Phenyl 2-pyridyl Ketoxime Research Articles

Synthesis and characterisation of new Ni2Mn, Ni2Mn2 and Mn8 clusters by the use of 2-pyridyl oximes

The initial employment of methyl 2-pyridyl ketoxime, (py)C(Me)NOH, in mixed metal Ni/Mn cluster chemistry, provided access to complexes [NiII2MnIII{(py)C(Me)NO}6](ClO4) (1) and [NiII2MnIII2{(py)C(Me)NO}6(OMe)2(MeOH)2](ClO4)2 (2) that display a linear and a zig-zag metal arrangement, respectively. 1 and 2 are synthesized by reacting Ni(ClO4)2·6H2O, (py)C(Me)NOH, Mn(ClO4)2·6H2O and NaOMe in different molar ratios (2:6:1:6, 1; 1:3:1:3, 2) in MeOH, and they are the first examples of 3d–3d′ mixed-metal clusters bearing (py)C(Me)NOH. The employment of phenyl 2-pyridyl ketoxime, (py)C(ph)NOH, instead of (py)C(Me)NOH, provided access to the octanuclear homometallic compound [MnII4MnIII4O4(NO3)2{(py)C(ph)NO}8(HCO2)2(MeOH)2] (3) that possesses a double-butterfly {MnII4MnIII4(μ4-O)2(μ3-O)2}12+ core. 3 joins the small family of Mn/(py)C(ph)NO− clusters. Variable-temperature, solid-state dc and ac magnetic susceptibility studies were carried out on 1 and 2 and revealed the presence of antiferromagnetic exchange interactions between the metal ions (JMn–Ni = −6.34 ± 0.14 cm−1 in 1;JMn–Ni = −4.57 ± 0.08 cm−1, JMn–Mn = −12.72 ± 0.12 in 2) and a diamagnetic ground state for both compounds.

Modeling the Solvent Extraction of Cadmium(II) from Aqueous Chloride Solutions by 2-pyridyl Ketoximes: A Coordination Chemistry Approach.

The goal of this work is to model the nature of the chemical species [CdCl2(extractant)2] that are formed during the solvent (or liquid-liquid) extraction of the toxic cadmium(II) from chloride-containing aqueous media using hydrophobic 2-pyridyl ketoximes as extractants. Our coordination chemistry approach involves the study of the reactions between cadmium(II) chloride dihydrate and phenyl 2-pyridyl ketoxime (phpaoH) in water-containing acetone. The reactions have provided access to complexes [CdCl2(phpaoH)2]∙H2O (1∙H2O) and {[CdCl2(phpaoH)]}n (2); the solid-state structures of which have been determined by single-crystal X-ray crystallography. In both complexes, phpaoH behaves as an N,N’-bidentate chelating ligand. The complexes have been characterized by solid-state IR and Raman spectra, and by solution 1H NMR spectra. The preparation and characterization of 1∙H2O provide strong evidence for the existence of the species [CdCl2(extractant)2] that have been proposed to be formed during the liquid-liquid extraction process of Cd(II), allowing the efficient transfer of the toxic metal ion from the aqueous phase into the organic phase.

Abstract 2847: Phenyl 2-pyridyl ketoxime induces cellular senescence-like alterations via NO production in human diploid fibroblasts

Abstract Phenyl-2-pyridyl ketoxime (PPKO) was found to be one of small molecules enriched in the extracellular matrix of near-senescent human diploid fibroblasts (HDFs). Treatment of young HDFs with PPKO reduced the viability of young HDFs in a dose and time-dependent manner, and resulted in senescence-associated β-galactosidase (SA-β-gal) staining and G2/M cell cycle arrest. In addition, the levels of some senescence-associated proteins, such as phosphorylated ERK1/2, caveolin-1, p53, p16ink4a, and p21waf1, were elevated in PPKO-treated cells. To monitor the effect of PPKO on cell stress responses, reactive oxygen species (ROS) production was examined by flow cytometry. After PPKO treatment, ROS levels transiently increased at 30 min but then returned to baseline at 60 min. The levels of some antioxidant enzymes, such as catalase, peroxiredoxin II, and glutathione peroxidase I, were transiently induced by PPKO treatment. SOD II levels increased gradually, whereas the SOD I and III levels were biphasic during the experimental periods after PPKO treatment. Cellular senescence induced by PPKO was suppressed by chemical antioxidants, such as N-acetylcysteine, 2,2,6,6-tetramethylpiperidinyloxy and L-buthionine-(S,R)-sulfoximine. Furthermore, PPKO increased nitric oxide (NO) production via inducible NO synthase (iNOS) in HDFs. In the presence of NOS inhibitors, such as L-NG-nitroarginine methyl ester and L-NG-monomethylarginine, PPKO-induced transient NO production and SA-β-gal staining were abrogated. Taken together, these results suggest that PPKO induces cellular senescence in association with transient ROS and NO production and the subsequent induction of senescence-associated proteins. Citation Format: Hyun-Jin Jang, Eunbi Jo, Young-Ho Chung, JunSoo Park, Sung-Jun Park, Ik-Soon Jang. Phenyl 2-pyridyl ketoxime induces cellular senescence-like alterations via NO production in human diploid fibroblasts. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2847.

