Crystal structure of catena-DI(2-thiobarbiturato-O,S)aqualead(II)

The crystal structure of catena-di(μ₂-2-thiobarbiturato-O,S)aqualead(II) C₈H₈N₄O₅S₂Pb (C₄H₄N₂O₂S is 2-thiobarbituric acid, H₂TBA) is determined. Crystallographic data for catena-[Pb(H₂O)(μ₂-HTBA-O,S)₂] are as follows: a = 6.5972(1) Å, b = 9.8917(2) Å, c = 10.0893(2) Å, α = 106.702(1)°, β = 93.395(2)°, γ = 107.48(1)°, V = 593.82(2) ų, space group $P\bar 1$ , Z = 2. The Pb²⁺ ion is linked with six monodentate HTBA^? ligands through two O atoms and four S atoms and also connected with a water molecule. Additionally, there is a shortened Pb-S contact (3.622 Å), given which the complex polyhedron represents a distorted square antiprism. Hydrogen bonds N-H…O and O-H…O form a branched three-dimensional network. The structure is also stabilized by the π-π interaction of heterocyclic HTBA^? ions.     

Influence of alkyl substituents in 1,3-diethyl-2-thiobarbituric acid on the coordination environment in M(H2O)2(1,3-diethyl-2-thiobarbiturate)2 M = Ca2+, Sr2+

Two new isostructural complexes, [Ca(H₂O)₂(μ₂-Detba-O,O′)₂]_n (1) and [Sr(H₂O)₂(μ₂-Detba-O,O′)₂]_n (2) (HDetba = 1,3-diethyl-2-thiobarbituric acid), were synthesized and characterized by single-crystal and powder X-ray diffraction analysis, TG-DSC, FT-IR, and emission spectroscopy. The single-crystal X-ray diffraction data revealed that 1 and 2 are polymeric where M²⁺ (M = Ca, Sr) is a six-coordinate octahedral binding four Detba^? ions and two water molecules. The octahedra are linked through bridging Detba^? ions forming a 2-D layer. Two intermolecular hydrogen bonds O–H…S in the crystal form a 3-D net. The comparison of M(Detba)₂ and M(Htba)₂ (H₂tba = 2-thiobarbituric acid) structures showed that the coordination number of metals in M(Detba)₂ does not exceed six and there are no π–π interactions, unlike compounds with Htba^?; Detba^? ions are only bridges in HDetba coordination compounds. Thermal decomposition of 1 and 2 includes dehydration, which mainly ends at 200 °C, and organic ligand oxidation at 300–350 °C with a release of CO₂, SO₂, H₂O, NH₃, and isocyanate. Upon excitation at 220 nm, 1 and 2 exhibit an intense emission maximum at 557 nm.     

Synthesis,crystal structure,and properties of a μ3-oxo-trichromium(III) propionate cluster with pyrazole

A new μ₃-oxo trinuclear chromium(III) propionate cluster, [Cr₃(μ₃-O)(O₂CCH₂CH₃)₆(pyr)₃]NO₃·0.25(H₂O) (1), has been synthesized by reaction of a μ₃-oxo trinuclear chromium(III) propionate precursor [Cr₃(μ₃-O)(O₂CCH₂CH₃)₆(H₂O)₃]NO₃ with a pyrazol ligand (pyr) and characterized by IR spectroscopy, single-crystal X-ray structure determination, and thermal analysis. Magnetic susceptibility and magnetization studies revealed antiferromagnetic exchange interactions within the trinuclear Cr(III) cluster (J = ?11.9 cm^?1) and determined the electronic ground state (S = ½) of the compound.     

Structural diversity for three Zn(II) coordination polymers from 4-nitrobenzene-1,2-dicarboxylate and bispyridyl ligand

