X-ray crystallographic,spectroscopic, and electrochemical properties of Group 12 metal-chlorides of di-2-pyridyl ketone acetic acid hydrazone (dpkaah)

Abstract

Di-2-pyridyl ketone acetic acid hydrazone hydrate, dpkaah.0.5H₂O (1), prepared from the acid catalyzed condensation of di-2-pyridyl ketone (dpk) with acetic acid hydrazide in refluxing ethanol, undergoes facile coordination to Group 12 metal-chlorides in CH₃CN to form [MCl₂(κ³-N,N,O-dpkaah)] {M=Zn (3), Cd (4) or Hg(5)}. X-ray structural analysis on single crystals of dpkaah (2) and 3–5 confirmed their identities and revealed pseudo-coordination of the carbonyl group (C=O). Infrared measurements confirmed the pseudo-coordination of the carbonyl group to MCl₂. The geometries of 3–5 vary, while 5 adopts a square pyramidal geometry, 4 has a structure halfway between square pyramidal and trigonal bipyramidal and 3 is less distorted from square pyramidal than 3. The extended structures of 3–5 exposed extensive networks of non-covalent interactions, and in the case of 4 chloride bridges of the type Cd(μ-Cl)₂Cd were observed. Spectroscopic measurements in different solvents and variable temperature studies confirmed the stability of the keto form of 1 and 3–5. Spectrophotometric titrations of protophilic solutions (dmf or dmso) of 1 with MCl₂ revealed facile coordination of MCl₂ to 1 and disclosed low concentrations of MCl₂ can be detected and determined using protophilic solutions of 1. Electrochemical measurements on dmf solutions divulged electrochemical decomposition of uncoordinated 1, the facile coordination of 1 to MCl₂, and the stability of 3–5 decreases as the size of the metal ion increases.     

Synthesis and analytical properties of di-2-pyridyl ketone guanylhydrazone

The synthesis and analytical properties of di-2-pyridyl ketone guanylhydrazone (DPGH) are described. The reagent was tested with 37 cations but only Co(II), Ni(II), Cu(II), Fe(II) and Pd(II) gave colored complexes. The spectral characteristics of the reagent and the above complexes as well as the procedures for a selective determination of total iron, cobalt(II), copper(II), nickel(II) and palladium(II) are reported.     

Physico-chemical properties of the first metal compound of di-2-pyridylketone p-nitrophenoxyacetic acid hydrazone (dpknxh), fac-Re(CO)3(κ2-Npy,Npy-dpknxh)Cl

Abstract

Di-2-pyridyl ketone p-nitrophenoxyacetic acid hydrazone (1), obtained from acid-catalyzed condensation of di-2-pyridyl ketone (dpk) with p-nitrophenoxyacetic acid hydrazide, reacts with Re(CO)₅Cl in refluxing toluene to form fac-Re(CO)₃(κ²-N_py,N_py-dpknxh)Cl (2). 1 and 2 were identified from the results of their elemental analyses, spectroscopic and electrochemical properties. X-ray structural analysis on single crystals of 1 and 2 grown from CH₃CN solutions and fac-Re(CO)₃(κ²-N_py,N_py-dpknxh)Cl·DMSO (3) grown from a DMSO solution of 2 confirmed their identities. Spectrophotometric titrations of protophilic solutions of 2 with protophilic solutions of NaBX₄ (X?=?H or F) divulged inter-conversion between the high- and low-energy ILCT transitions of 2 and its solvated complex. Substrates in low concentrations can be detected and determined using protophilic solutions of 2. Electrochemical measurements on 1 and 2 disclosed irreversible redox transformations leading to decomposition of 1 and 2 following the first electron transfer.     

Synthesis and Crystal Structure of Lanthanum Nitrate with Methyl－2－pyridyl Ketone Benzoyl Hydrazone

IntroductionThe coordination chemistry of Schiff base lig-ands has received more and more attention in thepast two decades[1— 4] .This kind of complexes pos-sesses a wide spectrum on biological and pharma-ceutical activities,such as antitumorand antioxida-tive activities[5,6] ,and studies on them are an inter-esting topic because of their electronic,magneticand photophysical properties[7] .Although a lot ofresearches have been reported,the studies con-cerned with the lanthanide complexes on t…     

Synthesis and characterization of metal 2-pyridine carboxaldehyde-N-methyl-N-2-pyridyl hydrazone complexes and their microbiological activity

Complexes of Cu(II), Mn(II), Co(II), Ni(II), Hg(II), Cd(II) and Rh(III) with 2-pyridine carboxaldehyde-N-methyl-N-2-pyridylhydrazone ( pamph) have been prepared and characterized. The new complexes have been characterized by elemental analysis, conductivity and magnetic measurements, IR, UV–vis and ¹H NMR spectroscopic methods. The microbiological activity of the complexes was investigated against bacteria and fungi. Most of the complexes studied appear to be active against bacteria while all are active against fungi. The Cu, Cd and Hg complexes exhibit the highest activity against both bacteria and fungi.     

