Synthesis, crystal structure, electrochemistry and thermal analysis of an oxalato bridged Cr(III)-Pb(II) heterometallic coordination compound

Oxalato bridged Cr(III)-Pb(II) compound of molecular formula [{Pb(phen)(2)}(2)Cr(ox)(2)(phen)] [Cr(ox)(2)(phen)](NO3)(2) (1) [ox = oxalate anion, C2O42-, phen = 1,10-phenanthroline] has been synthesized and characterized by X-ray crystallography, FT-IR and fluorescence spectroscopy, electrochemical and thermal analysis. The single crystal diffraction analysis revealed that the asymmetric unit of complex 1 comprises of a trinuclear cationic species [{Pb(phen)(2)}(2)Cr(ox)(2)(phen)](3+)(where metals are bridged by oxalate anions in eta(4)mu mode) counterbalanced by an anionic complex [Cr(ox)(2)(phen)](-) and two nitrate anions. Chromium atoms exhibit a distorted octahedral environment in both fragments, while the six-coordinated lead atoms show an hemidirected coordination geometry that allows the formation of weaker Pb center dot center dot center dot O NO2 interactions (tetrel bonds). At room temperature complex 1 exhibits fluorescence at 365 and 383 nm in methanol (lambda(ex)= 268 nm, Phi = 0.38). In addition, the complex is redox active and the cyclic voltammograms recorded at different scan rate showed that the irreversible peak corresponds to the Cr+3/Cr-2(+) couple. Thermogravimetric analysis indicates that the compound starts to decompose at 33.7 degrees C and collapses at similar to 277 degrees C. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

A novel oxalato bridged Cr(III)-Pb(II) compound was synthesized and characterized, showing fluorescence and redox properties, as well as good thermal stability. The complex exhibited fluorescence at room temperature and irreversible redox peaks corresponding to the Cr+3/Cr-2(+) couple. The compound started to decompose at 33.7 degrees C and collapsed at around 277 degrees C, indicating its thermal stability.