Synthesis,characterization, and in vitro antimicrobial activities of organotin(IV) complexes of Schiff bases with ONO‐type donor atoms

A new series of diorganotin complexes of the type R₂SnL (L¹: N‐(2‐hydroxy‐5‐chlorophenyl)‐ 3‐ethoxysalicylideneimine, R = Me, (Me₂SnL¹), R = n‐Bu, (n‐Bu₂SnL¹), R = Ph, (Ph₂SnL¹), L²: N‐(2‐hydroxy‐4‐nitro‐5‐chlorophenyl)‐3‐ethoxysalicylideneimine, R = Ph, Ph₂SnL², L³: N‐(2‐hydroxy‐4‐nitrophenyl)‐3‐methoxysalicylideneimine, R = Me, (Me₂SnL³), R = n‐Bu, (n‐Bu₂SnL³), L⁴: N‐(2‐hydroxy‐4‐nitrophenyl)‐3‐ethoxysalicylideneimine, R = Me, (Me₂SnL⁴), R = n‐Bu, (n‐Bu₂SnL⁴)) were synthesized and characterized by elemental analysis, infrared (IR), ¹H, and ¹³C NMR mass spectroscopic techniques, and electrochemical measurements. Ph₂SnL¹ and Ph₂SnL² were also characterized by X‐ray diffraction analysis and were found to show a fivefold C₂NO₂ coordination geometry nearly halfway between a trigonal bipyramidal and distorted square pyramidal arrangement. The C Sn C angles in the complexes were calculated using Lockhart's equations with the ¹J(^117/119Sn‐¹³C) and ²J(^117/119Sn‐¹H) values from the ¹H NMR and ¹³C NMR spectra. Biocidal activity tests against several micro‐organisms and some fungi indicate that all the complexes are mildly active against Gram (+) bacteria and the fungi, A. niger and inactive against Gram (−) bacteria. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:373–385, 2010; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20628     

Synthesis and structural characterization of monomeric and polymeric supramolecular organotin(IV) 4-chlorophenylethanoates

Four monomeric [n-Bu₂SnL₂ (1), Et₂SnL₂ (2), Me₂SnL₂ (3), and n-Oct₂SnL₂ (7)] and three polymeric {[n-Bu₃SnL]_n (4), [Me₃SnL]_n (5), and [Ph₃SnL]_n (6)} organotin(IV) carboxylates, where L?=?4-chlorophenylethanoate, were synthesized and characterized by elemental analysis, FT-IR, and multinuclear NMR (¹H, ¹³C, and ¹¹⁹Sn). Compounds 2 and 5 were also analyzed by X-ray single-crystal analysis showing monomeric and zigzag structures, respectively. Two types of O…H (2.641?Å) and Cl…H (2.943?Å) non-covalent interactions generate a 2-D supramolecular structure for 2. Layer-by-layer supramolecular structure was observed for 5 in which polymeric chains are connected via non-covalent interactions {Cl…H (2.869?Å), H…π (2.899?Å)}, and unconventional dihydrogen {H…H (2.381?Å)} interactions.     

Synthesis,crystal structure,and characterization of dimeric tetraorganodistannoxane and two tricyclohexyltin carboxylates

Three diorganotin(IV) series and triorganotin(IV) complexes, [(C₆H₁₁)₂Sn]₄(L₁)₂O₂(OH)₂ (1), (C₆H₁₁)₃Sn(HL₂) (2), and (C₆H₁₁)₃SnL₃ (3) (where HL₁ is 2-(4-isopropyl benzoyl) benzoic acid, H₂L₂ is phthalic acid and HL₃ is 2-benzoyl benzoic acid), were synthesized and their crystal structures were determined. There are four crystallographically unique Sn centers in the structure of 1, which consists of a Sn₄O₂(OH)₂ ladder unit, and the ladder consists of four tins held together by two µ₃-oxygens and two µ₂-oxygens. The supermolecular motif of 1 is a 2-D structure linked by O–H ··· O hydrogen bonds. The asymmetric unit of 2 contains two crystallographically independent monomers. The supramolecular architecture of 2 is a 2-D layer structure linked by face-to-face π–π interactions between phenyl rings of adjacent L₂ anions. The structure of 3 contains one tricyclohexyltin cation and one L₃ anion. The Sn ··· O interactions lead the whole structure to a supramolecular chain. Elemental analysis, infrared, and ¹H NMR of 1–3 were investigated and discussed.     

