1–D Framework l-arginine zinc(II) units bridged by oxalate: synthesis,structure, properties,and theoretical studies

We synthesized a l-arginine containing Zn²⁺ complex and oxalate ions. {[Zn₂(l-Arg)₂(ox)₂]·8H₂O}_n (1) (l-Arg =l-arginine, ox = oxalate) crystallize in the monoclinic space group P2₁ with a = 8.979(2), b = 9.840(2) (Å), c = 18.509(3) (Å), β = 95.58(3) (Å), V = 1627.6(6) ų, and Z = 2. The zinc centers are six-coordinate via one l-arginine zwitterion and two bridging oxalates. The binuclear [Zn₂(l-Arg)₂(ox)₂] units are linked via oxalate and form 1-D “stair-like” linear chains. The complex was characterized using FT-IR, FT-Raman, UV–vis spectroscopy, and thermal analysis techniques, as well as DFT methods. Electronic bands above 31,000 cm^?1 originate in ^1,3A_u (n→π*) transitions within oxalate ions. Theoretical studies were performed for the model compound {[Zn(l-Arg)(Hox)₂]·4H₂O} using the fragment of the crystallographic structure of 1. The interaction energy (ΔE) values for l-arginine and two oxalate ions are comparable at -145 kcal mol^?1. Natural bond orbital (NBO) analysis of the electronic structure and bonding is also discussed.     

Synthesis,characterization and crystal structure of a chiral polymeric Cu(II) complex bridged by tartrate

A chiral metal-organic coordination polymer, [Cu(Tar)(2,2′-bipy) · 5H₂O] (1) (Tar = L-tartrate dianion, 2,2′-bipy = 2,2′-bipyridine), has been synthesized by hydrothermal reaction of Cu(OAc)₂, Na₂T (H₂T = 2,3-O-isopropylidene-L-tartaric acid) and 2,2′-bipyridine, and characterized by IR, UV–vis spectra, elemental analyses, TG-DTA, and single crystal X-ray diffraction. In the hydrothermal reaction, the protection group isopropylidene for tartaric acid was hydrolyzed. The crystal structure of the coordination polymer 1 shows that each tartrate chelates two Cu(II) ions at opposite ends using one carboxylate oxygen and one hydroxyl oxygen and each Cu(II) ion is chelated by two halves of tartrate dianions, forming coordination polymer chains. Distorted octahedral geometry around copper is completed by a chelating 2,2′-bipyridine molecule. The 2,2′-bipyridine groups in two of parallel 1-D chains are interwoven, constituting ladder-shaped double chains. Strong offset π–π stacking interactions with a face-to-face distance of 3.33 Å for pyridine rings are observed. All the lattice water molecules hydrogen-bond to each other or to the carbonyl oxygen of tartrate, forming a 3-D supramolecular structure.     

Synthesis,Characterization and Crystal Structure of a Ternary Cu(II) Complex with 1,10-Phenanthroline and l-Leucinate

The complex [Cu(l-Leu)(phen)(H₂O)]NO₃ has been synthesized and characterized by elemental analysis, molar conductivity, spectroscopic and X-ray diffraction methods, where phen = 1,10-phenanthroline and l-Leu = l-leucinate. The complex crystallizes in the triclinic space group Pī with two molecules in a unit cell of dimensions a = 7.288(4) Å, b = 11.588(7) Å, c = 12.349(3) Å, α = 86.388(10)^o, β = 76.175(11)°, γ = 72.132(3)°, V = 963.8(10) ų, Z = 2, D _c = 1.564 g/cm³, μ = 1.177 mm^?1, F(000) = 470, R ₁ = 0.0611, and wR ₂ = 0.0711. The copper(II) is ligated in a distorted square-pyramidal geometry by the two nitrogen atoms of phen and the amino nitrogen atom and one carboxylate oxygen atom from each independent l-Leu moiety in the basal plane, and one water oxygen at the apical position. A supramolecular configuration is formed from strong phen-phen stacking interactions between neighboring [Cu(l-leu)(phen)(H₂O)]⁺cations in the crystal.     

