meta-Phenylene-bridged double Schiff base copper(II) complexes as building blocks for 1D coordination polymers: Synthesis,crystal structure and magnetic properties

The new double Schiff-base ligands H₆ipa-hyhb and H₆ipa-hyhh were synthesized by condensation of a 4,6-diformylresorcinol derivative (ipa) with 4-hydroxy-butanoic acid hydrazide (hyhb) and 6-hydroxy-hexanoic acid hydrazide (hyhh). The reaction with copper(II) perchlorate in the presence of an appropriate co-ligand (Him = imidazole, Hpz = pyrazole) leads to the novel coordination polymers {[Cu₂(H₄ipa-hyhb)(Hpz)₂](ClO₄)₂}_n (1), {[Cu₂(H₄ipa-hyhb)(Him)₂](ClO₄)₂}_n (2), and {[Cu₂-(H₄ipa-hyhh)(Hpz)₂](ClO₄)₂}_n (3). These coordination polymers are composed of primary building blocks with the general formula [Cu₂(H₄ipa-X)(L)₂]²⁺ (X = hyhb, hyhh; L = Him, Hpz) which are linked by coordination of the hydroxyl groups of the ligand side chains at the apical position of copper(II) centers of adjacent building blocks. The resulting chains possess different topologies and therefore different supramolecular structures due to the variation in length of the ligand alkyl side chains. For the complexes 1 and 2 double hydroxyalkyl-bridged distorted ladder like chains are formed. Whereas in case of complex 3 single hydroxyalkyl-bridged chains are obtained which assemble to hydrogen bonded double chains. In the case of 1 and 2 these chains are cross-linked by hydrogen bonding interactions with the perchlorate counterions, whereas for 3 additional π–π stacking interaction are observed. The temperature-dependent magnetic measurements indicate weak antiferromagnetic interactions with coupling constants J = −26.1 cm⁻¹ (1), J = −28.2 cm⁻¹ (2), and J = −26.5 cm⁻¹ (3). The magnetic exchange interaction is solely the result of a coupling within the dinuclear complex moieties through the central resorcinol moiety.     

3D Coordination Polymers with Chiral Structures, [Ln2(tda)2(H2O)3]·5H2O: Hydrothermal Synthesis,Structural Characterization,and Luminescent Properties

Reactions of H₃tda (H₃tda = 1H‐1, 2, 3‐triazole‐4, 5‐dicarboxylic acid) with Sm(NO₃)₃ · 6H₂O, Eu(NO₃)₃ · 6H₂O, and Tb(NO₃)₃ · 6H₂O, in the presence of NaOH under hydrothermal conditions, produced three new coordination polymers, [Ln₂(tda)₂(H₂O)₃] · 5H₂O [Ln = Sm ( 1 ), Eu ( 2 ), Tb ( 3 )]. These compounds were structurally characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), PXRD and single‐crystal X‐ray diffraction. The single‐crystal X‐ray diffraction studies of compounds 1 – 3 reveal that all compounds are three‐dimensional porous structures with chiral frameworks. Furthermore, the luminescence studies of compound 2 and 3 in the solid state reveal that they are potential luminescent materials at room temperature.     

Synthesis,Structures, and Photoluminescence Properties of Five Novel Zinc(II) and Cadmium(II) Coordination Polymers based on Different Zwitterionic Pyridine Ligands

