Bimetallic sheet and 3D threefold interpenetrating diamond-like network constructed by chelate Cu cations and Mn dicyanamide polymeric chains. Synthesis, crystal structure, and magnetism of [Cu(L)2][Mn(dca)4] (L=ethylenediamine or 1,3-diaminopropane; dca=dicyanamide N(CN)2)

Two novel bimetallic coordination polymers, [Cu(en)₂][Mn(dca)₄] (1) and [Cu(pn)₂][Mn(dca)₄] (2) (en, ethylenediamine; pn, 1,3-diaminopropane; dca, dicyanamide N(CN)₂⁻), have been synthesized and characterized. Both of them consist of Mndca anionic chains and chelate cations of copper. 1 has a sheet like architecture built by the [Cu(en)₂]²⁺ cations and the homoleptic trans-[Mn(dca)₄ ²⁻]_n chains. 2 shows unusual 3-D threefold interpenetrating diamond-like structure constructed by [Cu(pn)₂]²⁺ cations and the homoleptic cis-[Mn(dca)₄ ²⁻]_n chains. The magnetic susceptibilities obey the Curie-Weiss law with weak antiferromagnetic interactions.     

Mononuclear and polynuclear halide and nitrate Cu(II) compounds with 1,4,5-triazanaphthalene as a ligand: Characterization, magnetism and X-ray structures

Using the ligand 1,4,5-triazanaphthalene (abbreviated as tan) in combination with Cu(II) salts, three mononuclear compounds, Cu(tan)₂Cl₂ (1), Cu(tan)₂Br₂ (3), Cu(tan)₂(NO₃)₂ (5) and three polynuclear compounds, [Cu(tan)Cl₂]_n (2), [Cu(tan)Br₂]_n (4), [Cu(tan)(NO₃)₂]_n (6) have been synthesized and characterized by UV-Vis, EPR, FTIR and Far-FTIR spectroscopies. The crystal structures of compounds 1, 3, 5 and 6 are reported, as well as that of the dioxane adduct of compound 4, [Cu(tan)Br₂(C₄H₈O₂)](C₄H₈O₂) (4A).The structure of (2) was solved by X-ray powder diffraction. The coordination geometry around the Cu(II) atoms is tetrahedral for (1) and (3), square-pyramidal for (4A) and distorted octahedral for (5) and (6). Magnetic susceptibility measurements on the polynuclear compounds revealed weak antiferromagnetic interactions between the Cu(II) atoms with interaction constants (J) of J = −9.1 and −10.5 cm⁻¹, for 4 and 6, respectively. For compound 2 two options for possible interactions were considered, with interaction constants which vary for J_rung −22.0 to −13.5 cm⁻¹ and J_rail −19.6 to −17.0 cm⁻¹. These figures are discussed in the light of relevant structural parameters and literature.     

Insertion reactions of organic anhydrides into the M-O bond of CuOBu and Sb(OMe)3

The synthesis and structural characterization of the copper salts [Cu₂(2-Boc-benzoate)₄(dme)₂] (1), [Cu(2-Boc-benzoate)₂(tmeda)] (2), [Cu₂(2-Boc-benzoate)₂(dppm)] (3), [Cu(2-Boc-nicotinate)(PPh₃)₂] (4), [Cu₂{2-Boc-5,6-anhydride-naphthylcarboxylate}₂(dppm)₂] (5) [dme = 1,2-dimethoxyethane, dppm = bis(diphenylphosphino)methane, tmeda = N,N′-tetramethylethylenediamine, Boc = tert-butoxycarbonyl] prove that cyclic organic anhydrides and dianhydrides readily insert into the Cu-O bond of [CuO^tBu] forming carboxylate ligands with ester functionalities in the ligand periphery. [Sb(CO₂Ph-o-CO₂Me)₂(OMe)(tmeda)] (6) was synthesised by insertion reaction of Sb(OMe)₃ with phthalic anhydride.     