Formation of 1-D ladder- and 2-D sheet-like networks due to stereospecific π–π stacking and hydrogen bonding between enantiomeric sulfur-bridged dinuclear complexes of penicillaminates

Reaction of trans(N)-[Co(D-pen)₂]^? (pen = penicillaminate) or trans(N)-[Co(L-pen)₂]^? with [MCl₂(L)] {M = Pd or Pt, L = 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen)} in the presence of tetrafluoroborate stereoselectively gave an optically active S-bridged dinuclear complex, [M(L){Co(D-pen)₂}]BF₄ · 2H₂O or [M(L){Co(L-pen)₂}]BF₄ · 2H₂O. The mixture of equimolar amounts of these enantiomers in H₂O crystallizes as [M(L){Co(D-pen)₂}]_0.5[M(L){Co(L-pen)₂}]_0.5BF₄ · 4H₂O (DLbpyM · 4H₂O, DLphenM-A · 4H₂O), in which the enantiomeric complex cations are included by the ratio of 1 : 1. In crystals of DLbpyM · 4H₂O and DLphenM-A · 4H₂O, [M(L){Co(D-pen)₂}]⁺ and [M(L){Co(L-pen)₂}]⁺ interact stereospecifically with each other through π-conjugated systems to form dimeric structures. Other racemic crystals with the same chemical compositions as DLphenM-A · 4H₂O, DLphenM-B · 4H₂O, were obtained from equimolar amounts of [M(phen){Co(D-pen)₂}]⁺ and [M(phen){Co(L-pen)₂}]⁺ in aqueous acetonitrile solution. In the crystals of DLphenM-B · 4H₂O, [M(phen){Co(D-pen)₂}]⁺ and [M(phen){Co(L-pen)₂}]⁺ are arranged alternately while overlapping phen planes, and the π electronic systems of phen interact with each other. Although stereospecific hydrogen bonds between the coordinated ?NH₂ and ?COO^? groups are formed in both DLphenM-A · 4H₂O and DLphenM-B · 4H₂O, their bonding modes differ noticeably from each other. As a result, DLphenM-A · 4H₂O builds up 1-D ladder-like networks due to the stereospecific π–π stackings and hydrogen bondings between enantiomers, while 2-D sheet-like networks are established for DLphenM-B · 4H₂O.     

Synthesis and crystal structures of two rare-earth metal polymers of olsalazine

Two 1-D linear coordination polymers, {[Gd₂(L)₂ · (Phen)₂ · 2(H₂O) · 2(NO₃)] · 2(EtOH)} _n (1) (H₂L = olsalazine) and {[Eu₂(L)₂·(Phen)₂ · 2(H₂O) · 2(NO₃)] · EtOH} _n (2), were obtained from self-assembly of Gd(NO₃)₃ · 8H₂O or Eu(NO₃)₃ · 8H₂O with olsalazine. Both complexes are 1-D polymers, for 1 with crystal data: P 1, a = 11.651(4), b = 11.865(4), and c = 12.296(4) Å, α = 77.984(4)°, β = 65.559(4)°, and γ = 74.558(5)°, V = 1482.1(8) ų, Z = 1, R ₁ = 0.0389, wR ₂ = 0.0793, and 2 with crystal data: P 1, a = 11.626(3), b = 11.834(3), c = 12.287(4) Å, α = 77.743(3), β = 65.576(3), γ = 74.371(3)°, V = 1472.5(5) ų, Z = 1, R ₁ = 0.0609, wR ₂ = 0.1185. Central atoms (Gd or Eu) in both complexes adopt nine-coordinate tricapped trigonal prism geometry. CCDC No.: 694918 (1), 694919 (2).     

