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New diorganotin(IV) complexes (R2SnL, where R is Me, Et, Bu, and Ph) of Schiff base ligands N'-(2-hydroxybenzylidene)-3-methoxybenzohydrazide (H2L1), N'-(5-chloro-2-hydroxybenzylidene)-3-methoxybenzohydrazide (H2L2), N'-(2-hydroxy-5-nitrobenzylidene)-3-methoxybenzohydrazide (H2L3), and N'-(4-(diethylamino)-2-hydroxybenzylidene)-3-methoxybenzohydrazidefrom (H2L4) derived from 3-methoxybenzohydrazide with salicylaldehyde and its derivatives were synthesized. The ligands and their metal complexes were structurally characterized by spectroscopic techniques (FT-IR, 1H, 13C, and 119Sn NMR), elemental analysis, mass spectrometry, melting point, and molar conductance studies. The spectral data showed that ligands are coordinated to the tin atom in a tridentate manner with N and O donor sites of the azomethine-N, enolic-O, and aromatic hydroxyl-O to form a penta-coordinated geometry around central tin atom. The molar conductance data revealed that all compounds are non-electrolytes. In vitro antimicrobial activities of compounds were determined against various pathogens with reference to standard antibiotics which showed that compounds (12) (Ph2SnL2) and (16) (Ph2SnL3) are the most potent antimicrobial agents. Furthermore, the compounds were evaluated for antioxidant activity by using DPPH assay. The results obtained emphasized that the phenyl derivatives of complexes have enhanced antimicrobial and antioxidant activities as compared to other complexes. To check the drug-likeness, in silico studies of the synthesized compounds were carried out which described that all the compounds except (12) (Ph2SnL2), (19) (Bu2SnL4), and (20) (Ph2SnL4) can be used as orally active drugs. [ABSTRACT FROM AUTHOR]

The goal of this research work is to create a new class of diorganotin(IV) complexes with general formula R2SnL1-4, where R = CH3, C2H5, C4H9 & C6H5, and L1-4 are the Schiff base ligands derived from the condensation of indole-3-acetic acid hydrazide with salicylaldehyde derivatives in 1:1 molar ratio. Various spectral (FTIR, NMR and mass spectrometry) and physico-chemical (XRD, TGA) techniques were utilized to identify the structure of the prepared compounds. Spectroscopic evidence suggests that Schiff base ligands coordinate to the central tin atom in a tridentate manner with ONO as the donor site, thus forming a pentacoordinate environment around the metal ion. The serial dilution method was employed for carrying out the antimicrobial activity of the produced compounds against four bacterial strains and two fungal strains. The observed results of biocidal activity showed that compounds Ph2SnL3 (16) and Ph2SnL4 (20) were found to be most potent against the tested strains. Further, molecular docking studies for active compounds i.e., 16 and 20 were carried out in the active site of Escherichia coli 3-oxoacyl-[acyl-carrier-protein] synthase 2 (FabF). To check the drug-likeness, in silico studies of the synthesized compounds was carried out and it has been found that compounds can be used as orally active drugs. [ABSTRACT FROM AUTHOR]

We have synthesized new diorganotin(IV) complexes of the type R2SnL (where R; methyl, ethyl, butyl and phenyl) of Schiff base ligands N'-(5-chloro-2-hydroxybenzylidene)thiophene-2-carbohydrazide (H2L1), N'-(4-(diethylamino)-2-hydroxybenzylidene)thiophene-2-carbohydrazide (H2L2), N'-(3,5-dibromo-2-hydroxybenzylidene)thiophene-2-carbohydrazide (H2L3) and N'-(2-hydroxy-5-methoxy-3-nitrobenzylidene)thiophene-2-carbohydrazide (H2L4). Spectroscopic methods (FT-IR, UV–vis, 1H, 13C and 119Sn NMR), elemental analysis, mass spectrometry, melting point and molar conductance measurements were used to elucidate the structures of compounds (1-20). The spectroscopic data indicated that the Schiff bases are tridentate (NOO) in nature and coordinated to the tin metal through enolic oxygen, azomethine nitrogen and aromatic hydroxyl oxygen donor atoms to display pentacoordinated geometry around the central tin metal. To examine the biological profile, the synthesized compounds were tested for in vitro antimicrobial activity against different bacterial and fungal strains by using serial dilution method which revealed that compounds Bu2SnL3 (15) and Ph2SnL3 (16) were most active antimicrobial agent. The compounds were further tested for antioxidant activity by using DPPH (1,1-diphenyl-2-picrylhydrazyl) assay. Complex Ph2SnL3 (16) exhibited highest antioxidant potential with lowest IC50 value (2.95 μM) among all the tested compounds. [ABSTRACT FROM AUTHOR]