Two different 1D-chains in the structures of the copper(I) coordination polymers based on bidentate Schiff-base building units and thiocyanate anions as bridging ligands

The reaction of the bidentate Schiff-base ligands (3,4,5-MeO-ba)₂en (L¹) and (4-Me-ba)₂en (L²) with Cu(SCN) in CH₃CN yielded two copper(I) coordination polymers [Cu(L¹)(SCN)]_n (1) and [Cu(L²)(SCN)]_n (2), which have been characterized by elemental analyses, IR- and ¹H NMR-spectroscopy, and X-ray crystallography. The non-centrosymmetric structures of both Cu(I) complexes consist of an one-dimensional polymeric chain in which copper(I) ions are bridged by two thiocyanate groups bonding in an end-to-end fashion. The Cu(I)?Cu(I) separation is 5.604 Å in 1 and 5.706 Å in 2.     

Probing valence and spin situations in selective ruthenium-iminoquinonoid frameworks. An experimental and DFT analysis

The ruthenium-iminoquinone complexes, [Ru(tpm)(Cl)(Q)]⁺ [tpm = tris(1-pyrazolyl)methane, Q = 3,5-di-tert-butyl-N-aryl-1,2-benzoquinonemonoimine, where aryl = C₆H₅, [1]⁺; m-(OCH₃)₂C₆H₃, [2]⁺; m-(Cl)₂C₆H₃, [3]⁺] have been synthesized. The sensitive bond distances of “Q” in [1](ClO₄) and [2](ClO₄), C-O: 1.294(8), 1.281(2) Å; C-N: 1.352(8), 1.335(2) Å; and C-C(meta): 1.366(10)/1.367(9) Å, 1.364(2)/1.353(2) Å, respectively, and other analytical as well as theoretical (DFT) events suggest the valence configuration of [Ru^III(tpm)(Cl)(Q_Sq⁻)]⁺ for [1]⁺-[3]⁺. The paramagnetic [1]⁺-[3]⁺ show sharp ¹H NMR spectra with strikingly small J of 1.8-3.0 Hz. The DFT calculations on [1]⁺ predict that the triplet (S = 1) state exists above (1004 cm⁻¹) the singlet (S = 0) ground state. [1]⁺ exhibits μ = 2.2 BM at 300 K which diminishes to 0.3 BM near 2 K due to the steady decrease in the ratio of triplet to singlet population with the lowering of temperature. [1]⁺-[3]⁺ exhibit one oxidation and two successive reductions each in CH₃CN. Experimental and DFT analyses collectively establish the valence configurations at the non-innocent {Ru-Q} interface along the redox chain as [(tpm)(Cl)Ru^III(Q_Q^o)]²⁺ ([1]²⁺-[3]²⁺) → [(tpm)(Cl)Ru^III(Q_Sq⁻)]⁺ ([1]⁺-[3]⁺) → [(tpm)(Cl)Ru^II(Q_Sq⁻)] ↔ [(tpm)(Cl)Ru^III(Q_Cat)] (1-3) → [(tpm)(Cl)Ru^II(Q_Cat)]⁻ ([1]⁻-[3]⁻). The spectral features of [1]ⁿ-[3]ⁿ (n = +2, +1, 0) have been addressed based on the TD-DFT calculations on [1]ⁿ.     

Transition metal complexes based on pyridine ligand containing both bis(2-pyridyl) and 1,3-dithiole-2-ylidene units: Syntheses, structures, and magnetic studies

Two new mononuclear spin-crossover iron(II) complexes, [FeL₂(NCS)₂] · H₂O (1) and [FeL₂(NCSe)₂] (2), have been synthesized from the reaction of the versatile ligand 4,5-bis(2-cyanoethylthio)-2-bis(2-pyridyl)methylene-1,3-dithiole (L), Fe(ClO₄)₂, and KNCX (X = S/Se). Reactions of L with Cu^II or Co^II salts afford one mononuclear complex [CuL(hfac)₂] · CH₃OH (hfac = hexafluoroacetylacetonate) (3), one dinuclear complex [(CuLCl)₂(μ-Cl)₂] · CH₃OH (4), and two 1D chain species, [CuL₂]_n(BF₄)_2n (5) and [CoL₂]_n(ClO₄)_2n · 2nCH₂Cl₂ (6). The crystal structures of complexes 1 and 3-6 have been determined by X-ray crystallography. Short intermolecular S?S contacts between neighboring 1D arrays are observed in 5 and 6, which lead to the formation of the 2D structure. The magnetic properties are studied, and antiferromagnetic couplings between the Cu^II centers across the chloride bridges have been found in 4 (J = 2.04 cm^-1). Spin-crossover behaviors between high and low spin states are observed at T_1/2 = 80 K for 1 and T_1/2 = 300 K for 2, respectively.     

