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Journal of Organometallic Chemistry, 2007
The synthesis of three hexadentate Schiff base ligands has been carried out, which contain two sets of ONO donor atoms. These were reacted with diorganotin(IV) dichloride derivatives (R = Me, nBu, Ph) to prepare seven dinuclear diorganotin(IV) complexes in moderate yields. Aside from IR and NMR ( 1 H, 13 C, 119 Sn) spectroscopic studies, mass spectrometry and elemental analysis, four tin complexes were characterized by X-ray diffraction analysis. The spectroscopic analyses showed that in solution the tin atoms have five-coordinate environments with a distorted trigonal bipyramidal geometry. Each tin atom is coordinated to the nitrogen atom and forms covalent bonds with two oxygen atoms and two carbon atoms. Due to the presence of a methylene group as bridge between the two ONO chelates, the overall molecular structures can have cis or trans conformation, having either mirror or C 2 -symmetry. While in solution a fast equilibrium can be supposed, in the solid state different intermediate conformations have been detected. Furthermore, for the dialkyltin derivatives SnÁ Á ÁO intermolecular interactions were found allowing for a dimeric or crinkled polymeric organization, whereas for the diphenyltin derivatives no such interactions were observed.
Bioinorganic Chemistry and Applications, 2003
A number of diorganotin(IV) complexes with Schiffbase have been synthesized and characterized by elemental analysis, conductance measurements, molecular weight determinations, infrared, electronic and multinuclear magnetic resonance (1H, 3C and 119Sn NMR) spectral data. The molar conductivity data shows non-electrolytic nature of complexes. The bidentate nature of the ligands is inferred from IR and NMR spectral studies. The antimicrobial activities of the ligands and their tin complexes have been screened in vitro against the organism Escherichia coli; Staphylococus aureus, Prouteus mirabilis, Bacillus thurengiensis, Penicillium co.,sogenum, Aspergillus niger and Fusarium oxysporum.
Bioinorganic Chemistry and Applications, 2006
Three bidentate Schiff bases having nitrogen and sulphur donor sequences were prepared by condensing S-benzyldithiocarbazate (NH 2 NHCS 2 CH 2 C 6 H 5 ) with heterocyclic aldehydes. The reaction of diphenyltin dichloride with Schiff bases leads to the formation of a new series of organotin(IV) complexes. An attempt has been made to prove their structures on the basis of elemental analyses, conductance measurements, molecular weights determinations, UV, infrared, and multinuclear magnetic resonance ( 1 H, 13 C, and 119 Sn) spectral studies. Organotin(IV) complexes were five-and six-coordinate. Schiff bases and their corresponding organotin complexes have also been screened for their antibacterial and antifungal activities and found to be quite active in this respect.
Applied Organometallic Chemistry, 2007
A series of neutral complexes, namely, [N-(2-hydroxy-4-nitrophenyl)-3-hydroxysalicylideneiminato]- diphenyltin(IV) (Ia), [N-(2-hydroxy-4-nitrophenyl)-3-methoxysalicylideneiminato]diphenyltin(IV) (IIa) and [N-(2-hydroxy-4-nitrophenyl)-3-ethoxysalicylideneiminato]diphenyltin(IV) (IIIa) were prepared by the reaction of diphenyltin dichloride on the corresponding Schiff bases. The Schiff bases were the reaction products of 2-hydroxy-4-nitroaniline and appropriate salicylaldehydes. All the compounds were characterized by elemental analysis, 1H-NMR, 13C-NMR, IR and mass spectroscopy. Compound IIIa was also characterized by single crystal X-ray diffraction and shows a C2NO2 coordination geometry nearly half-way between a trigonal bipyramidal and square pyramidal arrangement. In the solid state, π− π interactions exist between the aniline fragments of neighbouring molecules. Copyright © 2007 John Wiley & Sons, Ltd.
