Supramolecular structures of Mn2+, Co2+ and Zn2+ complexes containing 1,3-bis(4-pyridyl)propane and aminosalicylate anion

In this study, the synthesis, spectroscopic properties and crystal structures of three new supramolecular compounds named [Mn₂(bpp)₄(H₂O)₄](AS)₄·H₂O (1), [Co₂(bpp)₄(H₂O)₄](AS)₄·H₂O (2) and [Zn(bpp)(AS)₂] (3), have been described, where bpp is 1,3-bis(4-pyridil)propane and AS^?  is aminosalicylate anion. By analysing the similarities between the X-ray powder diffraction results, it has been observed that compounds 1 and 2 are isomorphous, exhibiting an orthorhombic system with space group Pccn; for compound 3, another orthorhombic system was observed, with space group Aba2, which displays coordination between the Zn²⁺ metal ion and the aminosalicylate anion; this can be considered the first case in the literature involving the direct coordination to the metal ion. The vibrational spectra of compounds 1 and 2 are very similar. In the Raman spectra, the main bands are observed at ca. 1625 and 1020 cm^? 1, referring to the ^? O–C = O and CC/CN stretching modes of AS^?  and bpp ligands, respectively.     

Two new Cu(II) m-hydroxybenzoato complexes with chloro- and carboxylato-bridged dinuclear [Cu(µ2−Cl)(µ2−COO)Cu] cores

In aqueous methanolic solution, reactions of CuCl₂, m-hydroxybenzoic acid (HL), and NaOH with 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen) at room temperature afforded {[Cu(bpy)L](µ₂?Cl)(µ₂?L)[Cu(bpy)L]}?1.2H₂O (1) and {[Cu(phen)Cl](µ₂?Cl)(µ₂?L)[Cu(phen)L]} (2) with chloro- and carboxylato-bridged dinuclear [Cu(µ₂?Cl)(µ₂?COO)Cu] cores. The Cu₂ dimers in 1 are pairwise aggregated to form H-bonded tetranuclear motifs, which are extended by H₂O into 1-D H-bonded chains and further assembled into 2-D supramolecular networks. The Cu₂ dimers in 2 are also linked into 1-D H-bonded chains and further assembled into 2-D supramolecular layers. Magnetic measurements indicate that significant antiferromagnetic interactions (J = ?15.9, ?12.2 cm^?1) between Cu²⁺ ions are dominant in these dinuclear [Cu(µ₂?Cl)(µ₂?COO)Cu] cores. To the best of our knowledge, 2, crystallizing in the acentric polar orthorhombic space group Pna2₁, represents the first example of metal m-hydroxybenzoato complexes with ferroelectric properties with a remnant polarization (Pr) of ca. 0.04?µC cm^?2, coercive field (Ec) of ca. 2.52 kV cm^?1, and saturation of the spontaneous polarization (Ps) at ca. 0.195?µC cm^?2.     

Three Cu(II) (R)-2-chloromandelato complexes generated from dipyridyl-type ligands with different spacer lengths: syntheses,crystal structures,and ferroelectric properties

Three Cu(II) complexes, Cu₂(bpy)(H₂O)(Clma)₂ (1), Cu₂(bpe)(H₂O)₂(Clma)₂ (2), and Cu(bpp)(Clma) (3), were synthesized (HClma = (R)-2-Chloromandelic acid, bpy?=?4,4′-dipyridine, bpe?=?1,2-di(4-pyridyl)ethylene, bpp?=?1,3-di(4-pyridyl)propane). Complexes 1, 2, and 3 are constructed from 1-D coordination arrays generated from Cu₂(H₂O)(Clma)₂, Cu₂(H₂O)₂(Clma)₂, and Cu₂(Clma)₂ moieties and linked through bpy, bpe, and bpp co-ligands, respectively. 1 and 2 are assembled into 3-D supramolecular networks via O–H?O hydrogen bonds with topology of (6³)(6⁹·8) and (4¹²·6³), respectively, and 3 is assembled into a 3-D architecture through C–H?O hydrogen bonds with topology of (4³·6³)(4³)(4⁴·6⁵·8)(4⁶·6⁶·8³). Compounds 1, 2, and 3 crystallized in acentric space groups P2₁, P1, and P2₁, which exhibit significant ferroelectricity (remnant polarization Pr?=?0.008?μC?cm^?2, coercive field Ec?=?21.4?kV?cm^?1, the spontaneous saturation polarization Ps?=?0.167?μC?cm^?2 for 1, Pr?=?0.183?μC?cm^?2, Ec?=?1.69?kV?cm^?1, and Ps?=?0.021 μC?cm^?2 for 3). Results from infrared and thermal analyses are also discussed.     