1-D coordination chains of Cu(hfac)2 and Mn(hfac)2 bridged by phenyl-nitronylnitroxide derivatives

Two alternating 1-D metal-radical linear [L:Cu(hfac)₂]_n and zig-zag [L:Mn(hfac)₂]_n chains (where L = 4-trimethylsilylethynyl-1-(4,4,5,5-tetramethyl-3-oxylimidazoline-1-oxide)benzene) and hfac = hexafluoroacetylacetonate) are described and characterized by X-ray diffraction of their crystals. Bulk magnetic measurements of L:Cu(hfac)₂ indicated a ferromagnetic interaction with J = 6 cm⁻¹ and L:Mn(hfac)₂ yielded ferrimagnetic interactions with J = −95 cm⁻¹. For the latter, a strong increase of their magnetic moment at lowest temperatures was observed only at very low static magnetic field, while for H_dc > 0.05 T saturation effect led to a downward slope after reaching a maximum.     

New examples of low-dimensional metal-pydco complexes: Syntheses, structures and magnetic properties

This work presents a systematic investigation on coordination chemistry of a novel pyridine-2,6-dicarboxylic acid N-oxide (pydco), and also reveals the significant function of supramolecular interactions in dominating the resultant crystalline nets. Assemblies of pydco with transition-metal ions under similar conditions yield a series of polymers in the absence/presence of the organonitrogen ligands {[Cu(pydco)(L)_0.5(H₂O)] · 2H₂O}_n (L = bipy (1), bpa (2) and bpe (3)), {[M(pydco)(bpp)(H₂O)] · 2H₂O}_n (M = Cu (4) and Ni (5)), [Ag₂(pydco)]_n (6) and [Ag₂Cu(pydco)₂]_n (7) (bipy = 4,4′-bipyridine, bpa = 1,2-bis(4-pyridyl)ethane, bpe = 1,2-bis(4-pyridyl)ethene, bpp = 1,3-bis(4-pyridyl)propane). 1-5 feature different structural characteristics, although they exhibit analogous chain networks. Remarkably, extended architectures are further constructed with the aid of weak interactions. Reaction of pydco with AgAc yields a 2-D polymer 6, which was reported in our recent Communication. A mixed-metal coordination polymer 7 was obtained by the self-assembly of AgAc, Cu(Ac)₂ · H₂O and pydco.In 7, two left- and right-hand helical chains are constructed by carboxylic groups of pydco and Cu centers, which are further connected by [AgCO₂]₂ cores into a 2-D network. Structural evolution under the co-ligand intervention in this series of compounds, as well as the general coordination rule of pydco, has been further discussed. Furthermore, variable temperature magnetic properties of 1, 3 and 7 are also studied. The magnetic measurements of 1 and 3 reveal the existence of weak antiferromagnetic interactions with J₁ = −4.59 cm⁻¹ and J₂ = −4.63 cm⁻¹, respectively. Whereas 7 displays weak ferromagnetic interactions with J₃ = 1.81 cm⁻¹.     

Effects of flexible bridging ligands on DNA-binding of dinuclear ruthenium(II)-2,2′-bipyridine complexes

For reactions of [{RuCl(bpy)₂}₂(μ-BL)]²⁺ (bpy = 2,2′-bipyridine, BL = H₂N(CH₂)_nNH₂ (n = 4-8, 12), [Ru₂-BL]²⁺) with mononucleotides, the MLCT absorption bands of [Ru₂-BL]²⁺ blue-shifted with hyperchromism for GMP and hypochromism for TMP with time. Reactions of [Ru₂-BL]²⁺ with GMP or TMP proceed via initial Cl⁻ ions replacement by coordination to N7 of GMP and N3 of TMP, respectively. In competition binding experiments for [Ru₂-BL]²⁺ with GMP versus TMP, only GMP selectively coordinated to ruthenium(II). For reactions with calf thymus (CT) DNA, [Ru₂-BL]²⁺ complexes selectively bind to guanine residues of DNA. The higher degrees of binding of [Ru₂-BL]²⁺ to CT-DNA were observed with increasing n values for H₂N(CH₂)_nNH₂, which may be explained by the length of the bridging ligands. Studies on the inhibition of the restriction enzyme Acc I revealed that [Ru₂-BL]²⁺ complexes appear to be covalently favorable for the type of difunctional binding. In addition, it is very interesting to observe that circular dichroism spectroscopy of the supernatants obtained following the reactions of CT-DNA with racemic [Ru₂-BL]²⁺ show enrichments of the solutions in the ΔΔ isomers, demonstrating preferences of the ΛΛ isomers for covalent binding to CT-DNA.     