A series of diorganotin(IV) complexes of type R2SnL, (where R = Me, Et, Bu and Ph) were prepared by the reaction of tridentate (NOO) donor Schiff base ligands with diorganotin(IV) dichloride in an equimolar ratio. The products were characterized by various spectroscopic techniques and physical and analytical methods (UV–vis, FTIR, NMR, fluorescence, elemental analysis). Spectroscopic data suggest that the Schiff base acts as a tridentate ligand (NOO) coordinated with a central tin atom via two oxygen and one imine nitrogen atom in a pentacoordinated fashion. The synthesized compounds were assayed for their in vitro antimicrobial activity against bacterial and fungal strains. All the compounds displayed promising results with the complexes being more potent than free ligands. The antioxidant activity of the compounds was determined by interaction with 2,2-diphenyl-1-picrylhydrazyl free radical. Complex Ph2SnL3 (16) was found to have the most potential antimicrobial activity against all tested strains and also exhibited excellent antioxidant activity. Quantitative structure–activity relationship of compounds was studied for antimicrobial activity with molar refractivity indices as significant statistical parameter. [ABSTRACT FROM AUTHOR]

Hexacoordinated organosilicon complexes of type R3Si(L) (R = ethyl, butyl, phenyl; HL = ligand, obtained by the condensation of 4-aminoantipyrine with 2-hydroxyacetophenone, 2-hydroxybenzophenone, 2-hydroxybenzaldehyde, and 2-hydroxynapthaldehyde) have been synthesized and characterized by elemental analysis, molar conductance, and spectroscopic studies (IR, 1H, 13C, and 29Si NMR). The spectroscopic studies indicated that the ligands acted as tridentate coordinating through azomethine nitrogen, carbonyl oxygen, and oxygen of hydroxyl after deprotonation to the central silicon atom. The ligands and their organosilicon complexes have been evaluated for antimicrobial activities against fungi (Aspergillus niger and Candida albicans), and against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis), and Gram-negative bacteria (Escherichia coli). The aim of the present work is to synthesize novel eco-friendly fungicides and bactericides and to study the effect of the biological activity of ligands on the complexation with organosilicon moiety. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. [ABSTRACT FROM AUTHOR]

The Schiff bases derived from the condensation of 2-aminobenzothiazole derivatives and 2-hydroxy-3-methoxybenzaldehyde and their silicon(IV) complexes with the general formula R2Si(L)Cl (R = Et, Bu, Ph, L = 2-(2-hydroxy-3-methoxy) benzylideneaminobenzo-thiazole) have been synthesized. These complexes have been characterized by elemental analysis, molar conductance, and spectroscopic studies including IR and NMR (1H, 13C, and 29Si) spectroscopy. The analytical data suggest trigonal bipyramidal geometry around the silicon atom in the resulting complexes. The ligands and their organosilicon complexes have also been evaluated for in vitro antimicrobial activity against bacteria (Staphylococcus aureus, Bacillus subtilis, and Escherichia coli) and fungi (Aspergillus niger and Candida albicans). The complexes were found to be more potent as compared to the ligands. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. [ABSTRACT FROM PUBLISHER]