Syntheses,structural characteristics,and antimicrobial activities of new organotin(IV) 3-(4-bromophenyl)-2-ethylacrylates

New organotin(IV) carboxylates, [n-Bu₂SnL₂] (1), [Et₂SnL₂] (2), [Me₂SnL₂] (3), [n-Oct₂SnL₂] (4), [n-Bu₃SnL] _n (5), [Me₃SnL] _n (6), and [Ph₃SnL] _n (7), where L?=?3-(4-bromophenyl)-2-ethylacrylate, were synthesized and characterized by elemental analysis, FT-IR, and multinuclear NMR (¹H, ¹³C, and ¹¹⁹Sn). Spectroscopic studies confirm coordination of L to the organotin moiety via COO group. Single-crystal X-ray analysis reveals bridging mode of coordination in 6. Packing diagram established a supramolecular cage-like structure for 6 due to Sn–O interactions (3.287?Å). Subsequent antimicrobial activities proved them to be active biologically.     

Synthesis of new functionalized 5,5-dimethyl-1-pyrroline 1-oxides and their investigation as spin traps

The reactions of 5,5-dimethyl-3-oxo-1-pyrroline 1-oxide (3-oxo-DMPO, 1) with NH₂OH and N₂H₄ afforded oxime (2a) and hydrazone (2b), respectively. The reaction products were studied as spin traps for the short-lived radicals HO^·, Ph^·, PhCO₂ ^·, NC(Me₂)C^·, and NC(Me₂)CO^·. The nitroxides generated in the reactions of the above-mentioned short-lived radicals with nitrones 1 and 2a,b were characterized by ESR spectroscopy. Of these nitrones, oxime 2a is the most effective radical trap.     

Synthesis,spectroscopic characterization,X-ray crystal structure,biological screening and catalytic studies of organotin(IV) carboxylates of 3-(4-cyanophenyl) acrylic acid

A series of six organotin(IV) carboxylates [Me₂SnL₂] (1), [n-Bu₂SnL₂] (2), [n-Oct₂SnL₂] (3), [Me₃SnL] (4), n-Bu₃SnL (5) and [Ph₃SnL] (6), where L = 3-(4-cyanophenyl) acrylic acid have been synthesized and characterized by elemental analysis, FT-IR and NMR (¹H, ¹³C). The complex (4) was also analyzed by single crystal X-ray analysis which showed distorted trigonal bipyramidal geometry with polymeric bridging behavior. The complexes 1–6 were screened for antimicrobial activities and cytotoxicity. The results showed significant activity with few exceptions. The catalytic activity of complexes was assessed in transesterification reaction of Brassica campestris oil (triglycerides) to produce biodiesel (fatty acid methyl esters). The results showed that triorganotin(IV) complexes exhibited good catalytic activity than their di-analogues.     

Re-visiting of 5-[(E)-2-(aryl)-1-diazenyl]-quinolin-8-ol with tweaking of Sn-Ph groups: Synthesis, spectroscopic characterization and X-ray crystallography

Reactions of sodium 5-[(E)-2-(aryl)-1-diazenyl]quinolin-8-olates (LH, where the aryl group is an R-substituted phenyl ring such that for L¹H: R = H; L²H: R = 2′-CH₃; L³H: R = 3′-CH₃; L⁴H: R = 4′-CH₃; L⁵H: R = 4′-OCH₃ and L⁶H: R = 4′-OC₂H₅) with Ph₃SnCl in a 1:1 molar ratio yielded complexes of composition Ph₃SnL. The complexes have been characterized by ¹H, ¹³C, ¹¹⁹Sn NMR, IR and ^119mSn Mössbauer spectroscopic techniques in combination with elemental analyses. The crystal structures of Ph₃SnL¹ · 0.5C₆H₆ (1), Ph₃SnL² (2), Ph₃SnL⁵ · C₆H₆ (5) and Ph₃SnL⁶ · 0.5C₆H₆ (6) were determined. The results of the X-ray studies indicated that the benzene solvated compounds 1, 5 and 6 are distorted square pyramid, with one of the phenyl C atoms in the apex while the ligand arrangement around central Sn atom in 2 is distorted trigonal-bipyramidal, with a phenyl C and the oxinato N atoms in axial positions.     

