Synthesis,characterization, reactivity,and antifungal activity of chlorobis(2,4-dinitrophenoxo) monooxovanadium(V)

[VOCl(OC₆H₃(NO₂)₂-2,4)₂] (1) has been synthesized by the reaction of VOCl₃ with bimolar amounts of Me₃SiOC₆H₃(NO₂)₂-2,4 in toluene and characterized by elemental analyses, molar conductance, infrared (IR), ¹H and ¹³C NMR and mass spectral, and thermal studies. Molecular modeling dynamics of the complex suggests tetrahedral geometry around vanadium. The reaction of 1 with sodium alkoxides, NaOR (OR?=?OMe (methoxy); OEt (ethoxy), OBuⁿ(n-butoxy); OPrⁱ (isopropoxy); and OAmⁱ(isoamyloxy)) afforded mixed alkoxo–phenoxo complexes, [VO(OR)(OC₆H₃(NO₂)₂-2,4)₂] authenticated by physicochemical and IR spectral studies. The antifungal activities of the ligand and complexes against three fungi, namely Aspergillus niger, Byssachlamys fulva, and Mucor circinelloides have been assayed by the minimum inhibitory concentration method. The complexes have improved antifungal activity compared to free ligand.     

Synthesis,characterization, and antibacterial activity of organotin(IV) complexes with 2-hydroxyacetophenone thiocarbohydrazone

Six new organotin(IV) complexes were synthesized by direct reaction of RSnCl₃ (R?=?Me, Bu and Ph) or R₂SnCl₂ (R?=?Me, Bu and Ph) and 2-hydroxyacetophenone thiocarbohydrazone [H₂APTC] under purified nitrogen in the presence of base in 1?:?2?:?1 molar ratio (metal: base: ligand). Complexes 2–7 have been characterized by elemental analyses, molar conductivity, UV-Visible, IR and ¹H NMR spectral studies. Complexes 2–7 are non-electrolytes. The molecular structure of [Me₂Sn(APTC)]?·?(C₂H₅OH) (5) has been determined by X-ray diffraction analysis. The thiocarbohydrazone ligand (1) and 2–7 have been tested for antibacterial activity against Escherichia coli, Staphylococcus aureus, Salmonella typhi and Enterococci aeruginosa.     

Synthesis,characterization, antibacterial,and cytotoxic activities of organotin(IV) complexes derived from N(4)-cyclohexylthiosemicarbazone: X-ray crystal structure of [Ph2SnCl(L)]

Reaction of organotin(IV) chloride(s) with 2-benzoylpyridine-N(4)-cyclohexylthiosemicarbazone, [HL] (1) yielded [MeSnCl₂(L)] (2), [BuSnCl₂(L)] (3), [Me₂SnCl(L)] (4), and [Ph₂SnCl(L)] (5). The ligand (1) and its organotin(IV) complexes have been characterized by CHN analyses, molar conductivity, UV-Vis, FT-IR, ¹H, ¹³C, and ¹¹⁹Sn NMR spectral studies. The molecular structure of 5 was also determined by X-ray diffraction. There are two independent molecules in the asymmetric unit and the central tin(IV) atom is six-coordinate in distorted octahedral geometry. The ligand (1) and complexes were screened for their in vitro antibacterial activities. The cytotoxic activities of 1–5 were tested against A2780 and A2780/Cp8 cancer cell lines. The compounds have better antibacterial activities than the free ligand; 2–5 are more potent cytotoxic agents than 1, while the diphenyltin(IV) 5 is more active with IC₅₀ values of 0.05 and 0.54?µmol?L^?1 against A2780 and A2780/Cp8 cell lines, respectively.     

Organotin(IV) complexes with pyruvic acid phenylhydrazone (HPAPD): synthesis,spectral characterization,and in vitro antibacterial activity

The reaction of pyruvic acid phenylhydrazone [HPAPD, (1)] with organotin(IV) chloride(s) leads to the formation of five new organotin(IV) complexes: [MeSnCl₂(PAPD)] (2), [BuSnCl₂(PAPD)] (3), [PhSnCl₂(PAPD)] (4), [Me₂SnCl(PAPD)] (5), and [Ph₂SnCl(PAPD)] (6). The ligand [HPAPD, (1)] and its organotin(IV) complexes (2–6) have been characterized by CHN analyses, molar conductivity, UV-Vis, FT-IR, ¹H, ¹³C, and ¹¹⁹Sn NMR spectral studies. Spectroscopic data suggested that HPAPD is coordinated to tin(IV) through the carboxylato-O and azomethine-N as a mononegative bidentate chelating agent; the coordination number of tin is five. Compound 1 and its organotin(IV) complexes (2–6) were assayed for in vitro antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Enterobacter aerogenes, Escherichia coli, and Salmonella typhi. The screening results show that 2–6 have better antibacterial activity than 1 and that 6 exhibits significantly better activity than 2–5.     

