Theoretical Study of Structural Relationships and Electrochemical Properties of Supramolecular [14-MR Macrolides]@C_n Complexes

Abstract

Macrolides are a broad spectrum of antibiotics that are commonly used in human pathologies as well as in veterinary medicine. The electrochemical detection of macrolide antibiotics were studied at various methods using amperometric and coulometric detectors. Since the discovery of fullerenes (C_n), one of the main classes of carbon compounds, the unusual structures and physiochemical properties of these molecules have been discovered, and many potential applications and physicochemical properties have been introduced. Up to now, various empty carbon fullerenes with different numbers “n,” such as C₆₀, C₇₀, C₇₆, C₈₂, and C₈₆, have been obtained. Topological indices are digital values that are assigned based on chemical composition. These values are purported to correlate chemical structures with various chemical and physical properties. They have been successfully used to construct effective and useful mathematical methods to establish clear relationships between structural data and the physical properties of these materials. In this study, the number of carbon atoms in the fullerenes was used as an index to establish a relationship between the structures of Erythromycin-A (EA), Erythromycin-A enol ether (EMEN), Olendomycin (OM), and Anhydroerythromycin-A (AEA), 1-4 and fullerenes C_n (n = 60, 70, 76, 82 and 86), which create [Tetracyclines]@C_n, A-1 to A-5 ([EA]@C_n), B-1 to B-5 ([EMEN]@C_n), C-1 to C-5 ([OM]@C_n), and D-1 to D-5 ([AEA]@C_n). The relationship between the number of carbon atoms and the free energies of electron transfer (ΔG_et(1) to ΔG_et(4)) is assessed using the Rehm-Weller equation for A-1 to A-5, B1 to B-5, C-1 to C-5, and D-1 to D-5 supramolecular [14-MR Macrolides]@C_n complexes 5-24. Calculations are presented for the four reduction potentials (^Red.E₁ to ^Red.E₄) of fullerenes C _n . The results were used to calculate the four free-energies of electron transfer (ΔG_et(1) to ΔG_et(4)) of supramolecular complexes A-1 to A-18 to B-1 to B-18, C-1 to C-18, and D-1 to D-18 (5-76) for fullerenes C₆₀ to C₃₀₀.

Keywords:

• Anhydroerythromycin-A
• Electrochemical properties
• Erythromycin-A
• Erythromycin-A enol ether
• Free energy of electron transfer
• Fullerenes
• Macrolides
• Molecular topology
• Olendomycin
• Reduction potential
• Rehm-Weller equation

Acknowledgments

The author gratefully acknowledges colleagues in the Chemistry Department of The University of Queensland-Australia for their useful suggestions.

Notes

*The data of the free energy of electron transfer (ΔG _{et (1)} to ΔG _{et (4)}) for [EA]@C _n compounds had not been previously reported.

*The data of the free energy of electron transfer (ΔG _{et (1)} to ΔG _{et (4)}) for [EMEN]@C _n compounds had not been previously reported.

*The data of the free energy of electron transfer (ΔG _{et (1)} to ΔG _{et (4)}) for [OM]@C _n compounds had not been previously reported.

*The data of the free energy of electron transfer (ΔG _{et (1)} to ΔG _{et (4)}) for [AEA]@C _n compounds had not been previously reported.