Octahedral copper(II) carboxylate complex: synthesis, structural description, DNA-binding and anti-bacterial studies

<p>Self-assembly of CuSO₄, <i>para</i>-methyl-2-phenyl acetate and 1,10-phenanthroline afforded good-quality crystalline complex in quantitative yield. The complex was characterized by FTIR and UV-visible spectroscopy, electrochemistry, and powder and single-crystal XRD studies. Its structure was found to possess axially elongated octahedral symmetry with CuO₄N₂ chromophore. Its purity was assessed by powder XRD spectrum. Absorption study yielded a broad band corresponding to ²E_g→²T_2 g transition. Electrochemical solution study indicated diffusion-controlled irreversible electron transfer process corresponding to Cu(II)/Cu(I) redox couple with diffusion coefficient = 7.89(±0.1)×10⁻⁹ cm²s⁻¹. Results of spectroscopic techniques support each other. Complex exhibited excellent DNA-binding ability through UV-visible spectroscopy and cyclic voltammetry yielding <i>K</i>_<i>b</i> values 1.399 × 10⁴ M⁻¹ and 5.81 × 10³ M⁻¹, respectively. The complex exhibited significant activity against bacterial strains <i>Escherichia coli</i>, <i>Micrococcus luteus</i> and <i>Staphylococcus aureus</i> and good activity against <i>Bacillus subtilis</i>. These preliminary studies impart good biological relevance on the synthesized complex.</p

Synthesis, characterization, single crystal XRD and biological screenings of organotin(IV) derivatives with 4-(2-hydroxyethyl)piperazine-1-carbodithioic acid

<p>Organotin(IV) thiocarboxylates R₂SnL₂ (R = Me: <b>1:</b> Ph: <b>2</b>)/R₂(Cl)SnL (R = <i>n</i>-Bu: <b>3</b>; Ph: <b>4</b>)/R₃SnL (R = Me: <b>5</b>; <i>n</i>-Bu: <b>6</b>; Ph: <b>7</b>), where L = 4-(2-hydroxyethyl)piperazine-1-carbodithioate, have been synthesized by stirring together 1,2-hydroxyethylpiperazine and CS₂ in methanol, and then refluxing with a di-/triorganotin chloride. The synthesized products have been characterized by various spectroscopic (IR, ¹H NMR, ¹³C NMR, EI-MS) techniques and single crystal XRD. FT-IR data indicate bidentate binding of the ligand. The magnitude of ²<i>J</i>(¹¹⁹Sn–¹H) demonstrated a skew trapezoidal environment around tin(IV) in <b>1,</b> whereas the metal geometry in <b>5</b> was between distorted tetrahedral and trigonal bipyramidal in solution. ¹³C NMR revealed four- and five-coordinate environments in <b>6</b> and <b>7</b>, respectively, in non-coordinating solvent. EI-MS data agreed very well with the structural skeleton of the products. Single crystal XRD study has shown skew trapezoidal- and trigonal-bipyramidal Sn(IV) in <b>1</b> and <b>7</b>, respectively. Compound <b>6</b> interacted with salmon sperm DNA (SS-DNA) with significant hypochromic effect and an intercalating mode of binding. Diorganotin(IV) derivatives (<b>2</b> and <b>3</b>) generally exhibited poor antibacterial/antifungal potential as compared to their trialkyltin(IV)/triaryltin(IV) counterparts (<b>5</b> and <b>6</b>). The <i>in vitro</i> hemolytic activities show that average lysis of human red blood cells caused by <b>1</b>–<b>7</b> was significantly lower compared to triton X-100 (positive control, 100% lysis) and not very much higher than PBS (negative control, 0% lysis).</p

Isolation, structure elucidation and enzyme inhibition studies of a new hydroxy ester and other compounds from <i>Berberis jaeschkeana</i> Schneid stem