Synthesis of metal-organic frameworks from the system metal/L-glutamic acid/TEA/H2O

Three metal-organic frameworks (MOFs) with similar zeolite-like 3-D structures, Zn(L-Glu)(H₂O) · H₂O, Cu(L-Glu)(H₂O) · H₂O, and Co(L-Glu)(H₂O) · H₂O, have been obtained from metal/L-glutamic acid/TEA/H₂O systems, whereby the weak base triethylamine (TEA), rather than the more typically used NaOH or Na₂CO₃, has been used to adjust the pH of the solution. A systematic and detailed exploration of the synthesis conditions has revealed that not all transition metals may be coordinated to L-glutamic acid and that the range of conditions under which the three MOFs remained stable was different. The metal/L-glutamic acid/TEA/H₂O system offers an effective means of obtaining MOFs.     

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

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

Syntheses and structures of three chiral complexes derived from nucleophilic addition of L-proline to di-2-pyridyl ketone

In the presence of nickel acetate, a chiral ligand, (S)-Hdphp ((S)-N-[di(2-pyridyl)-hydroxy-methyl]-proline), was synthesized in situ by nucleophilic addition of L-proline to di-2-pyridyl ketone. Based on this ligand, three chiral mononuclear complexes, {Ni[(S)-dphp](DMF)(H₂O)}(ClO₄) (1), {Ni[(S)-dphp](H₂O)₂}(ClO₄)(H₂O)_1.5 (2), and {Ni[(S)-dphp](SCN)(H₂O)} (3), have been obtained and characterized by single-crystal X-ray diffraction, elemental analyses, and infrared spectra. By virtue of charge-assisted O–H?···?O hydrogen-bonding interactions, all the complexes possess double chain structures. The double chains were connected into 2-D networks via π?···?π stacking and CH?···?π interactions in 1. For 2, O–H?···?O hydrogen-bonding interactions between free water molecules and other oxygens as well as π?···?π stacking and CH?···?π interactions extend the chains into a 3-D network. Complex 3 exhibits 3-D structure via O–H?···?S interactions.     

Stereospecific interactions through π -conjugated systems of sulfur-bridged dinuclear Co(III)-Pd(II) and Co(III)-Pt(II) complexes of optically active penicillaminates

The reaction of trans(N)-[Co(D-pen)₂]^? (pen = penicillaminate) or trans(N)-[Co(L-pen)₂]^? with [MCl₂(L)] (M = Pd or Pt, L = 2,2′-bipyridine (bpy) or 4,4′-dimethyl-2,2′-bipyridine (dmbpy)) stereoselectively gave an optically active S-bridged dinuclear complex, [M(L){Co(D-pen)₂}]Cl · 3H₂O or [M(L){Co(L-pen)₂}]Cl · 3H₂O. The mixture of equimolar amounts of these two enantiomers in H₂O crystallizes as [M(L){Co(D-pen)₂}]_0.5[M(L){Co(L- pen)₂}]_0.5Cl · nH₂O (1cCl · 7H₂O: M = Pd, L = bpy, n = 7; 2cCl · 7H₂O: M = Pd, L = dmbpy, n = 7; 3cCl · 6H₂O: M = Pt, L = dmbpy, n = 6), in which the enantiomeric complex cations are included in the ratio of 1 : 1. In the crystals of 1cCl · 7H₂O, [Pd(bpy){Co(D-pen)₂}]⁺ (1a) and [Pd(bpy){Co(L-pen)₂}]⁺ (1b) are arranged alternately while overlapping the bpy planes along the a axis, and the π electronic systems of bpy moieties interact with each other. This is quite a contrast to the optically active 1aCl · 3H₂O or 1bCl · 3H₂O, which exist as monomers without intermolecular interactions. In crystals of 2cCl · 7H₂O and 3cCl · 6H₂O, similarly, the two enantiomeric complex cations interact with each other through the dmbpy frameworks. However, the interplane distances between the stacked π systems in these dmbpy complexes are considerably longer than in the bpy complexes. Such structural characteristics significantly reflect their diffuse reflectance spectra.     

