Highly luminescent half-lantern cyclometalated platinum(II) complex: synthesis, structure, luminescence studies, and reactivity

The half-lantern compound [{Pt(bzq)(μ-C(7)H(4)NS(2)-κN,S)}(2)]·Me(2)CO (1) was obtained by reaction of equimolar amounts of potassium 2-mercaptobenzothiazolate (KC(7)H(4)NS(2)) and [Pt(bzq)(NCMe)(2)]ClO(4). The Pt(II)···Pt(II) separation in the neutral complex [{Pt(bzq)(μ-C(7)H(4)NS(2)-κN,S)}(2)] is 2.910 (2) ?, this being among the shortest observed in half-lantern divalent platinum complexes. Within the complex, the benzo[h]quinoline (bzq) groups lie in close proximity with most C···C distances being between 3.3 and 3.7 ?, which is indicative of significant π-π interactions. The reaction of 1 with halogens X(2) (X(2) = Cl(2), Br(2), or I(2)) proceeds with a two-electron oxidation to give the corresponding dihalodiplatinum(III) complexes [{Pt(bzq)(μ-C(7)H(4)NS(2)-κN,S)X}(2)] (X = Cl 2, Br 3, I 4). Their X-ray structures confirm the retention of the half-lantern structure and the coordination mode of the bzq and the bridging ligand μ-C(7)H(4)NS(2)-κN,S. The Pt-Pt distances (Pt-Pt = 2.6420(3) ? 2, 2.6435(4) ? 3, 2.6690(3) ? 4) are shorter than that in 1 because of the Pt-Pt bond formation. Time dependent-density functional theory (TD-DFT) studies performed on 1 show a formal bond order of 0 between the metal atoms, with the 6p(z) contribution diminishing the antibonding character of the highest occupied molecular orbital (HOMO) and being responsible for an attractive intermetallic interaction. A shortening of the Pt-Pt distance from 2.959 ? in the ground state S(0) to 2.760 ? in the optimized first excited state (T(1)) is consistent with an increase in the Pt-Pt bond order to 0.5. In agreement with TD-DFT calculations, the intense, structureless, red emission of 1 in the solid state and in solution can be mainly attributed to triplet metal-metal-to-ligand charge transfer ((3)MMLCT) [dσ*(Pt-Pt) → π*(bzq)] excited states. The high quantum yields of this emission measured in toluene (44%) and solid state (62%) at room temperature indicate that 1 is a very efficient and stable (3)MMLCT emitter, even in solution. The high luminescence quantum yield of its red emission, added to its neutral character and the thermal stability of 1, make it a potential compound to be incorporated as phosphorescent dopant in multilayer organic light-emitting devices (OLEDs).     

Silver(I) complexes based on novel tripodal thioglycosides: synthesis, structure and antimicrobial activity

The reaction of tris(2-bromoethyl)amine hydrobromide with sugar thiols or thioacetates leads to the formation of novel carbohydrate substituted tripodal NS₃ ligands. Complexation with silver(I) ions gives stable complexes. NMR, X-ray, MS and EXAFS studies indicate their mononuclear C₃-symmetric structure. The highly water soluble complexes formed from the unprotected ligands show a wide spectrum of effective antimicrobial activities and their use lowers the cytotoxic and antiproliferative activities compared to the free silver salts.     

Silver(I) complexes of 9-anthracenecarboxylic acid and imidazoles: synthesis, structure and antimicrobial activity

