An oxovanadium(IV) complex of an l-serine Schiff base and 1,10-phenanthroline: synthesis,crystal structure,and DNA and albumin-binding properties

Transition Metal Chemistry - A new V(IV) complex, [VO(naph–ser)(phen)]·1.5CH3OH (naph–ser = Schiff base derived from l-serine and 2-hydroxy-1-naphthaldehyde,...     

Syntheses,crystal structures and in vitro anticancer activities of oxovanadium(IV) complexes of amino acid Schiff base and 1,10-phenanthroline ligands

Four oxovanadium(IV) complexes, namely [VO(desa-met)(phen)]·MeOH·2H₂O (1) (desa-met = Schiff base derived from 4-(diethylamino)salicylaldehyde and dl-methionine, phen = 1,10-phenanthroline), [VO(o-van-met) (phen)]·MeOH·CH₂Cl₂·3H₂O (2) (o-van-met = Schiff base derived from o-vanillin and dl-methionine), [VO(dtbs-napa)(phen)]·2H₂O (3) (dtbs-napa = Schiff base derived from 3,5-di-tert-butyl salicylaldehyde and 3-(1-naphthyl)-l-alanine) and [VO(hyna-napa)(phen)]·1.5H₂O (4) (hyna-napa = Schiff base derived from 2-hydroxy-1-naphthaldehyde and 3-(1-naphthyl)-l-alanine), were synthesized and characterized by IR, HRMS, UV–vis spectra, molar conductance and single-crystal X-ray diffraction (XRD). X-ray structural analysis showed that the V(IV) atoms in all four complexes are six-coordinated in a distorted octahedral environment. In the crystals of complexes 1 and 2, π–π stacking interactions together with hydrogen bonds connect the molecular units into 2D networks. Meanwhile, CH–π stacking interactions are observed between the aromatic rings in the crystals of 1 and 4, while the π–π stacking interactions between aromatic rings in the crystals of 2 and 3 are arranged with a face-to-face mode. The in vitro anticancer activities of these complexes against A-549 and HeGp2 cells were tested by MTT assay.     

Mixed-ligand oxovanadium complexes incorporating Schiff base ligands: synthesis, DNA interactions, and cytotoxicities

Three oxovanadium complexes, namely [VO(NOSAA)(bpy)] (1) (NOSAA = 2-hydroxy-5-nitrosalicylidene anthranilic acid, bpy = 2,2′-bipyridyl), [VO(NOSAA)(4,4′-dimebpy)] (2) (4,4′-dimebpy = 4,4′-dimethyl-2,2′- bipyridyl), and [VO(NOSAA)(phen)] (3) (phen = 1,10-phenanthroline), have been prepared and characterized. The binding modes and strengths of these complexes with calf thymus DNA (CT-DNA) were studied using various techniques. The chemical nuclease activities and photocleavage reactions of the complexes were also tested. All three complexes interact with CT-DNA through intercalative modes, and complex 3 possesses the largest binding affinity. All three complexes can efficiently cleave pBR322 DNA upon irradiation or under physiological conditions in the presence of H₂O₂, and complex 3 has the best cleaving ability. In vitro experimental results showed that the three complexes are cytotoxic against myeloma (Ag8.653) and gliomas (U251) cell lines and complex 3 again showed the highest efficacy.     

Synthesis,crystal structure,and interaction with DNA and BSA of a chromium(III) complex with naph-gly Schiff base and 1,10-phenanthroline