Structural diversity controlled by alkali/alkaline earth metals for heterometallic AeI/AeII-ZnII coordination polymers based on 4-nitrobenzene-1,2-dicarboxylate

Six heterometallic Zn(II) coordination polymers, Zn(H₂O)₃(FNA) (1), [NH₄]₂[Zn(H₂O)₂(FNA)₂] (2), [ZnNa₂(FNA)₂]·3H₂O (3), [ZnK₂(FNA)₂]·H₂O (4), [ZnRb₂(FNA)₂]·2H₂O (5) and [ZnMg(FNA)₂]·4H₂O (6) (H₂FNA = 4-nitrobenzene-1,2-dicarboxylic acid), were synthesised by introducing different alkali/alkaline earth (Ae^I/Ae^II) metals. These complexes exhibit diverse structures with the different Ae^I/Ae^II metals used and distinct ligand coordination modes the ions provide. For 1 and 2, the Zn(II) centres with distorted octahedra are connected by FNA to form 1-D chain structures. The Zn(II) centres in 3–6 with distorted tetrahedra are linked by FNA to form 2-D anionic grid layers. For 3–5, these 2-D anionic grid layers are connected by alkali metal (Na, K and Rb) with the O–Ae^I–O connectivity to exhibit 3-D framework structures, while 6 features a 2-D Zn–Mg network. Luminescence properties of 1–6 have been investigated.     

Syntheses and crystal structures of four new fpa-metal complexes through in situ ligand reaction

Four new fpa-metal complexes, [Co(fpa)₂(H₂O)₂] (1), [Cu(fpa)₂(H₂O)] (2), [Zn₂(fpa)₄(bpp)₂] _n (3), and {[Zn(bpy)(H₂O)₄]?·?2(fpa)} _n (4), have been synthesized and fully characterized by elemental analyses, IR spectroscopy, single-crystal X-ray diffraction, and thermogravimetric analysis (TGA), (Hfpa?=?2,2-difluoro-2-(pyridine-2-yl)acetate, bpp?=?1,3-bis(4-pyridyl)propane, bpy?=?4,4′-bipyridine). X-ray diffraction analyses reveal that 1 and 2 with 0-D structures are both extended into 3-D supramolecular networks through hydrogen bonds and π···π interactions. Complex 3 with chiral centers possesses a 1-D structure constructed by two kinds of bpp molecules and four kinds of fpa^? molecules with different conformations, with bbp and fpa^? bridging and capped ligands, respectively. In 4, bpy links [Zn(H₂O)₄]²⁺ into a 1-D polymeric cationic chain and uncoordinated fpa^? compensates the framework charge. The results of TGA reveal that fpa^? decomposes through two processes. Both 3 and 4 show strong fluorescence in the solid state at room temperature.     