Three Zn(II) complexes, [Zn₂(bpp)₂(FNA)₂]·H₂O (1), [Zn(bpp)(FNA)]·H₂O (2), and Zn₂(bpp)₂(FNA)₂ (3) (bpp = 1,3-bi(4-pyridyl)propane, H₂FNA = 4-nitrobenzene-1,2-dicarboxylic acid), were synthesized and characterized by single-crystal and powder X-ray diffraction methods, IR spectroscopy, TG analyses, elemental analyses, and fluorescent analysis. In 1, the Zn(II) ions are linked by FNA anions and bpp into 2-D layers. The Zn(II) ions in 2 are bridged by FNA anions into chiral chains, which are interlinked by bpp into 3-D metal–organic framework with (6⁵·8) CdS topology. Complex 3 features 1-D zigzag chains, which are interconnected by bpp ligands to give a 3-D framework with (6·7⁴·8)(6⁴·7·8) topology. Complexes 2 and 3 exhibit significant ferroelectric behavior (for 2 remnant polarization Pr = 0.050 μC cm^?2, coercive field Ec = 1.13 kV cm^?1, saturation of the spontaneous polarization Ps = 0.239 μC cm^?2; for 3 Pr = 0.192 μC cm^?2, Ec = 4.64 kV cm^?1, Ps = 0.298 μC cm^?2).     

Structures of bis(2-thiobarbiturato-O)tetraaquamagnesium and catena-[(μ2-2-thiobarbiturato-O,O)(2-thiobarbiturato-O) bis(μ2-aqua)diaquastrontium] monohydrate

The crystal structures of bis(2-thiobarbiturato-O)tetraaquamagnesium Mg(H₂O)₄(HTBA-O)₂ I and catena-[(μ₂-2-thiobarbiturato-O,O)(2-thiobarbiturato-O)bis(μ₂-aqua)diaquastrontium] monohydrate catena-[Sr(μ₂-H₂O)₂(H₂O)₂(μ₂-HTBA-O,O)(HBTA-O)] _n · nH₂O (II), where H₂TBA is 2-thiobarbituric acid C₄H₄N₂O₂S, have been determined. Crystal data for a=6.7598(2) Å, b = 7.6060(2) Å, c = 8.5797(2) Å, α = 79.822(2)°, β = 76.622(1)°, γ = 69.124(1)°, V = 398.82(2) ų, space group P $\bar 1$ , Z = 1; for II: a = 20.8499(4) Å, b = 19.2649(5) Å, c = 4.14007(9) Å, β = 92.023(2)°, V = 1661.91(7) ų, space group P2₁/n, Z = 4. The Mg²⁺ ion in I is bonded to six O atoms of two HTBA^? ions and four water molecules that form a nearly regular octahedron. Each Sr²⁺ ion in II is coordinated to three oxygen atoms of three HTBA^? ions and six water molecules that form an almost ideal tricapped trigonal prism. These polyhedra share edges to form infinite chains. Intermolecular hydrogen bonds create layered structures of I and II.     

Bridging behaviour of the 2‐thiobarbiturate anion in its complexes with LiI and NaI

The structures of the Li^I and Na^I salts of 2‐thiobarbituric acid (2‐sulfanylidene‐1‐3‐diazinane‐4,6‐dione, H₂TBA) have been studied. μ‐Aqua‐octaaquabis(μ‐2‐thiobarbiturato‐κ²O:O′)bis(2‐thiobarbiturato‐κO)tetralithium(I) dihydrate, [Li₄(C₄H₃N₂O₂S)₄(H₂O)₉]·2H₂O, (I), crystallizes with four symmetry‐independent four‐coordinated Li^I cations and four independent HTBA⁻ anions. The structure contains two structurally non‐equivalent Li^I cations and two non‐equivalent HTBA⁻ anions (bridging and terminal). Eight of the coordinated water ligands are terminal and the ninth acts as a bridge between Li^I cations. Discrete [Li₄(HTBA)₄(H₂O)₉]·2H₂O complexes form two‐dimensional layers. Neighbouring layers are connected via hydrogen‐bonding interactions, resulting in a three‐dimensional network. Poly[μ₂‐aqua‐tetraaqua(μ₄‐2‐thiobarbiturato‐κ⁴O:O:S:S)(μ₂‐thiobarbiturato‐κ²O:S)disodium(I)], [Na₂(C₄H₃N₂O₂S)₂(H₂O)₅]_n, (II), crystallizes with six‐coordinated Na^I cations. The octahedra are pairwise connected through edge‐sharing by a water O atom and an O atom from the μ₄‐HTBA⁻ ligand, and these pairs are further top‐shared by the S atoms to form continuous chains along the a direction. Two independent HTBA⁻ ligands integrate the chains to give a three‐dimensional network.     