Coordination polymer incorporating cobalt(II) and glycine acid: structure and magnetism

We report the structure and magnetism of a cobalt(II) compound with glycine acid, Co(C₂H₄NO₂)₂ · H₂O (1). It crystallizes in the orthorhombic system, space group P2(1)2(1)2(1) with a = 5.2301(10) Å, b = 10.837(2) Å, c = 13.542(3) Å, R ₁ = 0.0448, wR ₂ = 0.1151. In 1, Co(II) has a slightly distorted square-pyramidal geometry defined by two O atoms and two N atoms from two glycine ligands, and by one O atom from an aqua ligand in the apical position. The molecules form a three-dimensional supramolecular network through O–H ··· O and N–H ··· O hydrogen bonds. Magnetic characterization shows 1 exhibits a negative Curie–Weiss constant and dominant spin-orbit coupling for Co(II).     

Synthesis and X-Ray Structure of New Copper(II) Nitrates: Cu(NO3)2 · H2O and β-modification of Cu(NO3)2

Blue crystals of a Cu(NO₃)₂ · H₂O were synthesized by interaction of CuO with boiling 100% HNO₃. Stable β-Cu(NO₃)₂ modification was obtained by the sublimation of copper(II) nitrate in evacuated ampoule over the 150→100°C temperature gradient for 24 hr. According to X-Ray single crystal analysis Cu(NO₃)₂ · H₂O is monoclinic with a = 6.377(1), b = 8.548(1), c = 9.769(1) Å, β = 100.41(1)°, Z = 4, and space group P2₁/c. β-modification Cu(NO₃)₂ is orthorhombic with a = 14.161(5), b = 7.516(3), c = 12.886(2) Å, Z = 12, and space group Pbcn. In the both structures Cu atoms are square coordinated by 4 O atoms at the distances ranging from 1.92 to 2.02 Å. In each structure there are also additional Cu? O bonds with the distance of 2.33 or 2.35 Å and some weaker ones with the distances in the range of 2.65–2.72 Å. In the Cu(NO₃)₂ · H₂O structure the [CuO₄] squares are connected by the bridging NO₃ groups into zigzag chains, which are linked into layers by the longer Cu? O bonds. In the β-Cu(NO₃)₂ structure the [CuO₄] fragments of two types are joined by the bridging NO₃ groups in a three-dimensional framework. Some correlations were found between N? O distances and coordination functions of O atoms.     

A 1-D ladder-like aggregate constructed from Preyssler anion and transition metal linkers

A 1-D ladder-like aggregate, K₂Na₆[Na(H₂O)Fe₂(H₂O)₈(P₅W₃₀O₁₁₀)] · 23.5H₂O (1; K₂Na₆[1a] · 23.5H₂O) has been obtained by conventional aqueous solution reaction. X-ray diffraction analysis reveals that 1 crystallizes in the monoclinic system, space group P 2 ₁ /m, a = 16.938(3) Å, b = 21.396(4) Å, c = 17.520(4) Å, β = 98.14(3)°, V = 6285(2) ų, and Z = 2. Polyoxoanion 1a shows a 1-D ladder-like chain, built up of Preyssler anion and Fe³⁺ linkers, which represents the first extended structure based on Preyssler anion and transition metal linkers. The 1-D chains in 1 are further connected into a 3-D open framework by potassium and sodium cations. Compound 1 displays electrocatalytic activity towards the reduction of nitrite.     

Cd(II) and Cu(II) coordination polymers based on a multidentate N-donor ligand: syntheses,crystal structures,optical band gaps,and photoluminescence