A series of d transition metal coordination complexes: Structures and comparative study of surface electron behaviors (n = 9, 8, 7, 6, 5)

Ten transition metal coordination complexes [Cu₂(phen)(p-tpha)(μ-O)]_n1, [Cu(m-tpha)(imH)₂]_n2, [Ni(5-Haipa)₂(H₂O)₂]_n3, [Ni(phen)₂(H₂O)₂]·btc·[Ni(H₂O)₆]_0.5·9H₂O 4, [Co(2,5-pdc)(H₂O)₂]_n·nH₂O 5, [Co₂(2,5-pdc)₂(H₂O)₆]_n·2nH₂O 6, [Fe(2,5-Hpdc)₂(H₂O)₂]·H₂O 7, [Co(C₆H₄NO₂)₃]·H₂O 8, [Fe₂(μ₂-btec)(μ₂-H₂btec)(bipy)₂(H₂O)₂]_n9, [Mn(phen)(2,5-pdc)(H₂O)₂]·H₂O 10 (H₄btec = 1,2,4,5-benzenetetracarboxylic acid, phen = 1,10-phenanthroline, 2,5-H₂pdc = 2,5-pyridine-dicarboxylic acid, p-tpha = p-phthalic acid, m-tpha = m-phthalic acid, bipy = 2,2′-bipyridine, 5-H₂aipa = 5-aminoisophthalic acid, imH = imidazole, H₃btc = 1,3,5-benzenetricarboxylic acid) were synthesized through hydrothermal method. They were characterized by UV-Vis absorption spectra, single-crystal X-ray diffraction and surface photovoltage spectra (SPS). Structural analysis indicated that the complexes 1, 2, 3, 5, 6 and 9 were linked into infinite structures bridged by organic acid ligands. The other four complexes were molecular complexes and further connected to 2D or 3D structures by the hydrogen bonds. The SPS of complexes 1-10 indicate that there are positive response bands in the range of 300-800 nm showing different levels of photo-electric conversion properties. The intensity, position, shape and the number of the response bands in SPS are obviously different since the structure, species, valence, dⁿ electrons configuration and coordinated environment of the center metals are different. There are good relationships between SPS and UV-Vis spectra.     

Synthesis, characterization, and magnetic study of pyrazine bridged polymeric complexes of copper(II)

The synthesis, structural characterization and magnetic property of two new coordination polymers [Cu(pyz)(μ-CH₃CO₂)₄]_n (1) and [Cu(pyz)(μ-CCl₃CO₂)₄]_n (2) (pyz = pyrazine) are reported. Here, the carboxylato bridged two dinuclear copper(II) complexes are linked through pyrazine giving a 1-D alternating chain. The magnetic property of the complexes indicates a significant difference originated from the introduction of electron withdrawing substituent on the bridging dicarboxylate. Complex 1 exhibits strong antiferromagnetic interactions with J = −344.61 cm⁻¹, whereas 2 exhibits comparatively less strong antiferromagnetic coupling with J = −238.53 cm⁻¹.     

Organotin(IV) 4-methoxyphenylethanoates: Synthesis, spectroscopic characterization, X-ray structures and in vitro anticancer activity against human prostate cell lines (PC-3)

A series of organotin(IV) carboxylates, [Bu₂SnL₂] (1), [Et₂SnL₂] (2), [Me₂SnL₂] (3), [Bu₃SnL]_n(4), [Me₆Sn₂L₂]_n(5), [Ph₃SnL]_n(6) and [Oct₂SnL₂] (7), where L = O₂CCH₂C₆H₄OCH₃-4, have been synthesized. These complexes have been characterized by elemental analysis, FT-IR and multinuclear NMR (¹H, ¹³C and ¹¹⁹Sn). Based on spectroscopic results, the ligand appeared to coordinate to the Sn atom through COO moiety. Single crystal analysis has shown a bridging behavior of ligand in tributyl- and trimethyltin(IV) derivatives, and a chelating bidentate mode in diethyltin(IV) complex. Bioassay results have shown that these compounds have good antibacterial, antifungal and antitumor activity. The activity against prostate cancer cell lines (PC-3) decreased in the order 1 > 5 > 2 > 3 > 7.     

