Ruthenium and osmium complexes of novel carbohydrate derived salen ligands: Synthesis, characterization and in situ ligand reduction

Synthesis and characterization of two ruthenium(II) and osmium(II) complexes (1 and 2) having carbohydrate derived salen ligand and in situ ligand reduction are reported. The1,2-O-isopropylidene-3,5-diazido-3,5-dideoxy-α-d-xylopyranoside (L1) was reduced by catalytic hydrogenation using continuous flow hydrogen reactor in the presence of salicylaldehyde to form the corresponding bis-imino derivative H2L2. The ligand H2L2 has been transformed to H2L3 upon reduction of one of the imine bonds in consequence to the oxidation of the leaving PPh3 group to POPh3. Systematic spectroscopic characterization, 1H and 13C NMR, mass spectrometry, electronic spectra reveals the composition of the complexes. X-ray crystal structures of both the complexes are reported. Detailed electrochemical studies reveal the redox behaviour of the complexes and DFT calculations help to get the idea about the intense lowest-energy absorption for these two complexes.

Synthesis and characterization of a Ruthenium(II) and a osmium(II) complexes having carbohydrate derived salen ligand and in situ ligand reduction are reported. The complexes were characterized by 1H and 13C NMR, electronic spectra, mass spectrometry and single crystal X-ray crystallography. To get an idea about the intense lowest-energy absorption for these two complexes, DFT calculation has been done.Figure optionsDownload as PowerPoint slideHighlights
► Synthesis of novel tetradentate carbohydrate derived salen ligand.
► In situ generation of a new ligand by redox reaction.
► Synthesis and characterization of the cis-configurated complexes of ruthenium and osmium with the in situ generated ligand.
► Detailed spectroscopic and spectrometric studies of all products.