Ethanol Ligands Research Articles

Synthesis, Characterization, and Bioactivity Studies of the Schiff Base Ligand and its Zinc(II) Complex

One of the largest concerns to global health in recent decades has been identified as the growth of bacteria resistance to antibiotics. The Schiff base (SBs) and the zinc(II) SBs complex compounds category have attracted a lot of interest because of their function in chemical syntheses and their potential for bioactive and pharmacological effects. The present study includes the synthesis of various SBs with different substituents. Equimolar mixtures of benzaldehyde derivatives (1, 2) and aniline derivatives (3, 4) are used to carry out a series of condensation reactions to get compounds (5-7). By stoichiometrically combining Zn (II) acetate and ZnCl2 separately with the SBs ligand (7) in ethanol, it has been possible to prepare the SBs zinc(II) complex (8). The structure of the ligand and its metal complex are analyzed using (Fourier transform infrared spectroscopy, 1H-NMR, 13C-NMR) spectroscopy, scanning electron microscopy, and liquid chromatography–mass spectrometry. Moreover, the synthesized compounds are verified in vitro against Escherichia coli Gram negative, Staphylococcus aureus Gram positive, and fungi (Candida albicans). Compounds (5, 7, and 8) indicated significant growth inhibition against E. coli Gram negative and fungi (C. albicans) with different inhibition zones starting from 7 to 17.5 mm.

High-Throughput Deposition of Recyclable SnO2 Electrodes toward Efficient Perovskite Solar Cells.

Chemical bath deposited (CBD) SnO2 is one of the most prevailing electron transport layers for realizing high-efficiency perovskite solar cells (PSCs) so far. However, the state-of-the-art CBD SnO2 process is time-consuming, contradictory to its prospect in industrialization. Herein, a simplified yet efficient method is developed for the fast deposition of SnO2 electrodes by incorporating a concentrated Sn source stabilized by the ethanol ligand with antimony (Sb) doping. The higher concentration of Sn source promotes the deposition rate, and Sb doping improves the hole-blocking capability of the CBD SnO2 layer so that its target thickness can be reduced to further save the deposition time. As a result, the deposition time can be appreciably reduced from 3-4h to only 5min while maintaining 95% of the maximum efficiency, indicating the power of the method toward high-throughput production of efficient PSCs. Additionally, the CBD SnO2 substrates are recyclable after removing the upper layers of complete PSCs, and the refurbished PSCs can maintain ≈98% of their initial efficiency after three recycling-and-fabrication processes.

Columnar Liquid Crystals of Copper(I) Complexes with Ionic Conductivity and Solid State Emission.

Two neutral copper(I) halide complexes ([Cu(BTU)2X], X = Cl, Br) were prepared by the reduction of the corresponding copper(II) halides (chloride or bromide) with a benzoylthiourea (BTU, N-(3,4-diheptyloxybenzoyl)-N'-(4-heptadecafluorooctylphenyl)thiourea) ligand in ethanol. The two copper(I) complexes show a very interesting combination of 2D supramolecular structures, liquid crystalline, emission, and 1D ionic conduction properties. Their chemical structure was ascribed based on ESI-MS, elemental analysis, IR, and NMR spectroscopies (1H and 13C), while the mesomorphic behavior was analyzed through a combination of differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and powder X-ray diffraction (XRD). These new copper(I) complexes have mesomorphic properties and exhibit a hexagonal columnar mesophase over a large temperature range, more than 100 K, as evidenced by DSC studies and POM observations. The thermogravimetric analysis (TG) indicated a very good thermal stability of these samples up to the isotropization temperatures and over the whole temperature range of the liquid crystalline phase existence. Both complexes displayed a solid-state emission with quantum yields up to 8% at ambient temperature. The electrical properties of the new metallomesogens were investigated by variable temperature dielectric spectroscopy over the entire temperature range of the liquid crystalline phase. It was found that the liquid crystal phases favoured anhydrous proton conduction provided by the hydrogen-bonding networks formed by the NH…X moieties (X = halide or oxygen) of the benzoylthiourea ligand in the copper(I) complexes. A proton conductivity of 2.97 × 10-7 S·cm-1 was achieved at 430 K for the chloro-complex and 1.37 × 10-6 S·cm-1 at 440K for the related bromo-complex.