A new chromium(III) complex, [CrCl(naph-gly)phen]?H₂O (naph-gly = Schiff base derived from 2-hydroxy-1-naphthaldehyde and glycine, phen = 1,10-phenanthroline), has been synthesized and characterized by elemental analysis, electrospray ionization mass spectroscopy, FT-IR, and X-ray single-crystal diffraction. The chromium(III) complex belongs to the trigonal crystal system, P3(1) space group with crystallographic data: a = b = 1.97017(16) nm, c = 1.02991(7) nm, α?=?β?=?90°, γ =120°, V = 3.4621(5) nm³, D_c = 1.476 g?cm^?3, Z = 6, F(0 0 0)?=?1578, R₁ = 0.0508, wR₂ = 0.0907. There are two independent molecules in the crystallographic asymmetric unit of the chromium(III) complex. Each Cr^III is six-coordinate to form an octahedral geometry. In the crystal, a 3-D structure is formed through intermolecular hydrogen bonds. The calf thymus DNA (CT-DNA)- and bovine serum albumin (BSA)-binding properties of the complex have been studied by UV absorption, fluorescence, and circular dichroism (CD) spectroscopy. Results indicate that the chromium(III) complex binds to CT-DNA in an intercalative mode, and it can bind to BSA and cause conformational changes of BSA.     

A copper(II) complex of the Schiff base from l-valine and 2-hydroxy-1-naphthalidene plus 1,10-phenanthroline: synthesis, crystal structure, and DNA interaction

A new Cu(II) complex, [Cu(naph-val)phen] (naph-val = Schiff base derived from 2-hydroxy-1-naphthaldehyde and l-valine, phen = 1,10-phenanthroline), has been synthesized and characterized by physicochemical methods. The crystal structure of the complex showed that there are four independent molecular structures in the crystallographic asymmetric unit, and each of them shows a distorted square-pyramidal CuN₃O₂ coordination geometry. In the crystal, the π − π stacking and intermolecular hydrogen bonds form a 2D network. The interactions between the Cu(II) complex and calf thymus DNA (CT-DNA) have been studied by spectroscopic methods, as well as viscosity and thermal denaturation measurements. The results indicate that the Cu(II) complex binds to CT-DNA in an intercalative mode. The cleavage reaction on pBR322 plasmid DNA has been investigated by agarose gel electrophoresis in the absence and presence of mercaptopropionic acid. The Cu(II) complex exhibits an efficient DNA cleavage activity.     

Synthesis, crystal structures, DNA binding and cleavage studies of two oxovanadium(IV) complexes of 1,10-phenanthroline and Schiff bases derived from tryptophan

Two new V(IV) complexes, [VO(Naph?Ctrp)(phen)]·CH₃OH (1) and [VO(o-Van?Ctrp)(phen)]·CH₃OH·H₂O (2) (Naph?CTrp?=?Schiff base derived from 2-hydroxy-1-naphthaldehyde and l-tryptophan, o-Van?Ctrp?=?Schiff base derived from o-vanillin and l-tryptophan, phen?=?1,10-phenanthroline), have been synthesized and characterized by physicochemical methods. The V(IV) atoms in both complexes are six-coordinated in a distorted octahedral environment. In the crystals of complex 1, the C?CH···?? and ?ШC?? stacking interactions form a 1D chain structure, whereas for complex 2, hydrogen bonds connect the molecular units into a 2D plane structure. The DNA binding properties and cleavage efficiencies of the complexes have been investigated by spectroscopic methods, viscosity measurements and agarose gel electrophoresis. The results suggest that both complexes can bind to CT-DNA in an intercalative mode and can also cleave pBR322 DNA.     

Synthesis, crystal structure, and DNA interaction studies of a mixed-ligand copper(II) complex of 1,10-phenanthroline and a Schiff base derived from isoleucine

A mixed-ligand Cu(II) complex, [Cu(o-van-ile)(phen)]·1.5H₂O (o-van-ile = Schiff base derived from o-vanillin and l-isoleucine, phen = 1,10-phenanthroline), has been synthesized and structurally characterized. The crystal structure shows 1-D linear chains formed by C?CH??O hydrogen bond interactions. The DNA-binding interactions of the Cu(II) complex with calf thymus DNA (CT-DNA) have been investigated by spectroscopic methods and agarose gel electrophoresis. The results indicate that the complex can bind to CT-DNA via an intercalative mode and show efficient cleavage activity in both the absence and presence of reducing agents.     