[Ag(2)(9-aca)(2)] (1) (9-acaH = 9-anthracenecarboxylic acid) reacts with a series of imidazoles to give [Ag(imidH)(2.3)(CH(3)CN)(0.7)](9-aca) (3), [Ag(6)(imidH)(4)(9-aca)(6)(MeOH)(2)] (4), {[Ag(1-Me-imid)(2)](2)[Ag(4)(9-aca)(6)]} (5), {[Ag(1-Bu-imid)(2)](2)[Ag(4)(9-aca)(6)]} (6) and [Ag(apim)](9-aca)·H(2)O (7) (imidH = imidazole; 1-Me-imid = 1-methylimidazole; 1-Bu-imid = 1-butylimidazole; apim = 1-(3-aminopropyl)imidazole). The mononuclear complex 3, hexanuclear 4-6, and polymeric 7, were all characterised using X-ray crystallography. While many of the complexes possess excellent in vitro antifungal and antibacterial activities they are, unanimously, more effective against fungal cells. The insect, Galleria mellonella, can survive high doses of the Ag(i) complexes administered in vivo, and a number of the complexes offer significant protection to larvae infected with a lethal dose of pathogenic Candida albicans cells.     

Design,synthesis of tri-substituted pyrazole derivatives as promising antimicrobial agents and investigation of structure activity relationships

The major diseases spread in the environment only because of microbes. Even, intensive care units in the hospitals are polluted by microorganisms, particularly, Gram-positive bacteria. Although many antibiotics are existed, there is a need to develop up to date microbial-resistant agents. Hence, the current study aimed to develop prominent antimicrobial drug-related compounds. Thus, a novel series of tri-substituted analogs and their intermediates were synthesized. In addition, total new compounds were screened for their antimicrobial assay and identified as the most efficient biologically active compounds. Moreover, minimal inhibitory antimicrobial activity and appropriate structure activity relationships were investigated. From the results it was observed that, viability of Gram-positive bacteria was most powerfully affected by all active compounds. Finally, this research demonstrated that, these biologically energetic amalgams can be utilized for further preclinical studies with the ambition of standing unique inventive drugs.     

Design,synthesis,characterization,cytotoxic and structure activity relationships of novel Ru(Ⅱ) complexes

Platinum containing compounds have shown antineoplastic potential, but their clinical applications have been limited by high toxicity. Ruthenium containing complexes have long been known to be well suited for biological applications, and have long been utilized as replacements to popular platinum based-drugs. Here, we report a novel series of ruthenium(II) arene compounds bearing thiosemicarbazone and isonicotinylhydrazone ligands with potent anticancer activity their structure activity relationships and apoptosis was studied. The cytotoxic activity of the new ruthenium(II) arene compounds has been evaluated in several cell lines (Molt 4/C8, L1210, CEM, HL60 and BEL7402). Among them, ten complexes were found to be excellent in vitro growth inhibitory activity against various cell lines with IC50 in the sub-micromolar range.     

Chalcone-derived thiosemicarbazones and their zinc(II) and gallium(III) complexes: spectral studies and antimicrobial activity

Chalcone-derived 3-phenyl-1-pyridin-2-ylprop-2-en-1-one thiosemicarbazone (HPyCTPh) (1), 3-(4-chlorophenyl)-1-pyridin-2-ylprop-2-en-1-one thiosemicarbazone (HPyCT4ClPh) (2), 3-(4-bromophenyl)-1-pyridin-2-ylprop-2-en-1-one thiosemicarbazone (HPyCT4BrPh) (3), and 3-(4-nitrophenyl-1-pyridin-2-ylprop-2-en-1-one thiosemicarbazone (HPyCT4NO₂Ph) (4) were obtained as well as their gallium(III) and zinc(II) complexes [Ga(PyCTPh)₂]NO₃ (Ga1), [Ga(PyCT4ClPh)₂]NO₃ (Ga2), [Ga(PyCT4BrPh)₂]NO₃ (Ga3), [Ga(PyCT4NO₂Ph)₂]NO₃ (Ga4), [Zn(PyCTPh)₂] (Zn1), [Zn(PyCT4ClPh)₂] (Zn2), [Zn(PyCT4BrPh)₂] (Zn3), and [Zn(PyCT4NO₂Ph)₂] (Zn4). The chalcones, thiosemicarbazones, and zinc(II) complexes were not active against Pseudomonas aeruginosa. The thiosemicarbazones proved to be more active than the parent chalcones against Staphylococcus aureus and Candida albicans. Coordination to zinc(II) resulted in activity improvement of most thiosemicarbazones against S. aureus. Coordination to gallium(III) significantly improved the antimicrobial activity of all thiosemicarbazones against the studied micro-organisms, suggesting this to be an effective strategy for antimicrobial activity enhancement.     

