Synthesis of 2-chloro-8-(2-pyridyl)-1-azaazulene and its metal complexes

Reaction of 2-chloro-1-azaazulenes with 2-pyridyllithium followed by dehydrogenation by chloranil gave 8-(2-pyridyl) -1-azaazulene (2). Formation of metal complexes (M = Cu, Fe, Pd) of 2 was achieved. The reaction of 2 with Cu(I) gave 1:1 -complex (3) and 2:1-complex (4). Complex (3) was deduced to have a polymeric chain structure with the copper center is +1. The ESR spectrum study of 4 showed that the copper center is +2. The structure of 4 was decided by X-Ray structural analysis and it is shown that the complex takes a trigonal bi-pyramidal structure.