Macrocycles, pseudorotaxanes and catenanes containing a pyrrolo-tetrathiafulvalene unit: absorption spectra, luminescence properties and redox behavior
The photophysical properties of (i) three macrocycles (1–3) of different size, each one incorporating a bis(2,5-dimethylpyrrolo[3,4-d])tetrathiafulvalene (TTFP) and a 1,4-dimethoxybenzene (DMB) electron-donating unit, (ii) the six pseudorotaxanes obtained by threading 1–3 with the electron acceptors dimethyldiazapyrenium (DMDAP2+) and dibenzyldiazapyrenium (DBDAP2+) and (iii) the three catenanes obtained by interlocking 1–3 with the electron-accepting cyclophane cyclobis(paraquat-p-phenylene) (CBPQT4+) have been investigated. The monooxidized and dioxidized species obtained by oxidation with Fe(III) of the TTFP unit contained in the above compounds have also been studied. The redox-driven dethreading/rethreading process has been investigated in the case of the pseudorotaxane based on the macrocycle 2 and the DMDAP2+ dication. In the catenanes, oxidation of the TTFP unit causes strong spectral changes, but does not promote disruption of the interlocked structures.