Phenyl 2-pyridyl ketoxime induces cellular senescence-like alterations via nitric oxide production in human diploid fibroblasts.

Phenyl-2-pyridyl ketoxime (PPKO) was found to be one of the small molecules enriched in the extracellular matrix of near-senescent human diploid fibroblasts (HDFs). Treatment of young HDFs with PPKO reduced the viability of young HDFs in a dose- and time-dependent manner and resulted in senescence-associated β-galactosidase (SA-β-gal) staining and G2/M cell cycle arrest. In addition, the levels of some senescence-associated proteins, such as phosphorylated ERK1/2, caveolin-1, p53, p16(ink4a), and p21(waf1), were elevated in PPKO-treated cells. To monitor the effect of PPKO on cell stress responses, reactive oxygen species (ROS) production was examined by flow cytometry. After PPKO treatment, ROS levels transiently increased at 30 min but then returned to baseline at 60 min. The levels of some antioxidant enzymes, such as catalase, peroxiredoxin II and glutathione peroxidase I, were transiently induced by PPKO treatment. SOD II levels increased gradually, whereas the SOD I and III levels were biphasic during the experimental periods after PPKO treatment. Cellular senescence induced by PPKO was suppressed by chemical antioxidants, such as N-acetylcysteine, 2,2,6,6-tetramethylpiperidinyloxy, and L-buthionine-(S,R)-sulfoximine. Furthermore, PPKO increased nitric oxide (NO) production via inducible NO synthase (iNOS) in HDFs. In the presence of NOS inhibitors, such as L-NG-nitroarginine methyl ester and L-NG-monomethylarginine, PPKO-induced transient NO production and SA-β-gal staining were abrogated. Taken together, these results suggest that PPKO induces cellular senescence in association with transient ROS and NO production and the subsequent induction of senescence-associated proteins.

Formation of Ni(II) Oxime-Bridged Basket-Like Complexes and their Structural Aspects

Two new Ni(II) complexes with phenyl 2-pyridyl ketoxime ligand are reported, displaying unprecedented basket-like topologies of their complex cores. The compounds are studied by X-ray diffraction, EDX and IR spectroscopy, confirming uncommon coordination of a DMF ligand in one of them.The reaction system is described in detail and some of the products are analyzed by EDX/SEM, including EDX mapping analyses of the elemental distribution. Keywords: Crystal structure, EDX, hydrogen bonding, IR, metal complex, nickel(II), oxime, perchlorate, SEM, synthesis.

Syntheses, structures, in vitro cytotoxicities and DNA-binding properties of four copper complexes based on a phenyl 2-pyridyl ketoxime ligand

Four complexes [Cu6L6(µ4–O)2(dca)2] (1), [Cu3L3(µ3–OH)Cl2] (2), [Cu3L3(µ3–OH)(OAc)2]·py (3) and [Cu2L4] (4) (HL = phenyl 2-pyridyl ketoxime; dca = dicyanamide anion) have been synthesized and characterized by physicochemical and spectroscopic methods. The structures of all three complexes consist of a single or off-set stacked inverse 9-MC-3 metallacrown formed by three L− ligands and three Cu atoms, and all of the Cu atoms are located in square planar or square pyramidal geometries with different apical ligands. In complex 4, four L− ligands link two Cu atoms to form a dinuclear structure, and the Cu atoms adopt square pyramidal coordination geometry. The in vitro cytotoxicities against four cell lines (A549, HL-60, HT-29 and HCT-116) have been assayed by colorimetric MTT assay. In addition, all four complexes interact strongly with calf thymus DNA, which may be directly responsible for their antitumor activities.

