Synthesis,crystal structures,and magnetic properties of cobalt(II) and nickel(II) complexes of 2,2′-bipyridine-6,6′-dicarboxylate: three three-dimensional networks formed via hydrogen bonding interactions

Three Co(II) and Ni(II) complexes, namely [Co(bpdc)(H₂O)₂] (1), [Ni(bpdc)(H₂O)₂] (2), and [Co₂(bpdc)₂(prz)_0.5(H₂O)₃]·0.5H₂O (3) (H₂bpdc = 2,2′-bipyridine-6,6′-dicarboxylic acid and prz = piperazine), have been synthesized from H₂bpdc and the corresponding metal salts under hydrothermal conditions. The complexes were characterized by physico-chemical and spectroscopic methods, as well as by X-ray crystallography. Compounds 1 and 2 both consist of neutral mononuclear molecules, of [Co(bpdc)(H₂O)₂] and [Ni(bpdc)(H₂O)₂], respectively. Compound 3 consists of a mononuclear molecule of [Co(bpdc)(H₂O)₂] and a binuclear molecule of [Co₂(bpdc)₂prz (H₂O)₂]. The discrete neutral complexes 1–3 further extend their structures into three-dimensional supramolecular architectures by intermolecular O–H⋯O and C–H⋯O hydrogen bonds as well as π–π stacking interactions. Magnetic susceptibility measurements show that complex 3 exhibits weak ferromagnetic interactions between the two Co(II) ions bridged by the prz ligand, with C = 5.41 cm³ mol⁻¹ K and θ = +27.6 K, respectively.     

Four complexes with a bulky carboxylate ligand: syntheses,crystal structures,and luminescent properties

Abstract  

Four complexes of 3,3-diphenylpropanoate (L) and 4,4′-bipyridine as auxiliary bridging ligands were synthesized and characterized, namely [Zn(L)₂(4bpy)(EtOH)₂]_∞ (1), [Co(L)₂(4bpy)(EtOH)₂]_∞ (2), [Ni(L)₂(4bpy)(EtOH)₂]_∞ (3), and [Cu(L)₂(4bpy)(H₂O)]_∞ (4) (4bpy = 4,4′-bipyridine). X-ray single-crystal diffraction analyses show that complexes 1–4 all take one-dimensional (1D) fishbone-like structures incorporating bridging 4bpy ligands. The complexes show different supramolecular frameworks interlinked via intermolecular hydrogen bonds, π···π stacking, and/or C–H···π supramolecular interactions. Complex 3 only has a simple one-dimensional fishbone-like chain, whereas complexes 1 and 2 show two-dimensional supramolecular structures by interchain C–H···O hydrogen bonds. Complex 4 is assembled into two-dimensional layers and then an overall three-dimensional framework by a combination of interchain O–H···O hydrogen bonds and C–H···π supramolecular interactions. The luminescent properties of the ligands and their complexes were investigated.     

Synthesis,structural characterization and substituent effects of two copper(II) complexes with benzaldehyde ortho-oxime ligands

Two new Cu(II) complexes, [Cu(L¹)₂] (1) and [Cu(L²)₂] (2) (HL¹ = (E)-3-bromo-5-chloro-2-hydroxy benzaldehyde O-methyl oxime; HL² = (E)-3-bromo-5-chloro-2-hydroxy benzaldehyde O-ethyl oxime), have been synthesized and characterized by physicochemical and spectroscopic methods. X-ray crystallographic analyses show that complexes 1 and 2 have similar structures, consisting of one Cu(II) atom and two L⁻ units. In both complexes, the Cu(II) atom, lying on an inversion center, is four-coordinated in a trans-CuN₂O₂ square-planar geometry by two phenolate O and two oxime N atoms from two symmetry-related N,O-bidentate oxime ligands. Moreover, both complexes form an infinite three-dimensional supramolecular structure involving intermolecular C–H···Br hydrogen bonds and π···π stacking interactions between the metal chelate rings and aromatic rings. Substituent effects in the two complexes are discussed.     