Novel bisbenzopyronopyran derivatives: photochemical synthesis and their in-vitro antimicrobial studies

The present research work describes the productive synthesis of novel bisbenzopyronopyran derivatives 4(a-h) and 5(a-h) via the photocyclization reactions of bischromones 3(a-h) under the inert conditions. The latter compounds have been realized efficiently through the O-alkylation reactions of the 3-hydroxychromone 2 with suitable dihalogenated aliphatic/aromatic/heteroaromatic reagents in the presence of dry acetone/anhydrous K₂CO₃/Bu₄N⁺I⁻ (PTC). The cyclization reaction of chalcone 1 under the Algar-Flynn-Oyamada reaction conditions (KOH/H₂O₂) could results in the formation of compound 2 in the good yield. The structural scaffolds of the newly prepared bischromones and resultant bisbenzopyronopyrans have been certified from the meticulous analysis of their various spectroscopic parameters such as UV-Vis, IR, ¹H/¹³C-NMR, and ESI-MS. It was found that o/m/p-xylene and pyridine-linked final symmetrical bistetracycles exhibited higher antimicrobial potencies as compared to alkyl chain-linked cyclized products. The bischromones 3(a-h) could be able to endow modest level of antimicrobial behavior.     

Study of the interaction between ruthenium(II) complexes and CT-DNA: synthesis,characterisation, photocleavage and antimicrobial activity studies

Two polypyridyl ligands 6-fluro-3-(1H-imidazo [4,5-f] [1,10]-phenanthroline-2-yl)-4H-chromen-4-one (FIPC), 6-chloro-3-(1H-imidazo [4,5-f] [1,10]-phenanthroline-2-yl)-4H-chromen-4-one (ClIPC) polypyridyl ligands and their Ru(II) complexes [Ru(bipy)₂FIPC]²⁺(1), [Ru(dmb)₂FIPC]²⁺(2), [Ru(phen)₂FIPC]²⁺(3), [Ru(bipy)₂ClIPC]²⁺(4), [Ru(dmb)₂ClIPC]²⁺(5) and [Ru(phen)₂ClIPC]²⁺(6) ((bipy = 2,2′-bipyridine, dmb = 4,4′-dimethyl-2,2′-bipyridine and phen = 1,10-phenanthroline) have been synthesised and characterised by elemental analysis, Mass spectra, IR, ¹H and ¹³C-NMR. The DNA-binding of the six complexes to calf-thymus DNA (CT-DNA) has been investigated by different spectrophotometric, fluorescence and viscosity measurements. The results suggest that 1–6 complexes bind to CT-DNA through intercalation. The variation in binding affinities of these complexes is rationalised by a consideration of electrostatic, steric factors and nature of ancillary ligands. Under irradiation at 365 nm, the three complexes have also been found to promote the photocleavage of plasmid pBR 322 DNA. Inhibitor studies suggest that singlet oxygen (¹O₂) plays a significant role in the cleavage mechanism of Ru(II) complexes. Thereby, under comparable experimental conditions [Ru(phen)₂FIPC]²⁺(3), [Ru(phen)₂ClIPC]²⁺(6) cleaves DNA more effectively than 1, 2, 4 and 5 complexes do. The Ru(II) polypyridyl complexes (1–6) have been screened for antimicrobial activities.     