Preparation, Structures and Antimicrobial Activity of Ni(II) Complexes on the Base of Enrofloxacin with Dicumarol Derivative

Objective: To synthesize Ni(II) complexes on the base of enrofloxacin with dicumarol derivative and to investigate their antioxidant and antimicrobial potentials. Methods: Ni(II) complexes have been synthesized by classical thermal methods by mixing aqueous metal solutions with ethanol ligands and enrofloxacin in a 1:1 molar ratio. A biologically strong ligand was prepared by refluxing a dicoumarol derivative in aldehyde and ethanol. The structures of the ligands and their nickel complexes were investigated and confirmed by elemental analysis, FT-IR, 1H-NMR, 13C-NMR and mass spectroscopy. The thermal behavior of newly synthesized mixed-ligand Ni(II) complexes was studied by thermogravimetric analysis. Ferric-reducing antioxidant power (FRAP) (antioxidant activity) of all complexes were measured. All the compounds were screened for their antimicrobial activity against E. coli; P. aeruginosa; S. pyogenes; C. albicans and A. niger using Luria Broth dilution method for MIC values. Both the ligand and its complex were screened for antioxidant and antimicrobial activity in vitro. Findings: Antioxidant and antimicrobial activities of complexes were found to be better than the parent ligands used for complex formation. MIC values for complex C5 (-CH3 derivative) were found to be between 40-70 mg/mL and FRAP values was 82.44 mmol/100g, indicative of its ferric reducing antioxidant power. These result show that complex C5 (-CH3 derivative) was found more potential as antimicrobial and antioxidant agent. Novelty : The coordination of metal complex with enrofloxacin (antibiotic) draws a scheme for the synthesis of new drug as well as increasing the activity of enrofloxacin that is currently in use. Current work supports that the activity of antibiotics could be increased by coordination of metal ion complex. There could be a possibility that these complexes allow to reduce the dose of drug introduced into the body. Keywords: Dicumarol; Antimicrobial; Antioxidant; Thermal Analysis; TGA

Ferromagnetic chloro-bridged copper(II) coordination polymer: Synthesis, structure, magnetism, and DNA cleavage effects

A new coordination polymer, [Cu(pmaeOH)Cl2]n, based on the copper(II) ion and 2-(2-pyridine-2-ylmethylamino)ethanol (pmaeOH) ligand was obtained from a methanol solution. The coordination polymer was characterized by elemental analysis, infrared spectroscopy, X-ray single-crystal diffraction, magnetic susceptibility measurements, and DNA cleavage effect. The crystal structure of the polymer consisted of a one-dimensional (1-D) chain with each copper(II) atom six-coordinated (by three nitrogen atoms and three chlorine atoms) in a severely distorted octahedral geometry. The polymer exhibited ferromagnetic behavior within the 1-D chain (J = 6.35 cm−1) through the long bond distances of copper(II) and chloride ions. The copper(II) complex cleaves scDNA through oxidative pathways, where the reactive oxygen species (ROS) involved in DNA cleavage are the superoxide radical (⋅O2–), singlet oxygen (1O2), and hydrogen peroxide (H2O2). This paper reports the new synthesis of a ferromagnetically coupled polymer bridged with a chloride ion and its DNA cleavage effect for molecular memory devices and DNA repair applications.

Ligand Effect in 1-Octanethiol Passivation of InP/ZnSe/ZnS Quantum Dots-Evidence of Incomplete Surface Passivation during Synthesis.