Group III quinaldates: synthesis,structure and photoluminescence

The reactions of Al(III), Ga(III) and In(III) nitrates with 2-quinaldic acid (qaH) afforded [Al₂(OH)₂(qa)₄]·2H₂O (1), [Ga(qa)₂(H₂O)₂]NO₃ (2) and [In(qa)₂(NO₃)(H₂O)] (3), respectively, in high yields. The crystal structures of 1, 2 and 3 have been determined by single-crystal X-ray crystallography. The structure of 1 features a di-hydroxo bridged [Al₂(μ-OH)₂]⁴⁺ dimer in which each Al(III) is further ligated by two bidentate chelate qa^? ligands. Complexes 2 and 3 are mononuclear with the M(III) ions in octahedral environments surrounded by two bidentate chelate qa^? and two H₂O in 2 or one H₂O and a terminal NO₃^? in 3. Characteristic IR as well as thermal analysis and solid-state fluorescence are discussed.     

Homo- and heterometallic complexes based on polytopic carboxylic acid: synthesis,characterization, and property

Two heterometallic [K₄M₄(HL)₄(H₂O)₁₂] (M=Co (1), Ni (2)) and two homometallic [M₂L(H₂O)₇]?·?2H₂O ((M=Co (3), Ni (4)) (H₄L?=?(2-(bis(carboxymethyl)amino) terephthalic acid) have been synthesized and characterized by elemental analysis, FT-IR spectrum, and single-crystal X-ray diffraction. The isomorphous 1 and 2 contain K⁺ and M²⁺, in which K⁺ were bridged with M²⁺ through μ-HL^3? and μ-H₂O, leading to 2-D layer structures. The isomorphous 3 and 4 show homometallic binuclear complexes with μ-HL^3? as the bridging ligand. Various H-bonds including different H-bond helical chains form, by which 3 and 4 assemble into 3-D supramolecular frameworks. TG analysis indicates that the decomposition temperatures are [K₄M₄(HL)₄(H₂O)₁₂] (1)?>?[M₂L(H₂O)₇]?·?2H₂O (3)?>?H₄L.     

A sandwich-type POM containing mixed cations: synthesis,thermal performance and proton-conducting properties

A new sandwich-type polyoxometalate, Na₅H[N(CH₃)₄]₂[Co(C₃N₂H₄)₂(H₂O)₄][Co₄(H₂O)₂(PW₉O₃₄)₂]·21H₂O (1), has been synthesized. 1 is composed of a Weakley-type polyanion, [Co₄₍H₂O)₂(PW₉O₃₄)₂]^10?, four kinds of cations (five Na⁺, two [N(CH₃)₄]⁺, one [Co(C₃N₂H₄)₂(H₂O)₄]²⁺, and one H⁺), and 21 crystalline H₂O molecules. The surface oxygen of the polyanion in 1, the crystalline water, and coordinated water molecules make an extended 3-D hydrogen-bonding network. Alternating current (AC) impedance experiments of 1 reveal good proton conductivity for 1 of 5.03 × 10^??4 S cm^?1 at 25 °C under 98% relative humidity (RH). Activation energy of 1 calculated from Arrhenius plots is 0.358 eV, indicating Grotthuss mechanism is dominant in the proton transfer. Thermal decomposition behavior of 1 was examined by thermogravimetry/mass spectrometry (TG/MS) measurements.     

Two cadmium(II) addition compounds with 3-hydroxy-2,7-naphthalenedisulfonate containing aromatic diamines and their 3-D net

{[CdCl(2,2′-bipy)₂(H₂O)]⁺·[Cd(3-O^?-2,7-NDS)(2,2′-bipy)₂]^?·3H₂O} (1) and {[Cd(phen)₃]²⁺·2[Cd(3-O^?-2,7-NDS)(phen)₂]^?·8.5H₂O} (2) (3-OH-2,7-NDS?=?3-hydroxy-2,7-naphthalenedisulfonate, phen?=?1,10-phenanthroline, and 2,2′-bipy?=?2,2′-bipydine) were prepared and characterized by X-ray single-crystal diffraction. Compound 1 contains a discrete coordination cation [CdCl(2,2′-bipy)₂(H₂O)]⁺ and a coordination anion [Cd(3-O^?-2,7-NDS)(2,2′-bipy)₂]^?; 2 contains a discrete coordination cation [Cd(phen)₃]²⁺ and two coordination anions [Cd(3-O^?-2,7-NDS)(phen)₂]^?. There are numerous weak interactions among the coordination cation, coordination anion, and free water molecules, such as O–H?···?O hydrogen bonds, π?···?π stacking, and Cl^??···?π interactions in 1 and π?···?π stacking and C–H?···?π interactions in 2. The cations and anions as building blocks are connected to construct different 3-D supramolecular architectures via weak intermolecular interactions. Particularly, the capsule structure of 1 was observed.     