Iridium(III) products isolated in a reaction of IrCl3 with phenyl 2-pyridyl ketoxime

Abstract Synthesis and properties of two iridium(III) complexes (1 and 2) isolated from the same system upon change in organic solvent, are presented. 1 is a mononuclear compound with two bidentate oxime ligands linked by a strong intramolecular hydrogen bond and with two chlorido ligands in the central Ir3+ ion coordination sphere. 2 is a binuclear centrosymmetric anionic complex with two Ir3+ ions double-bridged by chlorido ligands and three terminal chlorido ligands further coordinated to two sodium cations to form a characteristic aggregate with acetonitrile molecules completing coordination spheres of the metal ions. Both 1 and 2 may help to develop a route to products analogous to Co(II) SMMs (Single Molecule Magnets) also as starting materials.

Mononuclear manganese(II) complexes of phenyl 2-pyridyl ketoxime – models for studies of Q-band EPR properties

Abstract Structure and properties of a series of mononuclear manganese(II) complexes with phenyl 2-pyridyl ketoxime (ppkoH) as ligand are presented. [Mn(ClC6H4COO)2 (ppkoH)2] · 0.5 CH3OH and [Mn(ClC6H4COO)2(ppkoH)2](1 and 2) are isolated from the same reaction system and differ by disordered solvent content and conformation of the complex molecules. [MnCl2(ppkoH)2] · 0.02 C2H5OH(3) was obtained in order to modify the central Mn2+ ion coordination sphere with respect to 1/2. Strong intramolecular hydrogen bonds of the O–H···O and O–H···Cl type are present in 1/2 and 3, respectively. Moreover, weak C–H···O (1–3), C–H···Cl (3), π···π (1–2) and Cl···π (2) contacts can be found. The complexes display well-resolved Q-band EPR spectra and may serve as model compounds for further studies.

Structure and properties of a rare-topology [MnII4]-core complex with terminal bromido ligands

A rare-topology [Mn II 4 ]-core complex [Mn 4 Br 4 (ppko) 4 (CH 3 OH) 4 ] ( 1 ; ppkoH = phenyl 2-pyridyl ketoxime) was synthesized via a solvothermal route and characterized by X-ray diffraction, IR, EPR, ESI-MS and magnetic properties measurements. In 1 Mn 2+ ions are bridged with phenyl 2-pyridyl ketoxime ligands. Bromine atoms and methanol molecules are terminal ligands. A comparison is made to the reported analogues with different terminal ligands pattern.

Mixed-valent tetranuclear manganese complexes with an {MnII3MnIV} core

Abstract Two new examples of mixed-valent phenyl 2-pyridyl ketoxime complexes with an {Mn II 3 Mn IV -μ 4 -O} core are presented: cationic {Mn II 3 Mn IV O(OH)[Ph(py)CNO] 3 [Ph(py)CNOH](ClC 6 H 4 COO) 3 } + ( 1 ) and neutral {Mn II 3 Mn IV O[Ph(py)CNO] 4 (IC 6 H 4 COO) 4 } ( 2 ), representing two different structural types (types I and II, respectively). Also preliminary data are mentioned for two further complexes with (2-pyrimidylthio)acetate ( 3 ) or 2-(methylthio)nicotinate ( 4 ) ligands. 1 and 2 differ in magnetic properties, 1 representing the first {Mn II 3 Mn IV -μ 4 -O}-core cationic complex with dominating antiferromagnetic interactions.

A chiral copper(II) inverse-9-metallacrown-3 complex: Synthesis, crystal structure, ferroelectric and magnetic properties

The reaction of phenyl 2-pyridyl ketoxime (PhPyCNOH) with Cu(NO3)2·3H2O in methanol results in the chiral trinuclear complex [Cu3(OH)(PhPyCNO)3(NO3) (CH3OH)]·(NO3) (1), which has been characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. The structure of 1 exhibits a triangle of Cu(II) ions, centered by a triply bridging hydroxo ligand and with three edge-bridging oximate groups from the three PhPyCNO− ions. Preliminary variable-temperature magnetic susceptibility studies reveal an antiferromagnetically-coupled system showing antisymmetric exchange. Complex 1 crystallizes in an acentric space group (P21) that belongs to a polar point group, which displays second harmonic generation response and ferroelectric behavior, and provides a new strategy for designing functional coordination complexes.