Binary and ternary oxorhenium(V) complexes: synthesis,characterization, and crystal structure

A series of anionic five-coordinate binary oxorhenium(V) complexes with dithiolato ligands, Bu₄N[ReO(L¹)₂] (1a), Bu₄N[ReO(L²)₂] (1b), and Bu₄N[ReO(L³)₂] (1c), and a series of neutral octahedral ternary oxorhenium(V) complexes of mixed dithiolato and bipyridine ligands, [ReO(L¹)(bpy)Cl] (2a), [ReO(L²)(bpy)Cl] (2b), and [ReO(L³)(bpy)Cl] (2c) (where L¹H₂ = ethane-1,2-dithiol, L²H₂ = propane-1,3-dithiol, L³H₂ = toluene-3,4-dithiol, and bpy = 2,2′-bipyridine), were isolated and characterized by physicochemical and spectroscopic methods. The solid state structure of 1c was established by X-ray crystallography. All the mononuclear oxorhenium(V) complexes are diamagnetic. The redox behavior of all the complexes has been studied voltammetrically.     

Biological studies of organotin(IV) complexes with 2-mercaptopyrimidine

The known organotin(IV) complexes with 2-mercaptopyrimidine (L) [Me₂SnL₂] (1), [Buⁿ ₂SnL₂] (2), [Ph₂SnL₂] (3), and [Ph₃SnL] (4) were synthesized using a new approach. The effect of the synthesized compounds on peroxidation of fatty acids (oleic and linoleic) was studied. Complexes 1–4 promote the peroxidation of oleic acid. Their effect on the enzymatic peroxidation of linoleic acid with lipoxygenase was compared with that of cisplatin and in vitro cytoxicity against sarcoma cancer cells was determined. The antiproliferative effect of complexes 2–4 was demonstrated. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 737–743, April, 2007.     

Ten complexes constructed by two reduced Schiff base tetraazamacrocycle ligands: syntheses,structures, magnetic and luminescent properties

Ten new complexes, [Cu₂(L¹)(NO₃)₂]·2H₂O (1), [Cu₄(L¹)₂]·4ClO₄·H₂O (2), [Cu₂(L¹)(H₂O)₂]·(adipate) (3), [Cu₆(L¹)₂(m-bdc)₄]·2DMF·5H₂O (4), [Cu₂(L¹)(Hbtc)]·5H₂O (5), [Cu₂(L¹)(H₂O)₂]·(ntc)·3H₂O (6), [Co₂(L²)]·[Co(MeOH)₄(H₂O)₂] (7), [Co₃(L²)(EtOH)(H₂O)] (8), [Ni₆(L²)₂(H₂O)₄]·H₂O (9) and [Zn₄(L²)(OAc)₂]·0.5H₂O (10), have been synthesized. 1 displays a [Cu₂(L¹)(NO₃)₂] monomolecular structure. 2 shows a supramolecular chain including [Cu₂L¹]²⁺. In 3, two Cu(II) ions are connected by L¹ to form a [Cu₂(L¹)(H₂O)₂]²⁺ cation. In 4, the m-bdc anions bridge Cu(II) ions and L¹ anions to form a layer. Both 5 and 6 display 3-D supramolecular structures. 7 consists of both [Co₂L²]^2? and [Co(MeOH)₄(H₂O)₂]²⁺ units. 8 and 9 show infinite chain structures. In 10, Zn(II) dimers are linked by L² to generate a 3-D framework. The magnetic properties for 4 and 8 and the luminescent property for 10 have been studied.     

Electrochemical Synthesis and Characterization of Tin(IV) Complexes of Dianionic Terdentate Schiff Base Ligands