Temperature-dependent synthesis, crystal structures, characterizations, and DFT calculations of two new copper(II) complexes with p-fluorobenzoic acid and 2,2′-bipyridine ligands

Two new copper(II) complexes, [Cu(p-FBA)₂(2,2′-bpy)]·(H₂O) (1) and [Cu(p-FBA)(2,2′-bpy)₂]·(p-FBA)₂ (2) {p-FBA = p-fluorobenzoic acid, 2,2′-bpy = 2,2′-bipyridine} have been obtained from an identical starting mixture using temperature as the only independent variable and characterized by X-ray single crystal diffraction as well as with infrared spectroscopy, elemental analysis, and thermogravimetric analysis. The results reveal that 1 has 1D infinite chain structure formed by O–H···O hydrogen bonds, while 2 features a 0D structure. Additionally, there exist C–H···O hydrogen bonds and π–π stacking interactions in 1, forming 2D supramolecular structure. Furthermore, density functional theory (DFT) calculations of the structures, stabilities, orbital energies, composition characteristics of some frontier molecular orbitals and Mulliken charge distributions of the [Cu(p-FBA)₂(2,2′-bpy)] of 1 and [Cu(p-FBA)(2,2′-bpy)₂]⁺ cation of 2 were performed by means of Gaussian 03W package and taking B3LYP/lanl2dz basis set.     

Supramolecular self-assembly of two Cu(II) complexes with 1,2,4-triazole derivatives: syntheses,crystal structures and magnetic properties

Two two-dimensional coordination complexes, {[Cu₄(BTM)₆(OPA)₄] · 4DMF · 3H₂O} _n (1) and {[Cu(BDTM)(OH)](ClO₄) · 2H₂O} _n (2) (BTM = bis(1,2,4-triazol-1-yl)methane, BDTM = bis(3,5-dimethyl-1,2,4-triazol-1-yl)methane, OPA²⁻ = ortho-phthalic dianion, DMF = N,N-dimethylformamide), were synthesized and structurally characterized. Each Cu(II) ion locates in a distorted square pyramidal geometry in 1, in which OPA²⁻ ligands bridge Cu²⁺ ions along a axis to form a magnetic transmission chain and BTM ligands act as flexible spacers to construct the two-dimensional layer structure. In 2, each Cu²⁺ ion adopts tetra-coordination geometry to two hydroxyl groups and two triazolyl nitrogen atoms from two different BDTM ligands. Two hydroxyl groups bridge two Cu²⁺ ions to form a rhombic diamond, and four BDTM ligands connect four diamonds to form a 36-membered macrocyclic structure with large channels along a axis. Magnetic properties revealed that both OPA²⁻ and OH⁻ mediate anti-ferromagnetic interactions between Cu²⁺ ions with J = − 0.06(3) and −301.9(2) cm⁻¹ for 1 and 2, respectively. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis,structures and electrochemical properties of four organic–inorganic hybrid polyoxometalates constructed from polyoxotungstate clusters and transition metal complexes

Four novel organic–inorganic hybrid compounds [Cu₅ ^I(4,4′-bpy)₃(2,2′-bpy)₄][BW₁₂O₄₀] · H₂O (1), [Ni_0.5(2,2′-bpy)_1.25][Ni(2,2′-bpy)₃][Ni(2,2′-bpy)₂(H₂O)(SiW₁₁^VIW^VO₄₀)] · 0.5H₂O (2), [H₂bpy]₂[Zn(2,2′-bpy)₃]₂[Si₂W₁₈O₆₂] · 1.5H₂O (3) and [Cu^II(2,2′-bpy)₂]₂[SiW₁₂O₄₀] · 2H₂O (4) (2,2′-bpy = 2,2′-bipyridine, 4,4′-bpy = 4,4′-bipyridine) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, thermal gravimetric analysis, electrochemical measurements and single-crystal X-ray diffraction. Compound (1) is a novel [BW₁₂O₄₀]⁵⁻ polyoxoanion bisupported by copper(I) coordination cations with mixed 2,2′-bpy and 4,4′-bpy ligands. Compound (2) is constructed from the [SiW₁₁^VIW^VO₄₀]⁵⁻ polyoxoanions supported by [Ni(2,2′–bpy)₂]²⁺. Compound (3) is composed of a novel [Si₂W₁₈O₆₂]⁸⁻ cluster and [Zn(2,2′–bpy)₃]²⁺ complexes, which held together into a three-dimensional (3D) supramolecular network through hydrogen-bonding interactions. Compound (4) shows a 2D layer framework constructed from a bisupporting Keggin polyoxoanion cluster and [Cu(2,2′–bpy)₂]²⁺ coordination polymer fragments, resulting in 3D networks via supramolecular interactions. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis,characterization and magnetic properties of supramolecular metal–organic complexes constructed from flexible–rigid mixed ligands