Tetradentate Schiff base oxovanadium(IV) complexes

Summary Eleven oxovanadium(IV) complexes of tetradentate Schiff bases, obtained by condensating two moles of an o-hydroxycarbonyl compound with a diamine, have been prepared and characterized by elemental analysis, m.p., and i.r. and electronic spectra. The i.r. and electronic spectra of the free ligand and the complexes are compared and discussed. The Gaussian analysis of the vis. spectra of the complexes, normally C₁ or C_s, in MeCN yielded four peaks at ca. 12000, 15000, 17700 and 20000–23000cm^–1, assigned to the four d-d transitions.     

A new ternary Cu (II) complex with 4,7-dimethyl-1,10-phenanthroline and NOO-type tridentate Schiff base ligand: Synthesis,crystal structure,biomacromolecular interactions,and radical scavenging activities

NOO-type tridentate Schiff base, N-salicylidene-2-aminobenzoic acid, (H₂L), and its ternary Cu (II) complex containing H₂L Schiff base and 4,7-dimethyl-1,10-phenanthroline (4,7-dmphen), [Cu(4,7-dmphen)(H₂L)]₂7H₂O, have been synthesized and characterized by CHN analysis, ESI-MS, FTIR, and single-crystal X-ray diffraction techniques. The interaction of alone H₂L Schiff base ligand and ternary Cu (II) complex with biomacramolecules {calf thymus DNA (CT-DNA) and bovine serum albumin (BSA)} has been investigated by electronic absorption and fluorescence spectroscopy. The experimental results indicate that H₂L Schiff base ligand and ternary Cu (II) complex bind to CT-DNA by means of a moderate intercalation mode. Furthermore, the fluorescence quenching mechanism between H₂L Schiff base ligand and ternary Cu (II) complex with BSA possesses a static quenching process. Radical scavenging activity of H₂L Schiff base ligand and ternary Cu (II) complex was measured in terms of EC₅₀, using the DPPH and H₂O₂ methods. Biomacromolecule interactions and scavenging activity studies revealed that ternary Cu (II) complex yielded better results than H₂L Schiff base ligand alone.     

Ternary copper(II) complex of 1,10-phenanthroline and L-glycine: crystal structure and interaction with DNA

A ternary copper(II) complex, [Cu(phen)(L-Gly)(H₂O)] ·?NO₃ ·?1.5H₂O (phen =?1,10-phenanthroline, L-Gly =?L-glycine), has been synthesized and structurally characterized. The complex crystallized in a monoclinic system with space group C2/c, a =?20.572(3) Å, b =?6.9987(10) Å, c =?23.561(3) Å, β?= 98.776(5)°. The five-coordinate copper(II) center is a distorted square pyramid. Absorption spectra, fluorescence spectra and viscosity measurements showed interaction between the copper complex and DNA through an intercalative mode. The complex exhibited efficient DNA cleavage activity at micromolar concentration in the presence of ascorbate with hydroxyl radicals as the active species.     

Synthesis, crystal structure, DNA- and albumin-binding properties of a chromium(III) complex with 1,10-phenanthroline and a Schiff base derived from glycine

A new Cr(III) complex, [CrCl(sal-gly)phen]·0.5H₂O (sal-gly = Schiff base derived from salicylaldehyde and l-glycine), has been synthesized and characterized by physicochemical methods. There are two independent complex molecules and a water molecule in each asymmetric unit. Each Cr(III) atom is six-coordinated in a distorted octahedral coordination environment. In the crystal, a 3D network is formed via intermolecular hydrogen bonds. The interactions between the Cr(III) complex and calf thymus DNA (CT-DNA) and Bovine serum albumin (BSA) have been studied by spectroscopic methods. The results show that the complex binds to CT-DNA in an intercalative mode, and it can also bind to BSA and produce conformational changes in the protein.     

