Right-handed Helical Chains Research Articles

Crystal Structure, Cytotoxicity and Interaction with DNA of Zinc (II) Complexes with o-Vanillin Schiff Base Ligands.

Two new zinc complexes, Zn(HL1)2 (1) and [Zn2(H2L2)(OAc)2]2 (2) [H2L1 = Schiff base derived from o-vanillin and (R)-(+)-2-amino-3-phenyl-1-propanol, H3L2 = Schiff base derived from o-vanillin and 2-amino-2-ethyl-1,3-propanediol], have been synthesized and characterized by single crystal X-ray diffraction, elemental analyses, TG analyses, solid fluorescence, IR, UV-Vis and circular dichroism spectra. The structural analysis shows that complex 1 has a right-handed double helical chain along the crystallographic b axis. A homochiral 3D supramolecular architecture has been further constructed by intermolecular C-H··· π, O-H···O and C-H···O interactions. Complex 2 includes two crystallographically independent binuclear zinc molecules. The two binuclear zinc molecules are isostructural. The 2-D sheet supramolecular structure was formed by intermolecular hydrogen bonding interaction. The fluorescence of ligands and complexes in DMF at room temperature are studied. The interactions of two complexes with calf thymus DNA (CT-DNA) are investigated using UV-Vis, CD and fluorescence spectroscopy. The results show that complex 1 exhibits higher interaction with CT-DNA than complex 2. In addition, in vitro cytotoxicity of the complexes towards four kinds of cancerous cell lines (A549, HeLa, HL-60 and K562) were assayed by the MTT method. Investigations on the structures indicated that the chirality and nuclearity of zinc complexes play an important role on cytotoxic activity.

A pair of novel helical Zn(II) enantiomers constructed from l- and d-threonine Schiff bases: Synthesis, crystal structures and properties

Two novel homochiral helical Zn(II) coordination polymers, {[Zn2(nap-l-thr)2(H2O)2]·H2O}n (1) and {[Zn2(nap-d-thr)2(H2O)2]·H2O}n (2) (H2nap-l-thr=N-(2-hydroxy-1-naphthylmethylidene)-l-threonine, H2nap-d-thr=N-(2-hydroxy-1-naphthylmethylidene)-d-threonine) have been successfully synthesized and characterized by elemental analysis, IR, UV–visible and single-crystal X-ray diffraction. It is interesting to note that both complexes are a pair of enantiomers: 1 exhibits 1D right-handed helical chain of [Zn-COO−]∞ and 2 is 1D left-handed helical chain of [Zn-COO−]∞. There are various hydrogen bonds between the adjacent helical chains which result in a 2D homochiral supramolecular layer structure. Notably, under similar synthetic procedure by using the NO3−, CH3COO−, Cl− salts of Zn2+ ion as a starting reagent, and identical compounds were obtained. In addition, the chiral nature of complexes 1 and 2 are confirmed by the results of circular dichroism (CD) spectra measurements. Thermal stability and luminescence properties were also investigated.

1D helical or ladder Mn(II) supramolecular isomerism based on imidazo-[4,5-f]-1,10-phenanthroline ligand

Two isomeric Mn(II) complexes, [Mn(IDP)SO4 · 2H2O]n (I) and {[Mn(IDP)SO4 · H2O] · H2O}n (II), have been prepared by solvo-thermal reactions of imidazo-[4,5-f]-1,10-phenanthroline (IDP) ligand with manganese sulfate. The crystal structures of IDP, complexes I and II are characterized by single-crystal X-ray diffusion analyses (CIF files CCDC nos. 988128 (IDP), 988129 (I), and 988130 (II)). The structural analyses show that there are H-bonds and π-π stacking interactions resulting in the 3D supramolecular structure for IDP. Complex I exhibits 1D chain-like structure featuring the left- and right-handed helical chains, while in II, the 1D structure is a ladder-like structure. The π-π stacking interactions take an important role in the formation of supramolecule structures for complexes HL, I, II due to the large conjugated system of IDP ligand. The IR and UV-Vis absorption spectra of complexes I and II exhibit the difference, but the liquid-state photoluminescence of I and II is similar attributing to the intraligand π-π* transition.

