Synthesis, Characterization and Catalytic Studies of Chromium(iii) Porphyrin Complex with Axial Cyanate Ligands

We report the synthesis and the spectroscopic, structural and electrochemical characterization of a new chromium(III) coordination compound namely the bis(cyanato-kappa N)[meso-tetratolylporphyrinato] chromate(III) (cryptand-222)potassium dihydrate [K(crypt-222)][Cr-III(TTP)(NCO)(2)]center dot 2H(2)O (complex I). This compound crystallizes in the orthorhombic crystal system with the non-centrosymmetric space group C222(1). The chromium and the potassium atoms are located at special positions in a two-fold axis. The crystal lattice of complex I is stabilized by O--H center dot center dot center dot O, C-H center dot center dot center dot O, C-H center dot center dot center dot N and C-H center dot center dot center dot pi intermolecular contacts involving the negatively charged [Cr-III(TTP)(NCO)(2)](-) species, the [K(crypt-222)](+) counterions and the two non-coordinated water molecules. Further insights on these weak intermolecular contacts are provided by the Hirshfeld surface analysis. Molecular electrostatic potential (MEP) theoretical calculation on [K(crypt-222)][Cr-III(TTP)(NCO)(2)]center dot 2H(2)O are reported. The new Cr(III) complex was efficient as a catalyst in the decomposition of the Rhodamine B (RbH) dye by hydrogen peroxide. This coordination compound was also tested as a photocatalyst of the photodecomposition of the RbH dye by molecular oxygen. (C) 2021 Elsevier B.V. All rights reserved.