Tin(IV) complexes of the series of dianionic terdentate Schiff bases N‐[(2‐pyrroyl)methylidene]‐N′‐tosylbenzene‐1,2‐diamine, (H₂L¹), N‐[(2‐hydroxyphenyl)methylidene]‐N′‐tosylbenzene‐1,2‐diamine (H₂L²) and some R substituted 2‐{[(2‐hydroxyphenyl)imino]methyl}phenols [R = H (H₂L³), 4,6‐(OCH₃)₂ (H₂L⁴), 3‐(OC₂H₅) (H₂L⁵) and 3,5‐Br₂ (H₂L⁶)] have been synthesized. The compounds were obtained by the electrochemical oxidation of a tin anode in a cell containing an acetonitrile solution of the corresponding ligand. The complex [SnL¹₂] was also obtained by reaction of SnCl₂·2H₂O and H₂L¹ in methanol in the presence of triethylamine. The crystal structure of the ligand [H₂L⁶] and the complexes [SnL¹₂] (1) , [SnL²₂] (2) , [SnL³₂] (3) and [SnL⁶₂] (6) were determined by X‐ray diffraction. In the complexes, the tin atom is in an octahedral environment coordinated by two dianionic terdentate ligands. Spectroscopic data for the complexes (IR, ¹H and ¹¹⁹Sn NMR and mass spectra) are discussed and related to structural information.     

Mercapto derivatives of triorganotin Y,C,Y-pincer complexes: Role of Y,C,Y-chelating ligands in a new coordination mode of organotin compounds

We report the use of triorganotin fragments R₂L^1-2Sn containing N,C,N and O,C,O-ligands L^1-2(L¹ = C₆H₃(Me₂NCH₂)₂-2,6⁻, L² = C₆H₃(^tBuOCH₂)₂-2,6⁻) on stabilization of both thiol-form in R₂L^1-2Sn-2-SPy (2-SPy = pyridine-2-thiolate) and thione-form in R₂L^1-2Sn(mimt) (mimt = 1-methylimidazole-2-thiolate) of the polar groups. Treatment of ionic organotin compounds [Me₂L¹Sn]⁺[Cl]⁻ (1) and [Ph₂L²Sn]⁺[OTf]⁻ (2) with appropriate sodium salts Na-2-SPy and Na(mimt) resulted in the isolation of Me₂L¹Sn-2-SPy (3), Ph₂L²Sn-2-SPy (4), Me₂L¹Sn(mimt) (5), Ph₂L²Sn(mimt) (6). While polar group 2-SPy exists in its thiol-tautomeric form in compounds 3 and 4, the second polar group (mimt) has been stabilized as the thione-tautomeric form by triorganotin fragments R₂L^1-2Sn in compounds 5 and 6. The products were characterized by ¹H, ¹³C and ¹¹⁹Sn NMR and IR spectroscopy, ESI/MS, elemental analyses and structures of 3, 6 were determined by X-ray diffraction study. The reactivity of compound 4 containing non-coordinated nitrogen atom of 2-SPy polar group towards CuCl and AgNO₃ is also reported. The reactions led to isolation of organotin compounds Ph₂L²SnCl (7) and Ph₂L²SnNO₃ (8) as the result of polar group transfer. The mechanism of this reaction has been investigated and compounds Ph₃Sn-2-SPy (9) and Ph₂L²Sn-4-SPy (10) (4-SPy = pyridine-4-thiolate) have been prepared for this purpose.     

Four silver-containing coordination polymers based on bis(imidazole) ligands

Four coordination polymers, [Ag(L¹)](m-Hbdc) (1), [Ag(L¹)]₂(p-bdc)?·?8H₂O (2), [Ag(Hbtc)(L¹)][Ag(L¹)]?·?2H₂O (3) and [Ag₂(L²)₂](OH-bdc)₂?·?4H₂O (4), where L¹?=?1,1′-(1,4-butanediyl)bis(imidazole), L²?=?1,2-bis(imidazol-1-ylmethyl)benzene, m-H₂bdc?=?1,3-benzenedicarboxylic acid, p-H₂bdc?=?1,4-benzenedicarboxylic acid, H₃btc?=?1,3,5-benzenetricarboxylic acid, and OH–H₂bdc?=?5-hydroxisophthalic acid, were synthesized under hydrothermal conditions. Compound 1 contains a–Ag-L¹–Ag-L¹–chain and a hydrogen-bonding interaction induced–(m-Hbdc)-(m-Hbdc)–chain. Compound 2 consists of two independent–Ag-L¹–Ag-L¹–chains. P-bdc anions are not coordinated. Hydrogen bonds form a 3D supramolecular structure. A novel (H₂O)₁₆ cluster is formed by lattice water molecules in 2. Compound 3 contains a–Ag-L¹–Ag-L¹–and a–Ag(Hbtc)-L¹–Ag(Hbtc)-L¹–chain. The packing diagram shows a 2D criss-cross supramolecular structure, with?π?···?π?and C–H ···?π?interactions stabilizing the framework. Compound 4 contains a [Ag₂(L²)₂]²⁺ dimer with hydrogen-bonding,?π?··· π, and Ag ··· O interactions forming a 3D supramolecular framework. The luminescent properties for these compounds in the solid state are discussed.     

