Interaction of Mn(acac)3 with Asymmetrical Schiff Base Ligands containing an Amido Group

Interaction of asymmetrical Schiff base ligands H₃Lⁿ [where H₃Lⁿ are substituted 3–aza–4–(2–hydroxyphenyl)–N– (2–hydroxyphenyl)but–3–enamide] with Mn(acac)₃ (acac = acetylacetonate) has been investigated. Two different type of manganese(III) complexes have been obtained depending on the nature of the substituents on the ligand. We have found that ligands containing donor substituents drives to the formation of two different kinds of complexes from the same reaction: Mn(Lⁿ)(H₂O)_x ( 1a–5a ) and [Mn(HLⁿ)(acac)](H₂O)_y ( 1b–5b ) (where Lⁿ and HLⁿ signify the ligand in its trianionic and dianionic form, respectively). However, when the substituents are electron withdrawing or poor donor only compounds of the type [Mn(HLⁿ)(acac)](H₂O)_y ( 6–10 ) are obtained. All these compounds have been characterized by elemental analyses, IR and ¹H NMR spectroscopy, FAB mass spectrometry, magnetic measurements and molar conductivities. The electrochemical behaviour of these complexes has also been studied.     

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…     

含双水杨醛Schiff碱配体的双核配合物的合成及晶体结构

合成了4个含双水杨醛Schiff碱配体的双核过渡金属配合物,并通过元素分析、红外光谱、紫外光谱,热重分析以及X-射线单晶衍射等手段对所得配合物进行了表征。结果表明,配合物1、3和4都属于三斜晶系,空间群为P1,而配合物2属于单斜晶系,空间群为C2/c。在配合物1中,2个Cu髤离子具有不同的配位构型,其中一个Cu髤形成了五配位的四角锥构型,而另一个Cu髤形成了平面正方形构型。配合物4中,通过酚氧原子的桥联作用,双核单元相互连接形成了一维链状结构。     

以Schiff碱N-丁酰基水杨酰肼为配体的三核镍(Ⅱ)配合物的合成与结构

The trinuclear nickel (Ⅱ) complex Ni3(C11H11N2O3)2(C5H5N)4 was prepared by the reaction of Ni(OAc)2 @ 4H2Owith N-butylsalicylhydrazide Schiff base ligand and characterized by X-ray crystallography. The crystal belongs totriclinic, Mr=930.91, space group P1 with cell parameters a =9. 8489(2)A, b = 12. 3110(2) A, c = 18. 4035(3) A, α=71.353(2)°, β=76.638(2)°, γ=84.815(2)°, V=2056.72(6)A3, Z=2, Dc=1.503g@cm-3,μ(MoKα) = 1. 417mm-1, F(000) = 964, R = 0. 0317, wR = 0. 0868. A total of 5393 independent reflectionswere collected, of which 4448 reflections with I ≥ 2 σ(I) were observed. There are two centrosymmetrical trin-angle of 180°. The interatomic distances between the nickel atoms on the two sides are 9. 2030(8) A and 9. 1876(9) A for the two molecules, respectively. The central nickel atom adopts an axially elongated octahedral geometrywhereas the nickel atoms on the two sides have square-planar coordination environment. CCDC: 194083.     

Characterization and Crystal Structure of some Schiff Base Copper(II) Complexes derived from Enantiomeric Pairs of Chiral Amines

Copper(II) complexes of three chiral enantiomeric pairs of o‐hydroxy Schiff bases derived from (R)‐(+)‐1‐phenylethylamine and (S)‐(‐)‐1‐phenylethylamine, were prepared and characterized. Elemental analyses, specific rotation, i.r., electronic, cd and mass spectra,and some X‐ray crystal structures were obtained. The X‐ray study of four complexes shows that the geometry around the metal atom is distorted square planar. Epr studies of all these complexes in DMF solution at 77 K suggest that their geometries in solution are slightly different to that observed in the solid state by X‐ray crystallography. Although, cd spectra only show charge transfer absorptions, the data confirm the enantiomeric character of the three pairs of the obtained complexes.     

The Synthesis of Quinoline‐based Tin Complexes with Pendant Schiff Bases

Whilst pursuing the synthetic utility of quinoline‐based tin complexes, Me₂Sn(Quin‐NO₂)₂ ( 1 ) and Ph₂Sn(Quin‐NO₂)₂ ( 2 ) (Quin‐NO₂ = 5‐nitroquinolino‐8‐oate) were synthesized bearing coordinatively inert nitro groups. Conventional reduction methodologies successfully converted 1 to Me₂Sn(Quin‐NH₂)₂ ( 3 ) and 2 to Ph₂Sn(Quin‐NH₂)₂ ( 4 ) (Quin‐NH₂ = 5‐aminoquinolino‐8‐oate). The synthetically useful amine groups proved difficult to exploit in the presence of the central tin atom, however, a complete Schiff base functionalized Sn complex of the dimethyltin pro‐ligand Me₂Sn(Quin‐py)₂ ( 6 ) was successfully synthesized from 5‐[(pyridin‐2‐ylmethylene)amino]quinolin‐8‐ol (HQuin‐py; 5 ) in good yield via an alternative strategy exploiting the oxophilic tendencies of tin. All species were fully characterized by NMR (including ¹¹⁹Sn NMR spectroscopy), HR‐ESI MS and single‐crystal X‐ray diffraction, and preliminary studies of their supramolecular potential are also discussed.     

