Nickel(II) complex with an asymmetric tetradentate Schiff base ligand: synthesis,characterization, crystal structure,and DFT studies

Abstract

A new asymmetric tetradentate Schiff base, bis(5-methoxysalicylidene)-4-methylbenzene-1,2-diamine), H₂L, and its Ni(II) complex were prepared and characterized using elemental analyses (CHN), FTIR, UV–Vis, ¹H NMR, and ¹³C{¹H} NMR spectroscopic techniques, and crystal structures of both were determined by X-ray crystallography. For both ligand and Ni(II) complex, density functional theory calculations to find geometry parameters, IR frequencies, electronic properties, and natural bond orbital analysis (NBO) were done with M062X method and Def2-TZVP basis set. All calculated data are consistent with the experiments. NBO data for the Ni(II) complex show that the main type of transition in UV-Vis is interligand charge-transfer, which is assigned as π-π*.     

Syntheses,Crystal Structures and Antibacterial Activities of Schiff Base Ligand and Its Nickel(Ⅱ) Complex

A complex [NiL2] was synthesized, in which L, or to be exact, a Schiff base ligand(HL), was derived from the condensation of 1-phenyl-3-methyl-4-phenylacetyl-5-pyrazolone(PMPAP) with L-phenylalanine methyl ester. They were characterized by IR and single-crystal X-ray diffraction. Green block crystals of both ligand and its complex were grown at room temperature. The ligand, which consists of two individual fragments, crystalizes in the P1 space group(a = 5.6268(5), b = 10.6892(11) and c = 19.4869(18) ). The complex crystalizes in the P21 space group(a = 21.4076(18), b = 9.4792(8) and c = 25.287(2) ), which consists of a nickel six-coordinated compound. Every fragment is a distorted octahedron with four oxygen and two nitrogen atoms. The Schiff base ligand(HL) and its complex have been tested in vitro to evaluate their antibacterial activity against bacteria Escherichia Coli and Bacillus subtilis. It is found that the complex has higher activity than the corresponding free Schiff base ligand(HL) against the same bacterial.     

Synthesis and Crystal Structure of Zn(II) Complex with Tridentate Ligand N-(2-Hydroxy-1-naphthylidene)-L-serine

1 INTRODUCTION As the basic building blocks of proteins or enzy- mes, amino acids are versatile ligands showing flexi- ble coordination modes[1]. Recently, researchers have synthesized some metal complexes with amino acids and their derivatives[2～6]. Considerable efforts have been devoted to the preparation and structure of amino acid Schiff base complexes with transition metals[6～11]. In such cases, some Zn(II) complexes have been reported. However, most of them have been carried out…     

镉(Ⅱ)、锌(Ⅱ)与2-乙酰吡啶缩邻氨基苯甲酰腙配合物合成及晶体结构

采用Schiff碱配体2-乙酰吡啶缩邻氨基苯甲酰腙(L)分别与Cd(NO3)2·4H2O和Zn(CH3COO)2·2H2O进行配位反应,得到2个配合物[Cd L(NO3)2·H2O](1)和[Zn L2](2)。分别采用1H NMR、FTIR和元素分析等手段对化合物进行了表征,并测定了2个配合物的单晶结构。结构解析表明,配合物1属于单斜晶系,P21/n空间群,配合物2属于单斜晶系,P21/c空间群。对配体和配合物的体外抑菌活性进行了初步考察,结果表明,配体L和配合物1具有一定的抑菌活性。     

Synthesis and Crystal Structure of a Co(II) Complex with Schiff Base and Imidazole Ligand

1 INTRODUCTION The chemical behavior of metal complexes with Schiff base ligand has attracted much attention be- cause of their catalytic activity in some industrial[1, 2] and biochemical processes[3~5]. As some metal com- plexes have shown the catalytic activity in some polymerization reactions[2, 6], we are recently inte- rested in polymerizartion of organo-silicon com- pounds catalyzed by Schiff base complexes of tran- sition metals. A series of Schiff base complexes have been prepare…     

Synthesis,characterization, crystal structure,and antibacterial evaluation of Ni (II) complex with new dithiophosphorus compound

The reaction of 2,4-bis (4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide (Lawesson^’s reagent) with phenylethylamine produced [H₃NCH₂CH₂C₆H₅]⁺ [(C₆H₅CH₂CH₂NH)(p C₆H₄OMe)PS₂]^? (1). Furthermore, reaction of 1 with NiCl₂ in dry methanol led to the novel complex 2. The compounds were characterized by ¹H and ³¹P NMR, IR spectroscopy, and elemental analysis. A single crystal X-ray structure of complex 2 showed that the nickel complex is square planar. The complex formed a supramolecular structure via intermolecular S1…H7B and O1…H2N2 hydrogen bonds. The X-ray crystallography of complex showed [R²₂](18) and R⁴₄(18) motifs in the monomers were connected to each other via S1…H7B, O1…H2N2 hydrogen bonds with donor–acceptor distance of 2.89 and 2.51 Å, respectively. The new compounds were additionally tested in view of their antibacterial properties.     

