Tylosin is a well-established antibiotic that has been widely employed in human and veterinary medicines. It can act as a potential ligand binding metal ions due to various donor atoms in the structure. Our study on the complexation of various metal ions with tylosin ligand revealed that they preferably coordinate with mycaminose fragment to establish Novel trends complexes. Tylosin ligand (TYS) behaves as bidentate for complexation with different metal ions such as Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II). Various essential metal complexes of tylosin were synthesized and characterized by techniques such as UV, IR, Elemental analysis, magnetic susceptibility and ESR spectra of Cu(II) complex. These techniques are used to know their geometries and mode of bonding, with stoichiometry, 2:2 (M:L). Thermal analysis (TGA and DTA) of ligands and their metal complexes were carried out to distinguish between the coordinate and hydrate solvents and to estimate the stability ranges, peak temperatures. The thermodynamic parameters, such as activation energy (ΔE*), the enthalpy of activation (ΔH*), entropy of activation (ΔS*) and Gibbs free energy (ΔG*) are calculated and discussed. Some tylosin complexes show higher activity than tylosin for some bacterial and fungal strains. Low concentration value of minimum inhibitory concentration (MIC) results is 15.625 µg/ml for both complexes [Zn 2 (TYS) 2 Cl 2 (H 2 O) 4 ]•25H 2 O and [Cu 2 (TYS) 2 Cl 2 (H 2 O) 4 ]•25H 2 O with B. cereus genus maybe a valuable data used to produce novel therapeutic agent. This study constitutes several essential aspects for future research on tylosin metal complexes as antibacterial assessment and as potential medicinal agents.

This work underlines some important features for the research on metal complexes of Niclosamide as antioxidants and antimicrobial evaluation of some of these compounds as possible therapeutic agents. Niclosamide metal complexes show a significant leap in the study of antibiotic resistance bacteria including Methicillin Resistant S.aureus (MRSA). The synthesized metal complexes of niclosamide in our current innovation are highly effective at eliminating this destructive sort of bacteria. Niclosamide metal complexes were synthesized then characterized by elemental analysis, Infra‐Red, electronic spectra, magnetic susceptibility, Mass spectra and ESR spectra of Cu (II) complex to know their geometries and mode of bonding, with stoichiometry, 1 : 1 (M : L). All the Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) metal ions complexes were proposed to be with distorted octahedral geometry. Powder X‐Ray Diffraction technique is being utilized to further investigation of synthesized Niclosamide metal complexes. Expo2014 software was also employed to solve the structure of these novel complexes which proven the distortion of crystal structure. The TGA and DTA curves were employed to derive the kinetic thermodynamic parameters. The thermal decomposition of the complexes ended with the formation of divalent metal oxide, MO or trivalent, M2O3 as a final product except in case of Hg complex. The results of the antimicrobial activity of tested new metal complexes compounds exhibited potent antibacterial and antifungal activities in comparison to the Niclosamide ligand as reference. Quantum chemical parameters were estimated and provided noticeable values which completely matched with antimicrobial results that [Mn(NIC)(Cl2)(H2O)2] ⋅ 0.4H2O has higher biological activity than ligand and other novel complexes. low concentration value of MIC results by 125 μg/ml for both niclosamide (NIC) complexes [Ni(NIC)(Cl2)(H2O)2] and [Cu(NIC)(Cl2)(H2O)2] ⋅ 2.5H2O with Methicillin Resistant S.aureus (MRSA) genus maybe a valuable data used to produce novel therapeutic agent. Depending on their structure and on the source of the oxidative stress, metal complexes of Niclosamide might act as antioxidants or pro‐oxidants.

Tylosin is a well-established antibiotic that has been widely employed in human and veterinary medicines. It can act as a potential ligand binding metal ions due to various donor atoms in the structure. Our study on the complexation of various metal ions with tylosin ligand revealed that they preferably coordinate with mycaminose fragment to establish Novel trends complexes. Tylosin ligand (TYS) behaves as bidentate for complexation with different metal ions such as Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II). Various essential metal complexes of tylosin were synthesized and characterized by techniques such as UV, IR, Elemental analysis, magnetic susceptibility and ESR spectra of Cu(II) complex. These techniques are used to know their geometries and mode of bonding, with stoichiometry, 2:2 (M:L). Thermal analysis (TGA and DTA) of ligands and their metal complexes were carried out to distinguish between the coordinate and hydrate solvents and to estimate the stability ranges, peak temperatures. The thermodynamic parameters, such as activation energy (ΔE*), the enthalpy of activation (ΔH*), entropy of activation (ΔS*) and Gibbs free energy (ΔG*) are calculated and discussed. Some tylosin complexes show higher activity than tylosin for some bacterial and fungal strains. Low concentration value of minimum inhibitory concentration (MIC) results is 15.625 µg/ml for both complexes [Zn 2 (TYS) 2 Cl 2 (H 2 O) 4 ]•25H 2 O and [Cu 2 (TYS) 2 Cl 2 (H 2 O) 4 ]•25H 2 O with B. cereus genus maybe a valuable data used to produce novel therapeutic agent. This study constitutes several essential aspects for future research on tylosin metal complexes as antibacterial assessment and as potential medicinal agents.