The lack of anionic carboxylate ligands on the surface of InP/ZnSe/ZnS quantum dots (QDs), where zinc carboxylate ligands can be converted to carboxylic acid or carboxylate ligands via proton transfer by 1-octanethiol, is demonstrated. The as-synthesized QDs initially have an under-coordinated vacancy surface, which is passivated by solvent ligands such as ethanol and acetone. Upon exposure of 1-octanethiol to the QD surface, 1-octanethiol effectively induces the surface binding of anionic carboxylate ligands (derived from zinc carboxylate ligands) by proton transfer, which consequently exchanges ethanol and acetone ligands that bind on the incomplete QD surface. These systematic chemical analyses, such as thermogravimetric analysis-mass spectrometry and proton nuclear magnetic resonance spectroscopy, directly show the interplay of surface ligands, and it associates with QD light-emitting diodes (QD-LEDs). It is believed that this better understanding can lead to industrially feasible QD-LEDs.

Solvent-mediated surface ligand exchange to enhance the performance of quantum-dot light-emitting diodes

Colloidal quantum dots (QDs) with core-shell structure and long-chain organic ligands are widely used as emitting-material layers (EMLs) for quantum-dot light-emitting diodes (QLEDs). However, the poor conductivity of long-chain organic ligands severely affects charge injection into QD-EMLs and charge transport among QDs, usually leading to poor device performance. To address the issue, we partially replaced the original long-chain oleic acid (OA) ligands capping on the QD surface with short-chain 1,2-ethanedithiol (EDT) ligands via solvent-mediated solid-state ligand exchange to fabricate high-performance QLEDs. The effects of solvent (acetonitrile and ethanol)-mediated EDT ligand exchange on the properties of QDs and device performance were comparatively investigated. Our results show that the ligand exchange is more sufficient when using ethanol instead of acetonitrile as the solvent for EDT, which is not only capable of improving charge transport among QDs but also capable of enhancing hole-electron injection balance in QLEDs. As a result, the QLED device based on QDs after EDT (in ethanol) ligand exchange exhibits a maximum luminescence of 190,200 cd/m 2 , a maximum current efficiency of 18.34 cd/A, a maximum power efficiency of 9.60 l m/W and a peak external quantum efficiency of 12.26%, appreciably outperforming those based on pristine QDs and QDs after EDT (in acetonitrile) ligand exchange. After aging, its maximum current efficiency, maximum power efficiency and peak external quantum efficiency can reach up to 35.91 cd/A, 23.30 l m/W and 24.00%, respectively. Our results highlight the importance of surface chemistry control via solvent-mediated ligand exchange to fabricate high-performance QLEDs, and suggest that ethanol may be a more suitable solvent for EDT to fulfill solid-state ligand exchange of core/shell QDs. • Solvent mediated 1,2-ethanedithiol (EDT) ligand exchange is reported to enhance the performance of QLEDs. • The ligand exchange is more sufficient when using ethanol instead of acetonitrile as the solvent for EDT. • Ethanol mediated ligand exchange can improve charge transport among QDs and enhance hole-electron injection balance in QLEDs. • Devices based on EDT/ethanol ligand-exchanged QDs surpass those based on pristine or EDT/acetonitrile ligand-exchanged QDs.

UV-Vis Spectroscopic Study on a New Synthesized 4-Hydroxy-N-[(E)-(2-hydroxyphenyl)methylidene]benzohydrazide as Calorimetric Reagent For Mg2+ Ions

This study is concerned about the study of the chromogenic properties of hydrazone compound, i.e. 4-hydroxy-N-[(E)-(2-hydroxyphenyl)-methylidene]benzo-hydrazide towards magnesium ion recognition. The hydrazone compound was synthesized and characterized by FT-IR and NMR spectroscopy. The complexation ability of the studied ligand towards Mg2+ was investigated using UV-Vis spectroscopy. Experimental parameters that affect the ligand-metal ion complexation such as effect of solvent, standing time, metal concentration and ligand concentration were investigated. Results show that HNHMB is preferentially to bind with Mg2+ in ethanol. The addition of Mg2+ to the ligand in ethanol gives rise to a large hyerchromic shift resulting in a colour darkness. From the linear regression analysis, Beer’s law was obeyed in at least 0.1–1.4× 10-4 M. The complex showed maximum absorptions (λmax) at 396 nm.