Synthesis and characterization of Co(II), Ni(II), Zn(II) and Cu(II) complexes with a new tetraazamacrocyclic Schiff base ligand containing a piperazine moiety: X-ray crystal structure determination of the Co(II) complex

Two macrocyclic Schiff base ligands, L¹ [1+1] and L² [2+2], have been obtained in a one-pot cyclocondensation of 1,4-bis(2-formylphenyl)piperazine and 1,3-diaminopropane. Unfortunately, because of the low solubility of both ligands, their separation was unsuccessful. In the direct reaction of these mixed ligands (L¹ and L²) and the appropriate metal ions only [CoL¹(NO₃)]ClO₄, [NiL¹](ClO₄)₂, [CuL¹](ClO₄)₂ and [ZnL¹(NO₃)]ClO₄ complexes have been isolated. All the complexes were characterized by elemental analyses, IR, FAB-MS, conductivity measurements and in the case of the [ZnL¹(NO₃)]ClO₄ complex with NMR spectroscopy.     

Syntheses, Characterizations, Crystal Structures and Antibacterial Activities of Two Zinc(II) Complexes with a Schiff Base Derived from o-Vanillin and p-Toluidine

Two new zinc(II) complexes, [Zn2L2Cl4]·2[ZnL(CH3OH)Cl2] 1 and [ZnL2(NO3)2] 2, were synthesized by reacting ZnX2·nH2O (X = Cl-, NO3-) and a Schiff base ligand 2-[(4-me- thylphenylimino)methyl]-6-methoxyphenol (C15H15NO2, L) which was obtained by the condensation of o-vanillin (2-hydroxy-3-methoxybenzaldehyde) with p-toluidine. Both 1 and 2 were characterized by single-crystal X-ray diffraction technique, elemental analysis, molar conductance, FT-IR, UV-Vis, 1H-NMR spectra and thermogravimetric analysis. The Schiff base ligand and its zinc(II) complexes have been tested in vitro to evaluate their antibacterial activity against bacteria, viz., Escherichia Coli, Staphylococcus aureus and Bacillus Subtilis. The results show that these complexes have higher activity than the corresponding free Schiff base ligand against the same bacteria.     

水合镍的4,9-二甲基-5,8-二氮杂十二烷-4,8-二烯-2,11-二酮配合物的晶体结构

β-二酮和乙二胺缩合所形成的多齿Schiff碱型配体可以和过渡金属元素形成一系列配合物。它们在均相催化和生物化学体系模拟中有一系列的潜在应用。文献已有这类配合物合成的报道,但其晶体结构的报道尚少。我们曾合成了平面型四方配位的Ni(ENAC),其中含有配位不饱和的Ni(II)和电负性较大的N、O配位原子,分子同时具有Lewis酸性中心和Lewis碱性中心。类似地,H_2O分子也同时具有带部分正电荷的氧和带     

Synthesis and Crystal Structure of a Copper(II) Complex with 2,4-Dihydroxybenzylidene Benzoylhydrazone Ligand

1 INTRODUCTION The chemical properties of acylhydrazones Schiff bases and their complexes with some transition metal ions have been intensively investigated in several re- search areas because of their chelating capability and pharmacological applications[1～10]. Intriguingly, the copper(II) complexes are shown to be signifycantly more potent than the metal free chelate, suggesting that the metal complex is the biologically active species. Owing to the biological interest in these types …     