Four Cd(II)- and Cu(II)-containing coordination polymers (CPs) based on a multidentate N-donor ligand and varied dicarboxylate anions, [Cd(3,3′-tmbpt)(p-bdc)]·2.5H₂O (1), [Cd(3,3′-tmbpt)(m-bdc)]·2H₂O (2), [Cu(3,3′-tmbpt)(m-bdc)]·H₂O (3), and [Cu(3,3′-tmbpt)(p-bdc)]·2H₂O (4), where 3,3′-tmbpt = 1 ? ((1H-1,2,4-triazol-1-yl)methyl)-3,5-bis(3-pyridyl)-1,2,4-triazole, p-H₂bdc = 1,4-benzenedicarboxylic acid, and m-H₂bdc = 1,3-benzenedicarboxylic acid, have been prepared hydrothermally. The structures of the compounds were determined by single-crystal X-ray diffraction analyses and further characterized by infrared spectra and elemental analyses. Compound 1 exhibits a 3-D twofold interpenetrating framework with a 6⁵·8 CdSO₄ topology. Compound 2 is a 2-D layer containing meso-helical chains with a 4⁴·6² sql topology. Compound 3 shows a 1-D → 3-D interdigitated architecture while 4 displays a 2-D → 3-D interdigitated architecture. The structural differences of the compounds indicate that the dicarboxylate anions and the central metal ions play important roles in the resulting structures of CPs. Optical band gaps and solid-state photoluminescent properties have also been studied.     

Syntheses and structures of two copper coordination polymers with bis (1,2,4-triazol-1-ylmethyl)benzene and benzenedicarboxylate

Two copper coordination polymers [Cu(obtz)(bdc)] _n (1) and {[Cu(obtz)(phth)] · 2H₂O} _n (2) (obtz = 1,2-bis(1,2,4-triazol-1-ylmethyl)benzene, bdc = 1,3-benzenedicarboxylate, phth = 1,4-benzenedicarboxylate) were synthesized and characterized. Both 1 and 2 are 2-D networks constructed via the bridging ligands bdc and phth. The obtz ligands do not extend the dimension (2-D network) but add their thickness, 10.9 Å for 1 and 11.6 Å for 2. Complex 1 further constructs a 3-D network via π?π stacking interactions between the benzene rings of obtz ligands of adjacent 2-D networks. The thermal stabilities have been investigated.     

Synthesis,Crystal Structure and DNA Cleavage Activity of a Ternary Copper(Ⅱ)Complex of Dipyrido[3,2-d:2',3'-f]-quinoxaline and Glycine

A ternary copper(II) complex, [Cu(Dpq)(Gly)(H₂O)]·NO₃·1.5H₂O (Dpq=dipyrido[3,2‐d:2′,3′‐f]quinoxaline, Gly=glycine), has been synthesized and structurally characterized. The complex crystallized in a triclinic system with space group P‐1, a=6.6979(9) Å, b=7.6351(10) Å, c=18.980(2) Å, α=85.815(2) °, β=88.182(2) °, γ=71.203(2) °. The five‐coordinate copper(II) center is a distorted square pyramid. Absorption spectra, fluorescence spectra and CD spectra showed that there were interactions between the copper complex and DNA through a groove binding mode. The complex exhibited efficient DNA cleavage activity at micromolar concentration in the presence of ascorbate with hydroxyl radicals as the active species.     

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.     

Synthesis,Crystal Structure,and Magnetic Properties of {[Cu(phen)]2(C4H2O4)2} · 4.5H2O with C4H4O4 = Maleic Acid

Reaction of CuCl₂ · 2H₂O, phenanthroline, maleic acid and NaOH in CH₃OH/H₂O (1:1 v/v) at pH = 7.0 yielded blue {[Cu(phen)]₂(C₄H₂O₄)₂} · 4.5H₂O, which crystallizes in the monoclinic space group C2/c (no. 15) with cell dimensions: a = 18.127(2)Å, b = 12.482(2)Å, c = 14.602(2)Å, β = 103.43(1)°, U = 3213.5(8)ų, Z = 4. The crystal structure consists of the centrosymmetric dinuclear {[Cu(phen)]₂(C₄H₂O₄)₂} complex molecules and hydrogen bonded H₂O molecules. The Cu atoms are each square‐pyramidally coordinated by two N atoms of one phen ligand and three carboxyl O atoms of two maleato ligands with one carboxyl O atom at the apical position (d(Cu‐N) = 2.008, 2.012Å, equatorial d(Cu‐O) = 1.933, 1.969Å, axial d(Cu‐O) = 2.306Å). Two square‐pyramids are condensed via two apical carboxyl O atoms with a relatively larger Cu···Cu separation of 3.346(1)Å. The dinuclear complex molecules are assembled via the intermolecular π—π stacking interactions into 1D ribbons. Crossover of the resulting ribbons via interribbon π—π stacking interactions forms a 3D network with the tunnels occupied by H₂O molecules. The title complex behaves paramagnetically between 5—300 K, following the Curie‐Weiss law _χm(T—θ) = 0.435 cm³ · mol^—1 · K with θ = 1.59 K.     