Monomeric and polymeric structures of oxovanadium(IV) complexes with Schiff base ligands derived from (R,R)-2,4-pentanediamine: Synthesis and crystal structure

New tetradentate Schiff base–oxovanadium(IV) complexes which have electron donating or withdrawing groups at the 5-position of the salicylaldehyde moieties, [VO{Xsal-(R,R)-2,4-ptn}] (H₂{Xsal-(R,R)-2,4-ptn}: N,N′-di-Xsalicylidene-(R,R)-2,4-pentanediamine; X=5-MeO (methoxy), 5-Br, and 5-NO₂) were prepared. The structures and redox potentials for the V(V)/V(IV) couple of the complexes were compared with those of other [VO{Xsal-(R,R)-2,4-ptn}] (X=3-EtO (ethoxy), 3-MeO, and H). The 5-MeO substituted complex which has electron donating groups at the 5-position of the salicylaldehyde moieties forms a monomeric structure in the solid state. The 3-EtO substituted complex has both monomeric and polymeric structures. On the other hand, the other [VO{Xsal-(R,R)-2,4-ptn}] (X=H, 3-MeO, 5-Br, 5-NO₂) complexes have only polymeric structures. X-ray crystal structure analysis of [VO{5-MeOsal-(R,R)-2,4-ptn}]⋅CH₃OH (1) was carried out. Complex 1 has a monomeric five-coordinate square–pyramidal structure. The six-membered N–N chelate ring forms a distorted flattened boat form with two methyl groups in the axial positions.     

Synthesis and crystal structure of a Cu(II) complex with mixed malonate/1,10-phenanthroline ligands

A Cu(II) complex with mixed ligands, [Cu₃(mal)₃(phen)₃(H₂O)₂]?·?11H₂O (mal?=?malonate, phen?=?1,10-phenanthroline) was synthesized and characterized by elemental analysis, IR, UV, electron paramagnetic resonance (EPR) and luminescence spectra and single-crystal X-ray diffraction. The complex crystallizes in the monoclinic system, space group Cc with a?=?13.1631(10)?Å, b?=?20.1089(10)?Å, c?=?20.1267(13)?Å, β?=?103.500(3)°, V?=?5180.2(6)?ų, Z?=?4, and R ₁?=?0.0476 for 7993 observed reflections. In the complex, one Cu is coordinated by a mal dianion and a phen molecule, exhibiting N₂O₂ square-planar geometry, while the other two Cu atoms are coordinated, respectively, by a mal dianion, a phen and water molecules, exhibiting N₂O₃ square pyramidal coordination geometry.     

A chiral binuclear nickel(II) complex with Schiff base ligand: synthesis,crystal structure,DNA/BSA binding interactions and SOD activity

Transition Metal Chemistry - A chiral binuclear Ni(II) complex [Ni2(o-van-ala)2(phen)2] (o-van-ala?=?a Schiff base derived from o-vanillin and l-alanine,...     

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。     

Manganese(IV) complex with a polydentate Schiff base ligand: synthesis,crystal structure,TDDFT calculation,electronic absorption and EPR spectral study

A six-coordinate Mn(IV) complex, [Mn(H₂L)₂] (1) [H₄L = 2-methoxy-6-(tris(hydroxymethyl)methyliminomethyl)phenol], was synthesized and characterized by elemental analysis, single-crystal X-ray crystallography, FTIR, UV–Vis electronic absorption, and EPR spectroscopy. The single-crystal structural determination reveals that the complex crystallizes in tetragonal space group P4₁2₁2 and the tridentate Schiff base ligands are arranged in mer configuration chelating manganese, which exhibits as slightly distorted octahedral coordination sphere with a N₂O₄ chromophore. Weak hydrogen bonding interactions of uncoordinated hydroxyl groups result in a 2-D supramolecular structure. The UV–Vis electronic absorption and IR spectral data of 1 have been compared with the results obtained by employing DFT and time-dependent density functional theory calculation using B3LYP, B3PW91, and MPW1PW91 functionals, with 6-31G (d-p) and LanL2MB basis sets. The results of these calculations are functional-dependent and, among those used, B3PW91 proved to better reproduce the experimental results.     