A series of five new Zn^II and Cd^II mixed‐ligand coordination polymers, namely, {[Zn(L₁)(4,4′‐bpy)] · (ClO₄) · 2H₂O} ( 1 ), {[Zn(L₂)(4,4′‐bpy)_0.5] · (ClO₄)} ( 2 ), {[Zn(L₃)(4,4′‐bpy)] · (NO₃) · 2H₂O} ( 3 ), {[Cd(L₄)(4,4′‐bpy)_0.5(NO₃)] · 5H₂O} ( 4 ), and {[Zn(L₄)(4,4′‐bpy)] · Cl · H₂O} ( 5 ) [4,4′‐bpy = 4,4′‐bipyridine, L₁ = 4‐carboxy‐1‐(4‐carboxybenzyl)pyridin‐1‐ium chloride, L₂ = 3‐carboxy‐1‐(4‐carboxybenzyl)pyridin‐1‐ium chloride, L₃ = 4‐carboxy‐1‐(3‐carboxybenzyl)pyridin‐1‐ium chloride, and L₄ = 3‐carboxy‐1‐(3‐carboxybenzyl)pyridin‐1‐ium chloride], were obtained by the reactions of the 4,4′‐bipyridine with four dicarboxylate zwitterionic pyridine ligands. Single‐crystal X‐ray structural analyses reveal that the five complexes demonstrate different molecular frameworks coming from various coordination modes and flexibilities of different dicarboxylate zwitterionic pyridine ligands and central metal atoms. Mononuclear twofold dinuclear 2D twofold interpenetrating net for 2 , four‐coordinate mononuclear twofold interpenetrating 2D layer for 3 , mononuclear 2D layer arranged in parallel and with large grids for 4 , and twofold trans interpenetrating 2D network for compound 5 . The structural diversities in 1 – 5 indicate that the nature of the ligands and the presence of different metal atoms have a great influence on central metal coordination modes and the structural topologies of the metal‐organic molecular architectures. In addition, π ··· π stacking interactions also play important roles in the final crystal packing and supramolecular frameworks. The powder X‐ray diffraction, elemental analysis, and photoluminescence properties of 1 – 5 were studied, which show that architectures play an important role in emission bands and intensities.     

Syntheses,Crystal Structures and Photophysical Properties of a Series of Cadmium(II) Coordination Polymers

Three cadmium(II) coordination polymers [Cd(NA)₂(H₂O)₂]_n ( 1 ), {[Cd(NA)(phen)(NO₃)]·(H₂O)_1/2}_n ( 2 ), {[Cd(NA)(CH₃C₆H₄COO)(H₂O)₂]·(CH₃C₆H₄COOH)}_n ( 3 ) (HNA = nicotinic acid, phen = 1, 10‐phenanthroline) have been synthesized by hydrothermal method. Their single‐crystal structures were determined by X‐ray diffractometry. The absorption, excitation and emission spectra were investigated and all the complexes emit strong fluorescence: λ^em_max = 544 nm (λ^ex = 492 nm), 1 ; λ^em_max = 466 nm (λ^ex = 393 nm), 2 ; λ^em_max = 430 nm (λ^ex = 313 nm), 3 . At room temperature in the solid state the fluorescence lifetimes of the complexes were investigated and the relationships between the spectra were discussed as well as the connections of luminescence and crystal structures.     

Synthesis,Crystal Structures,and Magnetic Properties of Two Copper(II) Radical Heterospin Complexes

Two heterospin complexes [Cu(NIT3Py)(cda)H₂O] · H₂O ( 1 ) and [Cu(NIT2Py)(cda)H₂O] · H₂O · CH₃OH ( 2 ) with Cu^II ions and pyridyl‐substituted nitronyl nitroxide radicals (NITxPy = 2‐(x′‐pyridyl)‐4,4,5,5‐tetramethyl‐imidazoline‐1‐oxyl‐3‐oxide, x = 3, 2; H₂cda = 4‐hydroxy‐pyridine‐2,6‐dicarboxylic acid) were synthesized and characterized structurally and magnetically. The single crystal structures show that the two complexes are both two‐spin complexes, in which the different radicals make the two complexes have different hydrogen bonding interactions to form 2D and 1D supramolecular network for complexes 1 and 2 , respectively. The magnetic measurements indicate that complexes 1 and 2 both exhibit antiferromagnetic interactions between Cu^II and radicals.     

Three New Lanthanide Coordination Polymers Built from H2bpdc Ligands: Syntheses,Structures, and Properties

Three new lanthanide‐organic coordination polymers, {[Ln₂(bpdc)₂(H₂O)₆(NO₃)] · NO₃} [Ln = La ( 1 ), Ce ( 2 ), Pr ( 3 )] (H₂bpdc = 2, 2′‐bipyridine‐6, 6′‐dicarboxylic acid) were synthesized under hydrothermal conditions and structurally characterized by elemental analysis, IR spectroscopy as well as single‐crystal and powder X‐ray diffraction. Single‐crystal X‐ray diffraction analysis revealed that compounds 1 – 3 are isostructural, composed of two dimensional honeycomb network linked by bpdc ligands. The magnetic property of compound 3 was investigated.     