A Trinuclear Cu(II) Complex from the Use of Phenyl 2-Pyridyl Ketoxime: Structure and Magnetic Behavior

The reaction of phenyl 2-pyridyl ketoxime (PhPyCNOH) with Cu(BF 4 ) 2 · 6H 2 O in methanol results in the trinuclear complex [Cu 3 (OH)(PhpyCNO) 3 (H 2 O)](BF 4 ) 2 (1), which has been characterized by elemental analyses, IR spectrum and single-crystal X-ray diffraction techniques. The structure of 1 exhibits a triangle of Cu(II) ions, centered by a triply bridging hydroxo ligand and with three edge-bridging oximate groups from the three PhPyCNO− ions. The Cu 3 OH units have an average Cu-O distance of 1.962(4) Å, an average Cu-Cu distance of 3.177(4) Å, and an average Cu-O-Cu angle of 108.2(2)°. Variable-temperature magnetic susceptibility studies reveal an antiferromagnetically-coupled system showing antisymmetric exchange.

Copper inverse-9-metallacrown-3 compounds interacting with DNA

Interaction of phenyl 2-pyridyl ketoxime (PhPyCNO)/X(-)"blends" (X(-) = OH(-), Cl(-), ClO(4)(-), 2,4-D) (2,4-DH = 2,4-dichlorophenoxyacetic acid) with copper perchlorate has yielded trinuclear clusters that have been characterized as inverse-9-metallacrown-3, accommodating one or two anions. The structure of the complex [Cu(3)(PhPyCNO)(3)(mu(3)-OH)(2,4-D)(2)] x 1.25CH(3)OH.0.25CH(3)CN (1) has been determined by single-crystal X-ray crystallography. Spectroscopic studies of the interaction of copper inverse {(OH)[9-MC(CuN(PhPyCNO))-3]} metallacrowns with DNA showed that these compounds bind to dsDNA by intercalative mode with an additional covalent {(OH)[9-MC(Cu(PhPyCNO))-3]}-DNA interaction leading to hydrolytic cleavage of DNA that may be assigned to the presence of the hydroxyl group in the inverse metallacrown ring. The binding strength of [Cu(3)(PhPyCNO)(3)(mu(3)-OH)(2,4-D)(2)] (1) complex for CT-DNA was determined to be 0.56 x 10(5) M(-1). All the complexes exhibited the ability to displace the DNA-bound EthBr. DNA electrophoretic mobility experiments showed that all complexes, at low cluster concentration, are capable of binding to pDNA and linear DNA. At higher cluster concentration and in the absence of any reducing agent they showed marked chemical nuclease activity.

Experimental and Theoretical Study of the Antisymmetric Magnetic Behavior of Copper inverse-9-Metallacrown-3 Compounds

Use of PhPyCNO (-)/X (-) "blends" (PhPyCNOH = phenyl 2-pyridyl ketoxime; X (-) = OH (-), alkanoato, ClO 4 (-)) in copper chemistry yielded trinuclear clusters that have been characterized as inverse-9-metallacrown-3 compounds and accommodate one or two guest ligands. The magnetic behavior showed a large antiferromagnetic interaction and a discrepancy between the low-temperature magnetic behavior observed experimentally and that predicted from a magnetic model. The discrepancy between the Brillouin curve and the experimental result provides clear evidence of the influence of the antisymmetric interaction. Introducing the antisymmetric terms derived from the fit of the susceptibility data into the magnetization formula caused the simulated curve to become nearly superimposable on the experimental one. The EPR data indicated that the compound [Cu 3(PhPyCNO) 3(mu 3-OH)(2,4,5-T) 2] ( 1), where 2,4,5-T is 2,4,5-trichlorophenoxyacetate, has isosceles or lower magnetic symmetry (delta not equal 0), that antisymmetric exchange is important ( G not equal 0), and that Delta E > hnu. The structures of the complexes 1 and [Cu 3(PhPyCNO) 3(mu 3-OH)(H 2O)(ClO 4) 2] ( 2) were determined using single-crystal X-ray crystallography. Theoretical calculations based on density functional theory were performed using the full crystal structures of 1, 2, [Cu 3(PhPyCNO) 3(OH)(CH 3OH) 2(ClO 4) 2] ( 3), and [Cu 3(PhPyCNO) 3(mu 3-OMe)(Cl)(ClO 4)] ( 4). The geometries of the model compounds [Cu 3(kappa (3) N, N, O-HNCHCHNO) 3(mu 3-OH)(mu 2-HCOO)(HCOO)] ( 5), [Cu 3(kappa (3) N, N, O-HNCHCHNO) 3(mu 2-HCOO)(HCOO)] (+) ( 6), [Cu 3(kappa (3) N, N, O-HNCHCHNO) 3(mu 3-O)] (+) ( 7), and [Cu 3(kappa (3) N, N, O-HNCHCHNO) 3] (3+) ( 8) were optimized at the same level of theory for both the doublet and quartet states, and vibrational analysis indicated that the resulting equilibrium geometries corresponded to minima on the potential energy surfaces. Both e g and t 2g magnetic orbitals seem to contribute to the magnetic exchange coupling. The latter contribution, although less important, might be due to overlap of the t 2g orbitals with the p-type orbitals of the central triply bridging oxide ligand, thereby affecting its displacement from the Cu 3 plane and contributing to the antiferromagnetic coupling. The crucial role of the triply bridging oxide (mu 3-O) ligand on the antiferromagnetic exchange coupling between the three Cu(II) magnetic centers is further evidenced by the excellent linear correlation of the coupling constant J with the distance of the mu 3-O ligand from the centroid of the Cu 3 triangle.