Russian Journal of General Chemistry, 2017
Six new bis-diorganotin(IV) complexes, [(Me 2 Sn) 2 L] (1), [(Et 2 Sn) 2 L] (2), [(n-Bu 2 Sn) 2 L] (3), [(Ph 2 Sn) 2 L] (4), [(n-Oct 2 Sn) 2 L] (5), and [(tert-C 4 H 9) 2 Sn) 2 L] (6), where L = N 1' ,N 4'-bis(2-oxidobenzylidene)succinohydrazide, were synthesized and characterized by elemental analysis, FT-IR, NMR (1 H, 13 C, and 119 Sn) and Mass spectra. Spectroscopic data authenticated the existence of two pentacoordinated tin centers in all complexes, formed via coordination of bis-ONO donor sites with dialkyltin(IV) moieties. Biological screening against selected pathogenic strains of bacteria and fungi revealed high activity of compound 3 against Bacillus subtilis and Aspergillus flavis, it also exhibited highest cytotoxicity against Artemia salina.
Journal of Organometallic Chemistry, 2006
The heterocyclic ligands [1,2,4]triazolo-[1,5-a]pyrimidine (tp) and 5,7-dimethyl-[1,2,4]triazolo-[1,5-a]pyrimidine (dmtp), react with diorganotin dichlorides giving the addition compounds Me 2 SnCl 2 (tp) 2 , Et 2 SnCl 2 (tp) 2 , Me 2 SnCl 2 (dmtp) 2 , Et 2 SnCl 2 (dmtp) 2 , Bu 2 SnCl 2 (dmtp), Ph 2 SnCl 2 (dmtp). The organotin:ligand stoichiometry goes from 1:2 to 1:1 by increasing the steric hindrance of the organic groups bound to tin. The compounds have been characterized by means of infrared, 119 Sn Mö ssbauer and 1 H AND 13 C NMR spectroscopy. The ligands presumably coordinate to tin classically through the nitrogen atom at the position 3. The 1:1 complexes adopt trigonal bipyramidal structures, with the organic groups on the equatorial plane and the ligand in the apical position. All-trans octahedral structures are inferred for the 1:2 complexes, except for Et 2 SnCl 2 (tp) 2 , characterized by a skew-trapezoidal structure. 119 Sn Mö ssbauer measurements, at room temperature, in concomitance with DFT calculations, performed on isomeric structures of R 2 SnCl 2 (tp) 2 (R = Me, Et), allowed us to conclude that the all-trans octahedral coordination induces self-assembly in the solid state, possibly accomplished through p-p stacking interactions among the planar ligands coordinated to the organotin(IV) compound, while the skew-trapezoidal structure attributed to Et 2 SnCl 2 (tp) 2 , induces the formation of monomeric adducts in the solid state. In vitro antimicrobial tests showed that [n-Bu 2 SnCl 2 (dmtp)] has interesting properties as anti Gram-positive and antibiofilm agent.
The synthesis and characterisation of diorganotin(IV) monomeric derivatives of pyridine Schiff bases and pyridinic carboxylic acids are reported. All complexes were characterised by mass spectrometry, elemental analyses, IR spectra, and multinuclear NMR analyses. Among them, complexes 5a, 5d, 5e, 5g, and 6a were also confirmed by X-ray crystallography diffraction analyses, which led to establishing that the tin atom is seven-coordinated and has a distorted pentagonal–bipyramidal coordination environment in the solid state and also revealed that both ligands occupy the equatorial positions and the organic substituents the axial positions. The antioxidant activity of the synthetic derivatives towards 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) as well as the thiobarbituric acid reactive substances (TBARS) assay were determined, and were compared with standard antioxidants, showing a dose-dependent activity in both cases. A prominent response was obtained depending on the substituent. The anti-inflammatory activity was also evaluated on a 12-O-tetradecanoylphorbol-13-acetate (TPA) model of induced acute inflammation. The results of the biological tests are discussed in terms of structural characteristics.