Two Coordination Polymers based on a Flexible Tritopic Pyridyldicarboxylate Ligand: Structures and Magnetic Properties

The coordination polymers, [Ni(L)₂]_n ( 1 ) and [Mn₂(L)₂(DMF)₂(H₂O)]_n ( 2 ) were synthesized by using a tritopic ligand 5‐(4′‐carboxylphenoxy)nicotinic acid (H₂L). The structural analysis shows that compound 1 exhibits a ten‐connected three‐dimensional (3D) architecture with the point symbol 3¹².4²⁶.5⁷, 2 displays an eight‐connected topology network with a point symbol of 4²⁴.6⁴. The structures and formulas of 1 and 2 were determined by X‐ray diffraction, elemental analysis, and thermogravimetric analysis (TGA). In addition, the magnetic behaviors for 1 and 2 were investigated.     

From 1D to 2D Cd(II) and Zn(II) Coordination Networks by Replacing Monocarboxylate with Dicarboxylates in Partnership with Azine Ligands: Synthesis,Crystal Structures,Inclusion, and Emission Properties

Eight mixed-ligand coordination networks, [Cd(2-aba)(NO₃)(4-bphz)_3/2]_n·n(dmf) (1), [Cd(2-aba)₂(4-bphz)]_n·0.75n(dmf) (2), [Cd(seb)(4-bphz)]_n·n(H₂O) (3), [Cd(seb)(4-bpmhz)]_n·n(H₂O) (4), [Cd(hpa)(3-bphz)]_n (5), [Zn(1,3-bdc)(3-bpmhz)]_n·n(MeOH) (6), [Cd(1,3-bdc)(3-bpmhz)]_n ·0.5n(H₂O)·0.5n(EtOH) (7), and [Cd(NO₃)₂(3-bphz)(bpe)]_n·n(3-bphz) (8) were obtained by interplay of cadmium nitrate tetrahydrate or zinc nitrate hexahydrate with 2-aminobenzenecarboxylic acid (H(2-aba)), three dicarboxylic acids, sebacic (decanedioic acid, H₂seb), homophthalic (2-(carboxymethyl)benzoic acid, H₂hpa), isophthalic (1,3-benzenedicarboxylic acid, H₂(1,3-bdc)) acids, bis(4-pyridyl)ethane (bpe) and with four azine ligands, 1,2-bis(pyridin-4-ylmethylene)hydrazine (4-bphz), 1,2-bis(1-(pyridin-4-yl)ethylidene) hydrazine (4-bpmhz), 1,2-bis(pyridin-3-ylmethylene)hydrazine (3-bphz), and 1,2-bis(1-(pyridin-3-yl) ethylidene)hydrazine (3-bpmhz). Compounds 1 and 2 are 1D coordination polymers, while compounds 3–8 are 2D coordination polymers. All compounds were characterized by spectroscopic and X-ray diffraction methods of analysis. The solvent uptakes and stabilities to the guest evacuation were studied and compared for 1D and 2D coordination networks. The de-solvated forms revealed a significant increase of emission in comparison with the as-synthesized crystals.     

Synthesis,Crystal Structures,Thermal and Magnetic Properties of New Selenocyanato Coordination Polymers with Pyrazine as Co‐Ligand

Reaction of iron(II), cobalt(II) and nickel(II) selenocyanate with pyrazine in water at room temperature leads to the formation of the isotypic new ligand‐rich 1:2 (1:2 = ratio between metal and co‐ligand) compounds [M(NCSe)₂(pyrazine)₂]_n (M = Fe ( 1 ), Co ( 2 ), Ni ( 3 )). The crystal structure of 2 was determined by X‐ray single crystal analysis and those of 1 and 3 were refined from X‐ray powder data with the Rietveld method. In their crystal structure the metal(II) cations are coordinated by four pyrazine co‐ligands, which connect them into layers, and two terminally N‐bonded selenocyanato anions in a distorted octahedral arrangement. The terminal coordination mode of the selenocyanato anions was further emphasized by IR spectroscopic investigations. On heating, all compounds decompose in a single heating step without the formation of ligand‐deficient intermediates like previously reported for related thiocyanato compounds. Magnetic measurements of compound 1 show a long‐range antiferromagnetic ordering with an ordering temperature of T_N = 6.7 K, which must be mediated by the aromatic π‐system of the pyrazine ligand, whereas 2 and 3 show only Curie–Weiss behavior with antiferromagnetic exchange interactions.     