Two new supramolecular metal–organic complexes have been synthesized under hydrothermal conditions. Complex 1 exhibits a three-dimensional supramolecular network, constructed from [Co₂(H₃BPTC)₂(phen)₂] (H₄BPTC = 3,3′4,4′-benzophenone tetracarboxylate acid, phen = 1,10-phenanthroline) discrete units. Complex 2 similarly exhibits discrete [Cu₂(DPA)₂(bipy)₂(H₂O)₂] (DPA = 1,1′-biphenyl-2,2′-dicarboxylate acid, bipy = 2,2′-bipyridine) units, which are linked to form a three-dimensional supramolecular network through π–π interactions. It is interesting that during the synthesis of complex 1, the H₄BPTC ligands undergo partial decomposition to give 1,2,4-benzenetricarboxylate (H₃BTC) ligands, which react with Co to form [Co₃(BTC)₂]_n (3). Complex 3 shows a three-dimensional covalent network. The magnetic properties of complexes 1 and 2 have been studied.     

Sandwich-type Uranium-Substituted of Bismuthotungstate: Synthesis and Structure Determination of [Na(UO2)2(H2O)4(BiW9O33)2]13?

The sandwich-type [Na(UO₂)₂(H₂O)₄(BiW₉O₃₃)₂]¹³⁻ uranium (VI) has been synthesized by reacting the trivacant species of B-α-[BiW₉O₃₃]⁹⁻ with and investigated by IR and UV–Vis spectroscopy, and elemental analysis. The X-ray single crystal analysis was carried out on Na₁₃[Na(UO₂)₂(H₂O)₄(BiW₉O₃₃)₂] · 33H₂O (I) which crystallizes in the orthorhombic system, space group Pna2₁ with a = 33.8454(19) ?, b = 21.1484(12) ?, c = 13.2403(7) ?, α = 90°, β = 90°, γ = 90°, and Z = 4. The polyanion consists of two lacunary B-α-[BiW₉O₃₃]⁹⁻ groups which sandwich two uranyl cations and one sodium cation. The uranium atoms adopt distorted pentagonal–bipyramidal coordination, achieved by two equatorial bonds to each BiW₉O₃₃ unit and one external water ligand. The coordination of each uranium atom is evident by the shift of ν_as(W–O_b–W) and ν_as(Bi–O) stretching vibrational bonds. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis,characterization, and urease inhibitory activity of two copper(II) complexes of cyclohexanecarboxylate

The crystal structures of two copper(II) complexes of the cyclohexanecarboxylate ligand, namely [Cu(C₆H₁₁CO₂)₂(H₂O)₂]·H₂O (1) and [Cu(dpyam)₂(C₆H₁₁CO₂)](NO₃)·H₂O (2) (C₆H₁₁CO₂H = cyclohexanecarboxylic acid; dpyam = di-2-pyridylamine), have been determined by single-crystal X-ray analysis. Complex 1 contains the square-planar trans-CuO₄ chromophore, while 2 shows the square pyramidal cis-distorted octahedral CuN₄OO′ chromophore. Both complexes were found to show strong inhibitory activity against jack bean urease (IC₅₀ = 1.75 and 8.57 μM for 1 and 2, respectively), when compared with acetohydroxamic acid (IC₅₀ = 63.12 μM).     

Hydrothermal Synthesis and Structural Characterization of Three One-Dimensional Heteropolytungstates Formed by Mono-CopperII-Substituted Dawson or Keggin Cluster Units

Abstract  Reactions of monovacant Dawson-/Keggin-polyoxoanions, formed in situ from trivacant Dawson-/Keggin-precursors, with copper complexes under hydrothermal conditions lead to three inorganic–organic hybrid polyoxotungstates [Cu(en)₂(H₂O)]₂{[Cu(en)₂(H₂O)]₂[Cu(en)₂]₄[Cu(en)₂][α₂-P₂W₁₇CuO₆₁]₂}·(OH)₂·12H₂O (1), [Cu(dap)₂][Cu(dap)₂(H₂O)]₂[α-PW₁₁CuO₃₉]·(OH)·2H₂O (2) and (H₂en)₂[α-PW₁₁CuO₃₉][Cu(en)₂(H₂O)₂]_0.5·1.5H₂O (3) (en = ethylenediamine and dap = 1,2-diaminopropane). X-ray structural analyses demonstrate that 1 exhibits the first zigzag 1-D chain arrangement constructed from mono-copper^II-substituted Dawson dimeric polyoxoanions [α₂-P₂W₁₇CuO₆₁]₂¹⁶⁻ linked by [Cu(en)₂]²⁺ bridges, whereas 2 and 3 display 1-D linear chain architectures made up of mono-copper^II-substituted Keggin polyoxoanions [α-PCuW₁₁O₃₉]⁵⁻ linked together via corner-sharing MO₆ octahedra (M = Cu or W). Graphical Abstract  Reactions of monovacant Dawson or Keggin polyoxoanions with copper complexes under hydrothermal conditions lead to three novel 1-D chain-like inorganic- organic hybrid polyoxotungstates.      

