New dicyanide-salen based chromium(III) complexes: Synthesis, crystal structures, electrochemical and thermal investigations

Two compounds with formulas [K(H2O)(CH3OH)Cr III(valen)(CN)2]2 ( 1 ) and PPh4[Cr III(valen)(CN)2] center dot 8.5H2O ( 2 ) were synthesized and structurally characterized (H2valen is the Schiff base resulted from the conden-sation of o-vanillin with ethylenediamine). For compound 1 , a solid-state transformation (130 degrees C), consist-ing in the elimination of CH3OH and H2O ligands, was observed. The exposure of the resulting crystal to the humidity from air led to [K(H2O)2Cr III(valen)(CN)2]2 ( 3 ). The single-crystal X-ray diffraction analysis of 1 and 3 revealed that they are isostructural, their structure consisting of a tetranuclear centrosym-metric complex, {Cr2K2 }, with the CrIII ions located into the (N2O2) coordination sites and the potassium ions located into the open (O2O'2) compartments of the two organic ligands. For compound 2 , the crystal structure consists of discrete anionic mononuclear species, [Cr III(valen)(CN)2] -, and tetraphenylphospho-nium counter cations. Thermal (TG-DTG-DSC) and electrochemical investigations of the newly synthesized complexes were performed.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

Two compounds, [K(H2O)(CH3OH)Cr III(valen)(CN)2]2 ( 1 ) and PPh4[Cr III(valen)(CN)2]·8.5H2O ( 2 ), were synthesized and structurally characterized. Compound 1 exhibited solid-state transformation upon heating at 130 degrees C, resulting in the elimination of CH3OH and H2O ligands. Exposure of the resulting crystal to humidity led to the formation of compound 3. Compound 2 consists of discrete anionic mononuclear species [Cr III(valen)(CN)2] - and tetraphenylphosphonium counter cations. Thermal and electrochemical investigations were performed on the newly synthesized complexes.