Two non-interpenetrating 3D coordination networks with (3, 4)-connected topologies

Two new coordination polymers, namely [Zn₃(1,3,5-BTC)₂(L¹)₂(H₂O)₂] · 2H₂O (1) and [Cd₃(1,2,3-BTC)₂(L²)₃] · H₂O (2) (where L¹ = 1,2-bis(imidazol-1-ylmethyl)benzene, L² = 1,1′-(1,4-butanediyl)bis(imidazole), 1,3,5-H₃BTC = 1,3,5-benzenetricarboxylic acid and 1,2,3-H₃BTC = 1,2,3-benzenetricarboxylic acid), were synthesized in hydrothermal conditions. In 1, each 1,3,5-BTC anion coordinates to three Zn cations, and the framework of 1 can be simplified as (6 · 8 · 10)₂(6² · 8 · 10³)(8² · 10)(6² · 10) topology. In 2, 1,2,3-BTC anions coordinate to three cadmiums, and the whole structure displays a (6² · 8⁴)₂(6⁴ · 8 · 10)(6² · 8)₂ network containing three different types of nodes. The luminescent properties for 1 and 2 are discussed.     

Biological evaluations and spectroscopic characterizations of 3-(4-ethoxyphenyl)-2-methylacrylate based organotin(IV) carboxylates derivatives

Six new organotin(IV) carboxylates, [Me₂SnL₂] (1), [n-Bu₂SnL₂] (2), [n-Oct₂SnL₂] (3), [Me₃SnL] (4), [n-Bu₃SnL] (5) and [Ph₃SnL] (6), where L = 3-(4-ethoxyphenyl)-2-methylacrylate, have been synthesized and characterized by FT-IR, NMR spectroscopy and elemental analyses. The synthesized compounds were tested for in vitro antibacterial and antifungal activities. The complexes 4–6 demonstrated higher activity than the complexes 1–3. UV-Vis absorption spectroscopy indicated that the ligand and its complexes interacted with DNA via partial intercalation as well as minor groove binding.

     

Dithiobiuretes in reactions with electrophilic acetylenes. New derivatives of 1,3,5-dithiazines,-thiadiazines and-triazines as the products of competing reactions of nucleophilic cycloaddition

The nucleophilic addition of 2,4-dithiobiurete, 1- and 1,4-substituted 2,4-dithiobiuretes (2 a-e) with benzoylacetylene (1) has been studied. 2-(Benzoylmethyl)-4-(R¹-imino)-6-(R²-imino)dihydro-4H-1,3,5-dithiazinium perchlorates (3 a-e) are obtained in glacial acetic acid (AcOH) in the presence of equimolar quantities of HClO₄. The reaction of benzoylacetylene with 1,5-diphenyl-2,4-dithiobiurete in either of MeOH, C₆H₆, or MeCN solvents proceeds non-selectively to give a mixture of products such as 2-(benzoylmethyl)-4,6-di(phenylimino)dihydro-4H-1,3,5-dithiazine (5), 2-(benzoylmethyl)-4-(β-benzoylvinyl)thio-3-phenyl-6-(phenylimino)-3,6-dihydro-2H-1,3,5-thiadiazine (8), 2-(benzoylmethyl)-1,3-diphenylhexahydro-1,3,5-triazine-4,6-dithione (7) and N-(β-benzoylvinyl)-N-phenylthioureas (6).     

Synthesis and Characterization of Triphenyltin(IV) Carboxylates with Isophthalic Acid and Benzoic Acid Derivatives: X‐ray Crystal Structures of 1D Supramolecular Chains

The reaction of triphenyltin(IV) hydroxide with the isophthalic acid and benzoic acid derivatives, 5‐(1,3‐dioxo‐1,3‐dihydro‐isoindol‐2‐yl)‐isophthalic acid (H₂L¹) and 4‐(1,3‐dioxo‐1,3‐dihydro‐isoindol‐2‐yl)‐benzoic acid (HL²) yielded the complexes [(SnPh₃)₂L¹] ( 1 ) and [(SnPh₃)L²] ( 2 ). All complexes were characterized by elemental analysis and FT‐IR and NMR (¹H, ¹³C, ¹¹⁹Sn) spectroscopy. Interestingly, the supramolecular structures of 1 and 2 are found to consist of 1D molecular chains built up by intermolecular C–H ··· O hydrogen bonds. Their thermal stabilities were also investigated.     

