Metallo-celluloses, 2 Synthesis of cellulose derivatives bearing lateral bis-terpyridine ruthenium(II) complexes

Abstract

An efficient method is described for the simultaneous introduction of 4’-p-benzyl-2,2’:6’,2’’-terpyridine and benzyl side groups into cellulose. For this purpose, cellulose triacetate was treated in dimethyl sulfoxide/NaOH solution with mixtures of 4’-p-bromomethylphenyl-2,2’:6’,2’’-terpyridine and benzyl bromide. An almost quantitative conversion of the cellulose hydroxyl groups was reached when less than one terpyridine substituent was attached to the cellulose repeating units on average. At higher degrees of terpyridine substitution, some of the cellulose hydroxyl groups seem to remain unsubstituted. This conclusion has been drawn on the basis of NMR, IR and solubility measurements. We assume that steric hindrance of the bulky side groups is responsible for incomplete conversion. In a final step, the terpyridine substituents of the cellulose derivatives could be converted quantitatively into ruthenium(II) complexes via treatment with activated [Ru(tpy)Cl3] in N,N-dimethylacetamide/1-butanol (tpy: 2,2’:6’,2’’-terpyridine).

Complexation of Terpyridine‐Containing Dextrans: Toward Water‐Soluble Supramolecular Structures

“…[20,21] In continuation of prior work, dealing with linear coordination polymers based on poly(ethylene glycol) (PEG) terpyridine ruthenium(II) complexes, [3] one end of a PEG chain was functionalized with a terpyridine moiety and connected to the dextran by complexation. In contrast to the polysaccharides substituted with terpyridine ruthenium (II) complexes described by Rehahn and co-workers, [17] the here described dextran PEG comb-polymer still possesses hydroxyl groups and is water soluble. For this purpose, the macromolecule can be further modified with biologically active substances, targeting functions, or sensor devices while retaining the possible solubility switch to hydrophobic dextran derivatives.…”

“…[6] Rehahn and coworkers showed the successful substitution of cellulose triacetate with 4 0 -p-benzyl-2,2 0 :6 0 ,2 00 -terpyridine and the complexation of this functionalized cellulose using a ruthenium 2,2 0 :6 0 ,2 00 -terpyridine complex. [17] Recently, it was shown how the composite of a terpyridine-modified schizophyllan (TPySPG) and single-walled carbon nanotubes (SWNT) yielded sheetlike morphologies in the presence of Fe II ions. [18] Moreover, these TPySPG can act as hosts that helically wrap nanomaterials such as carbon nanotubes, conjugated polymers, DNA, and gold nanoparticles.…”

“…Furthermore, also Rehahn et al reported that polysaccharides can partly decompose applying the used conditions and, therefore, broadened SEC traces slightly shifted to higher retention times were obtained. [17] It is known from literature that the hydrodynamic radius of a comb-polymer is smaller than its linear analogue with the same molar mass; this represents another reason for the only slightly shifted molar masses from M n ¼ 59 200 g Á mol À1 (3) to 65 400 g Á mol À1 (12).…”