A Novel Cu(II) Coordination Polymer Containing Single-stranded Helical Chains: Crystal Structure, Thermal Stability, and Fluorescent Property

Graphical The reaction of 2-(2′-pyridyl)benzothiazole, L-alanine and perchlorate copper salt in methanol/water system affords a novel Cu(II) coordination polymer [Cu(PBT)(L-Ala)]n(ClO4)n [PBT = 2- (2′- pyridyl)benzothiazole, L-Ala = L-alaninate]. The structure of the polymer has been determined by elemental analysis, IR, X-ray single-crystal diffraction. The results reveal the carboxyl oxygen atoms of L-Ala brige adjacent Cu(II) atoms into 1D single-stranded chiral helical chains, and the Cu(II) coordination polymer consists of the left- and right-hand helical chains arranging alternately. In the Cu(II) coordination polymer, there exist strong aromatic π–π stacking interactions between benzothiazole rings and pyridyl rings, and hydrogen bonding interactions between perchlorate groups and the helical trains. Moreover, the thermal stability and fluorescent properties of the polymer are described.

Four new coordination polymers constructed using 2,2′-oxybis(benzoic acid) and auxiliary N-donor ligands: Syntheses, structures, magnetic behavior and DFT studies

Four new coordination polymers [Cu(oba)(phen)] (1), [Co(oba)(phen)] (2), [Ni2(oba)2(bpe)] (3) and [Ni(oba)(bpe)1.5]·2.5H2O (4) [H2oba=2,2′-oxybis(benzoic acid), phen=1,10-Phenanthroline, bpe=1,2-bis(4-pyridyl)ethylene] were synthesized by hydrothermal reactions and characterized by single-crystal X-ray diffraction, thermogravimetric analyses, IR spectroscopy and elemental analysis. Compound 1 shows a discrete binuclear structure. Compound 2 is a right-handed 1D helical chain, though π–π stacking interactions to form a 2D wavelike network. Compound 3 displays a 2D wavy layer with the paddle-wheel SBUs. Compound 4 features a 2-fold interpenetrating 3D structure with 2D brick-wall networks. The magnetic properties of compounds 1, 2 and 4 have also been investigated. According to the crystal structures, the full geometry optimizations of compounds 1–4 were carried out by using hybrid DFT methods at B3LYP/6-31G(d) level. Meantime, the DFT-BS approach was applied to study the magnetic coupling behavior for compounds 1, 2 and 4, the result reveals that the calculated exchange coupling constants J were in good agreement with the experimental data.

Syntheses, crystal structures, and properties of four coordination polymers with a new bifunctional ligand

Four new coordination polymers, {[Cd2(L)2·H2O]·4DMF·14H2O}n (1), {[Cd (L)]·2DMF·6H2O}n (2), {[Zn2(L)2]·4DMF·5H2O}n (3) and {[Cu (L)]·2DMF}n (4) (H2L=2,5-bis((4H-1,2,4-triazol-4-yl)carbamoyl)terephthalic acid), have been synthesized under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction. All of them exhibit three-dimensional structures possessing one-dimensional channels filled with solvent molecules. 1 is a 3D framework with large 1D channels (6.60×8.56Å2) filled with free DMF molecules and the 3D structure of 1 is a new (4, 8) network with Schläfli symbol {416.612}{44.62}2. 2 and 3 with different metal centers have similar structure except for the numbers of free water molecules. They both feature a (4, 4)-connected 3D network of {65.10} {65.8} topology with left- and right-handed helical chains along b-axis. While 4 is a 3D framework with typical CdSO4 topology. In addition, 1–3 show strong fluorescent emissions at room temperature, which can be assigned to the ligand-to-ligand charge transfer (LLCT) emissions.

Four coordination networks constructed by MII/titb units (titb = 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene) pillared by “rods”