Quinone-functionalized Transition Metal Complexes for Multi-electron Transfer. The Electrochemistry of a Bis -Naphthoquinone-Functionalized Schiff Base Ni(II) complex

Ni(II)NQ 2 en, a Ni(II) complex with two naphthoquinone groups incorporated into a Schiff-base ligand, undergoes two reversible reductions in which the naphthoquinone (NQ) groups are each reduced by one electron to naphthsemiquinone radical anions (SQ): $$\eqalignno{& {\rm Ni}({\rm II}){\rm NQ}_2 {\rm en} + {\rm e}^ - \mathop \to \limits^{E_1^{\,0} }[{\rm Ni}({\rm II})({\rm SQ}, {\rm NQ}){\rm en}]^ - \cr & [{\rm Ni}({\rm II})({\rm SQ}, {\rm NQ}){\rm en}]^ - + {\rm e}^ - \mathop \to \limits^{E_2^{\,0} } [{\rm Ni}({\rm II}){\rm SQ}_2 {\rm en}]^{2 - } \cr}$$ Analysis of the cyclic and differential pulse voltammetry waves shows that $E_2^0 - E_1^0 = - 36\, {\rm mV}$ , a j E 0 that corresponds to two noninteracting redox centers.     

Solvolthermal Syntheses and Crystal Structures of Three Linear Trinuclear Schiff Base Complexes of Zinc(II) and Cadmium(II)

Three linear trinuclear Schiff base complexes, {Zn[Zn(CH₃COO)(C₁₇H₁₆N₂O₂)]₂} ( 1 ), {Zn[Zn(CH₃COO)(C₂₅H₂₀N₂O₂)]₂} ( 2 ), and {Cd[Cd(CH₃COO)(C₁₈H₁₈N₂O₂)]₂} ( 3 ), were synthesized for the first time under solvolthermal conditions. Their structures have been characterized by elemental analyses, X-ray single crystal determinations, and infrared spectroscopy. There are three bridges across the M-M atom pairs (M is Zn for 1 and 2 , or Cd for 3 ) in each complex, involving two O atoms of a Schiff base ligand (N,N′-bis(salicylidene)-1, 3-propanediaminate (SALPD^2-) for 1 , N, N′-bis(2-hydroxy-naphthalmethenylimino)-1, 3-propanediaminate (NAPTPD^2-) for 2 , and N,N′-bis-(salicylidene)-1,4-butanediaminate (SALBD^2-) for 3 ), and an O-C-O moiety of a μ-acetato group. In each of the complexes, the central M²⁺ ion is located on an inversion center and has a distorted octahedral coordination involving four bridging O atoms from two Schiff base ligands in the equatorial plane and one O atom from each bridging acetate group in the axial positions. The coordination around the terminal M²⁺ ions is irregular square pyramidal, with two O atoms and two N atoms of the Schiff base ligand in the basal plane and one O atom from an acetate group in the apical position. The acetate bridges linking the central and terminal M²⁺ ions are mutually trans. The M…M distances are 3.050(3) Å in 1 , 3.139(2) Å in 2 , and 3.287(6) Å in 3 .     

Efficient Red Electroluminescent Devices with Sterically Hindered Phosphorescent Platinum(II) Schiff Base Complexes and Iridium Complex Codopant

Sterically hindered platinum(II) Schiff base complexes were prepared. Complex 4 , which displays red emission with a quantum yield of 0.29 in a thin film and a self‐quenching rate constant of 1×10^?7 dm³ mol^?1 s^?1, was used to fabricate organic light‐emitting diodes with single or double emissive layers (EMLs). An iridium(III) complex with a wide band gap was codoped into the electron‐dominant EML to act as a deep electron trapper, and red‐light‐emitting devices with the highest current, power, and external quantum efficiencies of 20.43 cd A^?1 18.33 Lm W^?1, and 11.7 %, respectively, were fabricated. A high current efficiency and EQE of up to 14.69 cd A^?1 and 8.3 %, respectively, were achieved at a high brightness of 1000 cd m^?2. The significant delay of efficiency roll‐off is attributed to the bulky 3D structure of the norbornene moiety at the periphery of the Schiff base ligand of 4 and to the new device design strategy. The fabricated device had a projected lifetime (LT50) of 18 000 h.     

