Synthesis and Characterization of Linear Luminescent Schiff-Base Polyelectrolytes with Europium(III) in the Backbone^1a

Abstract

The first luminescent linear europium(III) Schiff-base polyelectrolytes with europium in the polymer backbone have been synthesized and characterized. Europium-containing polyelectrolytes with ligand triplet states at or above the 5D0 state of europium luminesce with high quantum yields, consistent with the intramolecular energy-transfer mechanism established for europium(III) complexes. New [NaY(tstm)] n polyelectrolytes, where tstm4- is the anionic ligand derived from N,N‘,N‘‘,N‘‘‘-tetrasalicylidene-3,4,3‘,4‘-tetraaminodiphenylmethane, were synthesized with n values (up to 21 600) based on NMR end-group analysis. Intrinsic viscosities provide Mark−Houwink constants of a = 0.52 and K = 0.066 cm3/g for [NaY(tstm)] n . Mixed-metal [NaY x Eu1 - x (tstm)] n polyelectrolytes provide enhanced emission over [NaEu(tstm)] n . The intensity is most enhanced for polyelectrolytes with Y:Eu ratios between 1:2.5 and 1:9, probably by intrachain energy transfer from the yttrium units of the polyelectrolytes to the EuIII ions. [NaY0.2Eu0.8(tstm)] n (Y:Eu = 1:4) luminesces more strongly than any other compound investigated and has a quantum yield of 0.74 at 77 K.

Synthesis and characterization of thermally stable Schiff base polymers and their copper(II), cobalt(II) and nickel(II) complexes

“…Due to the reagents used for the reaction process, the oxidative polycondensation (OP) may also be regarded as a good example of environmentally benign or green synthetic process of polymeric materials. SBP and their metal complexes have been prepared because of their interesting and important properties, such as their ability to bind toxic and heavy metal ions, thermal stability, and exhibition of catalyst and photoluminescence properties [4][5][6][7][8][9][10][11][12][13][14][15][16]. Synthesis of metal complexes of SBP has received the attention of various groups as the metal ions drastically alter the thermal stability as well as the functional properties of the polymer backbone.…”

Introduction to Metal‐Coordination Polymers

“…An excellent example of polymer formation by reacting a bis-chelating ligand with metal ions was provided by Chen and Archer. 36,37 Trivalent lanthanide nitrates were reacted with the sodium salts of bridging tetradentate Schiff-based ligands 10 and 11 to generate polymers 12 and 13 in DMSO. Dimethyl sulfoxide was able to solubilize both the lanthanide nitrates and the ligand salts.…”

“…36,37,[107][108][109] Unlike the strategy used by Goodwin and Bailor that involved the coordination of metal ions to preexisting polymers, Archer and co-workers reacted organic Schiff base ligands that could complex with two metal ions producing coordination polymers. Archer and co-workers prepared and studied the luminescent properties of lanthanide-coordinated Schiff coordination polymers 12 and 13 mentioned earlier in this chapter.…”

“…Archer and co-workers prepared and studied the luminescent properties of lanthanide-coordinated Schiff coordination polymers 12 and 13 mentioned earlier in this chapter. 36,37 Included in their studies was the influence of different spacer groups and counterions on polymer solubility. Through the use of end-group analysis using nuclear magnetic resonance (NMR), molecular weights of 21,600 (M ϭ Y) and 18,500 (M ϭ Eu) were found.…”

Fluorescent properties of europium(III) complexes with polyacrylic acid containing graftedo-phenanthroline groups

“…1 The intensity of fluorescence of Ln 3+ in macromoleeular complexes (MMC) is, as a rule, low because of the weak absorption of the tanthanide ions (~ __< 1) and the absence of effective intramolecular transfer of energy from the levels of the macromolecular ligand (MML) to the Ln 3+ levels. The transfer of the excitation energy from the chromophore molecule contained in the macromolecule to the resonance levels of Ln 3+ (the antenna effect) z'3 is one of the channels of energy transformation in the lanthanide MMC and a possible way of sensitization of fluorescence.…”