Great Efficiency of Nucleosides as Organizing Tools

Sonja Merkaš,Souhaila Bouatra,Mladen Žinić,Régis Rein,Nathalie Solladié,Ivo Piantanida

doi:10.5562/cca3247

Abstract

Bis-porphyrins with flexible linkers such as uridine or 2’-deoxyuridin pre-organize in a face-to-face conformation and form stable sandwich complexes with bidentate base such as DABCO. The gain in stability can be even greater when a dinucleotide linker is used. Such pre-organization increases the association constant by one to two orders of magnitude when compared to the one of DABCO with a reference porphyrin. Comparison with rigid tweezers shows a better efficiency of nucleosidic dimers. The choice of rigid spacers is not the only way to pre-organize bis-porphyrins, and well-chosen nucleosidic linkers offer an interesting option for the synthesis of such devices.

Highlights

E LABORATION of non-covalent multiporphyrinic assemblies represents an important challenge in relation to the mimicry of bacterial photosynthesis[1] and the design of functional molecular materials.[2]
The complexations were monitored by UV-visible spectrophotometric titration of a solution of tweezers in CH2Cl2 ([1] = 2.7 × 10–5 M, [2] = 3.0 × 10–5 M, [3] = 2.4 × 10–5 M), which resulted as expected in a significant red-shift of the Soret and Q bands in the porphyrin (Figure 2).[10]
The complexations were monitored by UV-visible spectrophotometric titration of a solution of tweezers in CH2Cl2 ([2] = 2.9 × 10–5 M, [3] = 2.2 × 10–5 M), which resulted as expected in a significant red-shift of the Soret and Q bands in the porphyrin.[10]

Summary

Introduction

E LABORATION of non-covalent multiporphyrinic assemblies represents an important challenge in relation to the mimicry of bacterial photosynthesis[1] and the design of functional molecular materials.[2]. The synthesis of dimers 1, 2 and 3 has already been described.[8,9] The ability of tweezers 1, 2 and 3 to accommodate guests of various size was investigated through binding studies carried out in dichloromethane with DABCO or 4,4’-bipyridine as bidentate bases.

Results

Conclusion