Iron(III) and nickel(II) template complexes derived from benzophenone thiosemicarbazones

New iron(III) and nickel(II) chelates were synthesized by template reaction of 2,4-dihydroxy- and 2-hydroxy-4-methoxy-benzophenone S-methylthiosemicarbazones with 2-hydroxy- and 5-bromo-2-hydroxy-benzaldehydes. The template complexes were isolated as stable solids and characterized by elemental analysis, conductivity and magnetic measurements, IR, ¹H NMR, UV–Visible, and mass spectra. The crystal structure of N ¹-(2-hydroxy-4-methoxyphenyl)(phenyl)methylene-N ⁴-(2-hydroxy-phenyl)methylene-S-methyl-thiosemicarbazidato-Fe(III) was determined by X-ray diffraction. A five-coordinate, distorted square-pyramidal geometry was established crystallographically for the iron(III) complex. Cytotoxicity and proliferation properties were determined using human erythromyeloblastoid leukemia and HL-60 mouse promyelocytic leukemia cell lines. For K 562 and HL-60 cells, compounds 1a and 2b were found to be cytotoxic at concentrations of 10 and 20 µg mL^?1.     

Directed synthesis of a heterobimetallic complex based on a novel unsymmetric double-Schiff-base ligand: preparation, characterization, reactivity and structures of hetero- and homobimetallic nickel(II) and zinc(II) complexes

A series of bimetallic zinc(II) and nickel(II) complexes based on the novel dinucleating unsymmetric double-Schiff-base ligand benzoic acid [1-(3-{[2-(bispyridin-2-ylmethylamino)ethylimino]methyl}-2-hydroxy-5-methylphenyl)methylidene]hydrazide (H(2)bpampbh) has been synthesized and structurally characterized. The metal centers reside in two entirely different binding pockets provided by the ligand H(2)bpampbh, a planar tridentate [ONO] and a pentadentate [ON(4)] compartment. The utilized ligand H(2)bpampbh has been synthesized by condensation of the single-Schiff-base proligand Hbpahmb with benzoic acid hydrazide. The reaction of H(2)bpampbh with two equivalents of either zinc(II) or nickel(II) acetate yields the homobimetallic complexes [Zn(2)(bpampbh)(mu,eta(1)-OAc)(eta(1)-OAc)] (ZnZn) and [Ni(2)(bpampbh)(mu-H(2)O)(eta(1)-OAc)(H(2)O)](OAc) (NiNi), respectively. Simultaneous presence of one equivalent zinc(II) and one equivalent nickel(II) acetate results in the directed formation of the heterobimetallic complex [NiZn(bpampbh)(mu,eta(1)-OAc)(eta(1)-OAc)] (NiZn) with a selective binding of the nickel ions in the pentadentate ligand compartment. In addition, two homobimetallic azide-bridged complexes [Ni(2)(bpampbh)(mu,eta(1)-N(3))]ClO(4) (NiNi(N(3))) and [Ni(2)(bpampbh)(mu,eta(1)-N(3))(MeOH)(2)](ClO(4))(0.5)(N(3))(0.5) (NiNi(N(3))(MeOH)(2)) were synthesized. In all complexes, the metal ions residing in the pentadentate compartment adopt a distorted octahedral coordination geometry, whereas the metal centers placed in the tridentate compartment vary in coordination number and geometry from square-planar (NiNi(N(3))) and square-pyramidal (ZnZn and NiZn), to octahedral (NiNi and NiNi(N(3))(MeOH)(2)). In the case of complex NiNi(N(3)) this leads to a mixed-spin homodinuclear nickel(II) complex. All compounds have been characterized by means of mass spectrometry as well as IR and UV/Vis spectroscopies. Magnetic susceptibility measurements show significant zero-field splitting for the nickel-containing complexes (D=2.9 for NiZn, 2.2 for NiNi(N(3)), and 0.8 cm(-1) for NiNi) and additionally a weak antiferromagnetic coupling (J=-1.4 cm(-1)) in case of NiNi. Electrochemical measurements and photometric titrations reveal a strong Lewis acidity of the metal center placed in the tridentate binding compartment towards external donor molecules. A significant superoxide dismutase reactivity against superoxide radicals was found for complex NiNi.     

