Synthesis, structure, and properties of supramolecular charge-transfer complexes between bis(18-crown-6)stilbene and ammonioalkyl derivatives of 4,4′-bipyridine and 2,7-diazapyrene

摘要

4,4′-Bipyridine and 2,7-diazapyrene derivatives (A) having two ammonioalkyl N-substituents were synthesized. The complex formation of these compounds with bis(18-crown-6)stilbene (D) was studied by spectrophotometry, cyclic voltammetry, ~1H NMR spectroscopy, and X-ray diffraction analysis. In MeCN, π-donor D and π-acceptors A form supramolecular 1:1 (D?A) and 2:1 (D?A?D) charge-transfer complexes. The D?A complexes have a pseudocyclic structure as a result of ditopic binding of the ammonium groups to the crown-ether fragments. The better the geometric matching between the components, the higher the stability of the D?A complexes (log K up to 9.39). A key driving force of the D?A?D complex formation is the excessive steric strain in the precursor D?A complexes. The pseudocyclic D?A complexes involving the ammoniopropyl derivative of 4,4′-bipyridine were obtained as single crystals. Crystallization of the related ammonioethyl derivative was accompanied by transition of the D?A complexes to a structure of the (D?A)_m coordination polymer type.