呋喃酰腙及其镍、锰配合物的合成与晶体结构及抑菌活性

通过2-呋喃甲醛与4-甲氧基苯甲酰肼缩合,得到一种新型的希夫碱配体2-呋喃甲醛缩-4-甲氧基苯甲酰腙(HL),将HL与Ni(NO₃)₂·6H₂O、MnCl₂·4H₂O分别在乙醇与丙酮的混合溶剂中反应,采用溶剂挥发获得配体单晶、不同构型的新型配合物NiL₂和Mn(HL)₂Cl₂单晶。采用元素分析、红外光谱、核磁共振、X-射线单晶衍射对HL、NiL₂和Mn(HL)₂Cl₂进行表征,结构分析表明HL属于三方晶系,空间群R3,晶胞参数a=2.442(2)nm,b=2.442(2)nm,c=1.1354(10)nm,γ=120°,Z=18。NiL₂和Mn(HL)₂Cl₂均属于单斜晶系,空间群P2₁/n和P2₁/c。NiL₂属于近似平面四方构型,晶胞参数a=1.2067(8)nm,b=0.5774(4)nm,c=1.8418(13)nm,β=107.122(11)°,Z=2;Mn(HL)₂Cl₂属于扭曲八面体构型,晶胞参数a=0.9155(4)nm,b=0.7217(4)nm,c=2.0336(9)nm,β=96.047(9)°,Z=2。用琼脂扩散法测定了配体和配合物对大肠杆菌、金黄色葡萄球菌、绿脓杆菌的抑制活性,结果显示NiL₂对金色葡萄球菌有显著的抑制作用。     

Syntheses,characterizations, crystal structures,and biological activities of two new mixed ligand Ni(II) and Cu(II) Schiff base complexes

Two mixed-ligand complexes, [Cu(L)(2imi)] (1) and [Ni(L)(2imi)]·MeOH (2) [L = 2-(((5-chloro-2-oxyphenyl)imino)methyl)phenolato) and 2imi = 2-methyl imidazole], have been prepared by the reaction of appropriate metal salts with H₂L and 2-methyl imidazole. Their structures were characterized by microanalysis, FT-IR, UV–vis, molar conductivity, and ¹H NMR for [Ni(L)(2imi)]·MeOH. The structures were determined using single crystal X-ray diffraction. Each four-coordinate metal center, Cu(II) in 1 and Ni(II) in 2, is surrounded by donors of Schiff base (L^2?) and N of 2-methyl imidazole in square planar geometries. α-Amylase activities of these compounds have also been investigated. The experimental data showed that α-amylase was inhibited by Ni(II) complex while the Cu(II) complex causes a 1.3-fold decrease in K_m value. Antimicrobial results show that these compounds, especially the Cu(II) complex, have potential for antibacterial activity against Gram negative and Gram positive bacteria and antifungal activity against Aspergillus fumigatus.     

呋喃酰腙及其镍、锰配合物的合成与晶体结构及抑菌活性

通过2-呋喃甲醛与4-甲氧基苯甲酰肼缩合,得到一种新型的希夫碱配体2-呋喃甲醛缩-4-甲氧基苯甲酰腙(HL),将HL与Ni(NO3)2·6H2O、MnCl2·4H2O分别在乙醇与丙酮的混合溶剂中反应,采用溶剂挥发获得配体单晶、不同构型的新型配合物NiL2和Mn(HL)2Cl2单晶。采用元素分析、红外光谱、核磁共振、X-射线单晶衍射对HL、NiL2和Mn(HL)2Cl2进行表征,结构分析表明HL属于三方晶系,空间群R3,晶胞参数a=2.442(2)nm,b=2.442(2)nm,c=1.135 4(10)nm,γ=120°,Z=18。NiL2和Mn(HL)2Cl2均属于单斜晶系,空间群P21/n和P21/c。NiL2属于近似平面四方构型,晶胞参数a=1.206 7(8)nm,b=0.577 4(4)nm,c=1.841 8(13)nm,β=107.122(11)°,Z=2;Mn(HL)2Cl2属于扭曲八面体构型,晶胞参数a=0.915 5(4)nm,b=0.721 7(4)nm,c=2.033 6(9)nm,β=96.047(9)°,Z=2。用琼脂扩散法测定了配体和配合物对大肠杆菌、金黄色葡萄球菌、绿脓杆菌的抑制活性,结果显示NiL2对金色葡萄球菌有显著的抑制作用。     

Novel Isatin-Schiff Base Cu (II) and Ni(II) Complexes. X-ray Crystal Structure of Bis[3-(4-hexylphenylimino)-1H-indol-2(3H)-one]-dichlorocopper(II) Complex

Schiff bases of isatin were reported to possess antibacterial, antifungal, antiviral, anti-HIV, antiprotozoal, and anthelmintic activities1. They also exhibit significantanticonvulsant activity, apart from other pharmacological properties2. Conductingsubs…     

Synthesis and Crystal Structure of a Novel Binuclear Cu（ Ⅱ ） Complex with Tetradentate Schiff-base Ligand

1 INTRODUCTION Many metalloenzymes containing in their active sites two copper ions that operate cooperatively occur in plants and animals. They are utilized for dioxygen transport or activation, electron transfer, reduction of nitrogen oxides, and hydrolytic che- mistry[1]. Consequently binuclear copper complexes with two ions in close proximity have received a great deal of attention[2～4]. These complexes are particularly of interest in the field of biomimetic chemistry to provide impr…     