Synthesis and Crystal Structure of a New Hexadentate Ligand N,N＇-Bis（di（2-pyridyl）methyl）ethylenediamine

The reaction of di(2-pyridyl)ketone with ethylenediamine produced hexadentate Schiff base 1 which can be reduced to form a new ligand N,N-bis(di(2-pyridyl)-methyl)ethylene- diamine (BDPM) in ethanol solution. The two compounds were characterized by elemental analyses and spectroscopic methods. Their structures were determined by X-ray diffraction study. Crystal data for 1: C24H20N6, Mr = 392.5, monoclinic, P21/c, a = 13.871(3), b = 13.510(2), c = 12.153(2) ? b = 112.97(2)? Z = 4, V = 2094.1(6) ?, Dc = 1.245 g/cm3, m(MoKa) = 0.078 mm-1, F(000) = 824, the final R = 0.0545 and wR = 0.0557 for 2048 observed reflections (I > 2s(I)); for BDPM: C24H24N6, Mr = 396.49, monoclinic, C2/c, a = 21.411(3), b = 8.053(1), c = 11.868(1) ? b = 92.63(1)? Z = 4, V = 2044.2(4) 3, Dc = 1.288 g/cm3, m(MoKa) = 0.080 mm-1, F(000) = 840, the final R = 0.0401 and wR = 0.0939 for 1673 observed reflections (I > 2s(I)).     

连二-2-吡啶酮三核钴簇合物的溶剂热合成及其晶体结构

用二-2-吡啶酮作为配体与羧酸钴在溶剂热中反应,得到两个新型连二-2-吡啶酮三核钴簇合物--Co3(Py2CO2H)2(PhCO2)5]·MeCN(1)和Co3(Py2CO)2(PhCO2)6(2),其结构经XRD, IR和元素分析表征.1属单斜晶系,P(2)1空间群,晶胞参数:a=1.068 7(3) nm, b=2.258 0(5) nm, c=1.163 9(3) nm, α=90.000°, β=104.805(5)°, γ=90.000°, V=2 715.6(4) nm3, Z=2, Dc=1.497 g·cm-3.2属三斜晶系,P-1空间群,晶胞参数:a=1.133 5(3) nm, b=1.140 8(3) nm, c=1.181 8(3) nm, α=85.59 8(6)°, β=75.973(5)°, γ=69.519(5)°, V=1 388.8(2), Z=1, Dc=1.521 g·cm-3.     

Synthesis and Crystal Structure of a New Hexadentate Ligand N,N''''-Bis(di(2-pyridyl)methyl)ethylenediamine

1 INTRODUCTION The interest in the development of new poly- pyridine ligands derives from several respects. The formation of a stable complex that can be used as a model for the active sites presents in some metallo- proteins. The uncoordinated donor at…     

Structural and spectral investigations on some new Ni(II) complexes of di-2-pyridyl ketone N(4)-phenylthiosemicarbazone

Ni(II) complexes (1–5) of di-2-pyridyl ketone N(4)-phenylthiosemicarbazone (HL) have been synthesized and spectrochemically characterized. Elemental analyses revealed a NiL₂ · 2H₂O stoichiometry for compound 1. However, the single crystals isolated revealed a composition NiL₂ · 0.5(H₂O)0.5(DMF). The compound crystallizes into a monoclinic lattice with the space group P2₁/n. Complexes 2, 3 and 4 are observed to show a 1:1:1 ratio of metal:thiosemicarbazone:gegenion, with the general formula NiLX · yH₂O [X = NCS, y = 2 for 2; X = Cl, y = 3 for 3 and X = N₃, y = 4.5 for 4]. Compound 5 is a dimer with a metal:thiosemicarbazone:gegenion ratio of 2:2:1, with the formula [Ni₂L₂(SO₄)] · 4H₂O.     