Copper(II) Supramolecular Complex: Synthesis,Crystal Structure,and Electrochemical Property

A novel complex {Cu(Bobb)₂](pic)₂}₂ [pic = picrate anion, Bobb = 1,3‐bis(1‐benzylbenzimidazol‐2‐yl)‐2‐oxopropane] was synthesized and characterized by means of elemental analyses and electrical conductivity. The crystal structure of the copper complex has been determined by single‐crystal X‐ray diffraction. A study of the electrochemistry of the title compound was carried out by using cyclic voltammetry. It revealed that the copper complex exhibits a quasi‐reversible redox process. The X‐ray structure of the above complex shows that the unit cell consists of two centrosymmetric, crystallographically independent molecules, in which the copper(II) ions have the same coordination environment and should be described as distorted octahedron. The complex is formed of { ··· Cu(2) ··· Cu(1) ··· Cu(1) ··· }_∞ supramolecular configuration by π ··· π stacking interactions between the benzimidazole rings. The complex was also identified by IR and electronic spectroscopy.     

Synthesis and Crystal Structure of a New Nickel(II) Complex with Unsymmetric Quadridentate Schiff Base Containing Oxime

1 INTRODUCTION The interest in the complexes of transition met-als with ketoxime ligands[1, 2] as potential modelsfor metal binding sites in ferroverdin[3, 4] hasprompted the investigations on the structures andthe overall coordination geometry of the metalcenters in these complexes. Oxime derivatives areinteresting ligands since the ketoximes are foundto chelate transition metals through the N (oxime)and O (ketone) donors[5～10]. Herein we report thesynthesis…     

Synthesis and Crystal Structure of a Dinuclear Cu(II) Complex with Tridentate Schiff Base and Azido Bridge

1 INTRODUCTION The azido ligand is an efficient superexchange path-way for propagating magnetic interaction between theparamagnetic centers, such as copper(II), giving di-nuclear, tetranuclear, 1D, 2D and 3D complexes[1～4].The versatility of this ligand due to its diverse bin-ding modes leads to the variation in magnetic pro-perties that depend on its orientation with respect tothe magnetic centers. In general, the bridging modesobserved for the azido group are endtoend and en-don. In…     

Synthesis, Crystal Structure and Cytotoxic Activity of a Novel Nickel(II) Complex with Schiff Base Derived from Salicylhydrazide

A novel Schiff base complex with π-conjugated system, [Ni(L1)2(py)2] 1 (L1 = (E)-N'-(2,4-dichlorobenzylidene)-2-oxidobenzohydraizide), was synthesized and characterized by elemental analysis and single-crystal X-ray determination. Complex 1 crystallizes in the monoclinic system, space group P21/n with a = 12.8286(10), b = 16.3573(13), c = 19.0206(14) , β = 108.2920(10)o, V = 3789.6(5) 3, Z = 4, Mr = 833.17, Dc = 1.460 g/cm3, μ = 0.843 mm-1, F(000) = 1704, the final R = 0.0537 and wR = 0.0640 for 3836 observed reflections with I > 2σ(I). In the molecular structure of 1, the NiII atoms are six-coordinated by two N and two O atoms from two Schiff base ligands (L1) and two N atoms from two pyridine solvent molecules to form a distorted octahedral geometry. The cytotoxic activities of complex 1 have been experimentally studied against a human HeLa cell in vitro.     

Syntheses and Crystal Structures of Two VO(IV) Schiff Base Complexes with Oxyammonia Ligand

1 INTRODUCTION The insulin-mimetic property of vanadium complexes is the most noteworthy finding and the relationship between vanadium and diabetes mellitus has been extensively studied in the past decades[1～5]. Vanadium complexes are capable of increa…     

镓的席夫碱配合物的合成及晶体结构

在无水无氧条件下,合成了3个镓的席夫碱配合物GaCl3(C13H11NO)(1)、GaCl3(C14H13NO2)(2)和GaCl3(C13H9ClNO)(3),对它们进行了元素分析、核磁共振、红外光谱等表征,并用X射线衍射测定了配合物的单晶结构。各配合物配位方式均为配体中酚羟基氧原子与中心镓原子配位,在空间上形成畸变的四面体结构。配合物1属于正交晶系,Pnma空间群,晶胞参数:a=1.3295(3)nm,b=0.70115(16)nm,c=1.6164(4)nm,V=1.5068(6)nm3,Z=4,F(000)=744,R1=0.0295,wR2=0.0651。配合物依靠分子间的氢键作用进一步联结成二维网状结构。配合物2属于单斜晶系,P21/n空间群,晶胞参数:a=0.71303(18)nm,b=1.7153(4)nm,c=1.3503(4)nm,β=91.891(5)°,V=1.6507(7)nm3,Z=4,F(000)=808,R1=0.0443,wR2=0.0988。配合物依靠分子间的氢键作用进一步联结成二维网状结构。配合物3属于三斜晶系,P1空间群,晶胞参数:a=0.6986(2)nm,b=1.0449(4)nm,c=1.1369(3)nm,α=78.58(3)°,β=81.06(2)°,γ=87.87(3)°,V=0.8036(5)nm3,Z=2,F(000)=402,R1=0.0515,wR2=0.1244。配合物依靠分子间的氢键作用进一步联结成二维网状结构。     