Synthesis and characterization of azo-linked Schiff bases and their nickel(II), copper(II), and zinc(II) complexes

Azo compounds were prepared by coupling of benzenediazonium chloride ions with 1-amino-2-hydroxy-4-naphthalene sulfonic acid under alkaline conditions, and Schiff bases, L_1–3 were then obtained by the condensation of 1-amino-2-hydroxy-3-(phenylazo)-4-naphthalene sulfonic acid, 1-amino-2-hydroxy-3-(4-ethylphenylazo)-4-naphthalene sulfonic acid, and 1-amino-2-hydroxy-3-(4-nitrophenylazo)-4-naphthalene sulfonic acid with salicylaldehyde. New copper(II), nickel(II), and zinc(II) complexes of the Schiff base ligands were also prepared and characterized by spectroscopic methods, magnetic measurements, elemental, and thermogravimetric analysis.     

Eine neue photometrische bestimmung für nickel mit aethylendiamintetraessigsäure

It is possible to determine very high concentrations of nickel photometrically by means of ethylenediaminetetra-acetic acid, by working at a pH between 4.55 and 6.82. The absorption curves obtained for this complex are very reproducible; for these measurements an Elko II apparatus with filter S57E is used. High concentrations of ammoniacal salts hinder the measurement. The formation of the complex is not influenced by the anion of the compound of nickel used. The Lambert-Beer law is followed for strengths of nickel of 40 — 5000 mg/100 ml. This procedure is convenient for alloys rich in nickel.     

Transition metal bisdithiolene complexes based on extended ligands with fused tetrathiafulvalene and thiophene moieties: new single-component molecular metals

The gold and nickel bisdithiolene complexes based on new highly extended ligands incorporating fused tetrathiafulvalene and thiophene moieties (alpha-tdt=thiophenetetrathiafulvalenedithiolate and dtdt=dihydro- thiophenetetrathiafulvalenedithiolate), were prepared and characterised by using cyclic voltammetry, single crystal X-ray diffraction, EPR, magnetic susceptibility and electrical transport measurements. These complexes, initially obtained under anaerobic conditions as diamagnetic gold monoanic [nBu(4)N][Au(alpha-tdt)(2)] (4), [nBu(4)N][Au(dtdt)(2)] (3) and nickel dianionic species [(nBu(4)N)(2)][Ni(alpha-tdt)(2)] (8), [(nBu(4)N)(2)][Ni(dtdt)(2)] (7), can be easily oxidised to the stable neutral state just by air or iodine exposure. The monoanionic complexes crystallise in at least two polymorphs, all of which have good cation and anion segregation in alternated layers, the anion layers making a dense 2D network of short SS contacts. All of the neutral complexes, obtained as microcrystalline or quasi amorphous fine powder, present relatively large magnetic susceptibilities that correspond to effective magnetic moments in the range 1-3 mu(B) indicative of high spin states and very high electrical conductivity that in case of the Ni compound can reach sigma(RT) approximately 250 S cm(-1) with a clear metallic behaviour. These compounds are new examples of the still rare single-component molecular metals.     

Synthesis, Crystal Structure Determination, and Physicochemical Study of the Nickel(II) Complex of 4-(Pyridyl-2)-1,2,4-triazole

A new trinuclear nickel(II) complex with 4-(pyridyl-2)-1,2,4-triazole (pytrz), [Ni₃(pytrz)₆(H₂O)₆](NO₃)₆, has been synthesized, and its crystal structure has been determined. The compound was studied by X-ray phase analysis (XRPA), magnetochemical measurements, and electronic and IR spectroscopy.     

Thermal and electrical behaviour of nickel(II) and copper(II) complexes of 4-acetylamino-2-hydroxy-5-methylazobenzene

The thermal behaviour of the entitled nickel(II) and copper(II) complexes of ¯4-acetylamino-2-hydroxy-5-methyl azobenzene has been studied by means of differential thermal analysis (DTA), thermogravimetry (TG), X-ray powder diffraction, IR and electrical conductivity. A light has been thrown on the nature of interaction of the solvents of crystallization with the host complex. Some of the kinetic parameters are calculated and discussed.     

