Two novel interpenetrated zinc(II) and cadmium(II) coordination polymers based on 4-imidazole-benzoate: Syntheses,crystal structures and properties

Two novel interpenetrated coordination polymers, [Zn(IBA)₂] _n (1) and {[Cd(IBA)₂(H₂O)]·4H₂O} _n (2), have been synthesized by using 4-imidazole-benzoic acid (HIBA) as ligand under hydrothermal conditions. Complex 1 crystallizes in a chiral space group and has a two-fold interpenetrated 2D network structure with (4,4) topology, while complex 2 is a 3D porous dia network with four nets interpenetrating each other. The SHG activity of 1 and the photoluminescent property of 2 have been investigated. Supported by the National Natural Science Foundation of China (Grant Nos. 20731004 & 20721002) and the National Basic Research Program of China (Grant No. 2007CB925103)     

Four‐, five‐ and six‐coordinated transition metal complexes based on naphthalimide Schiff base ligands: Synthesis,crystal structure and properties

Two bidentate Schiff base ligands (HL¹ = N‐n‐butyl‐4‐[(E)‐2‐(((2‐aminoethyl)imino)methyl)phenol]‐1,8‐naphthalimide; and HL² = N‐n‐butyl‐4‐[(E)‐2‐(((2‐aminoethyl)imino)methyl)‐6‐methoxyphenol]‐1,8‐naphthalimide) with their metal complexes [Cu(L¹)₂] ( 1 ), [Zn(L¹)₂(Py)]₂?H₂O ( 2 ) and [Ni(L²)₂(DMF)₂] ( 3 ) have been synthesized and characterized. Single‐crystal X‐ray structure analysis reveals that complex 1 has a four‐coordinated square geometry, while complex 2 is a five‐coordinated square pyramidal structure and complex 3 is a distorted six‐coordinated octahedral structure. Cyclic voltammograms of 1 indicate an irreversible Cu²⁺/Cu⁺ couple. In vitro antioxidant activity assay demonstrates that the ligands and the two complexes 1 and 3 display high scavenging activity against hydroxyl (HO^?) and superoxide (O₂^??) radicals. Moreover, the fluorescence properties of the ligands and complexes 1 – 3 were studied in the solid state. Metal‐mediated enhancement is observed in 2 , whereas metal‐mediated fluorescence quenching occurs with 1 and 3 .     

Synthesis,crystal structure and fluorescence properties of two dinuclear zinc(II) complexes incorporating tridentate (NNO) Schiff bases

Reactions of hydrated zinc(II) trifluoroacetate and sodium azide with two tridentate Schiff bases HL¹ (2-((E)-(2-(dimethylamino)ethylimino)methyl)-4-chlorophenol) and HL² (2-((E)-(2-(dimethylamino)ethylimino)methyl)-4-bromophenol) under the same reaction conditions yielded two dinuclear isostructural zinc(II) complexes, [Zn(L¹)(N₃)]₂ (1) and [Zn(L²)(N₃)]₂ (2), respectively. The complexes were characterized systematically by elemental analysis, UV–Vis, FT-IR, and ¹H NMR spectroscopic methods. Single-crystal X-ray diffraction studies reveal that each of the dinuclear complexes consists of two crystallographically independent zinc(II) ions connected by double bridging phenoxides. All zinc(II) ions in 1 and 2 are surrounded by similar donor sets and display distorted square–pyramidal coordination geometries. The ligands and complexes reveal intraligand ¹(π → π*) flourescence. The enhancement of the fluorescence intensities for the complexes compared to the ligands indicates their potential to serve as photoactive materials.     

Hydrothermal synthesis,crystal structure and photoluminescence of two homochiral zinc(II) coordination polymers

Metal–organic frameworks (MOFs) have potentially useful applications and an intriguing variety of architectures and topologies. Two homochiral coordination polymers have been synthesized by the hydrothermal method, namely poly[(μ‐N‐benzyl‐L‐phenylalaninato‐κ⁴O,O′:O,N)(μ‐formato‐κ²O:O′)zinc(II)], [Zn(C₁₆H₁₆NO₂)(HCOO)]_n, (1), and poly[(μ‐N‐benzyl‐L‐leucinato‐κ⁴O,O′:O,N)(μ‐formato‐κ²O:O′)zinc(II)], [Zn(C₁₃H₁₈NO₂)(HCOO)]_n, (2), and studied by single‐crystal X‐ray diffraction, elemental analyses, IR spectroscopy and fluorescence spectroscopy. Compounds (1) and (2) each have a two‐dimensional layer structure, with the benzyl or isobutyl groups of the ligands directed towards the interlayer interface. Photoluminescence investigations show that both (1) and (2) display a strong emission in the blue region.     

