syn1-Periplanar Bisazo Skeletons — Syntheses and Reactions with Carbonylmetal Complexes

Preparatively useful synthesis for the novel, relatively mobile polycyclic syn1-periplanar bisazo polycycles 4 and 5 are based on hydrazine condensation with readily available dienedione 6 and acid-catalyzed rearrangement of bisurazole 12, respectively. In the preferred “closed” and “open” conformations of 4 and 5 the NN bonds are 314 and 496 pm, respectively, apart (MMX). From the reactions of 4 and 5 with carbonyliron and -ruthenium compounds, complexes are derived which are typical of monoazo ligands [4 · Fe(CO)4 20, 4 · Fe2(CO)721, 4 · Fe3(CO)922, 4[Fe2(CO)6]223, 4 · Ru3(CO)9 · 24, 5 · [Fe2(CO)6]2 25, 5 · Fe2(CO)6 · Fe3(CO)9 26]. For 21, 23 and 26 crystal structure analyses were performed, confirming i.a. in 26 the unique presence of a Fe2(CO)6 and a Fe3(CO)9 fragment attached to two azo units of the same molecule.