Carbonyl releasing Schiff base complex of Fe (III): synthesis, physicochemical characterization, antimicrobial and anticancer studies
Authors: Kupwade, R V
Sawant, V J
Journal: Journal of Chemical Sciences (2020)
Discipline: CHEMISTRY
Keywords: carbonyl releasing; Schiff base chelate; Fe(III) complex; wet chemical method; XRD pattern

Abstract: The carbonyl releasing Schiff base chelate derived Fe(III) complex has been synthesized following the simple wet chemical method. The rhombohedral packing of ligands with the metal ion in the complex was confirmed by its XRD pattern and FTIR spectrum. Compounds were characterized by UV-Vis., PL, FTIR, XRD and TEM techniques. Better biocompatibility of the complex than that of the pure Schiff base had been elaborated on gram-positive and gram-negative bacteria by Agar well disc-diffusion antibacterial screening. The complex also displayed pH-responsive in vitro anticancer therapy on MCF-7 breast cancer cells as revealed by MTT assay. The release of CO and Schiff base as well as the interaction of Fe(III) with the mitochondria inside the cell are the key factors of cell biocompatibility. This CORM complex had exhibited higher anticancer activity on MCF-7 cells than the Schiff base and thus potential candidate for the future biomedical applications. New carbonyl releasing CORM-Schiff base complex of Fe(III) has been synthesized. This CO releasing complex exhibits rhombic packing, octahedral geometry and exhibits antimicrobial activity at 25&nbsp;ppm concentration in water. The complex has good antimicrobial-anticancer potential.

Retracted: No

PubPeer comments:
 More than strange, the powder diffraction pattern shown in this paper and said to correspond to a Fe(III) complex is exactly the same as a ZnO powder pattern : ![file] and ZnO pure from elsewhere : ![file] So... unexplainable... , 
 #1 What the authors claim as a Fe(III) complex is actually Fe(V) complex according to their Scheme 1 (see below) in the paper. To compensate for the three nitrates and two phenolate oxygen Fe has to be in +5 state. However, in the entire paper there is mention of only Fe(III). This also is inexplicable. Unfortunately, no Fe(V) complexes are known to date and this also is NOT a Fe(V) complex because its powder pattern has been shown to be questionable. It is also NOT clear as to how authors managed to get ZnO when they were preparing a Fe complex. ![file] **Scheme 1** Synthesis protocol of Schiff base ligand and carbonyl-schiff base Fe(III) complex. , 
  *The gaseous CO ligand was produced in separate flask by the reaction of conc. HCl with calcium carbonate and zinc powder mixture. Then the CO ligands produced separately in another flask was passed and bubbled in ligand and metal precursor mixture to get carbonyl releasing CORM complex of Fe(III) containing CO ligands and Schiff base.*  From these details reported for  Wet chemical synthesis of CORM, carbonyl - Schiff base complex of Fe(III) in the experimental section, one can note that zinc powder along with CaCO3 was used to produce CO gas. However, CaCO3 with HCl gives carbon dioxide CO2 and Zn gives H2 gas which can reduce ferric. Consideration of the above, it appears that no CO gas was used in the reaction and no CO containing Fe compound was actually made. Also ZnO is colorless while ferric Schiff bases are colored. Will authors clarify what is the colour of the product they obtained? , 
 See more comments on that paper there : https: link.springer.com article 10.1007 s12039-021-01915-4 ,