Crystal structure of di-ethano-lbis(thio-cyanato)-bis(urotropine)cobalt(II) and tetra-ethano-lbis(thio-cyanato)-cobalt(II)-urotropine (1/2).

The reaction of one equivalent Co(NCS)2 with four equivalents of urotropine (hexa-methyl-ene-tetra-mine) in ethanol leads to the formation of two compounds, namely, bis-(ethanol-κO)bis-(thio-cyanato-κN)bis-(urotropine-κN)cobalt(II), [Co(NCS)2(C6H12N4)2(C2H6O)2] (1), and tetra-kis-(ethanol-κO)bis-(thio-cyanato-κN)cobalt(II)-urotropine (1/2), [Co(NCS)2(C2H6O)4]·2C6H12N4 (2). In 1, the Co cations are located on centers of inversion and are sixfold coordinated by two terminal N-bonded thio-cyanate anions, two ethanol and two urotropine ligands whereas in 2 the cobalt cations occupy position Wyckoff position c and are sixfold coordinated by two anionic ligands and four ethanol ligands. Compound 2 contains two additional urotropine solvate mol-ecules per formula unit, which are hydrogen bonded to the complexes. In both compounds, the building blocks are connected via inter-molecular O-H⋯N (1 and 2) and C-H⋯S (1) hydrogen bonding to form three-dimensional networks.

Photocatalytic Properties and Electronic Effects of Incorporation Bis(acetylacetonato) Ruthenium(II/III) Complexes with Bidentate Nitrogen and Sulfur Ancillaries

AbstractTreatment of cis‐[Ru(acac)2(CH3CN)2] (acac−=acetylacetonate) with 1.5 equiv. of corresponding bidentate nitrogen and sulfur ligands in ethanol gave a series of bis(acetylacetonato) ruthenium(II/III) complexes [(acac)2Ru(dimbpy)](PF6) (dimbpy=4,4′‐dimethyl‐2,2′‐bipyridine) (1), [(acac)2Ru(phen)] (phen=o‐phenanthroline) (2), [(acac)2Ru(opd)] (opd=o‐phenylenediamine) (3), [(acac)2Ru(4‐Bropd)] (4‐Bropd=4‐bromo‐o‐phenylenediamine) (4) and [(acac)2Ru(S2CNMe2)] (5), respectively. Complexes 1–5 were characterized by FT‐IR, NMR and UV‐Vis spectroscopies along with their electrochemical properties. The structures of complexes 1–5 have been unambiguously established by single crystal X‐ray crystallography. The photocatalytic properties for hydrogen production by water splitting of complexes 1–5 under visible light (λ>420 nm) were also investigated in the paper.

Synthesis, Identification, and Biological Study for Some Complexes of Azo Dye Having Theophylline.

This article includes the synthesis of heterocyclic azo dye of theophylline by coupling diazonium salt of 4-chloroaniline with theophylline which is, namely, 8-(1-(4-chlorophenyl)azo)theophylline (CPAT). The complexes of cobalt and nickel were prepared by reacting their ions with CPAT ligand in ethanol under 1 : 2 ratio metal-ligand. The CPAT ligand and its complexes were characterized by elemental analysis, infrared spectrometry, electronic absorption spectroscopy, molar conductivity, and magnetic moment. The cobalt and nickel complexes show octahedral geometry having general formula [M(CPAT)2Cl2]. This article addresses the properties of CPAT dye such as photochromic properties. The CPAT dye exhibited obvious and desired changes under irradiation with visible light (405 nm), high sensitive for pH changes which refer to its ability to be analysis indicator. CPAT dye exhibited solvatochromic properties presenting red shift with polar solvent. The CPAT and its complexes show interesting antibiological activities towards Staph. aureus and E. coli bacteria and Aspergillus fungi.

Ethanol(nitrato)[tris-(4-cyano-3-phenyl-1H-pyrazol-1-yl)hydroborato]nickel(II).

