Syntheses and characterization of four coordination compounds derived from 10,11,12,13-tetrahydro-4,5,9,14-tetraaza-benzo[b]triphenylene and benzene-dicarboxylic acids

[Co₂(TTBT)₄(1,2-BDC)₂] _n ?·?4nH₂O (1), [Pb₂(TTBT)₂(1,3-BDC)₂] _n ?·?nTTBT?·?2nH₂O (2), [Fe(TTBT)(1,4-BDC)(H₂O)] _n (3), and [Zn(TTBT)(1,4-BDC)(H₂O)] _n (4) have been hydrothermally synthesized by self-assembly of TTBT (TTBT?=?10,11,12,13-tetrahydro-4,5,9,14-tetraaza-benzo[b]triphenylene), benzene-dicarboxylic acid ligands 1,2-H₂BDC, 1,3-H₂BDC or 1,4-H₂BDC (1,2-H₂BDC?=?1,2-benzenedicarboxylic acid, 1,3-H₂BDC?=?1,3-benzenedicarboxylic acid, 1,4-H₂BDC?=?1,4-benzenedicarboxylic acid), and various metal salts. Compound 1 has dinuclear cluster units, four dimeric Co₂ units connected to form a 32-membered ring via weak offset π–π interactions, which are further stacked via strong π–π interactions to form a 3-D supramolecular framework. Complex 2 contains 2-D layers with rhombohedral grids, which are connected to a 3-D structure by π–π interactions. 3 and 4 feature 1-D infinite chains, which are further extended by strong π–π interactions and O–H···O hydrogen bonds resulting in 3-D supramolecular architectures. The photoluminescent properties of 2 and 4 have also been investigated.     

Lead(II) coordination frameworks with 3-fluorophthalic acid: hydrothermal synthesis,crystal structure,and luminescence

Hydrothermal reactions of Pb(NO₃)₂ and 3-fluorophthalic acid (H₂Fpht) in the absence or presence of 2,2′-bipyridine (bpy) gave two coordination polymers: Pb₅(Fpht)₄(Fba)₂ (1) and [Pb₂(Fpht)₂(bpy)(H₂O)]·3H₂O (2). The 3-fluorobenzoic acid (HFba) results from an in situ decarboxylation of H₂Fpht. Solid 1 displays a 2-D structure, comprising center-related hexanuclear [Pb₃(COO)₆]₂ units. There are three crystallographically different Pb(II) ions and two different ligands, Fpht and Fba. The Fpht ligands adopt μ_6?:?η⁵η³ and μ_6?:?η³η⁴ unusual bridging coordination modes. A 3-D supramolecular architecture is formed via C–H?F hydrogen bonds. Solid 2 possesses a 1-D chain structure, comprising center-related tetranuclear [Pb₂(COO)₄]₂ units. There are two crystallographically different Pb(II) ions. The Fpht ligands adopt μ_3?:?η²η³ and μ_4?:?η³η³ bridging coordination. The free water molecules form (H₂O)₃ clusters to link the 1-D chain by hydrogen bonds. A 3-D supramolecular assembly is constructed via hydrogen bonds between the free water and the F of Fpht ligands. Fluorescence of the complexes originates from π*–π transitions of the ligands.     

Two lead coordination polymers with nitrilotriacetic acid and oxydiacetic acid: synthesis,characterization, and crystal structure

Two lead coordination compounds [Pb₂(nta)]NO₃ (1) and [Pb(oda)] (2) have been synthesized by slow evaporation or hydrothermal conditions using nitrilotriacetic acid (nta) and 2,2′-oxydiacetic acid (oda) as ligands, respectively. Their structures were determined by single-crystal X-ray diffraction and further characterized by X-ray powder diffraction, infrared absorption spectrum, and thermogravimetric analysis. Compound 1 is a 2-D honeycomb-like layer structure with (6,3) topology. When the bonding limit of Pb–O extends from 2.76 to 2.90 Å, potential weak Pb–O bonds can be found in 1, and the 2-D layer structure can be further linked to generate a 3-D 4-connected supramolecular sra net with the (4².6³.8) Schläfli symbol. Compound 2 contains a 1-D infinite Pb–O chain which is connected through µ₃-, µ₄-, and µ₅-coordination modes of oda to form a new 3-D structure.     

Synthesis and crystal structures of two lead(II) complexes of 4,4,4-trifluoro-1-naphthyl-1,3-butanedione ligand,subtle interplay of weak intermolecular interactions

[Pb₂(tfnb)₄ (µ-CH₃OH)] _n (1) and [Pb₂(dmp)₂(tfnb)₄] (2) (tfnb and dmp are the abbreviations for 4,4,4-trifluoro-1-naphthyl-1,3-butanedionate and 2,9-dimethyl-1,10-phenanthroline) have been synthesized and characterized by elemental analysis, IR, ¹H NMR spectroscopy, and thermal analysis. The single-crystal structure of 1 shows that the complex forms two 1-D polymeric networks containing four types of Pb²⁺ with coordination numbers seven for Pb(1) and Pb(3), five for Pb(2), and six for Pb(4). The single-crystal structure of 2 shows that the complex forms a dinuclear complex with eight-coordinate Pb(II). The supramolecular features in this complex are guided by lone-pair activity and the control of weak directional intermolecular interactions and aromatic π–π stacking interactions.     