Four new coordination networks, namely, {[Cd3(titb)2(SO4)2(NO3)]·(NO3)·(H2O)}n (1), {[Co3(titb)2(L1)2.5Cl]·(H2O)4}n (2), {[Co3(titb)2(L2)3(H2O)]·(H2O)4}n (3) and {[Co2(titb)2(HL3)(H2O)3]Cl}n (4) (titb=1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene, H2L1=octanedioic acid, H2L2=4,4′-(2,2′-oxybis(ethane-2,1-diyl)bis(oxy))dibenzoic acid and H4L3=benzene-1,2,4,5-tetracarboxylic acid) have been successfully synthesized hydrothermally and structurally characterized by elemental analysis, IR spectra and X-ray diffraction analyses. All compounds contain MII/titb units, including 0D molecular cage for 1, 1D ladder-like chain for 3 and 2D sheets for 2 and 4, and all the counteranions (sulfate or carboxylate anions) act as a connector to pillar the MII/titb units to generate the 1D to 3D frameworks. Compound 1 exhibits a 1D chain based on discrete Cd3(titb)2 molecular cage connected by sulfates. Compound 2 is described in terms of 2D Co3(titb)2 sheet further linked by finite hexanuclear (Co6L15) chain to form a complicated 3D framework with pentanodal (3,4)-connected topology. Compound 3 is a 2D double-layer formed by the 1D Co3(titb)2 ladder-like chain connected by both pairs of (Co2L2Co3L2)n left-, right-handed helical chains and 1D (Co1L2)n linear chain. Compound 4 is tetranodal (3,5)-connected array based on Co2(titb)2 double-layered sheet pillared by HL4 ligands. Furthermore, the thermal and photoluminescent properties have also been studied.

Crystal structure of catena-poly[[silver(I)-μ-N-(pyridin-2-ylmeth-yl)pyridine-3-amine-κ(2) N:N'] tri-fluoro-methane-sulfonate

In the asymmetric unit of the title compound, {[Ag(C11H11N3)]CF3SO3} n , there are two Ag(I) atoms, two N-(pyridine-2-ylmeth-yl)pyridine-3-amine ligands (A and B) and two CF3SO3 (-) anions. Both Ag(I) atoms are bridged by two pyridine N atoms from two symmetry-related A or B ligands, forming right- or left-handed helical chains, respectively. The Ag(I) atom of the right-handed helical chain adopts a slightly distorted linear coordination geometry [N-Ag-N = 170.69 (14)°], while that of the left-handed helical chain adopts a bent geometry [N-Ag-N = 149.42 (14)°]. Both helical chains have the same pitch length [10.8437 (5) Å], propagate along the b-axial direction and are alternately arranged via Ag⋯Ag [3.0814 (5) Å] and π-π stacking inter-actions [centroid-centroid distances = 3.514 (3) and 3.487 (3) Å], resulting in the formation of a two-dimensional supra-molecular network extending parallel to the ab plane. Weak Ag⋯O [2.861 (4), 2.617 (3), and 2.624 (4) Å] and Ag⋯F [3.017 (3) Å] inter-actions as well as N-H⋯O and C-H⋯O, C-H⋯N and C-H⋯F hydrogen-bonding inter-actions occur between the helical chains and the anions.

Five solvent-induced cadmium coordination polymers (CPs) based on the same mixed ligands

Five new solvent-induced cadmium coordination architectures, {[Cd(bib)(5-Br-H2ip)]·EtOH}n (1), {[Cd0.5(bib)0.5(5-Br-H2ip)0.5]·3H2O}n (2), {[Cd2(bib)(5-Br-H2ip)2(MeOH)]}n (3), {[Cd(bib)0.5(5-Br-H2ip)(H2O)2]·H2O}n (4), and {[Cd(bib)0.5(5-Br-H2ip)(H2O)]}n (5), have been constructed from the same materials (1,4-bis(2-methyl-imidazol-1-yl)butane (bib), 5-bromoisophthalic acid (5-Br-H2ip) and Cd(Ac)2·2H2O) under different reaction solvents. As controlled by solvent systems, compound 1 shows a 3-fold interpenetrating 3D framework based on the left- and right-handed helical chains, while compound 2 reveals a 3-fold interpenetrating 3D network and each single net is based on the left-handed, right-handed and meso-helical chains. Compound 3 is a 3D framework that can be simplified as a 6-connected net with (48·62) topology. Both 4 and 5 display 3D supramolecular frameworks through weak aromatic π–π stacking interactions and hydrogen bonding interactions. However, the topologies of 4 and 5 are definitely different. Compound 4 presents a 3-connected net with (82·10) topology, while compound 5 reveals a 4-connected net with (42·63·8) topology. The effects of solvents on the crystal structures were discussed and thermogravimetric analysis and solid-state photoluminescence results for 1–5 were investigated.