Synthesis,antimicrobial activity,and structure–activity relationships of eugenol,menthol, and genistein esters

This study concentrates on the extraction of eugenol, menthol, and genistein, and the synthesis, antimicrobial activity, and structure-activity relationships of their ester derivatives. The esters were tested for antimicrobial activity against several bacteria and yeast, and the correlation between biological properties and various physicochemical properties was examined. The ester derivatives gave intense emissions upon irradiation by UV light and have photoluminescence quantum yields of 39, 35, and 36% and long excited-state lifetimes of 3.62, 3.23, and 3.40 ns, respectively. These esters may be used in herbal medicinal therapy, and additionally as a base for the development of new drugs for phytomedicine.     

Synthesis,structure, and antimicrobial activity of (carboxyalkyl)dimethylsulfonium halides

Reactions of a series of ω-halocarboxylic acids (2-bromo-, 2-chloroethanoic, 3-bromo- and 3-chloropropanoic) with dimethyl sulfide resulted in the formation of stable (carboxylalkyl)dimethylsulfonium bromides and chlorides. Composition and structure of the salts obtained were established by a complex of chemical, physical and physicochemical methods. The sulfonium salts obtained showed high antibacterial and antimycotic activities with respect to the pathogenic microflora of humans and animals.     

Binuclear vanadium(V) complexes of bis(aryl)adipohydrazone: synthesis,spectroscopic studies,crystal structure and catalytic activity

Three new binuclear vanadium(V) complexes of bis(aryl)adipohydrazones (H₄L¹ = bis((2-hydroxynaphthalen-1-yl)methylene)adipohydrazide, H₄L² = bis(5-bromo-2-hydroxybenzylidene)adipohydrazide, and H₄L³ = bis(2-hydroxy-3-methoxybenzylidene)adipohydrazide) were synthesized by direct reaction of [VO(acac)₂] with the hydrazone ligands. The ligands and complexes were characterized by FT–IR, UV–Vis, and NMR spectroscopic methods. The crystal structures of the complexes of L¹ and L³ were determined by X-ray analyses. The solid-state structure of the complex of L¹ features a 1D hydrogen-bonded chain from N⋯H–O hydrogen bonding. The catalytic activities of these complexes have been tested in the oxidation of various hydrocarbons using H₂O₂ as the terminal oxidant. Generally, good to excellent conversions have been obtained.     

Microwave-assisted synthesis of borneol esters and their antimicrobial activity

Seventeen borneol esters (1–17) were synthesised by conventional and microwave-assisted methodology using DIC/DMAP, and seven are described for the first time (8, 9, 10, 12, 13, 16 and 17). The microwave-assisted methodology was carried out without use of solvents, displayed short reaction times, and showed equal or higher yields for all the long-chain esters and three aromatic compounds (11, 12 and 14) when compared to the conventional approach. All the borneol esters were evaluated against the bacteria Streptococcus sanguinis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and the fungus Candida albicans. Compounds 12, 13 and 14 displayed promising antibacterial activity with a MIC equal to ampicilin (62.5 mg mL^?1) for some microorganisms. In fact, bornyl 3′,4′-dimethoxybenzoate (13) was active against all tested bacteria and fungus.     

Synthesis, spectral studies of cobalt(II) tetrathiocyanoto dicuperate(I) complexes with some acylhydrazones and their antimicrobial activity

Cobalt(II) complexes of the type Co[Cu(NCS)₂]₂ · L, where L is acetophenonebenzoylhydrazone (Abh), acetophenoneisonicotinoylhydrazone (Ainh), acetophenonesalicyloylhydrazone (Ash), acetophenoneanthraniloylhydrazone (Aah), p-hydroxyacetophenonebenzoylhydrazone (Phabh), p-hydroxyacetophenoneisonicotinoylhydrazone (Phainh), p-hydroxyacetophenonesalicyloylhydrazone (Phash), and p-hydroxyacetophenoneanthraniloylhydrazone (Phaah) were synthesized and characterized by elemental analyses, molar conductance, magnetic moments, electronic and IR spectra, and X-ray diffraction studies. The complexes are insoluble in common organic solvents and are non-electrolytes. These complexes are coordinated through the >C=O and >C=N groups of the hydrazone ligands. The magnetic moments and electronic spectra suggest a spin-free octahedral geometry around Co(II). The X-ray diffraction parameters (a, b, c) for Co[Cu(SCN)₂]₂ · Ainh and Co[Cu(SCN)₂]₂ · Phabh correspond to orthorhombic and tetragonal crystal lattices, respectively. The complexes show a fair antifungal and antibacterial activity against a number of fungi and bacteria. The activity increases with increasing concentration of the compounds. The text was submitted by the authors in English.     