Cobalt(II), nickel(II), and copper(II) complexes with Schiff bases, derivatives of 1-amino-8-hydroxynaphthalene-2,4-disulfonic acid

Five new cobalt(II), nickel(II), and copper(II) complexes with Schiff bases have been synthesized. The Schiff bases have been prepared by the condensation of monopotassium 1-amino-8-hydroxynaphthalene-2,4-disulfonate with benzoin (L¹) or 2-hydroxy-1-naphthaldehyde (L²). The compounds have been identified and studied by elemental analysis, X-ray diffraction, thermogravimetry, measurements of magnetic susceptibility and electrical conductivity, and IR, ESR, and diffuse reflectance spectroscopy. The dimeric (with oxo bridges) structure of the Co(II) complex with L¹ has been additionally confirmed by the EXAFS method.     

Hydrogenation of 4-(2-furyl)-2-oxobutenoic acid sodium salt on Raney nickel

The hydrogenation of 4-(2-furyl)-2-oxobutenoic acid sodium salt on a nickel catalyst has been studied. Using Raney nickel catalyst, the corresponding salts of 4-(2-furyl)-2-oxobutanoic acid, 4-(2-furtyl)-2-hydroxybutanoic acid, and aliphatic hydrogenolysis products of the initial compound were obtained. The sodium salt of 2-hydroxy-4-(2-tetrahydrofuryl) butanoic acid and the condensation product 4-(2-furylethyl)-3-(2-furylmethyl)-2-oxo-3,4-didehydroglutaric acid were detected in the hydrogenolysate. A method has been developed for obtaining the sodium salts of 4-(2-furyl)-2-oxobutanoic and 4-(2-furyl)-2-hydroxybutanoic acids.Latvian Institute of Organic Synthesis, Riga LV-1006, e-mail: elmira@osi.lanet.lv. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 41–45, January, 1998.     

Synthesis, structure and magnetism of a new ferromagnetic hexanuclear nickel cluster with a dicubane-like core

A new ferromagnetic nickel(II) hexameric structure based on the versatile N,O3-ligand 2,2',2"-nitrilotribenzoic acid has been prepared and characterised by X-ray crystallography and magnetic measurements; the compound represents a rare example of a nickel cluster with a dicubane-like core having only oxygen bridges.     

The coordination chemistry of macrocyclic diamides. Transition metal complexes of 5,7-dioxo-1,4,8,11-tetraazacyclotetradecane

Summary A convenient preparation of the 14-membered macrocyclic diamide 5,7-dioxo-1,4,8,11-tetraazacyclotetradecane (LH₂) is described. The pK _NH ⁺ values of the ligand are pK₁ = 5.76 and pK₂ = 9.63 at 25° and I = 0.1 mol dm^–3 (KNO₃). With metal ions able to ionise amide hydrogens, the ligand acts as a planar quadridentate, L^2–. Thus copper(II) and nickel(II) give the neutral complexes ML, and conductivity measurements confirm that they are nonelectrolytes in aqueous solution. Both the nickel(II) and copper(II) complexes are acid labile unlike the analogues of 1,4,8,11-tetraazacyclotetradecane (cyclam).The cobalt(III) complex [CoL(NH₃)₂]Cl has been characterised and¹H n.m.r. measurements established the N-meso stereochemistry at the chiral nitrogen centres.     

混合配体镍配合物[Ni（NCS）2（phen）2]的合成、晶体结构及荧光性质

合成了含异硫氰酸根和邻菲咯啉（phen）混合配体的镍配合物[Ni（NCS）2（phen）2],通过红外光谱、紫外光谱和X射线单晶衍射等手段对其结构进行了表征.研究了配合物的固体荧光光谱.单晶结构解析结果表明,标题化合物属于正交晶系,Pbcn空间群,晶胞参数为：a=1.296 2（2）nm,b=1.019 0（1）nm,c=1.759 5（2）nm,V=2.323 9（4）nm3,Z=4,Dc=1.530 g/cm3,μ=1.043 mm-1,F（000）=1 096,R1=0.042 1,wR2=0.108 1.配合物中镍离子采用6配位的八面体配位构型,晶体堆积中通过π-π作用形成一维超分子结构.     