Manganese(II) Coordination Polymer with μ1,1‐Azido Bridge: Synthesis,Crystal Structure,and Magnetic Properties

The manganese(II) coordination polymer [Mn(2‐Meimi)₂(μ_1,1‐N₃)₂]_n · nH₂O ( 1 ) (Meimi = 2‐methyl‐imidazole) with μ_1,1‐N₃ (end‐on, EO) bridge was synthesized by hydrothermal reaction of MnCl₂, NaN₃, and Meimi. It was characterized by elemental analysis, IR spectroscopy, powder XRD, and magnetic measurements. Single crystal X‐ray analysis revealed that compound 1 features a one‐dimensional (1D) catenated structure and the 1D chains are further connected by strong intermolecular hydrogen bonds to a 3D supramolecular framework. Variable‐temperature magnetic susceptibility measurements revealed that compound 1 displays dominant ferromagnetic interactions through the μ_1,1‐N₃ (end‐on, EO) bridging mode.     

Zinc(II) and Nickel(II) Complexes Based on Schiff Base Ligands: Synthesis,Crystal Structure,Luminescent and Magnetic Properties

Three new phenolate oxygen bridged transition metal complexes [Zn₃(HL¹)₃(μ₃‐CH₃O)]·(ClO₄)₂(H₂O)₃ ( 1 ), [Ni₂(HL¹)₂(μ_1,1‐N₃)(o‐vanillin)]·H₂O ( 2 ), [Ni₃(HL²)₂(PhCOO)₂(PhCOOH)₂(EtOH)₂] ( 3 ) have been synthesized by metal ions and potentially multidentate Schiff base ligands (H₂L¹ = 2‐((1‐hydroxy‐2‐methylpropan‐2‐ylimino) methyl)‐6‐methoxyphenol; H₃L² = (E)‐1‐((2‐hydroxy‐3‐methoxy‐benzylidene)amino)ethane‐1,2‐diol). All the three complexes 1 , 2 , and 3 have been characterized by elemental analysis, FT‐IR spectroscopy, and single‐crystal X‐ray diffraction studies. Crystal structures reveal that complex 1 is a trinuclear incomplete cubane‐like zinc cluster whereas complex 2 is a dinuclear nickel complex bridged by azide, and compound 3 is a trinuclear nickel complex. The luminescent property for complex 1 and magnetic behaviors for complexes 2 and 3 have been investigated.     

Heterotrimetallic Coordination Polymers: {CuIILnIIIFeIII} Chains and {NiIILnIIIFeIII} Layers: Synthesis,Crystal Structures,and Magnetic Properties