Three organic–inorganic hybrid complexes based on the Wells–Dawson polyoxoanion

Three new organic–inorganic hybrid complexes based on the Wells–Dawson polyoxoanion, namely (H₂bpp)[Ni₂(bpp)₂(H₂O)₄(P₂W₁₈O₆₂)]·H₂O 1, [Cu₆(Hbpy)₆(bpy)₃(P₂W₁₈O₆₂)₂]·2H₂O 2 and (Him)₅[Cu(im)₂(P₂W₁₈O₆₂)]·4H₂O 3 [bpp = 1,3-bis (4-pyridyl) propane, bpy = 4,4′-bipyridine, im = imidazole] have been synthesized and characterized. Complex 1 exhibits a three-dimensional (6, 3)-connected framework with anatase topology constructed from [α-P₂W₁₈O₆₂]⁶⁻ clusters and [Ni(bpp)]²⁺ fragments. Each [α-P₂W₁₈O₆₂]⁶⁻ anion links to six nickel atoms through six terminal oxygen atoms from four polar and two equatorial WO₆ octahedra, which shows a novel coordination mode of a Wells–Dawson cluster with a transition-metal atom. Complex 2 displays an interesting one-dimensional double-chain structure built from [α-P₂W₁₈O₆₂]⁶⁻ clusters and [Cu₂(bpy)(Hbpy)₂]²⁺ fragments. To our knowledge, complex 2 represents the first double-chain organic–inorganic hybrid complex based on a Wells–Dawson-type cluster. Complex 3 possesses a one-dimensional zigzag chain structure constructed from [α-P₂W₁₈O₆₂]⁶⁻ anions and [Cu(im)₂]⁺ units through weak Cu···O interactions.     

Syntheses,spectroscopic study and crystal structures of some new <Emphasis Type="Italic">N</Emphasis>-benzoylphosphoric triamides

The reaction of N-benzoylphosphoramidic dichloride with amines afforded some new N-benzoylphos-phoric triamides with formula C₆H₅C(O)NHP(O)(X)₂, X=NH–CH(CH₃)₂ (1), NH–CH₂–CH(CH₃)₂ (2), NH–CH₂–CH(OCH₃)₂ (3), N(CH₃)[CH₂CH(OCH₃)₂] (4) and N(CH₃)(C₆H₁₁) (5) that were characterized by ¹H,¹³C,³¹P NMR, IR spectroscopy and elemental analysis. The structures have been determined for compounds 4 and 5 by X-ray crystallography. These compounds contain one amidic hydrogen atom and form centrosymmetric dimmers via intermolecular –P–O⋯H–N–hydrogen bonds besides weak C–H⋯O hydrogen bonds that lead to three-dimensional polymeric clusters in the crystalline lattice.     

Polymorphism for a novel phosphoramidate; NMR and X-ray crystallography

Abstract  

New phosphoramidates with formula 3-NC₅H₄C(O)NHP(O)XY (X=Y=Cl (1), X=Y=NH–C(CH₃)₃ (2a,2b), X=Y=N(C₄H₉)₂ (3), X=Cl, Y=N(C₂H₅)₂ (4) were synthesized and characterized by IR, ¹H-, ¹³C-, ³¹P-NMR spectroscopy and CHN elemental analysis. Surprisingly, the reaction of compound 2a with LaCl₃, 7H₂O in 3:1 M ratio leads to a polymorph of this compound (2b). NMR spectra indicate that ² J(PNH_amide) in 2b (7.0 Hz) is very much greater than in 2a (4.1 Hz), while δ(³¹P) values are identical for both of them. In IR spectra, υ(P=O) is weaker but υ(C=O) is stronger in 2a than in 2b. The structures of 2a, 2b were determined by X-ray crystallography. These compounds form centrosymmetric dimers via two intermolecular P=O……H–N hydrogen bonds. Strong intermolecular N–H…N, N–H…O and weak C–H…O hydrogen bonds lead to a three-dimensional polymeric cluster in the 2a while intermolecular strong N–H……N and weak C–H……O hydrogen bonds form a two-dimensional polymeric chain in 2b.     