Synthesis,characterization, electrochemical study,and antimicrobial activity of bis(benzoylacetonato) vanadium(IV) complexes of biphenylphenols

New non-oxovanadium(IV) complexes of biphenylphenols, [VCl_{2? n} (bzac)₂(OAr^1,2) _n ], have been synthesized in quantitative yields from the reaction of bis(benzoylacetonato)dichlorovanadium(IV) with the trimethylsilyl derivative of 2- and 4-phenylphenols in carbon tetrachloride. The complexes have been characterized by physicochemical, magnetic moment measurements, IR, mass spectra, and electrochemical studies. The thermal behavior of the complexes has been studied by TGA–DTA. The complexes have been screened for their antimicrobial activity against some pathogenic bacteria, Escherichia coli and Staphylococcus aureus and fungi, Candida albicans, Aspergillus niger, and Fusarium oxysporum, by two-fold serial dilution.     

Antimicorbial effects of newly synthesized organotin(IV) and organolead(IV) derivatives

Triorganotin(IV) and triorganolead(IV) derivatives of the types Me₃Sn(SCZ) and Ph₃Pb(SCZ) (where SCZ^? is the anion of a semicarbanzone ligand) have been synthesized by substitution reactions of trimethyltin chloride and triphenyl-lead chloride with semicarbazones derived from heterocyclic ketones. The resulting complexes have been characterized by elemental analyses, molecualr weight determinations and conductivity measurements. The mode of bonding has been established on the basis of infrared and ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopic studies. Some respresentative complexes have also been evaluated for their antimicrobial effects on different species of pathogenic fungi and bacteria; the results of these investigations have been reported in the present paper.     

Synthesis,characterization, crystal structure and antiproliferative activity of platinum(II) complexes with 2-acetylpyridine-4-cyclohexyl-thiosemicarbazone

New platinum complexes have been synthesized by the reaction of Na₂PtCl₄ with 2-acetylpyridine-4-cyclohexyl-thiosemicarbazone, HAc4CyclHexyl (1). The new complexes [Pt(Ac4CyclHexyl)Cl] (2) and [Pt(Ac4CyclHexyl)₂] (3) have been characterized by elemental analyses and spectroscopic studies. The crystal structure of the complex [Pt(Ac4CyclHexyl)Cl] · DMF has been solved by single-crystal X-ray diffraction. The anion of Ac4CyclHexyl coordinates in a planar conformation to the central platinum(II) through the pyridyl N, azomethine N and thiolato S atoms. The crystal packing is determined by double intermolecular hydrogen interactions, π–π, Pt–C and Pt–π contacts. The cytotoxic activities of 1–3 have been evaluated for antiproliferative activity in vitro against the cells of three human cancer cell lines: MCF-7 (human breast cancer cell line), T24 (bladder cancer cell line), A-549 (non-small cell lung carcinoma) and a mouse L-929 (a fibroblast-like cell line cloned from strain L). The compounds 1–3 display IC₅₀ values in a μM range better than that of the antitumor drug cisplatin and are considered as agents with potential antitumor activity candidates for further stages of screening in vitro and/or in vivo.     

Diorganotin(IV) complexes of 2-chloridophenylacetohydroxamic acid as prospective antimicrobials: synthesis,characterization, and biological properties

New diorganotin(IV) complexes [Me₂Sn(2-ClC₆H₄CH₂CONHO)₂] (1) and [n-Bu₂Sn(2-ClC₆H₄CH₂CONHO)₂] (2) have been synthesized by reactions of Me₂SnCl₂ and n-Bu₂SnCl₂ with potassium 2-chloridophenylacetohydroxamate (2-ClPhAHK = 2-ClC₆H₄CH₂CONHOK) in 1:2 molar ratio in MeOH+C₆H₆ solvent medium and characterized by elemental analyses, molar conductivity, molecular weight determinations and spectroscopic techniques (IR, ¹H, ¹³C, and ¹¹⁹Sn NMR) and mass spectrometry. Bonding through carbonyl and hydroxamic oxygens (O,O coordination) and distorted-octahedral geometry around tin is proposed. The electrochemical behavior of 1 and 2 studied by cyclic voltammetry shows quasi-reversible reductions. Thermal behavior of 1 and 2 in N₂ shows decomposition in one step affording SnO as the residue. The in vitro antimicrobial activity assay against pathogenic Gram-negative bacteria viz. Salmonella typhi, Escherichia coli; Gram-positive Bacillus cereus and Staphylococcus aureus and fungi Aspergillus niger and Alternaria alternata by MIC method revealed their significant antimicrobial potential relative to the respective standard Chloramphenicol and Nystatin drugs.     

