A Sustainable Preparation of Functional Perylenophanes by Domino Metathesis

Heinz Langhals,Peter Mayer,Maximilian Rauscher

doi:10.4236/gsc.2019.92004

Heinz Langhals, Peter Mayer + Show 1 more

Open Access

https://doi.org/10.4236/gsc.2019.92004

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Abstract

A sustainable four-step synthesis of soluble perylenophanes for applications as fluorescent optical functional materials is presented and even allows upscaling because of starting with technical bulk products. Thus, terminal alkenylnitriles were alkylated reduced to amines, condensed with perylenetetracarboxylic bisanhydride and cyclised to cyclophanes by means of double cross metathesis in yields until 69% of isolated dyes. The first metathesis by means of the second-generation Hoveyda-Grubbs-catalyst brings the remaining reactive olefinic groups close together favouring the ring-closure to the cyclophanes where the locked neighboring of chromophores in a skew arrangement induce strong exciton interactions. The latter cause an increased the Stokes’ separation by means of a moderate hypsochromic shift of light absorption and a stronger bathochromic shift of fluorescence. Various applications such as for lasers, photonics, solar collectors or in analytics are discussed.

Highlights

The interaction of two or more chromophores offers many possibilities for modern optoelectronics [1] and functional materials because various optical effects can be generated where the perylene dyes [2] such as 1 [3] and other peri-arylenes [4] are suitable components because of their high chemical and photochemical stability and fluorescence quantum yields
The first metathesis by means of the second-generation Hoveyda-Grubbs-catalyst brings the remaining reactive olefinic groups close together favouring the ring-closure to the cyclophanes where the locked neighboring of chromophores in a skew arrangement induce strong exciton interactions
The electrostatic interactions remain still somewhat disfavorable because the comparably short distance of equal charges; the transition energy of the individual chromophores increases for the H orientation and causes a hypsochromic shift of light absorption

Summary

Introduction

The interaction of two or more chromophores offers many possibilities for modern optoelectronics [1] and functional materials because various optical effects can be generated where the perylene dyes [2] such as 1 [3] and other peri-arylenes [4] are suitable components because of their high chemical and photochemical stability and fluorescence quantum yields. The electrostatic interactions remain still somewhat disfavorable because the comparably short distance of equal charges; the transition energy of the individual chromophores increases for the H orientation and causes a hypsochromic shift of light absorption. The J-arrangement with linearly shifted chromophores induces a synchronous electron movement with more favorable attractive Coulomb interactions, lowers the transition energy, causes a bathochromic shift, increases the molar absorptivity because the extended antenna and allows fluorescence. The intensities of the individual bands depend from the exact orientation of the transition moments of the involved chromophores. Aggregates such as H and J arrangement of chromophores are only weakly held together by non-covalent interactions and are labile concerning dissociation such as with dilution. An efficient method for the preparation of such cyclophanes with increased solubility would bring about appreciable progress

Results and Discussions

Conclusions

Spectroscopy

Chemicals