The use of the [Fe^III(AA)(CN)₄]^? complex anion as metalloligand towards the preformed [Cu^II(valpn)Ln^III]³⁺ or [Ni^II(valpn)Ln^III]³⁺ heterometallic complex cations (AA=2,2′‐bipyridine (bipy) and 1,10‐phenathroline (phen); H₂valpn=1,3‐propanediyl‐bis(2‐iminomethylene‐6‐methoxyphenol)) allowed the preparation of two families of heterotrimetallic complexes: three isostructural 1D coordination polymers of general formula {[Cu^II(valpn)Ln^III(H₂O)₃(μ‐NC)₂Fe^III(phen)(CN)₂ {(μ‐NC)Fe^III(phen)(CN)₃}]NO₃ ? 7 H₂O}_n (Ln=Gd ( 1 ), Tb ( 2 ), and Dy ( 3 )) and the trinuclear complex [Cu^II(valpn)La^III(OH₂)₃(O₂NO)(μ‐NC)Fe^III(phen)(CN)₃] ? NO₃ ? H₂O ? CH₃CN ( 4 ) were obtained with the [Cu^II(valpn)Ln^III]³⁺ assembling unit, whereas three isostructural heterotrimetallic 2D networks, {[Ni^II(valpn)Ln^III(ONO₂)₂(H₂O)(μ‐NC)₃Fe^III(bipy)(CN)] ? 2 H₂O ? 2 CH₃CN}_n (Ln=Gd ( 5 ), Tb ( 6 ), and Dy ( 7 )) resulted with the related [Ni^II(valpn)Ln^III]³⁺ precursor. The crystal structure of compound 4 consists of discrete heterotrimetallic complex cations, [Cu^II(valpn)La^III(OH₂)₃(O₂NO)(μ‐NC)Fe^III(phen)(CN)₃]⁺, nitrate counterions, and non‐coordinate water and acetonitrile molecules. The heteroleptic {Fe^III(bipy)(CN)₄} moiety in 5 – 7 acts as a tris‐monodentate ligand towards three {Ni^II(valpn)Ln^III} binuclear nodes leading to heterotrimetallic 2D networks. The ferromagnetic interaction through the diphenoxo bridge in the Cu^II?Ln^III ( 1 – 3 ) and Ni^II?Ln^III ( 5 – 7 ) units, as well as through the single cyanide bridge between the Fe^III and either Ni^II ( 5 – 7 ) or Cu^II ( 4 ) account for the overall ferromagnetic behavior observed in 1 – 7 . DFT‐type calculations were performed to substantiate the magnetic interactions in 1 , 4 , and 5 . Interestingly, compound 6 exhibits slow relaxation of the magnetization with maxima of the out‐of‐phase ac signals below 4.0 K in the lack of a dc field, the values of the pre‐exponential factor (τ_o) and energy barrier (E_a) through the Arrhenius equation being 2.0×10^?12 s and 29.1 cm^?1, respectively. In the case of 7 , the ferromagnetic interactions through the double phenoxo (Ni^II–Dy^III) and single cyanide (Fe^III–Ni^II) pathways are masked by the depopulation of the Stark levels of the Dy^III ion, this feature most likely accounting for the continuous decrease of χ_M T upon cooling observed for this last compound.     

Four Transition Metal Coordination Polymers based on an Aromatic Multi‐carboxylic Acid as Ligand: Syntheses,Crystal Structures,and Fluorescent/Magnetic Properties

Four compounds, namely, [Zn(H₂L)₂ · 4H₂O] ( 1 ), [Cu(HL) · (H₂O)] · H₂O ( 2 ), [Ni₃L₂(bpy)₂ · 12H₂O] · 4H₂O ( 3 ), and [Co₃L₂(bpy)₂ · 12H₂O] · 4H₂O ( 4 ) [H₃L = 4, 4′‐[(5‐carboxy‐1, 3‐phenylene)bis(oxy)]dibenzoic acid], were synthesized under solvothermal conditions by employing a semi‐rigid aromatic multi‐carboxylic acid ligand (H₃L) and ancillary nitrogen ligand (bpy = 4, 4′‐bipyridine). X‐ray diffraction studies revealed that complexes 1 , 3 , and 4 show zero‐dimensional (0D) structures, which were further extended to distinct 3D supramolecular nets by extensive hydrogen‐bond interactions. However, in compound 2 , 1D chains of square‐shaped pores were linked together by HL^2– ligands to generate a 2D porous layer along the ac plane. Comparison of the structures indicated that not only the conformation of the functional ligand, but also the ancillary ligand helped in structural determination of the compounds. Compound 1 exhibited solid fluorescence emission originating from an intraligand π→π* transition. Magnetic susceptibility measurements demonstrated that compound 2 exhibited antiferromagnetic coupling between adjacent copper(II) ions, with the corresponding J values of –141.84 cm^–1. Furthermore, the thermal behaviors of the complexes 1 – 4 were studied by thermogravimetric analysis.     

