Synthesis, spectroscopic characterization and X-ray crystal structures of mononuclear and binuclear oxidorhenium(V) complexes containing indazolyl moieties

•A novel oxidorhenium(V) complexes of indazole were synthesized.•The complexes were characterized by FT-IR, 1H NMR, and UV–Vis spectroscopy.•The spectroscopic features of complexes were further investigated by DFT methods.

The paper presents a combined experimental and computational study of mononuclear and binuclear oxidorhenium(V) complexes incorporating indazolyl moieties – [{Re(O)Cl2(PPh3)}{η2-O(CH3)2C-ind}] and [{Re(O)Cl(PPh3)}2(μ-O)(μ-ind)2] (indH = 1H-indazole). The compounds were fully characterised by means of IR, NMR, UV–Vis and elemental analysis as well as X-ray crystallography. In the mononuclear complex, a six coordinated rhenium(V) atom is in octahedral environment with a trans arrangement of the oxido group and the oxygen atom of the anionic bidentate ind–C(CH3)2O−. Two octahedral rhenium(V) centers of [{Re(O)Cl2(PPh3)}{η2-O(CH3)2C-ind}] are linked through two bridging indazolato anions and an oxido group. DFT and time-dependent DFT (TDDFT) calculations have been carried out and the UV–Vis spectra of all of the reported complexes have been discussed on this basis.

Graphical abstractThe reactions of [ReOCl3(PPh3)2] with indazole (indH) have been examined and mono- and dinuclear oxidorhenium(V) complexes have been synthesized and characterized by spectroscopic methods (FT-IR, 1H NMR, UV–Vis). The crystal and molecular structures of [{Re(O)Cl2(PPh3)}{η2-O(CH3)2C-ind}] and [{Re(O)Cl(PPh3)}2(μ-O)(μ-ind)2] have been determined. The electronic structures and spectra of these complexes were investigated at the TDDFT level employing B3LYP functional in combination with LANL2DZ.Figure optionsDownload full-size imageDownload as PowerPoint slide