally used bpy-PAE demonstrates that variation in the chelation at the receptor site is an important variable in tuning selectivity. The observed dynamic quenching mechanism, combined with the solubility of this material, provides the opportunity to extend these initial investigations to thin solid films for use in real-time monitoring applications. 

Ru(II) based terpyridine polymers were prepared by Houston et al. in 2003.21 The polymers were prepared by reacting /h.v-terpyridine monomers with Ru(DMSO)4Cl2 in hot ethanol (Fig. 3). To improve the solubility of the coordination polymers, pinene moieties are attached to the monomers. The degree of polymerization of the polymers was studied by elemental analyses, gel permeation chromatography, vapor phase osmometry, STM and electrospray ionization mass spectrometry. However, no precise result was obtained, and the size of the polymers was estimated to be between 40 and 60 repeating units. 

In 2002, Wiirthner et al. reported a Zn(II) terpyridine polymer showing a rod-like structure (Fig. 4).11 The polymer exhibits a strong fluorescence, with an emission quantum yield of 0.61 in DMF solution. 

FIGURE 2. Synthetic scheme for self-assembled Fe(II) terpyridine polymer.20... 

In 2003, we first used self-assembled zinc(II) terpyridine polymers in the fabrication of PLEDs.22 We synthesized a series of monomers containing two terpyridine as chelating units, which are at opposite ends and separated by a spacer group (R) (Fig. 5). The self-assembled zinc(II) coordination polymers were easily prepared by the addition of Zn(OAc)2 into solution of monomers. The product yields were up to 80%, and the inherent viscosities of the polymers were in the range of 0.48 to 1.21 dL/g, as determined using an Ubbelohde viscometer in NMP at 30 0.1 °C. 

Spectroscopic data of la—li, monomers of la—li, and model compound 1 (zinc(II) fe(V-phenyl salicylaldiminato) are listed in Table 2. The absorption spectra of these zinc(II) terpyridine polymers are similar, with absorption maxima at 286—290 and 320—391 nm. PL of these polymers span violet, blue, green, and yellow color. The PL quantum yields ( I>PL) range from 25% for lb and le to 77% for If in DM Ac. The PL values of the polymer thin films were determined using integrating sphere,23 which were found to vary from 0.15 to 0.55 0.05 (Table 2). 

After publication of our work,22 new self-assembled Zn(II) terpyridine polymers were prepared and used in PLEDs. Following the methodology reported by us, Lin et al. similarly prepared a series metallopolymers by self-assembled reaction containing Zn(II) terpyridine units, including a metallo-homopolymer and metallo-u/t-copolymer containing carbazole pendants attached to the C-9 position of fluorene by long alkyl spacers.27... 

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