Synthesis,spectral studies of copper(II)tetrathiocyanato dithallate(I) complexes with some acylhydrazones and their antimicrobial activity

Heterobimetallic complexes of Cu[Tl(SCN)₂]₂ ·; L (where L?=?acetophenone benzoylhydrazone(abh), acetophenone isonicotinoyl hydrazone(ainh), acetophenone salicyloylhydrazone(ash), acetophenone anthraniloyl hydrazone(aah), p-hydroxy acetophenone benzoylhydrazone (phabh), p-hydroxy acetophenone isonicotinoyl hydrazone (phainh), p-hydroxy acetophenone salicyloylhydrazone(phash) and p-hydroxy acetophenone anthraniloyl hydrazone(phaah) were synthesized and characterized. Electronic spectra and μ_eff values suggest a distorted octahedral environment around copper(II). SCN groups bridge between two metal centers and the ligands are coordinated through >C=O and >C=N–groups. Thermal studies (TGA and DTA) on Cu[Tl(SCN)₂]₂?·?ainh indicate multi step decomposition of both endothermic and exothermic nature. ESR data show axial spectra for all the complexes and d _{x²???y ²} as the ground state. Powder X-ray diffraction parameters for some of the complexes correspond to orthorhombic crystal lattice. The complexes show significant antifungal activity against Rizoctonia sp. and Stemphylium sp. and moderate antibacterial activity against Clostridium sp. and Pseudomonas sp. The activity increases at higher concentration of the compound.     

Synthesis, characterization and properties of some divalent metal(II) complexes: their electrochemical, catalytic, thermal and antimicrobial activity studies

In this study, we synthesized the amine compound 2-(2-aminoethyliminomethyl)phenol (H(3)A) as the starting material, and then we prepared the polydentate Schiff base ligands from the reactions of the amine compound (H(3)A) with phtaldialdehyde (H(2)L), 4-methyl-2,6-di-formlyphenol (H(3)L(1)) and 4-t-butyl-2,6-di-formylphenol (H(3)L(2)) in the ethanol solution. Moreover, the complexes Cd(II), Cu(II), Co(II), Ni(II), Zn(II) and Sn(II) of the ligands H(2)L, H(3)L(1) and H(3)L(2) have been prepared. All compounds have been characterized by the analytical and spectroscopic methods. In addition, the magnetic susceptibility and molar conductance measurements have been made. The catalytic properties of the mono- and binuclear Co(II) and Cu(II) complexes have been studied on the 3,5-di-tert-butylcatechol (3,5-DTBC) and ascorbic acid (aa) as a substrate. The oxidative C-C coupling properties of the Co(II) and Cu(II) complexes have been investigated on the sterically hindered 2,6-di-tert-butylphenol (dtbp). The antimicrobial activity properties of the ligands and their mono- and binuclear complexes have been studied against the bacteria and fungi. The results have been compared to the antibacterial and fungi drugs. The TGA curves show that the decomposition takes place in three steps for all complexes. Electrochemical properties of the complexes Cu(II) and Ni(II) have been investigated for the first time in acetonitrile by cyclic voltammetry.     