Transition metal coordination complexes based on V-shaped bis-triazole ligand: syntheses,structures, and properties

Hydrothermal reactions of 1,3-bis(1,2,4-triazol-1-yl)benzene (btb) and M(NO₃)₂ (M = Co²⁺ (1), Cu²⁺ (2)) afforded two new coordination polymers, [Co(btb)₂(NO₃)(H₂O)]_n·NO₃·H₂O (1) and [Cu(btb)₂(NO₃)₂]_n (2), respectively. Single-crystal X-ray diffraction reveals that 1 crystallizes in the space group P2₁/m and 2 crystallizes in the space group Pī, both showing a double-stranded chain structure. The 1-D chains are interconnected via π?π interactions to lead to 2-D ladder-like supramolecular architectures. In addition, magnetic behavior and thermal stability of 1 and 2 have been investigated. For 1, weak antiferromagnetic interactions are observed at low temperature, and the data obey the Curie–Weiss law χ_M = C/(T?θ), with C = 3.22 cm³·mol^?1·K and θ = ?10.39 K. For 2, the decrease of the χT vs. T curve at low temperature is the result of intermolecular antiferromagnetic magnetic interactions.     

Mono-, di-, and trinuclear phosphonate oxygen-bridged copper(II) complexes: syntheses,structures, and properties

Reactions of copper salts, zoledronic acid, and 2,2′-bipyridine/1,10-phenanthroline in aqueous ethanolic solutions afforded four phosphonate oxygen-bridged copper complexes, Cu(bipy)(H₄zdn)(HSO₄) (1), [Cu₂(bipy)₂(H₂zdn)(H₂O)(Cl)]·4H₂O (2), [Cu₂(phen)₂(H₂zdn)(H₂O)(Cl)]·2.5H₂O (3), and [Cu₃(bipy)₃(H₄zdn)(H₂zdn)(SO₄)]·5H₂O (4) (H₅zdn = zoledronic acid, bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline). The copper centers of 1–4 have square pyramidal coordination geometries. The Cu(II) ions are coordinated to bipy/phen, zoledronate, and HSO₄^?/Cl^? forming mononuclear units for 1, dinuclear for 2 and 3, and trinuclear for 4. These building units are further extended into 3-D supramolecular networks via multiple hydrogen bond interactions. Temperature-dependent magnetic properties of 2 and 4 suggest weak antiferromagnetic coupling (J = ?4.53(8) cm^?1 for 2, J = ?1.69(4) cm^?1 for 4). The antitumor activity of 2 was evaluated against the human lung cancer cell line and indicates effective time- and dose-dependent cytotoxic effects.     

Synthesis,crystal structures,and magnetic properties of methoxido-bridged dinuclear MnIII complexes derived from tri-dentate chelating ligands

Two new doubly methoxido-bridged Mn^III dinuclear complexes, [Mn^III(mphp)(μ-OCH₃)(CH₃OH)]₂·2CH₃OH (1) and ([Mn^III(ahbz)(μ-OCH₃)(CH₃OH)]₂·2CH₃OH (2), have been synthesized by using the tridentate ligands H₂mphp (H₂mphp = 2-methyl-6-(pyrimidin-2-yl-hydrazonomethyl)-phenol) and H₂ahbz (H₂ahbz = N-(2-amino-propyl)-2-hydroxy-benzamide). The complexes have been characterized by single-crystal X-ray diffraction analysis and magnetic measurements. Complexes 1 and 2 have a similar dimeric molecular structure. Two [Mn(L)(CH₃OH)]⁺ moieties (L^2? = mphp^2? or ahbz^2?) are bridged by two μ-OCH₃^? groups in the axial-equatorial asymmetric manner. The coordination geometry of Mn^III is an axially elongated octahedron with two oxygens of a methanol ligand and a methoxido ligand situated at the axial positions. Magnetic measurements indicate that 1 and 2 exhibit antiferromagnetic behavior with the fitting parameter of J = ?1.49(3) cm^?1, D = ?1.3(1) cm^?1, g = 1.98(1) and zJ′ = ?0.18(4) cm^?1 for 1, and J = ?1.6(2) cm^?1, D = 4.5(3) cm^?1, g = 2.06(1) and zJ′ = 1.4(1) cm^?1 for 2 on the basis of the spin Hamiltonian ? = ?2J?_Mn1?_Mn2.     