The synthesis and structure is reported of TpPh,4CNNi(NO3)(EtOH) or [Ni(C30H19BN9)(NO3)(C2H6O)], the first half-sandwich complex of a cyano-scorpionate ligand. The pseudo-octa-hedral coordination sphere of the NiII ion is comprised of a tridentate tris-(4-cyano-3-phenyl-pyrazol-yl)borate ligand, a bidentate nitrate ligand and a neutral ethanol ligand. The phenyl substituents on the TpPh,4CN ligand are relatively parallel to the planes of the ethanol and nitrate ligands. An inter-molecular hydrogen-bonding inter-action is evident between the ethanol OH group and the pyrazole CN substituent. The ethanol ligand was modeled with a 0.572 (13)/0.428 (13) disorder of the methyl C atom.

Synthesis, crystal structures and catalytic activity of oxidovanadium(V) complexes with tridentate ONO aroylhydrazone ligands

Two oxidovanadium(V) complexes, [VOL1(OEt)] (1) and [V2O2(L2)2(OEt)2] (2), where L1 and L2 are the anions of 2-amino-N′-(2-hydroxybenzylidene)benzohydrazide (H2L1) and N′-(2-hydroxybenzylidene)-4-hydroxybenzohydrazide (H2L2), respectively, have been synthesized and characterized by elemental analysis, infrared and electronic spectra, and 1H NMR spectra. Structures of the complexes were further confirmed by single-crystal X-ray determination. The V atom in the mononuclear complex 1 is in square pyramidal coordination, and those in the dinuclear complex 2 are in octahedral coordination. Both aroylhydrazone ligands coordinate to the V atoms through the phenolate O, imino N, and enolate O atoms. The ethanol ligand in complex 1 is in terminal coordination mode, while that in complex 2 is in bridging coordination mode. The complexes function as effective olefin epoxidation catalysts with hydrogen peroxide as terminal oxidant and sodium hydrogen carbonate as a co-catalyst.

Synthesis, structural characterization and photocatalytic water-oxidation properties of mononuclear bis(o-phenanthroline) ruthenium(II) complexes with dithiocarbamate ligands

Treatment of cis-[(phen)2RuCl2]∙2H2O (phen = o-phenanthroline) with one equivalent of dialkyl-dithiocarbamate ligands in ethanol afforded four mononuclear bis(o-phenanthroline) ruthenium(II) complexes [(phen)2Ru(S2CNR2)](PF6) (R = Me, 1; Et, 2; nPr, 3; nBu, 4). Complexes 1 − 4 were characterized by IR, NMR and UV–Vis spectroscopies and their electrochemical properties were also investigated. The structures of complexes 1 − 3 have been unambiguously established by single crystal X-ray crystallography. The photocatalytic properties towards water oxidation of complexes 1 − 4 driven by visible light (λ > 420 nm) in a three-component system containing a photosensitizer [Ru(bpy)3]2+ and an electron acceptor S2O82− were also investigated.

Effects of functional alkali in magnetorheological finishing fluid

Magnetorheological (MR) fluids can be utilized for ultra-precise finishing, for instance, in fused silica (FS) optics in giant laser system. However, few modification methods of MR fluid can improve the material removal rate (MRR) and surface quality of the finished optics simultaneously. In this study, we investigated the application of functional alkali additives in MR finishing fluid. MRR was doubled over the untreated MR fluid; meanwhile the surface roughness of the FS converged to 0.44 nm. Such excellent finishing performance can be mainly attributed to the dual functional effects of the triethanol amine (TEA) alkali, the hydroxides released by TEA contributes to the MRR increase and the steric hindrance effect of the ethanol ligands helps improve the surface quality.

Ligand role on insulin-mimetic properties of vanadium complexes. Structural and biological studies

The syntheses of 16 vanadium(IV and V) complexes with ONO tridentate Schiff base ligands are described. The vanadium(IV) compounds were synthesized with 1,10-phenantroline as a co-ligand. In the case of five complexes of vanadium(V), the solvent molecule in form of ethanol or ethoxy ligand fill the coordination sphere of V(V) to six. In the crystal structure of selected complexes the mixture of isomers in 1:1 ratio in the unit cell is observed as the ligand is not symmetrical and forms both 5- and 6-membered rings in complex. All complexes were characterized also by elemental analysis, IR and UV–Vis spectroscopy, magnetic and cyclic voltammetry measurements. The stability of the complexes in DMSO-H2O mixture was performed at pH = 7.0 and 2.0. The relationship between phosphatase inhibition and cytotoxicity of the compounds and the key role of organic ligands in enhancing biological activity of vanadium complexes was also discussed.