Synthesis,crystal structure,antioxidation and fluorescence of two lanthanide complexes with a noncyclic polyether Schiff base ligand

Two lanthanide (Sm and La) complexes with the Schiff base ligand bis(3-methoxysalicylidene)-3-oxapentane-1,5-diamine (Bod) have been synthesized and characterized by physico-chemical and spectroscopic methods. [Sm(Bod)(NO₃)₃] {bis(3-methoxysalicylidene)-3-oxapentane-1,5-diamine samarium(III) trinitrate} (1) is a discrete mononuclear species and [La(Bod)(NO₃)₃(DMF)]_n {bis(3-methoxysalicylidene)-3-oxapentane-1,5-diamine dimethylformamide lanthanum(III) trinitrate}_n (2) formed an inorganic coordination polymer. In the two complexes, the metal ions are both ten-coordinate and the geometric structure around the Ln(III) ions can be described as distorted hexadecahedral. An antioxidant assay in vitro shows that complexes 1 and 2 exhibit better scavenging activity than both the ligand and the usual antioxidants on hydroxyl and superoxide radicals. Under excitation at room temperature, a red shift in the fluorescence band of the ligand in the complexes compared with that of the free ligand can be attributed to coordination of the rare earth ions to the ligand. Furthermore, 1 produced characteristic Sm(III) luminescence, which indicates the ligand Bod is a good organic chelator to absorb energy and transfer it to the Sm³⁺ ion.     

Two new cadmium(II) coordination polymers based on imidazole‐containing ligands: synthesis,structural characterization and fluorescence properties

The judicious selection of suitable ligands is vitally important in the construction of novel metal–organic frameworks (MOFs) with fascinating structures and interesting properties. Recently, imidazole‐containing multidentate ligands have received much attention. Two new Cd^II coordination frameworks, namely, poly[tris{μ‐1,4‐bis[(1H‐imidazol‐1‐yl)methyl]benzene‐κ²N³:N^3′}tetrakis(nitrato‐κ²O,O′)dicadmium], [Cd₂(NO₃)₄(C₁₄H₁₄N₄)₃]_n, (I), and poly[[bis{μ₃‐1,3,5‐tris[(1H‐imidazol‐1‐yl)methyl]benzene‐κ³N³:N^3′:N^3′′}cadmium] hexafluorosilicate], {[Cd(C₁₈H₁₈N₆)₂](SiF₆)}_n, (II), have been synthesized and characterized by elemental analysis, IR spectroscopy and single‐crystal X‐ray diffraction. In polymer (I), the 1,4‐bis[(1H‐imidazol‐1‐yl)methyl]benzene ligand bridges Cd²⁺ ions with a distorted seven‐coordinated pentagonal bipyramidal geometry, forming a one‐dimensional ladder chain, and the nitrate anions coordinate to the Cd²⁺ ions in a terminal bidentate fashion. In the crystal, adjacent chains are further connected by C—H…O hydrogen bonds to generate a two‐dimensional (2D) supramolecular structure. Polymer (II) exhibits a 2D layered structure in which 1,3,5‐tris[(1H‐imidazol‐1‐yl)methyl] benzene ligands join Cd²⁺ centres having a six‐coordinated octahedral structure. The layers are connected by hexafluorosilicate anions via C—H…F hydrogen‐bond interactions, giving rise to a three‐dimensional supramolecular network structure in the solid state. In addition, powder X‐ray diffraction (PXRD) patterns were recorded, thermogravimetric analyses (TGA) carried out and fluorescence properties investigated.     

Synthesis, crystal structure and imine bond activation of a copper(II) Schiff base complex

A new copper(II) complex [Cu(HL)(ClO₄)](ClO₄) (1), where HL is a multidentate Schiff base N,N′-(2-hydroxypropane-1,3-diyl)bis(pyridine-2-aldimine), is prepared, structurally characterized by X-ray crystallography and its spectral and electrochemical properties studied. The complex forms a one-dimensional chain in the solid state structure in which the monomeric Cu(HL) units are linked by the perchlorate ligand. The complex has an axially elongated six coordinate geometry (4+2) with a CuN₄O₂ core in which the Schiff base ligand displays a tetradentate mode of bonding in the basal plane. The axial ligand is perchlorate with a significantly long Cu–O bond of ca. 2.6 Å. The one-electron paramagnetic complex displays a cyclic voltammetric response for the Cu(II)/Cu(I) couple at 0.01 V versus SCE in MeCN–0.1 M TBAP. The azomethine bond of the Schiff base in 1 on treatment with H₂O₂ undergoes oxidative conversion to form a bis(picolinato)copper(II) · dihydrate species through the formation of an amido intermediate as evidenced from the solution infrared spectral studies.     