<div><p>Bioassay-guided isolation and fractionation of <i>Berberis jaeschkeana</i> Schneid var. <i>jaeschkeana</i> stem resulted in the isolation and characterisation of a new long chain hydroxy ester named as berberinol (<b>1</b>) along with six known compounds (<b>2</b>–<b>7</b>). All the structures were established from 1D and 2D spectroscopic data. Crude extract, sub-fractions and all the isolated compounds were evaluated for their anti-fungal and urease enzyme inhibition properties. All of the sub-fractions and compounds showed good anti-fungal and urease enzyme inhibition properties. Minimum inhibitory concentrations (MICs) were calculated for all active samples in case of urease enzyme inhibition. MICs values were found to be in the range of 39.03–49.78 μg/mL for urease enzyme inhibition.</p></div

A new isoquinoline alkaloid with anti-microbial properties from <i>Berberis jaeschkeana</i> Schneid. var. <i>jaeschkeana</i>

<div><p>One new isoquinoline alkaloid named berberidione <b>(1)</b> along with four new source alkaloids berberine <b>(2)</b>, palmatine <b>(3)</b>, jatrorrhizine <b>(4)</b> and chondrofoline <b>(5)</b> and three new source non-alkaloids syringic acid <b>(6)</b>, β-sitosterol <b>(7)</b> and stigmasterol <b>(8)</b> was isolated and characterised from different fractions of <i>Berberis jaeschkeana</i> Schneid var. <i>jaeschkeana</i>. All the structures were determined from 1D and 2D spectroscopic data. Crude extract, sub-fractions and isolated compounds showed excellent anti-microbial properties. The toxicity level for the alkaloids was found to be very low on THP-1 cells.</p></div

Synthesis and characterization of hetero-bimetallic complexes with 2-mercapto-5-methyl-benzimidazole: theoretical study and biological activities

<div><p>Heterobimetallic complexes have been synthesized by stirring 2-mercapto-5-methylbenzimidazole with carbon disulfide in methanol at room temperature. In the second step, the product was treated with R₂SnCl₂/R₃SnCl (R = Me, <i>n</i>-Bu, Ph) in 1 : 1 M ratio, then organotin(IV) complexes were treated with HgCl₂ in 2 : 1 M : L ratio to yield heterobimetallic complexes. The ligand and complexes have been characterized by elemental analysis, IR, ¹H- and ¹³C NMR spectroscopy, mass spectrometry (EI-MS), and semiempirical study to assess the binding mode of the heterobimetallic complexes. IR data showed the bidentate nature of the dithiocarbamate moiety, which is also confirmed by semiempirical study. Mass spectra correspond to the expected for the complexes. NMR spectroscopy confirmed the four-coordinate geometry in solution. Computed molecular descriptors, thermodynamic parameters, and electrostatic surface potential map of <b>4</b> were calculated by using the PM6 method. Biological screening data indicated that complexes exhibit significant activity against various bacterial and fungal strains with few exceptions. Ligand and <b>6</b> are excellent for phagocyte reactive oxygen species inhibition.</p></div

Synthesis and spectroscopic and thermogravimetric characterization of heterobimetallic complexes with Sn(IV) and Pd(II); DNA binding, alkaline phosphatase inhibition and biological activity studies