Binuclear vanadium(V) complexes of bis(aryl)adipohydrazone: synthesis,spectroscopic studies,crystal structure and catalytic activity

Three new binuclear vanadium(V) complexes of bis(aryl)adipohydrazones (H₄L¹ = bis((2-hydroxynaphthalen-1-yl)methylene)adipohydrazide, H₄L² = bis(5-bromo-2-hydroxybenzylidene)adipohydrazide, and H₄L³ = bis(2-hydroxy-3-methoxybenzylidene)adipohydrazide) were synthesized by direct reaction of [VO(acac)₂] with the hydrazone ligands. The ligands and complexes were characterized by FT–IR, UV–Vis, and NMR spectroscopic methods. The crystal structures of the complexes of L¹ and L³ were determined by X-ray analyses. The solid-state structure of the complex of L¹ features a 1D hydrogen-bonded chain from N⋯H–O hydrogen bonding. The catalytic activities of these complexes have been tested in the oxidation of various hydrocarbons using H₂O₂ as the terminal oxidant. Generally, good to excellent conversions have been obtained.     

Syntheses,structures, and properties of two mononuclear cobalt(III) azido complexes containing a tetradentate N-donor Schiff base as end-capping ligand

Two hexacoordinated mononuclear Co(III) compounds of the type cis-[Co(L)(N₃)₂] X [1, X = ClO₄; 2, X = PF₆; L = N,N′-(bis(pyridine-2-yl)benzylidine)-1,4-butanediamine] have been synthesized and characterized by physicochemical and spectroscopic methods. The crystal structures of complexes 1 and 2 both have distorted octahedral geometry with two terminal azides in mutual cis orientations. In the crystalline state, two mononuclear units of 1 are associated by weak C–H…π interactions to produce a dimeric unit, which packs through C–H…O hydrogen bonds and π…π interactions leading to a 2-D continuum. The mononuclear units in 2 are engaged in weak cooperative intermolecular C–H…π interactions and multiple C–H…F hydrogen bonds giving rise to a 3-D network structure. These diamagnetic compounds are redox active and show luminescence in DMF solutions.     

Hydrogen-bonded supramolecular structures constructed from trinuclear copper units

Four copper complexes with similar trinuclear copper units, [Cu₆(Bmshp)₂(SO₄)₂(H₂O)₇]·2H₂O (1), [Cu₃(Bmshp)(ClO₄)₂(H₂O)₄]·5H₂O (2), [Cu₃(Bmshp)(DMF)₄(H₂O)₂]·H₂O·2DMF·2ClO₄ (3) and [Cu₃(H₂Bcshp)(ClO₄)₂(H₂O)₄]·3H₂O (4) (H₄Bmshp = 2,6-bis[(3-methoxysalicylidene)hydrazinocarbonyl]pyridine, H₆Bcshp = 2,6-bis[(3-carboxylsalicylidene)hydrazinocarbonyl]pyridine), were synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction analysis. Due to the different anions, solvents and ligands used in the syntheses, complexes 1–4 exhibit diverse supramolecular structures constructed from the corresponding trinuclear copper units via H-bonds.     

Synthesis,structures and magnetic properties of three metal-organic frameworks containing manganese(II)

Two new Mn(II) coordination polymers formed with molecular formula [Mn(H₂O)₂(HBTC)·(H₂O)] 1 and [Mn(H₂O)₂(4,4′bipy)(HBTC)₂]·(H4,4′bipy)₂ 2, where BTC = 1,2,4-benzenetricarboxylate and 4,4′bipy = 4,4′bipydine, have been synthesized via hydrothermal approach and characterized by single crystal X-ray diffraction techniques. 1 is composed of Mn–H₂O–Mn 1D chains and further the chains are linked by HBTC ligands to form a 2D network in the ab plane; 2 is constructed by Mn–4,4′bipy–Mn 1D chains along the b direction with Mn²⁺ ions coordinated to H₂BTC and water as terminal ligands to form a 2D network. We also prepared a third compound with the molecular formula of [Mn(H₂O)(HBTC)·(H₂O)] which has been recently structurally reported elsewhere. The magnetic properties of the three compounds have been studied in detail under variable temperatures.     