The assembly of POM-induced inorganic–organic hybrids based on copper ions and mixed ligands

Three inorganic–organic hybrid materials based on Keggin-type polyoxometalates (POMs), [Cu^II₂(phen)₂(4,4′-bipy)(H4,4′-bipy)₂(H₂O)₂][PMo₁₂O₄₀]₂·2H₂O (1), [Cu^II(phen)₂(H4,4′bipy)][PW₁₂O₄₀]·H₂O (2), and [Cu^II₂(phen)₂(4,4′-bipy)(BW₁₂O₄₀)(H₂O)₂](H₂4,4′-bipy)_0.5·3H₂O (3) (phen = 1,10-phenanthroline, 4,4′-bipy = 4,4′-bipyridine), were synthesized using different POMs in the hydrothermal conditions. Compounds 1–3 were characterized by single-crystal X-ray diffraction, IR spectra, elemental analyses, powder X-ray diffraction analyses, and thermogravimetric analyses. Compound 1 presents a two-dimensional (2-D) network containing the Keggin-type [PMo₁₂O₄₀]^3? anion and dinuclear metal–organic units [Cu^II₂(phen)₂(4,4′-bipy)(H4,4′-bipy)₂(H₂O)₂]³⁺. Compound 2 is a 2-D architecture constructed from a [PW₁₂O₄₀]^3? and mononuclear metal–organic units [Cu^II(phen)₂(H4,4′-bipy)]³⁺. In 3, the [BW₁₂O₄₀]^5? anions link [Cu^II₂(phen)₂(4,4′-bipy)] units to form a one-dimensional (1-D) chain [Cu^II₂(phen)₂(4,4′-bipy)(BW₁₂O₄₀)(H₂O)₂]; the 1-D chain connects with protonated 4,4′-bipy ligands and lattice waters, yielding a 2-D layer. Fluorescence spectra, UV–vis spectra, and electrochemical properties of 1–3 have been investigated.     

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.     

Self-assembly of 1-D, 2-D,and 3-D transition-metal coordination polymers based on a T-shaped tripodal ligand 4-(4,5-dicarboxy-1H-imidazol-2-yl)pyridine 1-oxide

Three coordination polymers, {[Co(C₁₀H₅N₃O₅)(H₂O)₂]·H₂O}_n (1), {[Mn₃(C₁₀H₅N₃O₅)₂Cl₂(H₂O)₆]·2H₂O}_n (2), and {[Cu₃(C₁₀H₄N₃O₅)₂(H₂O)₃]·4H₂O}_n (3), based on a T-shaped tripodal ligand 4-(4,5-dicarboxy-1H-imidazol-2-yl)pyridine 1-oxide (H₃DCImPyO), were synthesized under hydrothermal conditions. The polymers showed diverse coordination modes, being characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray structure analysis. In 1, the HDCImPyO^2? generated a 1-D chain by adopting a μ₂-kN, O : kN′, O′ coordination mode to bridge two Co(II) ions in two bis-N,O-chelating modes. In 2, the HDCImPyO^2? adopted a μ₃-kN, O : kO′, O′′ : O′′′ coordination mode to bridge two crystallographically independent Mn(II) ions, forming a 2-D hcb network with {6³} topology. In 3, by adopting μ₄-kN, O : kO′, O′′ : kN′′, O′′′ : O′′′′ coordination, DCImPyO^3? bridged three crystallographically independent Cu(II) ions to form a 3-D framework having the stb topology.     