Construction of zinc–organic frameworks by flexible aliphatic dicarboxylates plus 2-(1H-imidazolyl-1-methyl)-1H-benzimidazole ligand

Three new Zn(II) complexes, [Zn(ox)(imb)] (1), [Zn₂(mal)₂(imb)₂] (2), and [Zn(suc)(imb)]·H₂O (3) (imb = 2-(1H-imidazolyl-1-methyl)-1H-benzimidazole, H₂ox = oxalic acid, H₂mal = malonic acid, H₂suc = succinic acid), have been synthesized and structurally characterized. Complex 1 is a 3-D framework with a 4-connected diamond topology with the topological notation of 6⁶. Complex 2 exhibits 2-D layers with (6,3) networks. Complex 3 displays a 3-D framework constructed through unusual 2-D → 3-D parallel interpenetration of corrugated 2-D (6,3) networks. IR spectra, PXRD patterns, thermogravimetric curves, and photoluminescence spectra are addressed.     

Synthesis, crystal structures and properties of four manganese coordination polymers with 4,4-bipyridine-derived ligands

Four new coordination polymers, namely Mn₂(4,4-bpy)₂(o-tol)₄ 1, Mn₂(4,4-bpy)₂(m-tol)₄ 2, Mn₂(bpp)₂(m-tol)₄ 3 and {[Mn₂(4,4-bpy)₂(p-tol)₄][Mn(4,4-bpy)₂(H₂O)₂(p-tol)₂]}·6H₂O 4 have been synthesized from 4,4′-bipyridine (4,4-bpy), 1,3-bis(4-pyridyl)-propane (bpp), o-toluic acid (o-Htol), m-toluic acid (m-Htol) and p-toluic acid (p-Htol). All four complexes feature dinuclear Mn₂(tol)₄ moieties, which are bridged by 4,4-bpy or bpp ligands to form 1D double-chain structures. The resulted 1D double-chains are assembled via hydrogen bonding or π···π stacking into 2D supramolecular layers. The complexes were characterized by physico-chemical (thermal behavior) and infrared spectroscopy. Variable temperature magnetic characterization suggest weak antiferromagnetic coupling exchange between dimeric Mn(II) centers (J = ?0.46 cm^?1 for 1, ?0.56 cm^?1 for 2, ?1.28 cm^?1 for 3 and ?0.59 cm^?1 for 4).     

Synthesis,characterization, and magnetochemical properties of two Mn4 clusters derived from 2-pyridinecarboxaldehyde Schiff base ligands

Two tetranuclear manganese complexes, [Mn₄(L¹)₆](ClO₄)₂?2.75H₂O (1) [HL¹ = 4-methyl-2-((pyridin-2-ylmethylene)amino)phenol] and [Mn₄(L²)₄(NO₃)₃(OH)]?pz?3H₂O (2) [HL² = (1H-pyrazol-1-yl)(pyridin-2-yl)methanol, pz = pyrazole], have been synthesized and characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction, and magnetic measurements. The structural analysis revealed that the central manganese ion is linked with three apical manganese ions through six phenoxo-bridges creating a Mn₄O₆ core for 1; 2 has a cubane-like topology with the Mn(II) ions and the deprotonated oxygens from L² alternatively occupying vertices. The magnetic studies indicated a weak ferromagnetic coupling interaction (J = 0.48 ± 0.087 cm^?1, g = 2.00, θ = ?0.78 K) for 1 and a weak antiferromagnetic spin-exchange interaction (J₁ = ?0.50 ± 0.075 cm^?1, J₂ = ?0.13 ± 0.082 cm^?1, g = 1.98) between Mn(II) ions for 2. The magnetostructural correlations of the two Mn₄ clusters have been discussed tentatively.     