镉配合物的合成、晶体结构与荧光性质

用水热合成法得到了镉的2个配合物[CdCl(pybma)·H₂O]_n (1)和[Cd₂(pybma)₂(OH-BDC)]_n (2)(Hpybma=2-(2-吡啶基)苯并咪唑基乙酸, OH-H₂BDC=5-羟基-1,3-苯二酸),对它们进行了元素分析、红外光谱、XRD,热重,荧光等表征,并用X-射线单晶衍射测定了配合物的单晶结构。配位聚合物1属单斜晶系,P2₁/c空间群, 配位聚合物2属三斜晶系,P1 空间群。2个配合物都是二维层状结构,其中配合物1通过氢键作用形成三维网状结构。实验结果表明2个配合物都具有较好的荧光性质,可以作为潜在的荧光光学材料。     

Synthesis and characterization of some Schiff base transition metal complexes derived from vanillin and L(+)alanine

The cobalt(II), nickel(II), copper(II) and zinc(II)-vanillidene-L(+)alanine complexes were synthesized and characterized by elemental analysis, conductivity measurements, magnetic behavior, infrared, electronic spectral measurements, X-ray powder diffraction and biological studies. The conductance measurements indicate that all the complexes are non-electrolytes. The infrared spectra indicate the coordination of imino nitrogen, phenolic oxygen and carboxylato oxygen atoms. The electronic spectral measurements demonstrate that cobalt(II) and nickel(II)-vanillidene-L(+)alanine complexes are tetrahedral, while copper(II)-vanillidene-L(+)alanine complex has square planar geometry. The cobalt(II) complex is found to be ferromagnetic. The powder XRD studies confirm the crystalline nature of the complexes. The ligand and complexes were less active against PN, PA and BC, whereas copper complex shows moderate activity against AN.     

Concentration Effects in the Hydrogenation of 4-Nitro-2′-Hydroxy-5′-Methylazobenzene over Skeletal Nickel in an Aqueous 2-Propanol Solution

The kinetics of hydrogenation of 4-nitro-2′-hydroxy-5′-methylazobenzene in aqueous 2-propanol solution over the skeletal nickel is investigated at different initial concentrations. It is established that the hydrogenation of 4-nitro-2′-hydroxy-5′-methylazobenzene over a skeletal nickel in azeotropic aqueous 2-propanol solution proceeds via two parallel pathways at both low and high initial concentrations. It is shown that increasing the initial concentration of the hydrogenated compound above its level of solubility raises the rate of azo group transformation in 4-nitro-2′-hydroxy-5′-methylazobenzene, while the content of 4-amino-2′- hydroxy-5′-methylazobenzene does not change in the hydrogenate and is not accumulated in the bulk of solution.     

3-氨基-2-羟基-4-苯基丁酸的合成

3-氨基-2-羟基-4-苯基丁酸的合成;乌苯美司;氨基羟基苯基丁酸;合成     

Magnetic ordering of Ni4 Cubane complexes through hydrogen bonds

The serendipity synthesis of the 2-hydroxy-3-methoxy-benzaldehyde or o-vanillin nickel(II) cubane complex, obtained by ourselves and other workers, can be rationalized to give the cubane in a high yield by direct use of 2-hydroxy-3-methoxy-benzaldehyde (H-ovan). The structural determinations of crystals obtained according to the two experimental processes show that the complex formulated [(MeOH)Ni(μ₃-OMe)(ovan)]₄ (ovan = deprotonated form of o-vanillin) is characterized in the two cases. Ni-Ni ferromagnetic interactions (J_NiNi = 5.8 cm⁻¹) giving an S = 4 ground state are active in the Ni₄ cubane. Replacement of methanol molecules coordinated to the Ni ions by a diol, an amino-alcohol or an amino-ether allows self-association of these Ni₄ units according to two different ways: by direct coordination bonds through the diol ligand or by hydrogen bonds involving the OMe groups of o-vanillin located at the periphery of the cubane and the hydrogen atoms of the primary amine functions. This association is suggested in the two cases by the presence of out-of-phase signals (χ”) when ac susceptibility measurements are performed at different frequencies. These molecules do not behave as SMM for these χ” signals, that are not frequency-dependent, correspond to the establishment of a three-dimensional ordering.     

