Mn(II) complexes with bipyridine, phenanthroline and benzoic acid: Biological and catalase-like activity

Abstract

Five mononuclear Mn(II) complexes, [Mn(phen) 2 (ClO 4) 2 ] (1), [Mn(phen) 3 ](ClO 4) 2 (H 2 CO 3) 2 (2), [Mn(bipy) 2 (ClO 4) 2 ] (3), [Mn(bipy) 3 ](ClO 4) 2) (4), and Mn(phen) 2 (ba)(H 2 O)](ClO 4)(CH 3 OH) (5), where bipy = 2,2'-bipyridine, phen = 1,10-phenanthroline, and ba = benzoic acid were prepared and characterized by Xray, IR and UV-Vis spectroscopies, and their catalase-like and biological activities were studied. The presence of two different types and the number of chelating NN-donor neutral ligands allowed for analysis of their effects on the catalase and biological activities. It was observed that the presence and number of phen ligands improved the activity more than the bipy ligand. Complexes 1 and 2, which contain more basic phen ligands, disproportionate H 2 O 2 faster than complexes 3 and 4, which contain less basic bipy ligands. The in vitro antimicrobial activities of all the complexes were also tested against seven bacterial strains by microdilution tests. All the bacterial isolates demonstrated sensitivity to the complexes and the antifungal (anticandidal) activities of the Mn(II) complexes were remarkably higher than the reference drug ketoconazole.

Synthesis, Crystal Structures, Thermal and Antimicrobial Properties of Mn(II) Complexes of 1,10-Phenanthroline With Some Co-Ligands

“…The N(2)-Mn(1)-N(1) chelating angle is 72.14(10)°. The bond lengths in the phenanthroline ring range from 1.328(6)-1.438(4) Å in C-C and from 1.323(4)-1.352(4) Å in C-N and this is similar to literature reported values for phenanthroline complexes (Ma, Wang et al 2001, Kani, Atlier et al 2016). (Table 4) and face-to-face π-π [C9-C4 3.369(6) Å; symmetry code -1/2+x,-1/2+y,3/2-z] stacking interactions (Janiak 2000), between adjacent phen ligands, stabilize the structure and assemble complex 1 into an interesting 3D supramolecular structure.…”

“…The 5-membered chelating rings of Mn(II) and N atoms of phen exhibit a near perfect plane; the N2−C11-C12-N1 torsion angle is 0.84(4)° for complex 1. The Mn-N bond lengths are in the range 2.289(3)-2.319(3) Å, which are similar to values reported in the literature (Ma, Wang et al 2001, Kani, Atlier et al 2016. The N(2)-Mn(1)-N(1) chelating angle is 72.14(10)°.…”

Crystal structures of [M(N3)2(phen)2] compounds, M = Mn, Co or Cu and phen = 1,10-phenanthroline

“…Copper compounds containing 1,10-phenanthroline or its derivatives also exhibit SOD mimetic activity (Devereux et al, 2007;Bijloo et al, 1990). The first chosen ligand, 1,10-phenanthroline (phen), is a strong field bidentate ligand that can form stable chelates with most first row transition metals and many of its compounds exhibit antimicrobial properties (Coyle et al, 2003;Kani et al, 2016). Nitrogen-containing heterocycles, such as 1,10phenanthroline, are electron-deficient aro matic systems and are predetermined for π-π stacking formation as π-acceptors , therefore, compounds of this type are interesting also from the supramolecular chemistry point of view (Sun & Xu, 2010).…”

Synthesis, X-ray structure and theoretical investigation of 2-(2’-quinolyl)benzimidazole metal complexes

“…Nitrogen-based ligands are extensively studied as complexes with many metal ions such as cobalt and manganese. 1,2 Coordination complexes based on nitrogen donor chelate ligands and cobalt or manganese ions, having a number of available oxidation states, have attracted great attention because of their potential applications in various fields of human interest such as antitumor, 3,4 antiviral, 5,6 antifungal and antibacterial 7,8 and antioxidant 9,10 drugs. In addition to the biological importance, diverse catalytic 11,12 and magnetic properties 13,14 of such compounds have been explored.…”