水杨醛缩2-芴胺席夫碱的合成、晶体结构及生物活性

芴在煤焦油中的含量为1%～2%,全国每年可从中提取1.4万吨芴.芴是一种带有荧光的片状化合物,作为一种新型的发光材料主要用于制备芴基金属化合物、有机光导体、树脂、染料、Ziegler-Natta催化剂的给电子体等.     

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.     

乙酰丙酮缩联苯胺席夫碱的合成及晶体结构

一个多世纪以来,己有大量有关席夫碱方面的文献报道.许多Schiff碱金属配合物因具有良好的抗肿瘤、抗病毒、杀菌抑霉等多种生物活性而得到了广泛应用[1-3];其特殊的催化行为以及在酶模拟方面的功效引起了化学家的普遍重视[4,5].席夫碱中,β一二酮类化合物是一类良好的金属螯合剂,因为它能够为金属提供两个键合点,形成稳定的六元螯合环,其与稀土离子形成的配合物具有稳定的化学性质和优异的发光性能,因而具有广泛的应用前景[6].     

Synthesis, crystal structures and fluorescence properties of four mixed-ligands Zn(Ⅱ) and Cd(Ⅱ) coordination compounds

Four new coordination compounds, [Zn(dba)(bpy)]n (1), {[Zn(dba)(phen)]·2H2O}n (2), [Cd(dba)(bpy)(H2O)2] (3) and [Cd2(dba)2(phen)2]n (4) (H2dba = 2,5-dihydroxy-p-benzenediacetic acid, bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline) have been prepared via solvothermal method and characterized by sin-gle-crystal X-ray diffraction, infrared spectroscopy, elemental analysis and powder X-ray diffraction. 1 and 2 possess 1D infinite chain structures. Complex 3 exhibits a mononuclear structure. Complex 4 owns bi...     

Synthesis,crystal structure and biological properties of Cd and Zn coordination polymers based on a flexible tripodal ligand

Two new coordination polymers, namely poly[[hexathiocyanatotetrakis{μ₃‐2,4,6‐trimethyl‐1,3,5‐tris[(triazol‐1‐yl)methyl]benzene}tricadmium(II)] 3.5‐hydrate], {[Cd₃(SCN)₆(C₁₈H₂₁N₉)₄]·3.5H₂O}_n ( 1 ), and poly[[hexathiocyanatotetrakis{μ₃‐2,4,6‐trimethyl‐1,3,5‐tris[(triazol‐1‐yl)methyl]benzene}trizinc(II)] 3.5‐hydrate], {[Zn₃(SCN)₆(C₁₈H₂₁N₉)₄]·3.5H₂O}_n ( 2 ), have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy and single‐crystal X‐ray diffraction analysis. From the X‐ray analysis, it is noteworthy that polymers 1 and 2 are isostructural, with their three‐dimensional structures composed of three kinds of four‐connection metal ions and two kinds of three‐connection 2,4,6‐trimethyl‐1,3,5‐tris[(triazol‐1‐yl)methyl]benzene (TTTMB) ligand nodes. Each metal ion is six‐coordinated in a slightly distorted octahedral geometry. The antioxidant activity against DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) and the antidiabetic activity against α‐amylase of the synthesized compounds were evaluated in vitro. The results of the DPPH free‐radical scavenging assay showed that polymers 1 and 2 exhibited strong antioxidant effects, with IC₅₀ values of 3.81 and 2.56 mg ml^?1, respectively. The IC₅₀ value in the antidiabetic studies of polymer 1 was 3.94 mg ml^?1, while polymer 2 exhibited no antidiabetic activity. Polymers 1 and 2 revealed different inhibitory activities on DPPH and α‐amylase, which indicated that the metal ions play important roles in the biological activity of coordination polymers. In addition, the solid‐state photoluminescence properties and thermal stability of 1 and 2 have been investigated.     