<div><p>A palladium complex, [KLCSS]₂Pd (<b>1</b>), has been prepared by stirring sarcosine (HLH), KOH and CS₂ in methanol and subsequently treating with palladium(II) chloride. Six heterobimetallic derivatives of the type [R₂(Cl)SnLCS₂]₂Pd (R = Me: <b>2</b>; Bu: <b>3</b>; Ph: <b>4</b>)/[R₃SnLCS₂]₂Pd (R = Me: <b>5</b>; Bu: <b>6</b>; Ph: <b>7</b>) were also synthesized by stirring sarcosine (HLH) with KOH and CS₂ in methanol followed by an addition of R₂SnCl₂/R₃SnCl and then PdCl₂. FT-IR data demonstrated bidentate binding of dithiocarbamate and carboxylate with four- and five-coordinate environments around Pd(II) and Sn(IV) centers, respectively, in the solid state. UV–visible studies verified the square planar arrangement around Pd(II) in solution. The magnitude of ²<i>J</i>(¹¹⁹Sn-¹H) demonstrates a distorted trigonal bipyramidal geometry around tin(IV) in solution. Elemental analysis (C, H, N, and S), mass spectroscopic (EI-MS and ESI), and thermogravimetric analyses verified the chemical composition of products. Complexes <b>1–7</b> exhibited interaction with salmon sperm DNA (SS-DNA). The palladium complex <b>1</b> had shown higher potential to bind with SS-DNA and to inhibit the alkaline phosphatase when compared to the heteronuclear products (<b>2–7</b>). However, the antifungal/antibacterial activities of the bimetallic complexes (<b>2–7</b>) were significantly higher than the palladated derivative <b>1</b>. The <i>in vitro</i> hemolytic activity investigations on human red blood cells showed that bimetallic derivative <b>2</b> with chlorodimethyltin(IV) exhibited the lowest hemolytic effects (17.55%), while <b>5</b> having trimethyltin(IV) center exhibited the highest hemolytic activity (78.64%).</p></div

Synthesis, characterization, HOMO–LUMO study, and antimicrobial activity of organotin(IV) complexes of 4-piperidine carboxamide and its Schiff base

<div><p>A series of organotin(IV) complexes has been synthesized by reacting 4-piperidine carboxamide with CS₂ and R₂SnCl₂/R₃SnCl in 1 : 1 M/L ratio at room temperature. The synthesized complexes were further treated with benzaldehyde to synthesize Schiff bases under stirring. All the complexes were characterized by elemental analysis, FT-IR, ¹H and ¹³C NMR. FT-IR and semi-empirical study confirm the bidentate nature of ligand. The complexes exhibit four-coordinate geometry in solution. Thermodynamic parameters and molecular descriptors were calculated by using semi-empirical PM3 method. HOMO–LUMO calculations show that chlorodiorganotin complexes are more susceptible to nucleophilic attack when compared with triorganotin complexes. Negative heats of formation at 298 K demonstrate that <b>1</b>, <b>4,</b> and <b>7</b> are thermodynamically stable. The antimicrobial results have shown that complexes containing Schiff base exhibit significantly better activity compared to complexes with carboxamide derivatives.</p></div

<i>One</i>-<i>pot</i> synthesis, characterization, DNA binding and enzymatic studies of 4-methyl <i>trans</i>-cinnamate zinc(II)-mixed ligand complexes

<div><p>Four new zinc(II) complexes formulated as [Zn(L)₂] (<b>1</b>), [Zn(L)₂(phen)] (<b>2</b>), [Zn(L)₂(bipy)H₂O] (<b>3</b>), and [Zn(en)₂(H₂O)₂](L)₂(H₂O)₂ (<b>4</b>), where HL = 4-methyl <i>trans</i>-cinnamic acid, bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline, and en = ethylenediamine, have been synthesized and characterized by FT-IR and NMR spectroscopy. Single-crystal XRD revealed distorted square-pyramidal structure for <b>3</b> and octahedral for <b>4</b>. The complexes were screened for DNA interaction via viscommetry and UV–visible spectroscopy. The apparent binding constants were calculated to be 1.18 × 10⁴, 1.26 × 10⁵, 4.64 × 10⁴_, and 1.89 × 10⁴ for <b>1</b>–<b>4</b>, respectively. The binding propensity to salmon sperm DNA was in the order: K₂ > K₃ > K₄ > K₁. Furthermore, these complexes demonstrated efficient inhibition of alkaline phosphatase, which was attributed to the binding of zinc(II) to the enzyme’s active site.</p></div