New di- and triorganotin(IV) complexes of tripodal Schiff base ligand containing three imidazole arms: Synthesis, structural characterization, anti-inflammatory activity and thermal studies

Some new tri- and diorganotin(IV) complexes of the general formula, R₃Sn(H₂L) and R′₂Sn(HL) [where R = Me, n-Pr, n-Bu and Ph; R′ = Me, n-Bu, Ph and n-Oct; H₃L = Schiff base (abbreviated as tren(4-Me-5-ImH)₃) derived from condensation of tris(2-aminoethyl)amine (tren) and 4-methyl-5-imidazolecarboxaldehyde (4-Me-5-ImH)] have been synthesized. The coordination behaviour of Schiff base towards organotin(IV) moieties is discussed on the basis of infrared and far-infrared, ¹¹⁹Sn Mössbauer and multinuclear (¹H, ¹³C and ¹¹⁹Sn) magnetic resonance (NMR) spectroscopic studies. Thermal studies of all of the synthesized organotin(IV) complexes have been carried out using TG, DTG and DTA techniques. The residues thus obtained from pyrolysis of the studied complexes have been characterized by X-ray powder diffraction analysis and IR. The newly synthesized complexes have been tested for their anti-inflammatory activity and toxicity (LD₅₀).     

Platinum(IV) complexes with N-alkylphenothiazines: synthesis,characterization, and antibacterial activity

Two new platinum(IV) complexes (1, trifluoperazinehydrochloride-aquapentachloridoplatinate(IV) and 2, chlorpromazine-chlorpromazinehydrochloridepentachloridoplatinate(IV)) were synthesized in the reaction of K₂[PtCl₆] with trifluoperazine dihydrochloride (TF·2HCl) or chlorpromazine hydrochloride (CP·HCl). The complexes were characterized by elemental analysis, molar conductivity measurement, and spectral (IR, ¹H, ¹³C, 2D ¹H–¹³C heteronuclear correlation spectra, ¹⁹⁵Pt NMR, and MS) methods. Outer-coordination sphere was proposed for 1; while in 2, the ligand was coordinated to the metal. The complexes exhibit antibacterial effect on strains of Bacillus subtilis, Bacillus cereus, Bacillus pumilus, and methicillin-resistant Staphylococci as Gram-positive bacteria and an Escherichia coli as Gram-negative bacteria, as well as the reference strains.     

Bioactive versatile azomethine complexes of organotin(IV) and organosilicon(IV)

Diorganotin(IV) and diorganosilicon(IV) derivatives of the types R₂MCl(TSCZ) and R₂M(TSCZ)₂ (where TSCZ is the anion of a thiosemicarbazone ligand, R=Ph or Me and M=Sn or Si) have been synthesized and characterized by elemental analyses, molecular weight determinations and conductivity measurements. The mode of bonding has been established on the basis of IR and ¹H, ¹³C ²⁹Si and ¹¹⁹Sn NMR spectroscopic studies. Some of the representative complexes have also been evaluated for their antimicrobial effects on different species of pathogenic fungi and bacteria in vivoas well as in vitro.The results of these investigations are reported. © 1998 John Wiley & Sons, Ltd.     

Synthesis,characterization, reactivity,and electrochemical studies of manganese(IV) complexes of bis(2-hydroxy-1-naphthaldehyde)adipoyldihydrazone

Manganese(IV) complexes [Mn^IV(npah)(H₂O)₂] (1) and [Mn^IV(npah)(A)₂]?·?nH₂O (where A?=?py (2), 2-pic (3), 3-pic (4), 4-pic (5)) and Mn^IV(npah)(NN)] (NN?=?bpy (6) and phen (7)) have been synthesized from bis(2-hydroxy-1-naphthaldehyde)adipoyldihydrazone in methanol. The composition of the complexes has been established by elemental analyses. Complex 3 has been characterized by mass spectral data also. Structural assessment of the complexes has been based on data from molar conductance, magnetic moment, electronic, electron paramagnetic resonance, and infrared (IR) spectral studies. Molar conductances of the complexes in DMSO suggest non-electrolytes. Magnetic moment and EPR studies suggest +4 oxidation state for manganese in these complexes. Electronic spectral studies suggest six-coordinate octahedral geometry around the metal ions. IR spectra reveal that H₄npah coordinates to the metal in enol form. Reaction of the complexes with benzyl alcohol and SO₂ has been investigated. Cyclic voltammetric studies of the complexes have also been carried out.     