配合物Ni(C14H10N2O3)(C5H5N)的合成和晶体结构

A novel nickel(Ⅱ) complex with 2,4-dihydroxybenzalidene benzoylhydrazone and pyridine ligands, Ni(C₁₄H₁₀N₂O₃)(C₅H₅N), has been synthesized and characterized by elemental analysis and IR. The crystal structure of the title complex has been determined by single crystal X-ray diffraction techniques. The crystal belongs to orthorhombic, space group Pbca. The cell parameters are: a=1.580 20(19) nm, b=1.362 18(16) nm, c=1.616 50(19) nm, and V=3.479 5(7) nm³, Z=8, D_c=1.497 Mg·m^-3, μ(MoKα)=1.139 mm^-1, F(000)=1 616, R=0.032 9 and wR=0.077 0 for 2 772 observed reflections (I>2σ(I)) out of 3810 unique ones. The nickel(Ⅱ) ion lies in a distorted square-planar environment composed of two oxygen atoms, one nitrogen atom of tridentate acyhydrazone schiff base ligand and one nitrogen atom of the pyridine ligand. The analysis of the crystal structure indicates that the complex has a one-dimensional chain structure, which is formed by intermolecular hydrogen bonds. CCDC: 244668.     

氨基酸席夫碱镍、钴配合物的合成、晶体结构与抑菌活性

合成了1-苯基-3-甲基-4-对氯苯甲酰基-5-吡唑啉酮缩L-苯丙氨酸甲酯Schiff碱Ni(Ⅱ)、Co(Ⅱ)配合物[NiL_2](CH_3OH)(1)和[CoL_2](CH_3OH)(2)。用元素分析、红外光谱和X-射线单晶结构进行了表征,配合物1和2的晶体结构都同时含有两个独立子单元及一个游离的甲醇分子,各子单元都形成六配位的八面体结构。采用琼脂扩散法测定了配体和配合物对大肠杆菌、金黄色葡萄球菌抗菌活性,结果表明配合物2对大肠杆菌的抑制作用最强。     

Synthesis, Crystal Structure and Electrochemistry Properties of a (N,N'-Ethylene-bis(salicylaldiminato)) Nickel(II) Complex, [Ni_2(salen)_2]·NCS·NH_4

A new Ni(II) complex [Ni2(salen)2]·(NCS)·NH4 (salen = N,N’-bis(salicylidenea- mino)ethanato) has been prepared and structurally characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. It crystallizes in the orthorhombic system, space group Pbca with a = 16.8725(13), b = 19.0046(15), c = 20.0583(16) , Z = 8, V = 6431.8(9) 3, C33H32N6Ni2O4S1, Mr = 726.13, Dc = 1.500 g/cm3, F(000) = 3008, μ = 1.284 mm-1, the final R = 0.0394 and wR = 0.0767 for 4449 observed reflections with I > 2σ(I). The complex involves a N,N’-ethylene-bis(salicylaldiminato) Schiff base, an isothiocyanato anion and an ammonium cation. The nickle(II) ion adopts a distorted square coordination geometry with N2O2 set of Schiff base ligand. The complexes are linked into a dimmer via intermolecular hydrogen bonds and the [Ni(salen)] moieties are connected together to form a 2-D layer structure by intermolecular N–H…O hydrogen bonds and π-π stacking. Cyclic-voltammetry method was used to characterize electrochemically the complex.     

Synthesis,crystal structures,and biological properties of a new naphthalimide Schiff base and its copper(II) complex

A new naphthalimide Schiff base N-allylamine-4-(ethylenediamine-3-methoxysalicylidene)-1,8-naphthalimide (HL) and its copper(II) complex {N-allylamine-4-(ethylenediamine-3-methoxysalicylidene)-1,8-naphthalimide copper(II)} (CuL₂) have been synthesized and characterized. The crystal structure of CuL₂ has been determined by X-ray single crystal diffraction. The central Cu(II) ion is four-coordinate with an N₂O₂ donor set which is afforded by two L ligands, forming a slightly distorted square planar geometry. The interactions of HL and CuL₂ with calf thymus DNA were investigated using electronic absorption titration, fluorescence titration, and viscosity measurements. The results indicate that free HL and CuL₂ bind to DNA in an intercalation mode, and their binding affinity for DNA takes the order CuL₂ > HL. Moreover, the antioxidant assay in vitro also shows that HL and CuL₂ possess significant antioxidant activities and CuL₂ is more effective than free HL.