Structures and magnetic properties of one-dimensional polymers constructed with copper(II) salts and pyridinecarboxamide-type ligands

Three complexes of the composition {[Cu(μ_1,5-dca)₂(mppca)₂] · H₂O}_n (1), [Cu(μ_1,5-dca)₂(nppca)₂]_n (2) and [Cu(μ-Cl)₂(mppca)₂]_n (3) (dca = dicyanamide, ; mppca = N-(4′-methylphenyl)-4-pyridinecarboxamide; nppca = N-(4′-nitrophenyl)-4-pyridinecarboxamide) have been synthesized and characterized by single crystal X-ray crystallography and magnetic susceptibility studies. Different supramolecular structures of the complexes have been constructed by different non-covalent motifs in the crystalline solids. In complex 1, adjacent copper(II) atoms are connected by double μ_1,5-dca(end-to-end) bridges to form a chain-like structure. The chains are linked by π-π interactions and hydrogen bonds between the ligands and water molecules to form a 3D network. In complex 2, copper(II) atom has a coordination environment similar to 1, but water molecules have not been found. Weak C-H?N hydrogen bonding and π-π interaction yield a 3D supramolecular network which is different from that of complex 1. Complex 3 is a 1D polymeric chain in which Cu(II) ions are bridged by Cl⁻, and only CH/π interactions had been found. Magnetic measurements revealed antiferromagnetic properties of 1, 3 and ferromagnetic behavior of 2.     

Hydrothermal syntheses and characterizations of 0D to 3D polyoxotungstates linked by copper ions

A new family of hybrid organic-inorganic materials built from polyoxotungstates and Cu(II) ions as linkers has been synthesized by hydrothermal reactions from a mixture of sodium tungstate, copper chloride and ethylenediamine. The initial pH and the presence or absence of heteroelement (P, Si) control the nature of the polyoxotungstate clusters and their connectivity via the copper ions, and hence the dimensionality of the framework. In the absence of heteroelement, three compounds have been isolated: at low pH (5) the molecular compound [Cu(en)₂(H₂O)]₂[{Cu(en)₂}H₂W₁₂O₄₀] · 10H₂O (1) is formed, at neutral pH the 3D material [{Cu(en)₂}₃{Cu(en)}₂H₂W₁₂O₄₂] · 27H₂O (2) and at high pH (11) the 2D compound [Cu(en)₂(H₂O)₂][Cu(en)₂][{Cu(en)₂}₃H₂W₁₂O₄₂] · 15H₂O (3). In the whole range of pH (5-11.5) a single phase has been obtained with silicium as heteroelement, namely the 2D material [Cu(en)₂(H₂O)][{Cu(en)₂}₂SiW₁₁CuO₃₉] · 7H₂O (4) with chains of Keggin polyoxotungstates linked by {Cu(en)₂}²⁺ groups. Finally, a phosphotungstate with a chain-like structure has been characterized, [{Cu(en)₂}₃PW₁₁CuClO₃₉] · 6H₂O (5), at low pH (5) which differs from the phase obtained at higher pH.     

Carboxyester hydrolysis promoted by Cu(II) complexes of pyridyl-amine carboxylate-pendant ligands