Syntheses,structures, and properties of three MOFs based on tertbutylphenyl imidazole dicarboxylate

By hydrothermal reactions of a newly designed ligand, 2-(p-tert-butylphenyl)-1H-imidazole-4,5-dicarboxylic acid (H₃BuPhIDC) with Cd(II) or Zn(II), three metal-organic frameworks, [Cd(μ₃-HBuPhIDC)(H₂O)]·2H₂O (1), [Cd(μ₃-HBuPhIDC)(4,4′-bipy)_0.5] (4,4′-bipy = 4,4′-bipyridine) (2), and [Zn₂(μ₃-HBuPhIDC)₂(CH₃OH)₂] (3), have been obtained and characterized by elemental analyses, IR spectroscopy, and single-crystal X-ray diffraction. In 1, small countless diamond grids form a mesh structure and then are bridged through μ₃-HBuPhIDC^2? linkers building a 3-D framework. Compared with 1, 4,4′-bipy participates in the construction of a 3-D structure of 2. Polymer 3 shows an interesting 3-D open architecture, which contains infinite 1-D octagonal channels built by left- and right-handed helical chains. Thermal and solid-state photoluminescence properties of the polymers have been investigated.     

Crystal structure of polymer hexaaqua-hexakis(2-thiobarbiturato)dieuropium(III)

Complex [Eu₂(HTBA)₆(H₂O)₆] _n (I), where H₂TBA is 2-thiobarbituric acid C₄H₄N₂O₂S, is synthesized. Its structure is determined by X-ray diffraction analysis (CIF file CCDC 987519). The crystals of complex I are monoclinic: a = 14.1033(4) Å, b = 10.0988(4) Å, c = 15.4061(5) Å, β = 110.003(1)°, V = 2061.9(1) ų, space group P2/n, Z = 2. All three independent ligands HTBA^? are coordinated to Eu³⁺ through oxygen atoms. Six HTBA^? ions (two terminal and four bridging) and two water molecules are coordinated to one of the independent Eu³⁺ ions. The second Eu³⁺ ion is bound to four bridging HTBA^? ions and four water molecules. The coordination polyhedra are square antiprisms. The bridging HTBA^? ions join the antiprisms into layers. The structure is stabilized by numerous hydrogen bonds and the π-π interaction between HTBA^?.     

Synthesis and anticancer property of one Ce(III) compound based on 5-(2-pyrazinyl)tetrazole-2-acetic acid

Mononuclear [Ce(pztza)₂(H₂O)₆](pztza)·H₂O (1) (pztza = 5-(2-pyrazinyl)tetrazole-2-acetato) has been prepared and characterized by IR, elemental analysis and single-crystal X-ray diffraction. PEG_-5000 (poly(ethyleneglycol_-5000)) coated [Ce(pztza)₂(H₂O)₆](pztza)·H₂O nanoparticles (NPs) can disperse into distilled water. In vitro study on Hela cells shows that Hpztza is nontoxic while [Ce(pztza)₂(H₂O)₆](pztza)·H₂O NPs show high toxicity with half-maximal inhibitory concentration (IC₅₀) of 17 μg/mL (1.93 × 10^?5 M). In addition, such NPs can inhibit the migration of Hela cells effectively.     

New Zn(II) complexes based on biologically active substituted acetic acid and nitrogen donor ligands: synthesis,crystal structure and biological applications

The complexes [Zn(phenylacetato)₂(2-aminopyridin)₂] (3), [Zn(phenylacetato)₂(1,10-phenanthroline)]·H₂O (4), and [Zn(phenylacetato)₂(2,9-dimethyl-1,10-phenanthroline)]·0.5 H₂O (5) were prepared and characterized by IR-, UV–Visible, ¹H and ¹³C NMR spectroscopy, and single crystal X-ray diffraction. BNPP hydrolysis of the complexes and their parent nitrogen ligands showed that the hydrolysis rate of bis-(4-nitrophenyl) phosphate (BNPP) was 1.7 × 10⁵ L mol^?1 s^?1 for 3, 3.1 × 10⁵ L mol^?1 s^?1 for 4 and 4.3 × 10⁴ L mol^?1 s^?1 for 5. Antibacterial activities show the effect of complexation on activity against Gram-positive (S. epidermidis, S. aureus, E. faecalis, M. luteus and B. subtilis) and Gram-negative (K. pneumonia, E. coli, P. mirabilis and P. aeruginosa) bacteria using the agar well diffusion method. Complex 4 showed good activity against G? bacteria except P. aeruginosa, and against G+ bacteria except E. ferabis. Complex 5 showed no activity against G? bacteria, low activity against M. luteus and B. subtilis bacteria and high activity against S. epidemidis and S. aureus. Complex 3 did not show any activity against G? or G+ bacteria.     