Copper inverse-9-metallacrown-3 compounds showing antisymmetric magnetic behaviour

The use of phenyl 2-pyridyl ketoxime (PhPyCNO)/X(-)"blends" (X(-) = OH(-), Cl(-), ClO(4)(-)) in copper chemistry has yielded trinuclear clusters that have been characterized as inverse-9-metallacrown-3 accommodating one or two anions. The magnetic behaviour has shown a large antiferromagnetic interaction. The discrepancy between the Brillouin curve and the experiment has been assigned to the influence of the antisymmetric interaction. By introducing in the magnetization formula the antisymmetric terms derived from the fitting of the susceptibility data the simulated curve become almost superimposable to the experimental one. From the EPR findings it has been shown that the compound [Cu(3)(PhPyCNO)(3)(OCH(3))(Cl)(ClO(4))] () having isosceles magnetic symmetry or lower (delta not equal 0), the antisymmetric exchange is important (G not equal 0) and DeltaE > hv. The structures of the two complexes have been determined by single-crystal X-ray crystallography.

Synthesis, structural characterization and reactivity of triosmium carbonyl clusters containing oxime ligands

Reaction of [Os3(CO)11(NCMe)] with phenyl 2-pyridyl ketoxime produced the clusters [Os3(CO)8{μ-η3-ONCPh(NC5H4)}2] 1 and [Os3H(CO)11{η2-ONCPh(NC5H4)}] 2 in 4 and 17% yields, respectively. Oxidative addition of the oximes to the clusters with O–H bond cleavage and the loss of labile acetonitrile groups, and in the case of complex 1 decarbonylation, are observed. Cluster 2 possesses an open linear metal skeleton attached to both the pyridine nitrogen and oximato nitrogen on one terminal Os atom. Heating 2 in refluxing toluene gave [Os3(μ-H)(CO)9{µ-η3-ONCPh(NC5H4)}] 3 in 13% yield. Treatment of a CH2Cl2 solution of [Os3(CO)10(NCMe)2] with phenyl 2-pyridyl ketoxime at ambient conditions afforded the bridging oximato clusters 1 and 3 in moderate yields. Cluster 3 and 1 equiv. of phenyl 2-pyridyl ketoxime in refluxing toluene led to conversion to clusters 1 and [Os3(CO)8{μ-η3-ONCPh(NC5H4)} {μ-η2-N(H)CHPh(NC5H4)}] 4 in 12 and 16% yields, respectively. In cluster 4, one of the oximato moieties is deoxygenated with N–O bond cleavage. Treatment of another oxime ligand, benzophenone oxime, with [Os3(CO)10(NCMe)2] gave [Os3(μ-H)(CO)10{μ-η2-ONCPh2}] 5 in moderate yield. On thermolysis of 5 in toluene, [Os3(μ-H)2(CO)9{μ-η3-ONCPh(C6H4)}] 6 and [Os3(CO)10(μ-OH){μ-NCPh2}] 7 were isolated in 27 and 21% yields, respectively. The oxime ligand in 6 is converted to a tridentate ligand. In addition to the μ-η2-oximato N–O bridge, the phenyl carbon on the ligand coordinates to the cluster core by ortho-metallation. Cluster 5 isomerizes thermally to 7, which is formed by oxidative addition of the oxime with N–O bond cleavage. A μ4-oxo hexaosmium cluster, [Os6(CO)16(μ4-O){μ-η3-NCPh(C6H4)}2] 8, was isolated in low yield upon refluxing 5 in octane. Vacuum pyrolysis of 5 in 140 °C yielded a pentaosmium carbonyl cluster, [Os5(CO)15{μ-η3-NCPh(C6H4)}] 9. All these clusters have been fully characterized by both spectroscopic and crystallographic techniques.

Rates of syn—anti Isomerization of Phenyl 2-Pyridyl Ketoxime1

Rates of syn—anti Isomerization of Phenyl 2-Pyridyl Ketoxime¹