Biological screening, DNA interaction studies, and catalytic activity of organotin(IV) 2-(4-ethylbenzylidene) butanoic acid derivatives: synthesis, spectroscopic characterization, and X-ray structure

<div><p>A series of organotin(IV) carboxylates, [Me₂SnL₂] (<b>1</b>), [Bu₂SnL₂] (<b>2</b>), [Oct₂SnL₂] (<b>3</b>), [Me₃SnL] (<b>4</b>), and [Ph₃SnL] (<b>5</b>), where L = 2-(4-ethylbenzylidene) butanoic acid, have been synthesized and characterized by elemental analysis, FT-IR, and NMR (¹H, ¹³C, and ¹¹⁹Sn). [Me₃SnL] (<b>4</b>) was analyzed by single crystal X-ray analysis which showed polymeric structure with distorted trigonal bipyramidal geometry. The complexes were screened for biological activities including antibacterial, antifungal, and cytotoxic activities. UV–vis absorption studies of <b>HL</b>, <b>1</b> and <b>4</b> with SS-DNA revealed groove binding as well as intercalation, which may be due to the presence of planar phenyl groups that facilitate interaction with DNA. The determined intrinsic binding constants, 6.04 × 10³ M⁻¹ (<b>HL</b>), 9.6 × 10³ M⁻¹ (<b>1</b>), and 1.7 × 10⁴ M⁻¹ (<b>4</b>), showed that <b>HL</b> and <b>1</b> have less binding strength than <b>4</b>. The catalytic activities of di- and tri-organotin(IV) complexes were assessed in transesterification of triglycerides (linseed oil) into fatty acid methyl esters (biodiesel). The tri-organotin(IV) complexes have better catalytic activity than their di-analogs.</p></div

Multinuclear (Sn/Pd) complexes with disodium 2,2′-(dithiocarboxyazanediyl)diacetate hydrate; Synthesis, characterization and biological activities

<p>Bimetallic chlorodi-/triorganotin(IV) derivatives of general formulas R₂(H₂O)SnLCSSSn(Cl)R₂ (R=Me: <b>1</b>; Ph: <b>2</b>) and R₃Sn(Na)LCSSSnR₃·H₂O (R=Bu: <b>3</b>; Ph: <b>4</b>) were prepared by reaction of iminodiacetic acid disodium salt hydrate (Na₂LH) with CS₂ and R₂SnCl₂/R₃SnCl in methanol. The reaction between Na₂LH, CS₂, and PdCl₂ produced [Na₂LCSS]₂Pd·2H₂O (<b>5</b>) which was treated with R₃SnCl to synthesize the heterobimetallic derivatives [R₃Sn(Na)LCSS]₂Pd·2H₂O (R=Me: <b>6</b>; Ph: <b>7</b>). The complexes were characterized by microanalysis, spectroscopic, and thermogravimetric analyses. Elemental analysis data, mass fragmentation, and thermal degradation patterns supported the molecular composition of the complexes. FT-IR data indicated monodentate binding of carboxylate while a chelating coordination mode of the dithiocarboxylate was verified in the solid state. A five-coordinate tin(IV) was demonstrated in the solid state. In solution, a tetrahedral/trigonal bipyramidal configuration around Sn(IV) and a square planar geometry of Pd(II) was indicated by multinuclear NMR (¹H and ¹³C) and UV-visible studies. The Pd(II) derivatives showed interaction with salmon sperm-DNA and caused an inhibition of alkaline phosphatase (ALPs). The antibacterial/antifungal potential of the coordination products varied with the nature of incorporated metal and a substitution pattern at tin(IV); the palladium metallation decreased the antimicrobial activities. The triorganotin(IV) products exhibited more powerful action against bacteria/fungi as compared to their diorganotin(IV) counterparts. The complexes displayed sufficiently lower hemolytic effects <i>in vitro</i> as compared to triton X-100 and slightly higher than PBS.</p