New diorganotin(IV) complexes with some Schiff bases derived from β-diketones: synthesis,spectral properties,thermal analysis,and antibacterial activity

The Schiff bases H₂L^a, H₂L^b, and H₂L^c have been prepared from the reaction of 2-amino-4-chlorophenol with acetylacetone, benzoylacetone, and dibenzoylmethane, respectively. Organotin(IV) complexes [SnPh₂(L^a)] (1), [SnPh₂(L^b)] (2), [SnPh₂(L^c)] (3), and [SnMe₂(L^c)] (4) have been synthesized from the reaction of SnPh₂Cl₂ and SnMe₂Cl₂ with these Schiff bases. The synthesized complexes have been characterized by elemental analysis and FT-IR, ¹H, ¹³C, and ¹¹⁹Sn NMR spectroscopy. Spectroscopic data suggest the Schiff bases are completely deprotonated and coordinated tridentate to tin via imine nitrogen and phenolic and enolic oxygen atoms; the coordination number of tin is five. Thermal decomposition of the complexes has been studied by thermogravimetry. The in vitro antibacterial activities of the Schiff bases and their complexes have been evaluated against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. H₂L^a, H₂L^c, and all complexes exhibited good activities and have potential as drugs.     

Synthesis,structures, and urease inhibition of nickel(II), zinc(II), and cobalt(II) complexes with similar hydroxy-rich Schiff bases

Four new nickel(II), zinc(II), and cobalt(II) complexes, [Zn(L¹)₂]?·?H₂O (1), [Ni(L¹)₂]?·?H₂O (2), [Ni(L²)₂] (3), and [Co(L³)₂]?·?H₂O (4), derived from hydroxy-rich Schiff bases 2-{[1-(5-chloro-2-hydroxyphenyl)methylidene]amino}-2-methylpropane-1,3-diol (HL¹), 2-{[1-(2-hydroxy-3-methoxyphenyl)methylidene]amino}-2-ethylpropane-1,3-diol (HL²), and 2-{[1-(5-bromo-2-hydroxyphenyl)methylidene]amino}-2-methylpropane-1,3-diol (HL³) have been synthesized and characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray determination. Each metal in the complexes is six-coordinate in a distorted octahedral coordination. The Schiff bases coordinate to the metal atoms through the imino N, phenolate O, and one hydroxyl O. In the crystal structures of HL¹ and the complexes, molecules are linked through intermolecular O–H···O hydrogen bonds, forming 1-D chains. The urease inhibitory activities of the compounds were evaluated and molecular docking study of the compounds with the Helicobacter pylori urease was performed.     

Diorganotin Complexes with N(4)-Phenylthiosemicarbazones: Synthesis,Spectroscopic Characterization,and Antibacterial Activity

Abstract

The organotin(IV) complexes, SnPh₂L^a (1), SnMe₂L^a (2), SnBu₂L^a (3), SnPh₂L^b (4), SnMe₂L^b (5), SnPh₂L^c (6), SnMe₂L^c (7), and SnBu₂L^c (8) were obtained by reaction of SnR ₂Cl₂ (R = Ph, Me, and Bu) with 1-(5-bromo-2-hydroxybenzylidene)-4-phenylthiosemicarbazide (H₂L^a), 1-((2-hydroxynaphthalen-1-yl)methylene)-4-phenylthiosemicarbazide (H₂L^b), and 1-(2-hydroxy-3-methoxybenzylidene)-4-phenylthiosemicarbazide (H₂L^c). The synthesized complexes have been investigated by elemental analysis, IR, ¹H NMR, and ¹¹⁹Sn NMR spectroscopy. The data show that the thiosemicarbazone acts as a tridentate dianionic ligand and coordinates via the thiol group, imine nitrogen, and phenolic oxygen. The coordination number of tin is 5. The in vitro antibacterial activities of the ligands and their complexes have been evaluated against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria and compared with the standard antibacterial drugs.

[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 following free supplemental files: Additional figures and tables]