Dipyrrin-Bis(N-Confused Porphyrin) Conjugate: Synthesis, Synergetic Ligation and Chirality Sensing.

A fully conjugated system 4 consisting of two 2-aza-21-carbaporphyrin (NCP) subunits bridged by dipyrrin was synthesized by a highly selective condensation of 3-pyrrole-NCP 2 with aryl aldehydes. The free base 4 as well as its silver(III) complex 5 exhibited flexibility of the bridge allowing synergetic binding of AgI , thus leading to a mixed-valence tetraporphyrinic assembly consisting of eight silver atoms which was characterized both in the solid state and in solution. Binding of chiral acid by 4 and 5 was shown by observation of an induced optical activity of the adducts.