Multidentate ligands containing tripodal pyridyl-amine moieties tethered to a carboxylate group by alkyl linkers of varying lengths were synthesized to obtain a series of water-soluble ligands to elucidate the effects of the differing coordination environments on the properties of the resulting metal complexes. These new, water-soluble ligands, [bis-(2-pyridin-2-yl-ethyl)-amino]-acetic acid (L¹), 3-[bis-(2-pyridin-2-yl-ethyl)-amino]-propionic acid (L²), 4-[bis-(2-pyridin-2-yl-ethyl)-amino]-butyric acid (L³), and 6-[bis-(2-pyridin-2-yl-ethyl)-amino]-hexanoic acid (L⁴), were treated with copper(II) perchlorate hexahydrate to yield the corresponding Cu(II) complexes, which have all been characterized by X-ray crystallography. L¹ binds Cu(II) to form the tetrameric complex {[Cu(μ-¹)][ClO₄] · 4H₂O}₄ (1) in the solid state, whereas the Cu(II) complexes of ligands L²-L⁴ form long-chain one-dimensional polymeric complexes {[Cu(μ-L²)][ClO₄] · H₂O}_n (2), {[Cu(μ-L³)][ClO₄] · H₂O}_n (3), and {[Cu(μ-L²)][ClO₄]  · H₂O}_n (4), respectively, in the solid state. Complexes 1-4 dissolved in 10% (v/v) CH₃CN aqueous solution were tested for their ability to promote the hydrolysis of the activated ester compound 4-nitrophenylacetate (NA), with 3 being the most active complex and 1 being the least active, possibly due to differences in the ability of the carboxylate moiety to act as either a general base or a nucleophile in the hydrolysis of NA as dictated by the tether length. The pK_a values of the copper-bound aquo ligands in solution were measured by spectrophotometric titration.     

Synthesis, structure and electronic spectra of new three-coordinated copper(I) complexes with tricyclohexylphosphine and diimine ligands

Three new copper(I) complexes with tricyclohexylphosphine (PCy₃) and different diimine ligands, [Cu(phen)(PCy₃)]BF₄ (1) (phen = 1,10′-phennanthroline), [Cu(bpy)(PCy₃)₂]BF₄ (2) (bpy = 2,2′-bipyridine) and [Cu(MeO-CNN)(PCy₃)]BF₄ (3) (MeO-CNN = 6-(4-methoxyl)phenyl-2,2′-bipyridine), have been synthesized and characterized. X-ray structure reveals that complexes 1 and 3 are three-coordinated with trigonal geometry, while complex 2 adopts distorted tetrahedron geometry. Complexes 1 and 3 exhibit ligand redistribution reactions in chloromethane solution by addition of excess amount of PCy₃, in which three-coordinated 1 changes into four-coordinated [Cu(phen)(PCy₃)₂]⁺, and 3 leads to form [Cu(PCy₃)₂]BF₄ and CNN-OMe. All the three complexes display yellow ³MLCT emissions in solid state at room temperature with λ_max at 558, 564 and 582 nm for 1, 2 and 3, respectively, and red-shift to 605, 628 and 643 nm at 77 K in dichloromethane solution.     

Synthesis, spectral and magnetic properties and crystal structures of copper(II) pyridinecarboxylates as potential antimicrobial agents

Synthesis and characterization of six new complexes [Cu{2,6-(MeO)₂nic}₂(H₂O)]₂ (1), [Cu{2,6-(MeO)₂nic}₂(H₂O)]₂ · 3DMF (2), where 2,6-(MeO)₂nic is 2,6-dimethoxynicotinate and DMF is N,N-dimethylformamide, [Cu(3-pyacr)₂(H₂O)₂]_n (3), where 3-pyacr is trans-3-(3-pyridyl)acrylate, [Cu(en)₂(H₂O)₂]X₂, where X is 2,6-(MeO)₂nic (4) or 3-pyacr (5) and en is ethylenediamine, and [Cu(3-pyacr)₂(dien)(μ-H₂O)_0.5]₂ · 7H₂O (6), where dien is diethylenetriamine are reported. The characterizations were based on elemental analysis, infrared, electronic and EPR spectra, and magnetic measurements over a temperature range of 1.8-300 K. Crystal structures of complexes 2, 4 and 6 have been determined by X-ray single crystal structure analysis. The available evidence supports dimeric structure of the acetate type for 1 and 2. Crystal structure of polymeric complex 3 has been determined from X-ray powder diffraction data. The 3-pyacr anions in pairs form bridges between two octahedrally surrounded copper(II) atoms in such a way that one 3-pyacr is coordinated to the first Cu^II by an oxygen atom of its carboxyl group and to the second Cu^II by the nitrogen atom of its pyridine ring, while the other is coordinated to the same two Cu^II atoms in a similar way, but the other way round. Environment about the copper(II) atom for 4 and 5 is a square bipyramid (4+2).In complex 6 both Cu^II central atoms are bridged only by an axial water molecule forming a dimeric structure with the considerably long separation of Cu^II atoms of 5.194 Å and the angle Cu1-O3-Cu1a of 150.79°. Moreover, results of the quantitative determination of antimicrobial activity of the complexes as well as above organic ligands alone are discussed.     