Some new morpholine-based Schiff-base complexes; Synthesis, characterization, anticancer activities and theoretical studies

A new morpholine-based ligand (2) has been prepared from condensation of a branched amine containing morpholine, N1-(3-morpholinopropyl)-N1-((pyridine-2-yl)methyl)ethane-1,2-diamine (1), and salicylaldehyde. Metal complexes were synthesized by reaction of the ligand and metal salts in ethanol and the resulting products were characterized by elemental analyses, ESI-MS, 1H and 13C NMR spectra, infrared, and UV–Vis spectroscopy. The structure of two complexes including [ZnL](ClO4) (3) and [NiHL](ClO4)·H2O (6a) have been determined by single crystal X-ray structural analysis, showing that the metal atoms are in a distorted trigonal bipyramidal (Zn) and a square planar (Ni) environment, respectively. Compounds were assayed for their anticancer activities against a panel of human tumor cell lines, including breast cancer cells (MCF-7, MDA-MB-231), prostate cancer cells (PC-3) and human normal lung fibroblast cells (WI-38). Compounds 1, 2, 7, 9 and 10 demonstrated lower activity against MCF-7, MDA-MB-231 and PC-3 cell lines (IC50s > 100 µM) compared to other compounds. It has been shown that complexes 3, 4, 5, 6, and 8 possess different anticancer potentials against MCF-7, MDA-MB-231 and PC-3. More importantly, it was observed that compounds 3, 5 and 6 demonstrate a lower activity against WI-38 normal cell line than they do against cancer cell lines. Our results indicated that compound 8 has the highest anticancer activity on cancer cell lines, and the reason for that can be attributed to the presence of a silver atom in the complex. These results clearly showed that the anticancer activities of these compounds depend on the type of metal in the complex as well as the tested cancer cell line. Furthermore, the geometries of the [ML]n+ (M = Zn2+, Cd2+, Mn2+, Cu2+, Ni2+, Ag+, Fe3+ and Co2+, n = 0, 1, 2) complexes have been optimized at the BP86/def2-SVP level of theory. The nature of M → L bonds in [ML]n+ complexes have been studied with the help of NBO analysis.

Synthesis, characterization, and cytotoxic activity studies of new N4O complexes derived from 2‐({3‐[2‐morpholinoethylamino]‐N3‐([pyridine‐2‐yl]methyl) propylimino} methyl)phenol

A new unsymmetrical five‐coordinate Schiff base ligand (HL) with an N4O donor set (2) has been prepared by condensation of N1‐(2‐morpholinoethyl)‐N1‐([pyridine‐2‐yl]methyl)propane‐1,3‐diamine with 2‐hydroxy‐benzaldehyde. Metal complexes [ML]n+ (M = Zn2+, Cd2+, Mn2+, Cu2+, Ni2+, Ag+, Fe3+, and Co2+ (3–10) were synthesized by the reaction of the ligand and metal salts in ethanol. The resulting products were characterized by elemental analyses, infrared, 1H and 13C nuclear magnetic resonance spectra (in the case of Cd and Zn complexes), UV–Vis, electrospray ionization‐mass spectrometric, and conductivity measurements. The structure of the complexes [ZnL](ClO4) (3), [CdL](ClO4) (4), and [CuL](ClO4) (7) has been determined by single‐crystal X‐ray diffraction analysis. The metal complexes were determined to have a distorted trigonal bipyramidal (Zn and Cd) or a distorted square pyramidal (Cu) geometry. The cytotoxic potential of each compound (1–10) against MCF‐7 and MDA‐MB‐231 (breast cancer cells), PC‐3 (prostate cancer cells), and WI‐38 human normal lung fibroblast cells was evaluated using the MTT (3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyl tetrazolium bromide) assay. Compounds 1, 2, and 10 did not display any activity toward any cell line tested. None of the compounds except compound 8 was cytotoxic toward PC‐3. Compounds 4 and 8 showed the highest cytotoxic activity against the MCF‐7 and MDA‐MB‐231 cell lines. Because compounds 3, 6, and 9 have similar half‐maximal inhibitory concentration values against cancer cells and normal cells, these compounds displayed poor selectivity between cancer and normal cells. More importantly, it was observed that compound 5 acts differently toward different types of cell lines. For example, it displays lower cytotoxicity against the WI‐38 normal cell line than it does against the MDA‐MB‐231 cell line.