A 1-D alternating copper(II) chain based on three acetate-bridging modes: synthesis,crystal structure,DNA binding and magnetic properties

A new 1-D alternating copper(II) polymer, [Cu₂(L)(OAc)₄]_n (1) (L = 5-chloro-2-(pyridine-2-yl)benzo[d]thiazole), has been isolated and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, and magnetic susceptibility. The complex crystallized in the triclinic space group P-1, a = 8.2277(16) Å, b = 9.4233(19) Å, c = 15.831(3) Å, α = 103.38(3)°, β = 99.95(3)°, γ = 92.70(3)°, V = 1171.3(4) Å³, and comprises a 1-D polymer linked by three kinds of acetate-bridging modes in an alternating manner. UV–visible and fluorescence spectra revealed that 1 is bound to CT-DNA in a partial intercalation mode. Through gel electrophoresis assays, 1 displayed an efficient oxidative cleavage activity on supercoiled plasmid DNA (pUC19) in the presence of H₂O₂. Magnetic measurements were performed from 2 to 300 K, and the experimental results were satisfactorily reproduced with J₁ = –160 ± 20 cm^?1, J₂ = 5.8 ± 0.2 cm^?1, zJ′ = 0.381 ± 0.005 cm^?1 and g = 2.1, showing antiferromagnetic coupling between Cu1 and Cu1i, ferromagnetic exchange between Cu2 and Cu2ii, and a weak ferromagnetic molecular field correction accounting for all interspecies interactions.     

Syntheses,structural determination,and binding studies of nine-coordinate multinuclear (mnH)2[EuIII(egta)]2·6H2O and binuclear (mnH)4[EuIII2(dtpa)2]·6H2O

Two lanthanide complexes, (mnH)₂[Eu^III(egta)]₂·6H₂O (1) (H₄egta = ethyleneglycol-bis-(2aminoethylether)-N,N,N′,N′-tetraacetic acid) and (mnH)₄[Eu^III₂(dtpa)₂]·6H₂O (2) (H₅dtpa = diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid), have been synthesized and characterized by FT-IR spectroscopy, thermal analysis, and single-crystal X-ray diffraction. X-ray diffraction reveals that 1 is multinuclear nine-coordinate and crystallizes in the monoclinic crystal system with space group C2/c. The obtained cell dimensions are a = 38.513(3)?Å, b = 13.5877(8)?Å, c = 8.7051(5)?Å, β = 99.6780(10)°, and 4490.6(5)?ų. Each methylamine (mnH⁺) cation in 1, through hydrogen bonds, connects three adjacent [Eu^III(egta)]^? anions. The [Eu^III(egta)]^? anions connect one another forming a 1-D multinuclear zigzag chain structure along the c-axis. Complex 2 is nine-coordinate binuclear structure with tricapped trigonal prismatic conformation and crystallizing in the monoclinic crystal system, but with space group P2₁/n. The obtained cell dimensions are a = 9.9132(8)?Å, b = 24.1027(18)?Å, c = 10.7120(10)?Å, β = 109.1220(10)°, and 2418.2(3)?ų. For 2, there are two kinds of methylamine cations (mnH⁺) connecting [Eu^III₂(dtpa)₂]^4? complex anions and lattice waters through hydrogen bonds, leading to formation of a 2-D ladder-like layer structure.     

Syntheses,structures, and luminescence of two Zn(II) coordination polymers based on 5-(4-imidazol-1-yl-phenyl)-2H-tetrazole and carboxylates