Coordination chemistry of amine bis(phenolate) cobalt(II), nickel(II), and copper(II) complexes

Cobalt(II), nickel(II), and copper(II) (1, 2, and 3) complexes of the dianionic form of the bis(phenolate) ligand N,N-bis(3,4-dimethyl-2-hydroxybenzyl)-N',N'-dimethylethylenediamine (H2L) have been synthesized by electrochemical oxidation of the appropriate metal in an acetonitrile solution of the ligand. When copper is used as the anode, the addition of 1,10-phenanthroline to the electrolytic phase gave rise to a different compound [CuL]2.2CH3CN (4). The compounds [CoL]2.2CH3CN (1), [Ni2L2(H2O)].H2O (2), [CuL]2.3H2O (3), and [CuL]2.2CH3CN (4) were characterized by microanalysis, IR, electronic spectroscopy, FAB mass spectrometry, magnetic measurements and by single-crystal X-ray diffraction. The crystal structures show that the complexes have a dinuclear structure. In compounds 1, 3, and 4, two metal ions are coordinated by the two amine nitrogens and the two phenol oxygen atoms of a deprotonated pendant phenol ligand, with one phenolic oxygen atom from ligand acting as a bridge. In compounds 1 and 3, each metal center has a geometry that is closest to trigonal bipyramidal. Magnetic susceptibility data for both compounds show an antiferromagnetic coupling with 2J = -15 cm(-1) for the cobalt(II) complex and a strong antiferromagnetic coupling with 2J = -654 cm(-1) for the copper(II) complex. However, in 4 the geometry around the metal is closer to square pyramidal and the compound shows a lower antiferromagnetic coupling (2J = -90 cm(-1)) than in 3. The nickel atoms in the dimeric compound 2 are hexacoordinate. The NiN2O4 chromophore has a highly distorted octahedral geometry. In this structure, a dianionic ligand binds to one nickel through the two amine nitrogen atoms and the two oxygen atoms and to an adjacent nickel via one of these oxygen atoms. The nickel atoms are linked through a triple oxygen bridge involving two phenolic oxygens, each from a different ligand, and an oxygen atom from a water molecule. The two nickel ions in 2 are ferromagnetically coupled with 2J = 19.8 cm(-1).     

Supramolecular Hydrogen‐Bonded Frameworks from a New Bisphosphonic Acid and Transition Metal Ions

The reaction of 2‐morpholinoethylimino‐bis(methylenephosphonic acid) (H₄L) with cobalt(II), nickel(II) acetate, and cadmium(II) chloride in ethanol/water mixed solvents afforded three new crystal‐engineered supramolecular metal phosphonates, Co(H₃L)₂ · 2H₂O ( 1 ), Ni(H₃L)₂ · 2H₂O ( 2 ), and [Cd₂Cl₄(H₂O)₆]_0.5[H₄L] ( 3 ) by using a layering technique. The cobalt(II) ions in complex 1 are hexacoordinated by four phosphonate oxygen atoms and two imino nitrogen atoms. The mononuclear units of complex 1 are connected through hydrogen bonds to form a three dimensional supramolecular network. The structure of compound 2 is analogous to that of 1 except that the cobalt(II) ion in compound 1 is replaced by nickel(II) in compound 2 . In the molecular structure of compound 3 , cadmium is coordinated to three chloride ions and three aqua oxygen atoms to form a novel neutral dinuclear complex. Several hydrogen bonds connect the dinuclear complex and the neutral form of the ligand to build a supramolecular three dimensional structure.     

Novel xanthate complexes of nickel. X-ray structure of [NiBr(S2CO-i-Am)(PPh3)] at 150 K

Nickel(II) isopropylxanthate complexes of composition [Ni2(-L)2(S2CO-i-Pr)2]·xCHCl3 (1) and (2) {HL = thiophenol or 4-methylthiophenol, x = 1/2 or 1/3} and [Ni(bpy)(S2CO-i-Pr)]Br (3) {bpy = 2,2-bipyridine} have been synthesized and characterized by elemental analyses, electronic and i.r. spectroscopy, magnetic moment studies and conductivity measurements. The results show that (1) and (2) are non-electrolytes, square-planar, binuclear nickel(II) complexes bridged via two L1– ligands, while compound (3) is ionic (1:1); the donor atom arrangement around the nickel(II) centre is tetrahedral with an NiS2N2 chromophore. The geometry of the [Ni(bpy)(S2CO-i-Pr)]+ cation has been optimized using MM+ calculations. The crystal and molecular structure of [NiBr(S2CO-i-Am)(PPh3)], as an example of an i-Am derivative of a starting complex for preparation of all the above compounds, has been determined. X-ray analysis of the complex reveals distorted square-planar geometry at the metal centre with an S2PBr donor set.