Crystal Structure and Magnetic Properties of a Hexanuclear Copper(II) Carboxylate

The synthesis and characterisation of the hexanuclear copper(II) carboxylate complex [Cu(O₂CCHPhOC₂H₄OC₂H₄OCH₃)₂]₆ ( 1 ) is described. Single‐crystal X‐ray structure analysis reveals that the copper(II) ions are arranged in a six‐membered ring which adopts a chair‐like conformation. The copper(II) ions are bridged by μ₂‐ and μ₃‐coordinating carboxylates. The magnetic behavior of 1 was measured between 2 and 300 K, revealing at low temperature a weak antiferromagnetic interaction. The χ_M(T) dependency was fitted mathematically with one coupling constant J₁ and a paramagnetic impurity α.     

2D Coordination Polymer with a 1D Carboxylate‐Copper Chain Based on Rare Icosanuclear and Tetranuclear Clusters

The 2D coordination polymer {[Cu₃₂( pa )₂₄(μ₂‐OH)₈(μ₃‐OH)₈( bibp )₈] · (CH₃OH)₃(H₂O)₅}_∞ was prepared by the solvothermal reaction of Cu(NO₃)₂ · 3H₂O with phthalic acid (H₂ pa ) and 4, 4′‐bis(imidazol‐1‐yl)biphenyl ( bibp ). The Cu^II ions show five different kinds of coordination environments, which are all connected by the pa ^2– ion into an interesting 1D carboxylate‐copper chain with rare icosacopper and tetracopper clusters. The 1D chain is further bridged by the bibp ligand to form a 2D layer, which could be viewed as an unprecedented (4, 4) lattice based on rectangular and butterfly‐shaped tetracopper clusters with the ratio of 2:6. The magnetic properties were studied, and the results show antiferromagnetic interaction in the complicated 1D chain.     

Hydrothermal Synthesis,Structural Characterization,Magnetic and Photoelectric Properties of Two Cobalt(II) Coordination Polymers

Two cobalt(II) coordination polymers, {[Co(μ‐4,4′‐bipy)(4,4′‐bipy)₂(H₂O)₂]·(OH)₃·(Me₄N)·4,4′‐bipy·4H₂O}_n ( 1 ) and {[Co(μ‐4,4′‐bipy)(H₂O)₄]·suc·4H₂O}_n ( 2 ) (4,4′‐bipy = 4,4′‐bipyridine, suc = succinate dianions), were hydrothermally synthesized and structurally characterized by X‐ray diffraction analysis, UV‐Vis‐NIR, and ICP. The main structure feature common to the both polymers is presence of the infinite linear chains, [Co(μ‐4,4′‐bipy)(4,4′‐bipy)₂(H₂O)₂]_n ( 1 ) and [Co(μ‐4,4′‐bipy)(H₂O)₄]_n ( 2 ), respectively. In 1 , the chains are further linked by the hydrogen‐bond and π‐π stacking interaction, producing extended layer structure. The 4,4′‐bipy molecules in 1 play three different roles. In 2 , the chains are linked into three‐dimensional network structure via complicated hydrogen bonding system. The variable temperature (2.0～300 K) magnetic susceptibility of 1 indicates a tendency of spin‐transition in the temperature range of 110 K to 22 K, which attributes to the transition of high‐spin to low‐spin from Co²⁺(d⁷) ion. Also, the result of surface photovoltage spectroscopy (SPS) reveals that the polymer 1 has significant photoelectric conversion property in the region of 300‐800 nm.     

One-dimensional and two-dimensional coordination polymers constructed from copper(II) nodes and polycarboxylato spacers: Synthesis,crystal structures and magnetic properties

Four new coordination polymers were obtained by employing polycarboxylato spacers and cationic copper(II) complexes as nodes: ^∞₂[Cu₃(trim)₂(NH₃)₆(H₂O)₃] (1); ^∞₁[Cu(tmen)(dhtp)] (2), ^∞₁[Cu(tmen)(hitp)(H₂O)] (3), ^∞₁[Cu(tmen)(nitp)] (4). (H₃trim = trimesic acid, H₂dhtp = 2,5-dihydroxy-terephthalic acid; H₂hitp = 5-hydroxy-isophthalic acid, H₂nitp = 5-nitro-isophthalic acid; tmen = N,N,N′,N′-tetramethyl-ethylenediamine). The crystal structures of the four compounds have been solved. Compound 1 consists of 2D coordination polymers with heart-shaped meshes, while compounds 2–4 contain infinite zigzag chains. The role of the hydrogen bond interactions in sustaining the supramolecular solid-state architectures in compounds 1 and 3 is discussed. The cryomagnetic investigation of compounds 1, 2, and 4 reveals antiferromagnetic interactions between the copper ions.     