Reactions of Zn(II) salts, 5-(4-(1H-imidazol-1-yl)phenyl)-1H-tetrazolate (HIPT) and 2-mercaptobenzoic acid or 2-propyl-1H-imidazole-4,5-dicarboxylic acid (H₃PrIDC), result in two mixed-ligand coordination polymers (CPs), [Zn₂(IPT)(DSDB)(OH)]_n (H₂DSDB = 2,2′-disulfanediyldibenzoic acid, 1) and [Zn₂(IPT)(PrIDC)(H₂O)]_n (H₃PrIDC = 2-propyl-1H-imidazole-4,5-dicarboxylic acid, 2). Compound 1 possesses a 2-D structure built by 1-D [Zn(IPT)]_n chains and DSDB^2? connectors, in which the DSDB^2? is generated via in situ reaction from 2-mercaptobenzoic acid. It displays a new intricate 4-nodal {3·4·6·7·8·9}{3·6·7·8·9·10}{3·8·9}{4·6·8} topology. Compound 2 displays a 3-D framework with new 3-connected topology with Schläfli symbol of (4·8·10) (8·12²), in which the 1-D Zn-carboxylate chains were bridged by 3-connected IPT^? ligands. The thermal stabilities and luminescence properties of 1 and 2 have also been studied. The compounds exhibit intense solid-state fluorescent emissions at room temperature.     

Crystal structures, magnetic, dielectric and ferroelectric properties of two copper(II) complexes with m-nitrobenzoic acid

Reactions of CuCl₂, m-nitrobenzoic acid (HNBA) and NaOH with 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen) in aqueous ethanol afforded two Cu(II) complexes Cu(bpy)(NBA)₂, 1, and [Cu(phen)(H₂O)₂(NBA)](NBA), 2. The monomolecular Cu(bpy)(NBA)₂ moieties are both bridged by hydrogen bonding interactions and interlayer π ^*–π ^*stacking interactions to form a 3D (3,4,6)-connected supramolecular architecture with the Schäfli symbol of (4⁴·6²)(4⁴·6⁶·8⁵)(6³)₂. Complex 2 crystallizes in a noncentrosymmetric space group P2₁ where all molecules show the same orientation along the polar b axis. Preliminary investigations suggest that 2 exhibits ferroelectric hysteresis loops at room temperature with remanent polarization (P _r) of ca. 0.09 μC cm^?2 and coercive electric fields of 2.53 kV cm^?1, respectively. It may be a potential ferroelectric with a relatively large spontaneous polarization (P _s) of 0.22 μC cm^?2. Furthermore, permittivity property measurements reveal a dielectric constant (ε _r) of 6.36. Variable-temperature (2–300 K) magnetic susceptibility measurements showed the presence of weak ferromagnetic interactions between the Cu(II) ions for both 1 and 2.     

Syntheses,structures, and properties of two coordination polymers based on 5-methoxyisophthalate and flexible dipyridines

Hydrothermal reactions of 5-methoxyisophthalic acid (MeO-H₂ip), 1,3-di(4-pyridyl)propane (bpp) with Cd(NO₃)₂·4H₂O and Ni(NO₃)₂·6H₂O produced [Cd₂(MeO-ip)₂(bpp)₂]_n·nH₂O (1) and [Ni(MeO-ip)(bpp)(H2O)]_n·nH₂O (2), respectively. Complex 1 is a 2-D layer consisting of dinuclear Cd(II)-carboxylate units, two carboxylates of MeO-ip adopt μ₂,η²-bridging and chelating modes. MeO-ip bridges three Cd(II) ions to form a 1-D [Cd₂(MeO-ip)₂]_n chain, which is further extended into a 2-D layer by bpp in a trans,trans-conformation. However, two carboxylates of MeO-ip in 2 are monodentate and chelating to link Ni(II) into a 1-D [Ni(MeO-ip)]_n chain with bpp in a trans-gauche conformation connecting [Ni(MeO-ip)]_n chains into a two-fold interpenetrating 3-D network. Coordinated water and carboxylate oxygen from different MeO-ip form strong hydrogen bonds. The frameworks of 1 and 2 are stable below 250 and 300?°C, respectively. Luminescence indicates that 1 shows maximum emission at 375 and 450 nm upon excitation at 320 nm. Magnetic measurement of 2 suggests the presence of ferromagnetic interactions in 2.     