Crystal structure and properties of a Cu(II) complex with the tridentate Schiff-base ligand,paeonol-(2-aminoethylpiperazine)

A new copper Schiff-base complex [Cu(C₁₅H₂₃N₃O₂)(NO₃)]NO₃ was synthesized and characterized by spectroscopic (IR), thermal (TG/DTA) and electrochemical methods. Single crystal X-ray diffraction revealed that the complex is monoclinic, space group P2(1)/c, with a = 23.549(2), b = 6.583(12), c = 12.765(15) Å, β = 102.823(2)°, V = 1929.4(5) ų, Z = 4, D _calcd = 1.601 Mg m^?3, F(000) = 964, goodness-of-fit = 1.034 and R ₁ = 0.0407. The Cu(II) is four-coordinate with distorted square planar geometry. The structure consists of isolated [Cu(C₁₅H₂₃N₃O₂)(NO₃)]⁺ and a nitrate, which are further linked to a 3D network by significant N–H ··· O, N–H ··· N hydrogen bonds and weak O ··· Cu interaction.     

Synthesis,crystal structure,and magnetic properties of a salt containing [Cu2Cl7]3− and 4-nitrobenzyl-4′-dimethylaminopyridinium

A new salt, [NO₂BzDMAP]₃[Cu₂Cl₇]?·?H₂O (1), has been synthesized, where [NO₂BzDMAP]⁺ is 1-(4′-nitrobenzyl)-4-dimethylaminopyridinium. Herein, the synthesis, spectral and structural characterization, and magnetic behavior of 1 are reported. It is orthorhombic, with space group Pca2₁, and a?=?26.639(2)?Å, b?=?9.638(1)?Å, and c?=?20.011(2)?Å with V?=?5137.5(7)?ų for Z?=?4. The anion shows a chloride-bridged binuclear structure with Cu?···?Cu distance of 3.872?Å; the two Cu(II) ions have a tetrahedral geometry. The cations stack through p?···?π and π?···?π interactions, and a complicated hydrogen-bonding network structure is formed through C–H?···?Cl and C–H?···?O hydrogen bonds. The variable temperature magnetic susceptibility measurements reveal that 1 exhibits strong antiferromagnetic interaction with J?=??193.0?cm^?1.     

Three double- or triple-stranded chains constructed from different cobalt(II) salts and a flexible bis-triazole ligand

Three coordination compounds, {[Co(btrp)₂(H₂O)₂]?·?NO₃?·?H₂O} _n (1), {[Co(btrp)₂(H₂O)₂]?·?H₂O?·?2H₂btc} _n (2), and {[Co(btrp)₃]?·?2ClO₄} _n (3) (btrp?=?1,3-bis(1,2,4-triazol-1-yl)propane; H₃btc?=?benzene-1,3,5-tricarboxylic acid), have been prepared via solvothermal method and characterized by single-crystal X-ray diffraction and elemental analyses. Compound 1 possesses a 1-D double-stranded chain composed of ribbons of 20-membered cycles. Binuclear water clusters link adjacent nitrate anions to form a 1-D supramolecular helix in the structure. Compound 2 has a 1-D double-stranded chain wherein free H₂btc ligands constitute 1-D negative chains through classical hydrogen-bonding interactions (O–H?···?O). Compound 3 exhibits a triple-stranded 1-D chain. For 1–3, 3-D supramolecular structures are consolidated by interchain weak hydrogen-bonding interactions as well as electrostatic interactions.