Coumarin-naphthohydrazone ligand with a rare coordination mode to form Mn(II) and Co(II) 1-D coordination polymers: synthesis,characterization, and crystal structure

The hydrazone (E)-3-hydroxy-N’-(1-(2-oxo-2H-chromen-3-yl)ethylidene)-2-naphthohydrazide (H₂L) was synthesized from the reaction of 3-acetylcoumarin and 3-hydroxy-2-naphthoic hydrazide in methanol. Compounds [Mn(H₂L)(NO₃)₂(CH₃OH)]·CH₃OH (1a), [Mn(HL)(NO₃)(CH₃OH)]_n (1b), [Co(HL)(NO₃)(CH₃OH)]_n (2), and [Cu(HL)(NO₃)] (3) were obtained by reaction of an equimolar amount of H₂L with nitrate salts of Mn(II), Co(II), or Cu(II) in methanol. The reaction of ligand and Mn(NO₃)₂·4H₂O was also carried out in the presence of sodium azide which led to the 1-D coordination polymer, [Mn(HL)(N₃)(CH₃OH)]_n (4). All of the synthesized compounds were characterized by elemental analyses and spectroscopic methods. Single-crystal X-ray analysis of 1–4 indicated that H₂L is neutral (in 1a) or mononegative ligand (in 1b, 2, 3 and 4). In 1b, 2 and 4 the 1-D polymeric chain is found by a rare coordination mode of this kind of hydrazone ligand since the naphtholic oxygen is coordinated to the neighboring metal ions while the NH moiety of hydrazone remains intact, also confirmed by FT-IR spectroscopic studies. The thermal stability of 2 and 4 were also studied from 30–1000 °C.     

Synthesis,crystal structure,and antimicrobial activity of a series of cobalt(III) Schiff base complexes

Abstract

A series of six new mononuclear Schiff base complexes, 1–6 of cobalt(III) of the general formula, [CoLX] or its adduct with methanol, is reported. The pentadentate Schiff base ligand (H₂L) was obtained by the condensation of N-(3-aminopropyl)-N-methylpropane-1,3-diamine with 1-(2-hydroxyphenyl)ethanone (H₂L¹) or 1-(2-hydroxyphenyl)propan-1-one (H₂L²). X stands for the pseudohalides, N₃^–, N(CN)₂^? , and NCS^–. The complexes have been synthesized by the reaction of equimolar amounts of cobalt(II) nitrate with H₂L¹ or H₂L² in the presence of the respective pseudohalide in methanol medium. All the complexes have been characterized by microanalytical, spectroscopic, single crystal XRD (except 3), and other physicochemical studies. Structural studies reveal that the central Co(III) ion in 1, 2, 4, 5, and 6 adopts a distorted octahedral geometry with a CoN₄O₂ chromophore. Weak intermolecular H-bonding and/or π-interactions are operative in these complexes to bind the molecular units. The antimicrobial activity of all the complexes and their constituent Schiff bases has been tested against some common bacteria and fungi.     

Syntheses,crystal structure and biological evaluation of three novel Cu (II) complexes with Schiff base derived from fluorinated amino acid and Salicylaldehyde

Three novel Cu (II) coordination complexes, formulated as [Cu₃(C₁₄H₈NO₃F) ₂ (CH₃COO)₂]_n ( 1 ), [Cu₂(C₁₄H₉NO₃F)₂(CH₃COO)Cl] ( 2 ) and [Cu(C₁₄H₈NO₃F)(CH₃OH)₂] ( 3 ), have been synthesized by 3-Fluoroanthranilic acid, Salicylaldehyde and Cu (II) salt as sources in different reaction conditions and characterized by single crystal X-ray diffraction, X-ray powder diffraction, IR spectroscopy and elemental analysis. Single-crystal diffraction analysis revealed that the complexes exhibited different coordination modes and conformations which were linked into multidimensional networks through some weak interactions. The biological activities vary greatly on account of the different Cu (II) numbers among the three complexes. In order to discuss the bioactivities, the complexes have been screened for antimicrobial activities against E. coli and S. aureus, antitumor activities against A549 (human lung cancer cells), Hela (human cervical cancer cells) and HepG-2(human liver hepatocellular carcinoma cells). Their interactions with calf thymus DNA were investigated by UV–visible and fluorescence spectrometry, as well as viscosity measurements. Interestingly, 1 (the rare 3-core Cu (II) coordination polymer) shows great antibacterial activities and highest DNA binding affinities. Antitumor studies revealed that complex 1 also exhibited highest activity.     