Synthesis and Crystal Structure of a Salicylaldehyde Ethylene Diamine Schiff Base Manganese (Ⅲ) Complex

1 INTRODUCTION Manganese is one of several first-row transition metal elements that have been found to play an important role in most biological systems. Perhaps the best known is in the process of photosynthesis during which water is oxidized to yield dioxygen, and it is generally believed that the process is related to a tetranuclear manganese cluster[1]. Other aspects of biological chemistry of manganese, such as three mononuclear manganese enzymes: manganese superoxide dismutase, per…     

单核Mn(III)-Shiff碱配合物的晶体结构与性质

报导了两个Schiff碱配体的单核Mn（Ⅲ）配合物（[Mn（Ⅲ）（L1）（H2O）］4CIO。·ZH。O（1）和［Mn（ffi）（LZ）厂Ic。·ZH。O（2》的合成、晶体结构及性反X一衍射晶体结构分析证实：配合物1的晶体属于正交晶系，Pna21空间群．其晶胞参数为α＝10．932（7）A，b＝22．393（5）A，c＝8．960（3）A，V=2193（1）A3，Z＝4．2的晶体属于正交晶系，P212121空间群，α＝17．345（3）A，b＝17．905（2）A，c=7．789（1）A，V＝2418．9（6）A3，Z=4．电化学研究结果显示：配合2是稳定的电化学产物，而1在电场作用下容易歧化．由此说明配位环境是影响化合物稳定性的重要因素．     

Synthesis,Crystal Structures,and Anti‐cervical Cancer Activity Evaluation of Three Trinuclear Transition Metal(II) Complexes with N,O‐Donor Schiff Base Ligand

A new bi‐nucleating Schiff base ligand, 2‐(((3‐(dimethylamino)propyl)imino)methyl)‐6‐methoxyphenol (HL₁) was prepared by a one‐pot condensation reaction, which was further used in the construction of three trinuclear Schiff base transition metal(II) complexes [Cu₃(L1)₂(OH)₂(H₂O)₂](NO₃)₂ ( 1 ), [Co₃(L1)₂(OH)₂(H₂O)₂](NO₃)₂ ( 2 ), and [Cu₃(L1)₂(N₃)₄] ( 3 ). Furthermore, a green hand grinding technique was implemented to reduce the particle size of the coordination complexes to generate the nanoscale compounds. The SEM studies reveal the formation of square and spherical particles for nano 1 and 2 , and nanorod for nano 3 . In addition, the anti‐proliferation activity of nano 1 – 3 was detected on the human cervical cancer Hela cells with CCK‐8 assay. The cell viability curves and IC₅₀ values indicated that only nano 1 has anti‐proliferation activity on Hela cells. To further investigate the mechanism of nano 1 induced Hela cell death, the Annexin V‐FITC/PI double staining assay, western blot assay, and ROS level detection was conducted.     

Synthesis and Characterization of Metal Complexes of a New Unsymmetrical Tridentate NNS Schiff Base Ligand: X‐ray Crystal Structure Determination of Nickel(II) Complex

A new unsymmetrical tridentate NNS Schiff base ligand, 2‐(2‐nitrophenylthio)‐N‐((pyridine‐2‐yl)methylene)benzenamine (L), and its Mn(II ), Ni(II ), Cu(II ), and Zn(II ) complexes were synthesized. These compounds were characterized by different physicochemical and spectroscopic techniques. The molecular structure of [NiL₂ ](ClO₄ )₂ was determined by single‐crystal X‐ray diffraction. In this complex, two ligands coordinate through azomethine‐N, pyridine‐N, and thioether‐S, forming a mononuclear 6‐coordinate distorted octahedral geometry about a nickel.     

过渡金属氨基酸席夫碱配合物的合成

合成了6个过渡金属氨基酸席夫碱配合物——L-酪氨酸缩水杨醛合铬(钼),L-赖氨酸缩水杨醛合铬(钼),DL-α-丙氨酸缩水杨醛合铬(钼),其结构经UV,IR和元素分析表征。UV测定结果表明,配合物均可与DNA发生插入作用。