Syntheses and characterization of five d coordination polymers derived from phenanthroline derivative and dicarboxylate mixed ligands

Five structurally diverse complexes, [Cd₂(pyip)₂(suc)₂]_n·1.5nH₂O (1), [Zn(pyip)(glu)]_n (2), [Cd(pyip)(glu)]_n (3), [Zn(pyip)₂(adip)₂]_n·2.5nH₂O (4), [Cd₃(pyip)₂(adip)₃]_n (5) (pyip = 2-(pyridin-3-yl)-1H-imidazo[4,5-f][1,10]phenan-throline, H₂suc = succinic acid, H₂glu = glutaric acid, H₂adip = adipic acid), have been hydrothermally synthesized. Complexes 1 and 4 are ribbon-like chains, in which pyip ligands attach to the both sides of the chain in pairs. Complex 2 is a one dimensional (1D) wave-like chain, while the pyip ligands attach to only one side of the chain. Complexes 3 and 5 are both two dimensional (2D) networks, in which the dicarboxylate ligands connect the dinuclear or trinuclear Cd^II units into layers with (4, 4) topological network. The structural differences among these complexes show that the organic acids have important influences on the final structures.     

Structure, magnetic properties and nuclease activity of pyridine-2-carbaldehyde thiosemicarbazonecopper(II) complexes

New complexes of formulae [Cu(HL²)(H₂O)(NO₃)](NO₃) (1), [{Cu(L¹)(tfa)}₂] (2), [{Cu(L¹)}₂(pz)](ClO₄)₂ (3) and {[{Cu(L¹)}₂(dca)](ClO₄)}_n (4), where HL¹ = pyridine-2-carbaldehyde thiosemicarbazone, HL² = pyridine-2-carbaldehyde 4N-methylthiosemicarbazone, Htfa = trifluoroacetic acid (CF₃COOH), pz = pyrazine (C₄H₄N₂) and dca = dicyanamide [N(CN)₂]⁻, have been synthesized and characterized. The crystal structures of these compounds are built up of monomers (1), dinuclear entities with the metal centers bridged through the non-thiosemicarbazone coligand (2 and 3) and 1D chains of dimers (4). In all the cases, square-pyramidal copper(II) ions are present, except for the square-planar ones in 3. Magnetic measurements show antiferromagnetic couplings in 2, 3 and 4. The susceptibility data were fitted by the Bleaney-Bowers’ equation for copper(II) dimers derived from H = -2JS₁S₂ being the obtained J/k values −4.8, −4.3 and −5.1 K for compounds 2-4, respectively. The magnetic susceptibility of the already known [{Cu(HL¹)(tfa)}₂](tfa)₂ compound has been also measured for the first time. The J/k value is -0.3 K, lower than that in 2. The nuclease activity of 3 and 4 has been analyzed.     

Syntheses, structures, and photoluminescent properties of four d metal-quinolinato coordination polymers with similar rod-like SBUs

Four M^II quinolinato complexes, [Zn₂(quin)₂(H₂O)₃]_n (1), [Zn(quin)(H₂O)₂]_n (2), [Zn(quin)(H₂O)]_n (3) and [Cd(quin)]_n (4) (H₂quin = 2,3-pyridinedicarboxylic acid or quinolinic acid), have been hydrothermally synthesized and structurally characterized. X-ray diffraction analyses reveal that all of these four complexes are constructed from similar rod-like SBUs, [M(quin)]_n (M = Zn or Cd). Complexes 1 and 2 have similar 1-D box-like chains but different packing structures; complex 3 has a 2-D grid-like network and complex 4 has an unusual 2-D bilayer structure. Due to the different structural features, these complexes exhibit different photoluminescent emissions: complex 1 at 439 nm (λ_ex = 345 nm), complex 2 at 428 nm (λ_ex = 360 nm), complex 3 at 508 nm (λ_ex = 304 nm) and complex 4 at 500 nm (λ_ex = 324 nm).