Synthesis and crystal structure of a novel hexanuclear Zr(IV) complex with 1,10-phenanthroline including carboxylato,hydroxo, and oxo bridging

A novel hexanuclear Zr(IV) complex, [Zr₆(O)₆(OH)₂(Ph₂CHCOO)₁₀(phen)₂]·4CH₃CN (1), where phen denotes 1,10-phenanthroline, has been prepared and characterized on the basis of elemental analysis, infrared-spectroscopy measurements, and X-ray crystallography. Complex 1 resides on a crystallographic inversion center, thus making only three of the six zirconium ions unique. The six zirconium ions are arranged in apices of an octahedron. One Zr(IV) metal ion (Zr1) is individually joined with two Zr(IV) metal ions (Zr2, Zr3) by one syn–syn bridging carboxylate group, and Zr1 has three μ₃-O and one μ₃-OH bridges through Zr2 and Zr3. The Zr2 atom is also connected by one syn–syn bridging carboxylate group through Zr3*. Moreover, Zr1 is coordinated by two nitrogen atoms of a bidentate 1,10-phenanthroline group with eight coordination. Besides these, Zr2 is coordinated by one carboxylate of a bidentate–chelate type, completing the eight coordination. The Zr3 atom is coordinated by one monodentate carboxylate oxygen, consequently has a novel seven coordination.     

Thorium(IV) complexes with tetradentate Schiff base ligands

Summary Some thorium(IV) complexes were synthesized with the tetradentate Schiff base ligands (N₂O₂ donor set) obtained by the condensation of ethylenediamine with salicylaldehyde (H₂salen) or acetylacetone (H₂ acacen). In all cases the neutral Schiff bases and not their anions are coordinated to the central thorium(IV) atom. The complexes have the general formula: ThL₂Xa (L = H₂ salen; X = Cl, Br, 1, NCS and L = lie acacen; X = Cl, 1, NCS, ClO₄) or ThLX₄ (L = H₂ salen; X = NO₃, ClO₄ and L = H₂ acacen; X = Br, NO₃). The stoichiometry and coordination number of the complexes was determined on the basis of elemental analysis, conductivity measurements, i.r. spectra and t.g.a./d.t.a. data. The coordination number of the complexes is either 12 or 8 for the bisor monocomplexes respectively.     

Dinuclear copper(II) complex and 1-D copper(II) complex with taurine Schiff base: synthesis,crystal structure,and properties

A dinuclear copper(II) compound, [Cu(btssb)(H₂O)]₂ · 4(H₂O) (1), and a 1-D chain copper(II) compound, [Cu(ctssb)(H₂O)] _n (2) [where H₂btssb is 2-[(5-bromo-2-hydroxy-benzylidene)-amino]-ethanesulfonic acid and H₂ctssb is 2-[(3,5-dichloro-2-hydroxy-benzylidene)-amino]-ethanesulfonic acid], were prepared and characterized. Compound 1 crystallizes in the monoclinic space group P2₁/c, with a = 10.109(2) Å, b = 20.473(4) Å, c = 6.803(1) Å, β = 100.32(3)°, V = 1385.1(5) ų, and Z = 2; R ₁ for 1796 observed reflections [I > 2σ(I)] was 0.0357. The geometry around each copper(II) can be described as slightly distorted square pyramidal. The Cu^II ··· Cu^II distance is 5.471(1) Å. Compound 1 formed a 1-D network through O–H ··· O hydrogen bonds and 1-D water chains exist. The 1-D chain complex 2 crystallizes in the triclinic space group P 1, with a = 5.030(2) Å, b = 7.725(2) Å, c = 17.011(5) Å, α = 92.706(4)°, β = 97.131(4)°, γ = 102.452(3)°, V = 638.6(3) ų, and Z = 2; R ₁ for 1897 observed reflections [I > 2σ(I)] was 0.0171. In 2, Cu(II) was also a slightly distorted square pyramid formed by two oxygens and one nitrogen from ctssb, one oxygen from another ctssb, and one water molecule. The complex formed a 1-D chain through O–S–O bridge of ctssb ligand. The 1-D chain further constructed a double chain through O?H ··· O hydrogen bonds.