Bipyridyl polymers

Numerous diamines and aromatic dianhydrides have been investigated. WhoUy aromatic Pis have been stmctiirally modified by incorporating various functional groups, such as ether, carbonyl, sulfide, sulfone, methylene, isopropjlidene, perfluoroisopropyUdene, bipyridyls, sdoxane, methyl phosphine oxide, or various combinations of these, into the polymer backbone to achieve improved properties. The chemistry and apphcations of Pis have been described in several review articles (4). 

Peter, K. and Thelakkat, M. (2003) Synthesis and characterization of bifunctional polymers carrying tris (bipyridyl)ruthenium(ll) and triphenylamine units. Macromolecules, 36, 1779-1785. 

Pei et al. [412] reported an alternating fluorene copolymer 331 with 2,2 -bipyridyl in a side chain that emitted at 422 nm. Treating this polymer with Eu3+ chelates formed the polymeric complexes 332-334. Their emission was governed by intramolecular Forster energy transfer, whose efficiency depends on the structure of the ligands and the Eu3+ content (Scheme 2.49) [412], The most effective energy transfer manifested itself in a single red emission band at 612 nm for the complex 332 with a maximum intensity achieved at —25 mol% content of Eu3+. 

Into a Schlenk tube was placed Auf 1,5-cyclooctadiene)-nickeI(0) (2.6 mmol), 2,2 -bipyridyl (2.6mmol), 1,5-cyclooctadiene (0.2ml), DMF (4ml), and toluene (8 ml). The reaction mixture was heated to 80°C for 0.5 h under argon. The dibromide comonomers 623 and 634 dissolved in degassed toluene (8 ml molar ratio of dibromides to nickel complex 0.65) were added under argon to the DMF-toluene solution and the polymerization maintained at 80°C for 3 days in the dark. 2-Bromofluorene (molar ratio of dibromides to monobromide 0.1) dissolved in degassed toluene (1ml) was added and the reaction continued for 12 h. The polymers were precipitated by addition of the hot solution dropwise to an equivolume mixture of concentrated HC1, methanol, and acetone. The isolated polymers were then dissolved in toluene or dichlor-omethane and reprecipitated with methanol/acetone (1 1). The copolymers were dried at 80°C in vacuo. The isolated yields of copolymers 240a-c were 79-85%. 

Recently, metal-centered coordination has been introduced to construct star polymers [118]. The principle is outlined for bipyridyl capped PEO when coordinated with Ru2+. 

Liu B, Yu W-L, Pei J, Liu S-Y, Lai Y-H, Huang W (2001) Design and synthesis of bipyridyl-containing conjugated polymers effects of polymer rigidity on metal ion sensing. Macromolecules 34 7932-7940... 

Following Adachi et al., aromatic compounds with similar functionalities were proposed for polymer electrolytes as redox shuttle additives, which included bipyridyl and biphenyl carbonates and di-fluoroanisoles. All these additives could protect the cathode from overcharging in the vicinity of 4.1... 

Comparison of the spectra of these Re(I)-containing polymers with those of the corresponding free oligomers demonstrates that metalation includes a substantial redshift of the lowest 71,71 absorption. Metalation forces the bipyridyl unit into a planar conformation, thereby effectively increasing the conjugation length [13, 69]. In addition to this effect, the electrophilic metal center likely decreases the LUMO energy and consequently decreases the HOMO-LUMO gap. 

PArEs with pendant bipyridyl or terpyridyl ligands have also been reported [26]. At 3.08x10" M polymer concentration, a concentration of 1.0x10" M quenched 24 and 25 to 10.9 and 38.2% of their respective initial fluorescence... 

The electroreduction of some typically inorganic compoimds such as nitrogen oxides is catalysed by the presence of polymeric osmium complexes such as [Os(bipy)2(PVP)2oCl]Cl, where bipy denotes 2,2 -bipyridyl and PVP poly(4-vinylpyridine). This polymer modifies the reduction kinetics of nitrite relative to the reaction at a bare carbon electrode, and provides calibration graphs of slope 0.197 nA with detection limits of 0.1 pg/mL and excellent short-term reproducibility (RSD = 2.15% for n = 20). The sensor performance was found to scarcely change after 3 weeks of use in a flow system into which 240 standards and 30 meat extracts were injected [195]. 

Polymer electrodes modified with pendant metal-bipyridyl groups have been studied in detail Eaves, J. G. Munro, H. S. Parker, D. Inorg. Chem. 1987,26,644 and references therein. 

Bis(2,2 -bipyridyl)ruthenium(II) was anchored onto poly(4-vinyIpyridine) (PVP) (6) 28>29), but the polymer complex is not suitable as photocatalyst, because it is susceptible to photoaquation. A polymer complex containing Ru bpy) + pendant groups was first prepared by reaction of polystyrene (PSt) as shown in Eq. (15)30). 

Polymer bound tris-(2,2 -bipyridyl)-ruthenium-(II)-derivatives were synthesized by reaction of 4-(3-chloroformyl-propyl)-4 -methyl-2,2 -bipyridyl with crosslinked amino-groups containing poly(styrene) gel or crosslinked sucrose-methacrylate gels, and by... 

A reactor was charged with the step 4 product (0.96 g), 2,2 -bipyridyl (0.55 g), and THF (80 g). After deaeration, bis(l,5-cyclooctadiene)nickel(0) (1.05 g) was added and the mixture heated to 60°C for 1.5 hours and then cooled and precipitated in 300 ml of ion exchange water. The precipitate was isolated and then dissolved in chloroform, filtered, and purified by passing through a column filled with alumina. The polymer was reprecipitated in methanol, reisolated, dried, and 0.5 g of product isolated having an Mn of 7.3 x 10s Da. 

Styrene Polymers. Polystyrene-divinylbenzene immobilized 3d metal bipyridyl-amine complexes also exhibit enhanced thermal stability as in the case with the polyacrylics. Biswas and Mukherjee [18] more recently reported the enhancement of thermal stability of 3d metal ion loaded PS-DVB-BPA-M(II)... 

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