Supramolecular frameworks composed of copper(II), zinc(II), and ferrous(II) complexes having 3-bromo or 3,8-dibromo-1,10-phenanthroline ligand with different molar ratios of metal and ligand

Abstract  

Three copper(II), one zinc(II), and one ferrous(II) complexes having 3-bromo or 3,8-dibromo-1,10-phenanthroline ligand with different metal/ligand molar ratios, formulated as [Cu(3-bromo-phen)(ClO₄)(C₃H₇NO)₂(H₂O)](ClO₄) (1), [Cu(3,8-dibromo-phen)(ClO₄)(C₃H₇NO)₂(H₂O)](ClO₄) (2), [Cu(3,8-dibromo-phen)(ClO₄)(H₂O)₃](ClO₄)(H₂O)₃ (3), [Zn(3,8-dibromo-phen)₂(H₂O)₂](ClO₄)₂(H₂O)₂ (4), and [Fe(3,8-dibromo-phen)₃](ClO₄)₂(H₂O)(CH₄O)(C₃H₆O)₂ (5) (phen = 1,10-phenanthroline), have been synthesized and characterized in this paper. X-ray single-crystal diffraction studies reveal the different crystallographic symmetry and packing fashions between neighboring phen rings in 1:1 Cu(II) complexes 1–3 due to the alteration of bromo substituent 1,10-phenanthroline ligands and coordinated or free solvent molecules. Additionally, in 1:2 Zn(II) and 1:3 Fe(II) complexes 4 and 5, continuous π–π stacking and alternating π–π and dimeric p–π stacking are found.     

Synthesis and X-ray crystal structures of a series of 3d–4f lanthanide complexes: lanthanide(III)–copper(II) coordination polymers with 2,5-pyridinedicarboxylic acid ligand

A series of lanthanide–transition metal (Ln–M) complexes, namely, {[Ln₂Cu(pydc)₄(H₂O)₃]·H₂O} _n (Ln = Tb, Eu, Sm or Gd) (H₂pydc = 2,5-pyridinedicarboxylic acid) have been synthesized hydrothermally by self-assembly of the lanthanide ions, copper(II) ions and 2,5-pyridinedicarboxylic acid. All the complexes were characterized by physicochemical and spectroscopic methods; in addition, structural analyses revealed that all four complexes crystallized in monoclinic space group P2₁ /c. The molecular structure contains both Cu and Ln atoms, with pydc ligands bridging the four coordinate Cu(II) centers and eight coordinate lanthanide centers to form a 3-D net structure. Hence, copper is oxidized from Cu(I) to Cu(II) during the preparation. In addition, the thermogravimetric analysis of 1 is discussed. Contrary to expectations, compounds 1–3 show no photoluminescent properties. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

DNA binding and cleavage activity of reduced amino-acid Schiff base complexes of cobalt(II), copper(II), and cadmium(II)

Three new reduced amino-acid Schiff base complexes, [Co(HL)₂(H₂O)₂] · 4H₂O (1), [Cu(HL)₂(H₂O)₂] · 2H₂O (2), and [Cd(HL)₂(H₂O)₃] · 2H₂O (3), where H₂L is the reduced Schiff-base ligand derived from the condensation of N-(4-hydroxybenzaldehyde) with L-glycine, have been synthesized and characterized by physico-chemical and spectroscopic methods. In these complexes, the two bidentate monoanionic Schiff base ligands coordinate the metal center through the secondary amine N atom and the carboxylate O atom. Water ligands complete a distorted octahedral (1, 2) or a pentagonal bipyramidal coordination geometry (3) around each metal center. The binding interactions of the complexes with CT-DNA have been investigated by UV–visible spectrophotometry and fluorescence quenching methods. The results show that these complexes bind to CT-DNA with an intercalative mode. In addition, DNA cleavage experiments have been also investigated by agarose gel electrophoresis. Complexes 1–3 show oxidative DNA cleavage activity in the presence of H₂O₂/sodium ascorbate and the reactive oxygen species responsible for the DNA cleavage is most likely singlet oxygen. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.