Mono- and penta-nuclear self-assembled silver(I) complexes of pyrazolyl s-triazine ligand; synthesis,structure and antimicrobial studies

The self-assembled [Ag (PTDM)NO₃] ( 1 ), [Ag (PTDM)₂(H₂O)]ClO₄^.H₂O ( 2 ) and [Ag₅(PTDM)₄(H₂O)₆(ClO₄)₄]ClO₄^.2H₂O ( 3 ) complexes were synthesized by the direct mixing of AgX (X = NO₃¯ or ClO₄¯) and 4,4′-[6-(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazine-2,4-diyl]dimorpholine ( PTDM ) ligand in water–methanol mixture. The coordination numbers of silver range from three to five. Complex 3 is a rare case in which one nitrogen atom from the same s-triazine core of the PTDM ligand has a μ(1,1) bridging mode between Ag1 and Ag2 in the penta-nuclear array with Ag1–N1 and Ag2–N1 distances of 2.666(4) and 2.418(3) Å, respectively. Its 3D topology has a kind of primitive dense packing derived from the α-Po type structure. Hirshfeld analysis showed that the percentages of the O^…H hydrogen bonds were 32.4, 25.4, and 42.0% in complexes 1 – 3 , respectively. While the ligand showed no antimicrobial activity at the applicable concentration, the penta-nuclear complex 3 had higher antibacterial (MIC = 3.7 μmol/L) and antifungal (14.6 μmol/L) potencies toward the tested microbes compared with complexes 1 and 2 . Also, the killing doses of 3 were in the range of 7.3–58.5 μmol/L compared with 18.2–291.1 and 20.1–160.6 μmol/L for 1 and 2 , respectively. It is clear that the higher Ag-content in 3 could be the main reason for its higher antimicrobial activity.     

Highly photostable silicon(IV) phthalocyanines containing adamantane moieties: synthesis, structure, and properties

Two new axially disubstituted silicon(IV) phthalocyanines 1 and 2 have been synthesized by treating silicon phthalocyanine dichloride with 1-adamantanemethanol or 1-adamamtaneethanol, respectively. The crystal structure of compound 2 has been characterized by X-ray diffraction analysis. Both compounds are efficient singlet-oxygen generator with a quantum yield of 0.40-0.43. With two rigid bulky adamantane moieties at the axial positions, these phthalocyanines not only are essentially non-aggregated in common solvents, but also exhibit a high photostability. They are about 100 times more stable than zinc phthalocyanine under the same irradiation conditions. With the goal of enhancing the biocompatibilities, interactions and conjugations of these two compounds with bovine serum albumin have also been investigated.     

Synthesis,spectroscopic studies,antimicrobial activity,and crystal structure of a Zn(II) complex based on Voriconazole

[Zn(FZ)₂Cl₂] (1) (FZ = Voriconazole, (2R,3S)-2-(2,4-difluorophenyl)-3(5-fluoropyrimidin-4-yl)-1-(1H-1,2,4-triazol-1-yl)butan-2-ol), has been obtained through the reaction of zinc chloride and FZ and has been characterized by FT-IR, UV–vis and fluorescence spectra, elemental analysis (EA), single crystal X-ray diffraction, powder X-ray diffraction and thermogravimetric analysis (TGA). FZ was also characterized by FT-IR, UV–vis spectra, single crystal X-ray diffraction and TGA. FZ crystallizes in the chiral space group P2₁ and 1 crystallizes in chiral space group P₁ with a mononuclear structure. In 1, there are three kinds of hydrogen bonding interactions and weak stacking interactions which generate a 3-D architecture. The primary antimicrobial results show that 1 exhibits potent activity against Aspergillus (Aspergillus niger, Aspergillus terreus, Aspergillus fumigatus and Aspergillus flavus) and Candida species (Candida albicans, Candida krusei, Candida glabrata and Cryptococcus neoformans), higher than that of free FZ. Fluorescence spectra of 1 and FZ have been discussed.     

Metal based sulfanilamides: A note on their synthesis,spectral characterization,and antimicrobial activity

Russian Journal of General Chemistry - Objectives of the current study were synthesis, spectral characterization and biological screening of sulfanilamide derived Schiff bases and their metal based...