Synthesis, characterization and DNA binding studies of penta- and hexa-coordinated diorganotin(IV) 4-(4-nitrophenyl)piperazine-1-carbodithioates

Two chlorodiorganotin(IV) complexes with general formula R₂SnClL (R = n-C₄H₉(1) and C₂H₅(2) and a diphenyltin(IV) derivative with general formula Ph₂SnL₂(3), where L = 4-(4-nitrophenyl)piperazine-1-carbodithioate ligand, were prepared and characterized by elemental analysis, Raman, FT-IR, multinuclear NMR (¹H, ¹³C and ¹¹⁹Sn) and mass spectrometry. On the basis of spectroscopic data the effective coordination number of Sn atom was found five (1 and 2) and six (3) both in solution and solid state. Electrochemical, kinetic and thermodynamic parameters of complexes 1-3, interacting with DNA were evaluated by cyclic voltammetry. The linearity of the plots between the peak current (I) and the square root of the scan rate (ν^1/2) indicated the electrochemical processes to be diffusion controlled. The diffusion coefficients of the free (D_f) and DNA bound forms (D_b), standard rate constants (ks) and charge transfer coefficients (α) were determined by the application of Randle-Sevcik, Nicholson and Kochi equations. The values of binding constant and binding site size were evaluated from voltammetric data. The results revealed the following increasing order of binding strength: 1 (5.4 × 10³) < 3 (8.4 × 10³) < 2 (1.24 × 10⁴) M⁻¹. The UV-Vis spectroscopic data also indicated the same order of binding strength. Furthermore, the binding mode was suggested on the base of shift in peak potential (CV) and absorption maxima (UV-Vis spectroscopy).     

Organotin(IV) complexes with 2-hydroxynaphthaldehyde-N(4)-ethylthiosemicarbazone: Synthesis,characterization, and in vitro antibacterial activity

Four new organotin(IV) complexes with 2-hydroxynaphthaldehyde-N(4)-ethylthiosemicarbazone [(H₂DNET), (1)] of the type [MeSnCl(DNET] (2), [BuSnCl(DNET)] (3), [PhSnCl(DNET)] (4), and [Ph₂Sn(DNET] (5) have been synthesized by the direct reaction of H₂DNET (1) with organotin(IV) chloride(s) in the presence of potassium hydroxide in absolute methanol. All the compounds were characterized by elemental analyses, molar conductivity, UV-Vis, IR, ¹H, ¹³C, and ¹¹⁹Sn NMR spectral studies. The molecular structure of ligand (1) has been confirmed by X-ray single crystal diffraction. Spectroscopic data clearly suggested that Sn(IV) center is coordinated with the ONS tridentate ligand (H₂DNET) and exhibits a five-coordinate geometry in solution. Antibacterial studies were carried out in vitro against four bacterial strains. All organotin(IV) compounds (2–5) showed good activity against various bacteria but lower activity than the reference drug (Ciprofloxacin). The results demonstrate that organic groups attached to tin(IV) moiety have significant effect on their biological activities. Among them, diphenyltin(IV) derivative 5 exhibits significantly good activity than the other organotin(IV) derivatives (2–4).     

Synthesis and characterization of diorganotin(IV) complexes of tridentate Schiff bases: crystal structure of [N-(3-hydroxypyridine-2-yl)-5-chlorosalicylideneiminato]dimethyltin(IV)