Zinc(II) complexes derived from di-2-pyridyl ketone N-phenyl-3-semicarbazone: Crystal structures and spectral studies

Six zinc(II) complexes, Zn(HL)Br₂ (1), Zn(HL)Cl₂ (2), ZnL(OAc) (3), ZnLN₃ (4), ZnL₂ (5) and ZnL₂ · H₂O (6), have been synthesized and characterized by different physicochemical techniques. Complex 1 is five coordinated and has a distorted square pyramidal geometry. Complexes 5 and 6 are six coordinated and have distorted octahedral geometries. In complexes 1 and 2, the ligand moieties are coordinated in the neutral form (HL), and in the other complexes they are monoanionic (L⁻).     

Structural and spectral studies on manganese(II) complexes of di-2-pyridyl ketone N(4)-methyl and N(4)-ethyl thiosemicarbazones

Four manganese(II) complexes of di-2-pyridyl ketone N(4)-methyl (HDpyMeTsc) and N(4)-ethyl thiosemicarbazones (HDpyETsc) were synthesized and physico-chemically characterized by means of partial elemental analyses, molar conductance measurements, electronic, infrared and EPR spectral studies. The complexes are represented as [Mn(DpyMeTsc)₂] (1), [Mn(HDpyMeTsc)Cl₂] (2), [Mn(HDpyMeTsc)₂](ClO₄)₂ · H₂O (3) and [Mn(DpyETsc)₂] · 2H₂O (4). The crystal structure of [Mn(DpyMeTsc)₂] was established by single crystal X-ray diffraction studies. The compound crystallizes into a monoclinic lattice with P2₁/n space group. Manganese(II) exists in a distorted octahedral geometry in the complex.     

Synthesis and biological evaluation of 4-methyl-1,2,3- thiadiazole-5-carboxaldehyde benzoyl hydrazone derivatives

To find new lead compounds with high biological activity,a series of novel 4-methyl-1,2,3-thiadiazole-5-carboxaldehyde benzoyl hydrazone derivatives were designed and synthesized.Their structures were confirmed by ~1H NMR,~(13)C NMR,IR spectrum and elemental analysis.Preliminary bioassay indicated that the title compounds exhibited moderate to strong fungicidal activity against six fungi in vitro at50 μg/mL.Moreover,some of the title compounds exhibited good curative activity against TMV in vivo at500 μg/mL.The structure-activity relationship analysis of compounds against Valsa mali showed that compounds containing halogen at the para position on phenyl exhibited the best activity.Especially compound 8k showed broad spectrum fungicidal activities against Valsa mali,Botrytis cinerea,Pythium aphamdermatum,Rhizoctonia solani,Fusarium moniliforme and Altemaria solani with the EC_(50) values of8.20,24.42,15.80,40.53,41.48,and 34.16 μg/mL,respectively.     

Synthesis and spectral studies of cadmium(II) complexes derived from di-2-pyridyl ketone and N-phenylsemicarbazide: First structural report of a cadmium(II) complex of semicarbazone

A new semicarbazone (HL) based on di-2-pyridyl ketone and its three cadmium(II) complexes [CdL(CH₃COO)]₂ · 2CH₃OH (1), Cd(HL)Br₂ (2) and [Cd₂L₂N₃]₂ · H₂O (3) were synthesized and characterized by different physicochemical techniques. The complex, [CdL(CH₃COO)]₂ · 2CH₃OH (1) is having a dimeric structure. In complexes 1 and 3, the ligand moieties are coordinated as monoanionic (L⁻) forms and in complex 2, the ligand is coordinated as neutral (HL) one. The coordination geometry around cadmium(II) in 1 is distorted octahedral, as obtained by X-ray diffraction studies.     

Synthesis and synchrotron X-ray characterization of two 2D Hoffman related compounds [Ni(p-Xylylenediamine)nNi(CN)4] and [Ni(p-tetrafluoroxylylenediamine)nNi(CN)4]

