SYN-PERIPLANAR BISAZO SKELETONS - SYNTHESES AND REACTIONS WITH CARBONYLMETAL COMPLEXES

Preparatively useful syntheses for the novel, relatively mobile polycyclic syn-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 N = N 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)7 = 21, 4 . Fe3(CO)9 = 22, 4 . [Fe2(CO)6]2 = 23, 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.