Pentagonal-Bipyramidal Oxidorhenium(V) Complex with N4-Tetradentate Ligand: Unusual Synthetic Route, Spectroscopic, Crystallographic, and DFT Studies

Herein we report the zwitterionic pentagonal bipyramidal oxidorhenium(V) complex trans -[ReOI 2 (bpp)] where bpp is (1E,3E)-1,3-bis(pyrimidin-2-ylimino)propan-2-ide anion. The complex trans -[ReOI 2 (bpp)] was unusually formed from the reaction of trans -[ReOI 2 (OEt)(PPh 3 ) 3 ] with 2-aminopyrimidine in propan-2-ol in the presence of triethylamine (Et 3 N). The anionic ligand bpp was formed by oxidorhenium(V)-catalysed dehydroxylation of propane-2-ol followed by condensation with 2-aminopyrimidine, and coordinates to the [ReO] 3+ core as tetradentate N-donor chelate. A few numbers of pentagonal bipyramidal complexes are known for oxidorhenium(V), and the complex trans -[ReOI 2 (bpp)] is another example. The complex was analyzed by 1 H NMR, IR, UV-visible and single crystal X-ray crystallography. In addition, density functional theory (DFT) was also studied.