Two tetranuclear Ni(II) complexes from substituted imidazole dicarboxylates: syntheses,structures, thermal and magnetic properties

Two tetranuclear nickel(II) complexes, [Ni₄ (p-BrPhHIDC)₄(py)₄(H₂O)₄]·CH₃OH (p-BrPhH₃IDC = 2-(p-bromophenyl)-1H-imidazole-4,5-dicarboxylic acid) (1) and [Ni₄(p-ClPhHIDC)₄ (CH₃CN)₄(H₂O)₄]·4H₂O (p-ClPhH₃IDC = 2-(p-chlorophenyl)-1H-imidazole-4,5-dicarboxylic acid, py = pyridine) (2), have been solvothermally synthesised and structurally characterised. Both compounds consist of similar tetranuclear Ni(II) cores, in which the imidazole dicarboxylate ligands adopt the similar coordination mode. The thermal properties of 1 and 2 have been investigated. Also, it is discovered that there exists antiferromagnetic coupling between the Ni(II) ions in 1 and 2; the best fittings to the experimental magnetic susceptibilities gave J = ? 9.89 cm^? 1 and g = 2.18 for 1, and J = ? 10.54 cm^? 1 and g = 2.14 for 2.     

Syntheses,crystal structures,and magnetism of two phenylacetate imidazolate copper(II) complexes

The influence of pH for the reaction system involving CuCl₂?·?2H₂O, imidazole (Him) and phenylacetic acid (HL) at room temperature was investigated. Cu₂(Him)₄L₄?·?2H₂O (1) and Cu₃(Him)₂(im)₂L₄ (2) were synthesized at pH 6.5 and 7.5, respectively. In 1, the Cu is coordinated by two nitrogen atoms of two Him and three oxygen atoms from three phenylacetates to form a square pyramid CuN₂O₃. Adjacent square pyramids share edges to form Cu₂N₄O₄ dimers, which are assembled by hydrogen bonds into a 2-D layer parallel to the (001) plane. In 2, copper atoms are interlinked by im^? and L^? to form a 2-D layer parallel to (100). The resulting layers have C–H···O hydrogen bonds leading to a 3-D supramolecular architecture. Variable temperature magnetism of 1 and 2 suggests a weak ferromagnetic or antiferromagnetic coupling exchange (J?=?0.58?cm^?1 for 1, J?=??10.24?cm^?1 for 2).     

Four Zn(II)/Cd(II) coordination polymers derived from isomeric benzenedicarboxylates and 1,6-bis(triazol)hexane ligand: synthesis,crystal structure,and luminescent properties

Four coordination polymers, [Zn(o-bdc)(bth)_0.5(H₂O)] _n (1), [Cd(o-bdc)(bth)_0.5(H₂O)] _n (2), [Zn(m-bdc)(bth)] _n (3), and [Cd(p-bdc)(bth)?·?(H₂O)₂] _n (4) (where o-bdc?=?1,2-benzenedicarboxylate, m-bdc?=?1,3-benzenedicarboxylate, p-bdc?=?1,4-benzenedicarboxylate, and bth?=?1,6-bis(triazol)hexane), have been hydrothermally synthesized and structurally characterized. Both 1 and 2 are isostructural, featuring two binodal architectures: (6³)(6⁵·8) topology in terms of o-bdc and Zn^II/Cd^II as three- and four-connected nodes. Complex 3 shows a 2-D (4,4) network with the Zn?···?Zn?···?Zn angle of 57.84°, whereas 4 exhibits planar 2-D (4,4) network. These 2-D networks of 3 and 4 are extended by supramolecular interactions, such as CH?···?π/π–π stacking and hydrogen-bonding into 3-D architecture. A structural comparison of these complexes demonstrates that the dicarboxylate building blocks with different dispositions of the carboxyl site play a key role in governing the coordination motifs as well as 3-D supramolecular lattices. Solid-state properties such as photoluminescence and thermal stabilities of 1–4 have also been studied.