Synthesis, structure and spectral characterisation of a hydrogen-bonded polymeric manganese(III) Schiff base complex

A new hydrogen-bonded polymeric Mn(III) complex C₁₉H₂₀Mn₁N₃O₃S₁ (1) has been synthesised by conventional procedure with a new Schiff base ligand (2Z,3Z)-N ¹,N ²-bis(1-(2-hydroxyphenyl)ethylidene)ethane-1,2-diamine (H ₂ L) bearing a tetradentate N₂O₂ donor site. The complex has been characterised with several spectroscopic techniques like FT-IR, UV/Vis and EPR and also well supported by variable temperature magnetic susceptibility study. The structure of the co-ordination complex has been unequivocally confirmed from single crystal X-ray diffraction study. The redox stability of the metal chelate complex has been investigated with a slow scan cyclic voltammetry.     

三氯化镓席夫碱配合物的合成与晶体结构

在无水无氧条件下,利用三氯化镓与水杨醛缩间氯苯胺反应合成了一种新的席夫碱配合物C13H10ClNO·GaCl3。利用元素分析、核磁共振、红外光谱和X射线衍射单晶结构分析对其进行了表征。单晶结构表明标题配合物晶体属于正交晶系,Pnma空间群,晶胞参数:a=17.873(3),b=7.0853(13),c=12.677(2),α=90,β=90,γ=90,V=1605.4(5)3,Z=4,F(000)=808,R1=0.0283,wR2=0.0649。该配合物中镓以四配位形式存在,形成畸变的四面体结构,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。     

A new Co(II) complex with N,O-donor Schiff base: Synthesis, structure and characterization

A new Co(II) complex with tridentate Schiff base ligand with a N,N,O donor set has been synthesized and characterized by single X-ray technique and spectroscopic techniques. The thermochemical properties have been studied. X-ray structure analysis of the title compound Co(II)L₂ [HL = 2-methyl-6-(2′-hydroxybenzylideneamino) pyridine] shows that the polyhedron around Co(II) is a distorted tetrahedron, and the self-assembly via intermolecular π-π interactions leads to a three-dimensional network. Crystal data for the title complex C₂₆H₂₂CoN₄O₂: Monoclinic, space group Ia, a = 11.741(7) Å, b = 8.149(5) Å, c = 22.764(16) Å, β = 98.530(12)°, V = 2154(2) ų, Z = 4.     

双水杨醛缩环己二胺类西佛碱及其配合物的合成、性质研究

合成了两种双水杨醛缩环已二胺类西佛碱N，N’-(二羟苯次甲基)环已二胺(1)和N，N’-二(3，5-二叔丁基-2-羟苯次甲基)环已二胺(2)，以及它们的金属锌配合物(3)和(4)，通过核磁共振、元素分析和红外光谱确定了四种物质的结构，研究了它们的紫外吸收光谱、荧光光谱，测定了(3)和(4)的荧光量子效率．(4)中四个叔丁基的存在使其荧光量子效率提高．此类双西佛碱金属配合物可以应用于有机电致发光材料中．     

A highly efficient antioxidant based on boron and a Schiff base bridged phenolic diphenylamine: synthesis,crystal structure and thermal and antioxidant properties

Antioxidants can effectively protect vegetable‐oil‐based lubricants against oxidative degradation and prolong their service life. A novel compound, (E)‐4‐({3,5‐di‐tert‐butyl‐2‐[(diphenylboranyl)oxy]benzylidene}amino)‐N‐phenylaniline (BSPD) or {2‐[(4‐anilinophenyl)iminomethyl‐κN]‐4,6‐di‐tert‐butylphenolato‐κO}diphenylboron, C₃₉H₄₁BN₂O, was synthesized by a one‐pot reaction of the Schiff base bridged phenolic diphenylamine 2,4‐di‐tert‐butyl‐6‐{N‐[4‐(phenylamino)phenyl]carboximidoyl}phenol (SPD) with phenylboronic acid. The corresponding single‐crystal X‐ray study revealed that the B atom in BSPD has a typical tetrahedral geometry, and the N,O‐chelated six‐membered ring adopts a chair conformation. According to thermogravimetric analysis, the 5% weight‐loss temperature of BSPD increases to 328 °C and the 95% weight‐loss temperature is up to 414 °C. More importantly, the antioxidant capability of BSPD in vegetable oil is much better than that of commercial antioxidants [diphenylamine (DPA) and 2,6‐di‐tert‐butyl‐4‐methylphenol (BHT)] and unmodified SPD.