Synchrotron X-ray single crystal structure determination of two 2D Hofmann-related compounds, [Ni(p-Xylyenediamine)_n-tetracyanonickelate] (abbreviated as Ni-pXdam) and [Ni(tetrafluoro-p-Xylyenediamine)_n-tetracyanonickelate] (abbreviated as Ni-pXdamF4), have been conducted. Both the pXdam and pXdamF4 ligands contain two short chains of -CH₂NH₂ at the para-positions of a phenyl ring. These flexible chains link the 6-fold coordinated Ni2 sites throughout the network. In Ni-pXdam, the closed-2D network of [Ni-(CN-Ni_1/4-)₄]_∞ is broken into 1D chains, leaving the C≡N groups at the trans-positions of the Ni(CN)₄ moiety unbridged. The resulting 1D chains [(trans-)-NC-Ni(CN)₂-CN-Ni-]_∞ runs along the [010] direction of the unit cell. The pXdam ligands bridge in pair between the Ni atoms of the adjacent chains. The catenation structure of [Ni{(pXdam)}]_∞ could be referred to as double -1D. In Ni-pXdamF4, the -CH₂NH₂ ligands connect the neighboring chains via the 6-fold Ni2 site. Surrounding the 4-fold Ni1 site, the two trans terminal C≡N groups were replaced by the Lewis base NH₃ during the synthesis process, therefore preventing the propagation of the 2D net to form a 3D network. Computed pore volume of both compounds indicated that there is not sufficient space in the structure to accommodate gas molecules. In both compounds, hydrogen bonds were found, and solvent of crystallization was absent due to the limited free space in the structure.     

Synthesis,characterization and magnetic properties of mixed-valence iron complexes with 2-pyridyl oximes

Abstract

Two new mixed-valence iron complexes with 2-pyridyl oximes, [Fe(mpko)₃Fe(H₂O)₂(NO₃)](NO₃)·2H₂O (1) (mpko^? = methyl(2-pyridyl)ketone oximate) and [{Fe(dpko)₃}₂Fe](ClO₄)·4H₂O (2) (dpko^? = bis(2-pyridyl)ketone oximate), have been prepared by reaction of Fe^III with mpkoH in methanol (1) and Fe^II with dpkoH in methanol/water (2). Dinuclear Fe^II(low-spin)Fe^III(high-spin) and trinuclear Fe^II(low-spin)Fe^III(high-spin)Fe^II(low-spin) cations are present in the crystal structure of 1 and 2, respectively. Intermolecular hydrogen bonds in 1 lead to weak antiferromagnetic interactions between pairs of neighboring Fe^III centers, which allows observation of single-ion zero-field splitting effects.     

X-ray crystallographic structure and physical properties of the pentacoordinated [TPAFeCl] complex

A new pentacoordinated ferrous compound [TPAFeCl]⁺ (TPA = tris(2-pyridylmethyl)amine) was synthesized from the reaction between H₃TPA(ClO₄)₃ and Fe(PⁿPr₃)₂Cl₂ in MeCN. The unique trigonal bipyramidal [TPAFeCl]⁺ complex was characterized as a S = 2 high spin complex based on the crystallographic structure, magnetic susceptibility, ¹H NMR spectrum and semi-empirical ZINDO/S calculations. Crystal of [TPAFeCl]₂(FeCl₄)(MeCN)₂ was monoclinic with a = 12.019(2) Å, b = 27.550(5) Å, c = 14.138(2) Å, β = 94.168(3)°, V = 4668.9(13) Å³, space group C/c, and the unit cell contained a racemic mixture of Δ and Λ isomers with ferrous tetrachloride anion.     

Synthesis, crystal structure, antioxidation and DNA-binding properties of the Ln complexes with 1-phenyl-3-methyl-5-hydroxypyrazole-4-carbaldhyde-(benzoyl)hydrazone

Two lanthanide complexes (Ln = La, Pr) with a PMFP Schiff-base, 1-phenyl-3-methyl-5-hydroxypyrazole-4-carbaldhyde-(benzoyl)hydrazone (H₂L) were synthesized and characterized. The crystal structure of the La complex was determined by single-crystal X-ray diffraction, the coordination polyhedron is a tricapped trigonal prism configuration with the nine-coordinate atoms composed of three nitrogens and six oxygens from three ligands. The complex crystallized in the monoclinic lattice with a space group P2/c. Electronic absorption titration spectra, fluorescence titration spectra, EtBr competitive experiment, viscosity measurement and CD spectra indicate that all the complexes can strongly bind calf thymus DNA, presumably via groove binding and intercalation mechanism. Furthermore, investigations of antioxidation properties show that all the complexes have some scavenging effects for hydroxyl radicals.     

Synthesis and Structural Characterization of [Mn（sapn）（H2O）2]Br

1 INTRODUCTION Many of the recent advances in the coordination chemistry of manganese have been driven by the involvement of the manganese in several biological redox-active systems[1,2], of which the most important is the oxygen-evolving complex (EOC) of photosystem II (PS II) in green plants [3]. Since the preparations and structural characterizations of the complexes containing N,O-donor ligands have been studied extensively as simple active-site models for the photosystem II[4,5]…