Syntheses, structures and luminescent properties of two new zinc coordination polymers based on 4′-(4-aminephenyl)-4,2′:6′,4″-terpyridine

Two new coordination polymers, namely, [Zn(L)Cl2]n (1) and [Zn4(L)4(ox)4]n·7nH2O (2) (L=4′-(4-aminephenyl)-4,2′:6′,4″-terpyridine, H2ox=oxalic acid), have been synthesized under hydrothermal condition and characterized by elemental analysis, IR, and single crystal X-ray diffraction. Compound 1 exhibits an achiral 2D supramolecular network constructed by left-handed single-helical chains and right-handed H-bonding helical chains, which further generated to a 2D+2D→2D parallel interpenetration framework. Compound 2 displays an achiral 2D layer based on a 1D left- and right-handed helical chains with alternate arrangement, which is further extended into a 2D+2D→3D supramolecular network by hydrogen bonds. Additionally, their photoluminescence properties have been investigated.

Syntheses, structures and photoluminescence of Cd(II) coordination polymers based on in situ synthesized bifunctional ligands

By employing Cd(II) salt, NaN3, and CN–(CH2)n–NC (n=1, 2) and with the absence or presence of secondary ligands, four new cadmium coordination frameworks, named, {[Cd4(btm)4(H2O)2]·3H2O}n (1); [Cd2(btm)2(H2O)]n (2); [Cd2(bte)(PMA)0.5(H2O)]n (3); and [Cd(tzp)(2,2′-bipy)]n (4) (H2btm=bis(tetrazole) methane: H2bte=1,2-bis(tetrazole-5-yl)ethane; H2tzp=1H-tetrazolate-5-propionic acid; bipy=bipyridine; PMA=1,2,4,5-benzenetetracarboxylic acid) were synthesized via in situ hydrothermal reaction. Single crystal X-ray diffraction reveals that compounds 1–3 are all three-dimensional (3D) frameworks. Compound 1 is constructed by Cd1– and Cd3–btm2− layers and large bridging metalloligands. Compound 2 exhibits a 3D framework with two-dimensional (2D) Cd–btm2− (adopting μ6:κN1, N1′: κN2: κN3: κN4: κN3′: κN4′coordination mode) layers pillared by μ3:κN1, N1′: κN2: κN4′ btm2−. Compound 3 is built up by the Cd–bte2− layers and the linker PMA, with left- and right-handed helical chains arranged alternately. It is notable that btm2− takes on six different coordination modes in 1 and 2. Compound 4 represents a 2D layered framework, which can be simplified into a Shubnikov plane net (4.8^2) topological network with 3-connected T shape linker tzp2− ligands. In addition, the research results show that compounds 1–4 exhibit different fluorescent behaviors and thermal stabilities.

Two new helical compounds based on Keggin clusters and N-donor multidentate ligand: Syntheses, structures and properties

Two isostructural polyoxometalate-based inorganic–organic hybrids with 1D helical chain, [CuH3L2(GeMo12O40)]·2H2O (1) and [CuH3L2(SiMo12O40)]·2H2O (2), where L=2,4,5-tri(4-pyridyl)-imidazole have been synthesized under hydrothermal conditions. It is the first time to use the L ligand to synthesis the Keggin-type polyoxometalate-based inorganic–organic hybrids. The two compounds possess the left- and right-handed helical chains and the POMs as pendants attach in the helical chains through Cu–O bonds. The two compounds have been characterized by elemental analyses, infrared (IR) spectroscopy, powder X-ray diffraction (PXRD), X-ray photoelectron spectra (XPS), thermogravimetric analysis (TGA) and photoluminescent spectroscopy. Moreover, nitrogen adsorption−desorption measurement, electrochemical and photocatalysis properties for degradation of methylene blue (MB) upon a UV irradiation of compound 1 have been examined.

Isomorphous and isostructural lanthanide coordination polymers based on 2-(4-chlorobenzoyl)benzoic acid: Synthesis, structure, characterization, and luminescent properties

Self-assembly of a flexible ligand Hcbba (2-(4-chlorobenzoyl)benzoic acid) and lanthanide salts yield a series of three-dimensional (3D) coordination polymers under hydrothermal conditions, namely, [Ln(cbba)3H2O]∞ (Ln = La(I), Pr(II), and Nd(III)). Their structures were determined by single-crystal X-ray diffraction analyses and characterized by elemental analyses and infrared spectroscopy, which verified that they are isomorphous and isostructural. Findings indicate that the subunit of cavate cages (Ln2O2(OCO)2) are observed in I–III, which are connected into a one-dimensional (1D) chain through cbba− anions in μ2-η1:η1 fashion and further assembled into 3D architecture via C–H⋯π and C–H⋯Cl interactions between the neighboring parallel 1D chains. I–III feature that the double-stranded helix entangled by one left- and one right-handed helical chain coaxially along c axis in each 1D infinite chain. Luminescent properties reveal that II and III may be potential ion-selective luminescent probes for Hg2+ and Ag+, respectively.

