Synthesis, spectral studies and in vitro antimicrobial activity of some new di/tri-organotin (IV) complexes of Schiff bases derived from 2-benzoylpyridine

Abstract

In the present work, a series of twenty-four organotin(IV) complexes of the type [R 2 SnClL, R 3 SnL] were synthesized by the condensation of 2-benzoylpyridine Schiff bases with R 2 SnCl 2 , R 3 SnCl (R = Me, n-Bu or Ph) in 1:1 mole ratio. These complexes were well characterized by IR, 1 Hand nd 13 C-, 119 Sn-NMR, XRD and mass spectral techniques. In the search for biologically more effective antimicrobial agents, all the synthesized ligands and organotin complexes were evaluated for their in vitro antimicrobial activities against two Gram-positive and two Gram-negative bacteria, and two fungal strains by the serial dilution method. The results of spectral data revealed that the formed complexes were hexacoordinated with tridentate ligands coordinated through azomethine N, pyridine N and carboxylate O ligation sites. The ligands on coordination with tin metal showed a discernible augmentation in biocidal activity; however, the Ph and Bu complexes were found to be more intoxicating. The results revealed that the synthesized complexes were more noxious towards Gram-positive strains as compared to Gram-negative strains, which may be attributed to the presence of the outer lipid membrane of lipopolysaccharides.

Some Aromatic Schiff Bases and Their Metal Complexes

“…Schiff bases containing N donors and their metal complexes showed to be promising candidates for fighting against drug resistance, which many microorganisms have developed toward the drugs used [32,33]. One of the good precursors for the synthesis of potentially biologically active imine derivatives is 2-acetylpyridine.…”

Synthesis and Characterization of Dimeric Thio-Schiff Bases by Nano Cerium Oxide and Examination of Their Antimicrobial Activities

“…1 HNMR (400 MHz, CDCl3, δ): 7.19 -7.07 (m, 2H), 6.66 (dd, 1H,J = 8.5, 1.3 Hz), 6.56 (td, 1H, J = 7.5, 1.2 Hz), 4.31 (s, 2H). 13 7.65 (dd, 1H, J = 7.7, 1.5 Hz), 7.53 (d, 1H, J = 5.0 Hz), 7.51 (d, 1H, J = 3.6 Hz), 7.15 (dd, 2H, J = 7.4, 1.7 Hz), 7.12 (dd, 1H, J = 3.4, 1.4 Hz), 7.01 (dd, 1H, J = 7.4, 1.6 Hz). 13…”

Correlating Structure and KA2 Catalytic Activity of ZnII Hydrazone Complexes

“…[1][2][3][4][5][6] Deprotonation of the À NH group results in the formation of keto-enol tautomerism (=NÀ N À À C=X or =NÀ N=CÀ X À ) and can create a different tridentate NNX donor modes (X = O, S). [7][8][9][10][11] Zn II has the ability to form complexes with different coordination numbers and different types of geometries, while the flexibility of this type of multidentate-ligands allows these complexes to act as good catalysts in many catalytic organic transformations. [12] Com-plexes encompassing NNX tridentate carbazone ligands form different types of coordination geometries.…”

“…Zn II complexes with hydrazone ligands bearing a NNO or NNS donor set of atoms have been the subject of studies over many years for their applications in diverse fields [1–6] . Deprotonation of the −NH group results in the formation of keto‐enol tautomerism (=N−N − −C=X or =N−N=C−X − ) and can create a different tridentate NNX donor modes (X=O, S) [7–11] . Zn II has the ability to form complexes with different coordination numbers and different types of geometries, while the flexibility of this type of multidentate‐ligands allows these complexes to act as good catalysts in many catalytic organic transformations [12] .…”