Coordination of a triazine ligand with CuII and AgI investigated by spectral, structural, theoretical and docking studies.

Two complexes of 5-phenyl-3-(pyridin-2-yl)-1,2,4-triazine (PPTA), namely (ethanol-κO)bis(nitrato-κO)[5-phenyl-3-(pyridin-2-yl-κN)-1,2,4-triazine-κN2]copper(II), [Cu(NO3)2(C14H10N4)(C2H6O)] or [Cu(NO3)2(PPTA)(EtOH)] (1), and bis[μ-5-phenyl-3-(pyridin-2-yl)-1,2,4-triazine]-κ3N1:N2,N3;κ3N2,N3:N1-bis[(nitrato-κO)silver(I)], [Ag2(NO3)2(C14H10N4)2] or [Ag2(NO3)2(μ-PPTA)2] (2), were prepared and characterized by elemental analysis, FT-IR spectroscopy and single-crystal X-ray diffraction. The X-ray structure analysis of 1 revealed a copper complex with square-pyramdial geometry containing two O-donor nitrate ligands along with an N,N'-donor PPTA ligand and one O-donor ethanol ligand. In the binuclear structure of 2, formed by the bridging of two PPTA ligands, each Ag atom has an AgN3O environment and square-planar geometry. In addition to the four dative interactions, each Ag atom interacts with two O atoms of two nitrate ligands on adjacent complexes to complete a pseudo-octahedral geometry. Density functional theory (DFT) calculations revealed that the geometry around the Cu and Ag atoms in 1opt and 2opt (opt is optimized) for an isolated molecule is the same as the experimental results. In 1, O-H...O hydrogen bonds form R12(4) motifs. In the crystal network of the complexes, in addition to the hydrogen bonds, there are π-π stacking interactions between the aromatic rings (phenyl, pyridine and triazine) of the ligands on adjacent complexes. The ability of the ligand and complexes 1 and 2 to interact with ten selected biomacromolecules (BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR, TrxR, TS, Top II and B-DNA) was investigated by docking studies. The results show that the studied compounds can interact with proteins better than doxorubicin (except for TrxR and Top II).

High retreatability and dimensional stability of polymer grafted waterlogged archaeological wood achieved by ARGET ATRP

To explore new methods to maintain the dimensional stability of waterlogged archaeological wood after drying and keep the natural cell lumens unaltered for future retreatments, activator regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP) is employed to consolidate archaeological wood. To prepare the ATRP process, the waterlogged archaeological wood samples (Pinus massoniana with maximum moisture content of around 529%) were first modified by 2-bromoisobutyryl bromide in CH2Cl2 to acquire C-Br bonds as initiators. Then, butyl methacrylate or styrene was polymerized to the remaining cell walls with catalyst (CuBr2), reductant (ascorbic acid) and ligand (PMDETA) in ethanol. After the treatment, the samples were washed and naturally dried. The results characterized by microscopy showed that the polymerization only took place within the remaining cell walls, showing no sign of collapse or distortion after air drying, and all natural cell lumens could be retained for future retreatments. Also, anti-shrinkage efficiencies as high as 87.8% for the wood sample grafted with polystyrene and 98.5% for the wood sample grafted with polybutylmethacrylate were obtained from the treatment described in this paper, indicating modification of grafting polymer through ARGET ATRP can help maintain the dimensional stability of water archaeological wood effectively.