Some five-coordinated dimethyltin(IV) complexes of the type Me₂SnL (where L is the anion of a bifunctional tridentate Schiff base) were synthesized. These Schiff bases are N-(3-hydroxypyridine-2-yl)-3-methoxysalicylideneimine, HOC₆H₃OCH₃CH=NC₅H₃NOH (1), N-(3-hydroxypyridine-2-yl)-3-ethoxysalicylideneimine, HOC₆H₃OC₂H₅CH=NC₅H₃NOH (2), N-(3-hydroxypyridine-2-yl)-5-chlorosalicylideneimine, HOC₆H₃ClCH=NC₅H₃NOH (3), and N-(3-hydroxypyridine-2-yl)-3-methoxy-5-bromosalicylideneimine, HOC₆H₂OCH₃BrCH=NC₅H₃NOH (4). Dimethyltin(IV) complex of 3 (3a) was characterized by single crystal X-ray diffraction method and a coordination geometry that is nearly halfway between trigonal–bipyramidal and square pyramidal arrangement was found. Dimethyltin complexes of (1), (2), and (4) were also prepared and characterized by the comparison of their elemental analysis and ¹H-NMR-, IR-, UV- and mass spectral data with those of (3a). For example, in the ¹H-NMR spectra, the ²J(¹¹⁹Sn-¹H) in the Sn-CH₃ moiety have values between 80 Hz and 90 Hz, typical of five-coordinated tin species. By using these values in Lockart’s Equations, H₃C–Sn–CH₃ angles in the complexes were estimated to lie between 130° and 145°. X-ray diffraction value for 3a, confirms this estimate within 3.4% relative deviation (129.7° exp. Vs. 134.9° estimate).     

The chemistry,properties, and characterization of organotin(IV) complexes of 2-(N-naphthylamido)benzoic acid

2-(N-naphthylamido)benzoic acid was synthesized by the reaction of phthalic anhydride with naphthylamine in glacial acetic acid at room temperature. Complexes 1–9 were synthesized under reflux in good yield with general formula R_{4? n} SnL _n (R = Me, n-Bu, Ph, n-Oct, Bz and n = 2, 3), which were studied by microanalysis, IR, NMR (¹H, ¹³C, ¹¹⁹Sn), and mass spectrometry. Cytotoxicity of the synthesized compounds was checked against Brine-shrimp larvae. In vitro activities against some Gram-positive and Gram-negative bacteria and fungi were also determined. Antimicrobial activities show that species with tetrahedral geometry in solution are more toxic.     

Synthesis,characterization and coordination behavior of 2-(1-carboxyl-2-hydroxyphenyl)thiazolidine

The reaction of 3-formylsalicylic acid with 2-aminoethanethiol produces 2-(1-carboxyl-2-hydroxyphenyl)thiazolidine (H₂chptz) which remains in equilibrium in solution with its corresponding Schiff base, 3-carboxysalicylidenethioethanolimine (H₃mcsalim) having an NSO-donor set of atoms. The reactions of the thiazolidine ligand with different metal salts leading to the synthesis of many new metal complexes and organometallic derivatives have been studied. For all the complexes the dianion of the Schiff base, H₃mcsalim acts as a tridentate NSO donor ligand. The reactions of [(Hmcsalim)Ti(π-C₅H₅)Cl] and [(Hmcsalim)Sn(Me)Cl], isolated in this study, with Me₃SiE (where, E stands for SMe, NMe₂ and C≡CPh) have also been studied. The elemental analyses, magnetic susceptibilities, molar conductance values, EPR-study, CV, molecular weights and spectroscopic (UV-Vis, IR, ¹H NMR) data characterize all the compounds under study. Based upon these data the geometry of the compounds has also been proposed.     

Synthesis,spectroscopic characterization,crystal structure,and anti-bacterial activity of diorganotin(IV) complexes with 5-bromo-2-hydroxybenzaldehyde-N(4)-ethylthiosemicarbazone

Three new diorganotin(IV) complexes, [Me₂Sn(BDET] (2), [Bu₂Sn(BDET)] (3), and [Ph₂Sn(BDET)] (4), were synthesized by reacting R₂SnCl₂ (R = Me, Bu, and Ph) with 5-bromo-2-hydroxybenzaldehyde-N(4)-ethylthiosemicarbazone [H₂BDET, (1)] in the presence of KOH in absolute methanol. The newly synthesized complexes were characterized by elemental analysis, molar conductivity, UV–vis, FT-IR, ¹H, ¹³C, and ¹¹⁹Sn NMR spectroscopies. The molecular structure of 4 was confirmed by X-ray crystallography. X-ray crystallography revealed that the doubly deprotonated O,N,S-tridentate thiosemicarbazone coordinates to tin(IV), resulting in a distorted trigonal bipyramidal geometry. Their ¹H, ¹³C, and ¹¹⁹Sn NMR spectra support a five-coordinate tin(IV) in solution for all complexes, in accord with the solid-state X-ray structure determined for 4. Compounds 1–4 were evaluated for their antibacterial activities against Staphylococcus aureus, Enterobacter aerogenes, Escherichia coli, and Salmonella typhi. The results exhibited that 2–4 were active with comparable potency compared to the standard drug. Antibacterial studies also indicated that the complexes have potential for biological evaluation.