Structural Insights into Influence of Isomerism on Properties of Open Shell Cobalt Coordination System.

Marcin Swiatkowski,Rafal Kruszynski,Tomasz Sieranski,Marta Bogdan

doi:10.3390/molecules24183357

Marcin Swiatkowski, Rafal Kruszynski + Show 2 more

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https://doi.org/10.3390/molecules24183357

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Abstract

The two coordination compounds of cobalt were designed and synthesized. The substrates were carefully selected to allow gentle tuning of the molecular structure of the designed compounds. The crystal, molecular and supramolecular structure of studied compounds has been determined and discussed. The spectroscopic and thermal properties of designed coordination compounds have been studied and their application as precursors for the synthesis of cobalt oxide nanoparticles has been demonstrated. It was proven that not only are parameters of conversion of the precursor to nanoparticles important, but also small changes in molecular structure can considerably affect the size of formed particles. For unambiguous determination of the influence of compounds structure on their UV-Vis radiation absorption, density functional theory and time-dependent density functions theory calculations have been performed. The complexity of the correct ab-initio reflection of the open shell molecular system was outlined and discussed. The results obtained from density functional theory (DFT) calculations have been also employed for discussion of the bonding properties.

Highlights

Extensive attention has been focused on the coordination chemistry of transition metals carboxylates, especially with N-donor ligands [1,2,3,4]
The concentrations of the respective cobalt salts in the final solutions were determined via edta titration of cobalt cations [37], and they were 0.0472 and 0.0458 mol·dm−3 respectively, for cobalt butyrate and cobalt isobutyrate
Cobalt cations are bonded with two monodentate 2-apy molecules coordinating by the nitrogen atom of the aromatic ring and two bidentate chelating carboxylate anions

Summary

Introduction

Extensive attention has been focused on the coordination chemistry of transition metals carboxylates, especially with N-donor ligands [1,2,3,4]. Coordination compounds belonging to this group are especially interesting because of their useful properties and wide applications (e.g., in wood preservation, as photoluminescent materials, in thermoelectric devices and magnetic materials) originating from their specific crystal structures [1,5,6]. Due to possessing various coordination modes, the carboxylate anions have been used for the synthesis of compounds with diverse structures and topologies. These anions exhibit excellent functional properties in terms of their strong coordination abilities. Because of their versatility, at the specific conditions they can adopt one of the wide of bonding modes (e.g., monodentate, bidentate, tridentate, symmetric, asymmetric, bridging, chelating) [7,8]. The introduction of the properly selected other ligand (in the studied case an N-donor one), leads to the increase in the structural diversity and improves the functionality of a compound

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