Two 1D Ladderlike Heterometallic Zinc(II) Coordination Polymers: Syntheses,Crystal Structures,and Fluorescence Properties

Two coordination polymers [Zn₂(ipt)₂(CuL)₂(H₂O)] ( 1 ) and [Zn₂(ipt)₂(NiL)₂(H₂O)] ( 2 ) (ML, H₂L = 2,3‐dioxo‐5,6,14,15‐dibenzo‐1,4,8,12‐tetraazacyclo‐pentadeca‐7,13‐dien; H₂ipt = isophthalic acid) were synthesized by solvothermal methods and characterized by single‐crystal X‐ray diffraction. Complexes 1 and 2 exhibit ladderlike chains, consisting of Zn₄Cu₄ and Zn₄Ni₄ units, respectively, which are connected via oxamide and isophthalate. These chains are further interlinked by hydrogen bonds resulting in a 2D supramolecular architecture. The fluorescence properties of compounds 1 and 2 are also discussed.     

Syntheses and Structural Characterization of 1D Chain and 1D Ladder Coordination Polymers Assembled from Exo‐bidentate Imidazolyl Ligands

Five novel coordination polymers, [(Cu(L¹)₂OH) · Cl · 3H₂O] ( 1 ) [L¹ = bis(N‐imidazolyl)methane], [Cd(L¹)₂(NCS)₂] ( 2 ), [Zn(L¹)₂(NCS)₂] ( 3 ), [Cu(L¹)₂(NO₃)₂] ( 4 ), and [Cu(L²)_1.5(NCS)₂] ( 5 ) [L² = 1,4‐bis(N‐imidazolyl)butane] were obtained from self‐assembly of the corresponding metal salts with flexible ligands and their structures were fully characterized by X‐ray diffraction (XRD) analysis, Fourier Transform Infrared (FT‐IR) spectroscopy, elemental analysis and thermogravimetric (TGA) measurements. X‐ray diffraction analyses revealed that complexes 1 , 2 , 3 , and 4 exhibit 1D double‐stranded chain structures, which result from doubly bridged [CuOH], [M(NCS)₂] (M = Cd, Zn), and [Cu(NO₃)₂] units, respectively. The polymeric copper complex 5 displays 1D ladder structure., These complexes, with the exception of complex 1 , are stable up to 300 °C.     

On Verdigris,Part III: Crystal Structure,Magnetic and Spectral Properties of Anhydrous Copper(II) Acetate,a Paddle Wheel Chain

Pure anhydrous Cu(CH₃COO)₂ was obtained both, by thermal dehydration of Cu(CH₃COO)₂ · H₂O and by drying a commercially purchased mixture of Cu(CH₃COO)₂ · H₂O and Cu(CH₃COO)₂ in a nitrogen atmosphere using P₂O₅ as drying agent. The crystal structure was solved ab initio from synchrotron X‐ray powder diffraction (XRPD) data at 150 °C and from laboratory XRPD data at ambient conditions and found to be isotypic to anhydrous chromium(II), molybdenum(II) and rhodium(II) acetate. Cu(CH₃COO)₂ crystallizes in space group P1 (no. 2) with lattice parameters of a = 5.1486(3) Å, b = 7.5856(6) Å, c = 8.2832(6) Å, α = 77.984(4)°, β = 75.911(8)°, γ = 84.256(6)° at ambient conditions. Cu₂(CH₃COO)₄ paddle wheels with short (2.6 Å) Cu–Cu distances form chains in a direction, which is the main motif in the crystal structure. Due to their identical structural main motif Cu(CH₃COO)₂ · H₂O and Cu(CH₃COO)₂ exhibit a similar bluish‐green color, almost identical UV/Vis spectra and comparable magnetic properties. The temperature dependent magnetic susceptibility also indicates only weak inter‐dimer spin exchange between neighbouring Cu₂(CH₃COO)₄ paddle wheels.