Syntheses, structures and fluorescent properties of cadmium coordination polymers based on 2,3′,5,5′-biphenyl tetracarboxylate and N-donor ancillary ligands

Self-assembly of cadmium(II) salt based on 2,3′,5,5′-biphenyl tetracarboxylate with or without various N-donor ligands affords a series of coordination polymers, namely {[Cd1.5(Hbptc)(H2O)4.5]·2H2O}n (1), {[Cd2(bptc)(2,2′-bipy)2]·2H2O}n (2), {[Cd2(bptc)(pyp)2(H2O)2]}n (3), [Cd(H3bptc)2(bip)2]n (4), and {[Cd2(bptc)(bpt)(H2O)]·H2O}n (5), where H4bptc=2,3′,5,5′-biphenyl tetracarboxylic acid, 2,2′-bipy=2,2′-bipyridine, pyp=3-(pyrid-2-yl)pyrazole, bip=3,5-bis(1-imidazol)pyridine, bpt=3,5-bis(4-pyridyl)-1,2,4-triazolyl. Their structures were determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis and IR spectra. Complex 1 shows a 2D helical layer, which is further extended to a 3D supermolecule network through inter-layer C–H⋯O hydrogen bonds and π⋯π stacking interactions. Complex 2 exhibits a (3,6)-connected (43)2(46.66.83)-kgd topology. Complex 3 possesses a 2D (3,5)-connected (4.5.6)(4.53.64.72) net based on 1D tube-like chains. Complex 4 has a 1D polymeric ribbon containing left- and right-handed helical chains, which are further hydrogen bonded to form a 2D supermolecule layer. Complex 5 possesses a 3D (4,5,7)-connected framework. Moreover, the fluorescent properties of 1–5 in the solid state have been investigated.

Synthesis and characterizations of two NbO topological gallium phosphites with low framework density

Two new 3D open-framework gallium phosphites Ga(HPO3)F2·(H2A)0.5, where A=C5N2H12(1) and C6N2H14 (2) have been solvothermally synthesized in the presence of 2-methyl piperazine and N,N′-dimethyl piperazine as template, respectively. Single crystal X-ray diffraction reveals that these two compounds have the similar inorganic framework structures, which may be viewed as the assembly of a second building unit (SBU), Ga2F2O4(HPO3)2 containing one dimer Ga2F2O8 and two HPO3 groups. The SBUs are linked with each other via vertex-sharing oxygen atoms to form a new 3D open-framework which possesses the left- and right-handed helical chains along c axis. With the SBU as 4-connected nodes, the structure can be simplified into a uninodal NbO topology. Moreover, compounds 1 and 2 show low framework density value of 9.4 and 9.7, respectively. Crystal data: compound 1, Trigonal, R-3 (148), a=b=18.315(3)Å, c=13.136(4)Å, γ=120°, V=3815.9(13)Å3 and Z=9; compound 2, Trigonal, R-3 (148), a=b=17.8476(4)Å, c=13.5159(6)Å, γ=120°, V=3728.5(2)Å3 and Z=18.

Two coordination polymers from 2-p-butylphenyl imidazole dicarboxylate: Syntheses, crystal structures, and thermal properties

By employing a newly designed ligand, 2-(p-tert-butylphenyl)-1H-imidazole-4,5-dicarboxylic acid (H3BuPhIDC) to react with manganese(II) or nickel(II) ions, two coordiantion polymers [Mn2(μ3-HBuPhIDC)2(CH3OH)2] (I) and [Ni(μ2-HBuPhIDC)(H2O)2] (II) have been solvothermally synthesized and structurally characterized by elemental analyses, IR spectroscopy, and single crystal X-ray diffraction. Polymer I shows a 3D framework bearing 1D octagonal channels constructed from left- and right-handed helical chains. Polymer II exhibits an infinite chain structure, which are joined through the π-π interactions and intramolecular hydrogen bonds to form a 3D architecture. The thermal properties of the polymers have been investigated as well. The coordination ability and modes of H3BuPhIDC have been investigated from both theoretical and experimental aspects.