Mononuclear and binuclear lanthanide(III) complexes: syntheses,structural, photophysical and thermal properties

Six new Ln(III) complexes viz., [Gd(tptz)(SCN)₃(CH₃OH)₂OH₂]·CH₃OH (1), [Eu(tptz)(SCN)₃(CH₃OH)₂OH₂]·CH₃OH (2), [Tb(tptz)(SCN)₃(OH₂)₃]₄ (3), [Gd(tptz)(OBz)₂(μ-OBz)OH₂]₂·2H₂O (4), [OH₂(OBz)₂(tptz)Eu₁(μ-OBz)₂Eu₂(tptz)(OBz)₂OH₂]·CH₃OH·7H₂O (5), and {[Tb₁(tptz)(OBz)₂(μ-OBz)]₂·[Tb₂(tptz)(OBz)₃CH₃OH]₂}·2CH₃OH·4H₂O (6) (Ln = Gd, Eu, Tb; tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine; BzONa = sodium benzoate), have been synthesized and characterized by physicochemical methods including single-crystal X-ray crystallography. The X-ray studies demonstrate that 1–3 are mononuclear, whereas 4–6 are binuclear. The photophysical properties of 1–6 have been studied with ultraviolet absorption and emission spectral studies. Their thermal properties have been studied by thermogravimetric (TG) and derivative thermogravimetric analysis (DTG), demonstrating that the final product after decomposition was Ln₂O₃ for all these complexes.     

Self-assembly and crystal structures of coordination polymers constructed by 4′-hydroxyisoflavone-3′-sulfonates with Cs(I) and Rb(I)

Four coordination polymers, [CsL1(H₂O)₂]·H₂O (1), [CsL2(H₂O)₂]·H₂O (2), [Rb₂(L2)₂(H₂O)₂]·2H₂O (3) and [RbL3(H₂O)] (4), were synthesized by Cs(I), Rb(I) and 4′-hydroxyisoflavone-3′-sulfonates L1–L3 [L1 = 7-methoxy-4′-hydroxyisoflavone-3′-sulfonate, L2 = 7-ethoxy-4′-hydroxyisoflavone-3′-sulfonate, L3 = 7-ethoxy-4′,5-dihydroxyisoflavone-3′-sulfonate]. The crystal structures of 1–4 were determined by single-crystal X-ray diffraction. The influences of 4′-hydroxyisoflavone-3′-sulfonate ligands and Cs⁺, Rb⁺ on their structural features and self-assembly were investigated. The sulfonates of L1–L3 not only coordinate with Cs⁺ or Rb⁺ directly, but also bridge the organic region and the inorganic region in 1–4. Non-covalent interactions such as coordination interaction, π–π stacking interaction and hydrogen bonding assembled 1–4 into 3-D networks together with the electrostatic interactions between Cs⁺, Rb⁺ and the sulfonate anions.     

Calcium coordination compounds based on phenoxyacetic acids: microwave synthesis,thermostability and influences on the crystal structures of chlorine substituent group on ligands

Three calcium coordination compounds, [Ca(CPA)(H₂O)₄]·(CPA), 1, [Ca(MCPA)₂(H₂O)₂]·H₂O, 2, and [Ca(TCPA)₂(H₂O)₃]·2H₂O, 3 [HCPA = 3-chlorophenoxyacetic acid, HMCPA = 2-methyl-4-chlorophenoxyacetic acid, and HTCPA = 2,4,6-trichlorophenoxyacetic acid], have been synthesized by the microwave method with advantages that include shorter reaction times, lower energy consumption, and higher product yield. The structures have been characterized by IR, elemental analysis, and single-crystal X-ray diffraction. Influences on the crystal structures by changing the number and position of chlorine substituent group in phenoxyacetic acid are discussed. Steric hindrance effects involving the Cl and an ability to form the O–H?Cl hydrogen bonds enrich the structure diversity. TG analysis reveals that the thermostability for the three compounds is 3 > 1 > 2, which could be influenced by the existence of hydrogen bonds (O–H?Cl and O–H?O).