A novel 2-D structure constructed from copper complexes and bi-capped tungsten-based Keggin clusters

A new compound, [Cu(en)2(H2O)]{[Cu0.5(en)]3[VVW6.5VIW3VV4.5IVO42Cu(en)2]}·3.5H2O (1) (en=ethylenediamine), has been hydrothermally synthesized and characterized by elemental analysis, IR, ESR, XPS, TG analysis and single-crystal X-ray diffraction analysis. Compound 1 exhibits a novel 2-D structure linked by 1-D infinite left- and right-handed helical chains and transition metal coordination fragments. Adjacent layers are further interconnected into a 3-D supramolecular structure via hydrogen bonds. The magnetic susceptibility of compound 1 demonstrated the presence of antiferromagnetic interactions.

A Rare L1D + R1D → 3D Luminescent Dense Polymer as Multifunctional Sensor to Nitro Aromatic Compounds, Cu2+, and Bases

A rarely reported L1D (left-handed helical 1D chain) + R1D (right-handed helical 1D chain) → 3D polycatenated network, [Cd(H2ttac)bpp]n (1), constructed from the vertical interpenetration of triple-stranded homochiral helices, has been synthesized under hydrothermal condition by H4ttac (1,1′,2′,1″-terphenyl-4,4′,4″,5′-tetracarboxylic acid), 1,3-bis(4-pyridyl)propane (bpp), and Cd(NO3)2·4H2O. The luminescent properties of 1 and the ones immersed in various kinds of organic compounds and nitrate@DMF solutions have been investigated. Importantly, 1 shows highly sensitive response to nitro aromatic compounds and Cu2+ through luminescence quenching effects, making it a promising luminescent sensor for nitro aromatic compounds and Cu2+. Besides, experiments upon deprotonation by NaOH, KOH, methylamine, and triethylamine are conducted, respectively. As base increases, the luminescence spectra exhibit gradual blue shifts. The mechanisms of the sensing properties have been studied in detail.

A novel 2D inorganic–organic hybrid compound constructed from {CuMo2O7}n bimetallic oxide chains bridged by N-containing ligand

A novel inorganic–organic hybrid compound [Cu(Mo2O7)(H2MDP)] (1) has been hydrothermally synthesized from the self-assembly of CuI, H2MoO4 and H2MDP ([Methylenebis(3,5-dimethylpyrazole)]). Compound 1 is constructed from one-dimensional {Cu(Mo2O7)}n bimetallic oxide chains bridged by H2MDP ligands into a novel two-dimensional hybrid compound. There exist left- and right-handed CuOMo helical chains in the bimetallic oxide chains.

Solvent-induced two Cu(II) complexes with 4-acyl pyrazolone derivative: From discrete structure to 1D helical chain

Two new copper(II) complexes [Cu2L2(CH3OH)]·CH3OH (1) and [CuL]n (2) (H2L=N-(1-phenyl-3-methyl-4-benzal-pyrazolone-5)-salicylidene hydrazide) with different structures have been synthesized by the reactions of copper acetate with the 4-acyl pyrazolone derivative H2L in MeOH or EtOH solvent, respectively. The X-ray diffraction analyses revealed that 1 displays a dinuclear structure which is further linked by weak coordination interactions and hydrogen bonds to generate an infinite 1D chain. Complex 2 exhibits 1D left-handed and right-handed helical chains structure in a 1:1 ratio along the c axis, and the 1D chains with the same handedness were linked by hydrogen bonds to form a racemic two-fold interpenetrated 3D framework. The results demonstrated that the solvents with different coordination abilities have significant effect on the structure of the complexes. On the other hand, the ligands H2L adopt tridentate chelating mode and tetradentate chelating-bridging mode to coordinate with Cu(II) ions in 1 and 2, which attested that the flexible 4-acyl pyrazolone Schiff base derivative can adopt different coordination modes to form complexes with varied structures. The variable temperature magnetic investigation indicates that 2 exhibits typical antiferromagnetic behavior.