PbCu3(OH)(NO3)(SeO3)3·1/2H2O und Pb2Cu3O2(NO3)2(SeO3)2: Synthese und Kristallstrukturuntersuchung

Crystals of PbCu₃(OH)(NO₃)(SeO₃)₃·1/2H₂O [a=7.761(3)Å,b=9.478(4)Å,c=9.514(4)Å, =66.94(2)°, =69.83(2)°, =81.83(2)°, space group P ,Z=2] and Pb₂Cu₃O₂(NO₃)₂(SeO₃)₂ [a=5.884(2)Å,b=12.186(3)Å,c=19.371(4)Å, space group Cmc2₁,Z=4] were synthesized under hydrothermal conditions. Their crystal structures were refined with three-dimensional X-ray data toR _w=0.033 resp. 0.055. In PbCu₃(OH)(NO₃)(SeO₃)₃·1/2H₂O the Cu atoms are [4+1] and [4+2] coordinated and via SeO₃ groups a three-dimensional atomic arrangement is built up. In Pb₂Cu₃O₂(NO₃)₂(SeO₃)₂ there are sheets, which are connected only via Pb-O bonds ranging from 2.98 Å to 3.16 Å.

     

A Pb2+-based coordination polymer with 5-(1H-tetrazol-5-yl)isophthalic acid ligand: structure and photoluminescence

A coordination polymer, [Pb₂(OH)(tzia)]·2H₂O (1), has been prepared by solvothermal reaction of 5-(1H-tetrazol-5-yl)isophthalic acid (H₃tzia) and Pb(NO₃)₂. The polymer 1 is based on an unprecedented centrosymmetric tetranuclear [Pb₄(OH)₂(COO)₄(ttaz)₂] cluster linked by a multidentate tzia ligand, affording a 2-D 3,6-connected kgd layer. The adjacent layers are further jointed by Pb?O interactions to form a 3-D supramolecular framework with a rare (3,8)-connected tfz-d; UO₃ topology. Photoluminescent properties of H₃tzia, 1, and 1-desolvated have been further investigated, and it was interesting to find that 1-desolvated due to the removal of lattice water molecules reveals stronger photoluminescence than 1.     

Isomeric organic ligand dominating polyoxometalate-based hybrid compounds: synthesis and as electrocatalysts and pH-sensitive probes

By introducing isomeric organic ligands into polyoxometalate (POM) systems, two new POM-based hybrid compounds, [Cu₆(m-pyttz)₂(H₂O)][HPMo₁₂O₄₀] (1) and [Ag₃(p-H₂pyttz)(p-Hpyttz)Cl][H₂PMo₁₂O₄₀]·6H₂O (2) (m-/p-H₂pyttz = 3-(pyrid-3/4-yl)-5(1H-1,2,4-triazol-3-yl)-1,2,4-triazolyl), have been hydrothermally synthesized and characterized. Single-crystal structural analysis shows the m-pyttz ligands link Cu^I ions to generate a two-dimensional layer with hanger-like rhombus, which is pillared by the PMo₁₂ anions in 1. Compound 2 exhibits a three-dimensional supramolecular framework, in which PMo₁₂ anions are building blocks facilitating the extension of the whole structure. The influence of the coordination modes of m-/p-H₂pyttz on the structures is discussed in detail. Furthermore, electrochemical properties of 1 and 2 have been studied and they display excellent electrocatalytic activities toward the reduction of nitrite and hydrogen peroxide and pH-dependent electrochemical behaviors.     

Syntheses,structures, and properties of four coordination compounds constructed from asymmetric semi-rigid V-shaped multicarboxylate ligand

Four new compounds, [Mn(HL)(phen)₂(H₂O)] (1), [Ni(HL)(phen)₂(H₂O)] (2), [Zn(HL)(4,4′-bipy)_1.5(H₂O)] _n ?·?2nH₂O (3) and [Zn₂(HL)₂(H₂O)₆] (4), have been synthesized from an asymmetric semi-rigid V-shaped multicarboxylate 4-(4-carboxy-phenoxy)-phthalic acid (H₃L) with 1,10-phenanthroline (phen), or 4,4′-bipyridine (4,4′-bipy) as auxiliary ligands. Single-crystal X-ray diffraction analysis reveals that 1, 2 and 4 have 0-D structures with 3-D supramolecular frameworks formed by intermolecular hydrogen bonds. Compound 3 shows a 1-D infinite ribbon bridged by 4,4′-bipy, which further forms a 3-D supramolecular architecture by π–π stacking interactions and hydrogen bonds. Thermal stabilities of 1–4 and luminescence properties of 3 and 4 have also been investigated.     

In Situ: 2-D Inorganic Layer Lead-MOF Built from [(<Emphasis Type="Italic">μ</Emphasis><Subscript>4</Subscript>-O)Pb<Subscript>4</Subscript>] Core

In situ lead-MOF derived from 2-Methyl-3-acetylnaphtho[2,3-b]furan-4,9-dione (MAFD), [Pb₇O₂(OH)₂(1,2-BDC)₄(H₂O)] 1, 1,2-BDC = C₆H₄(COOH)₂, phthalic acid, has been synthesized and characterized by elemental analysis, IR, TG-DTA, powder X-ray diffraction (XRD) and single crystal X-ray diffraction. Compound 1 possesses 2-D inorganic layer structure built from rare tetranuclear unit [(μ ₄-O)Pb₄]. In 1, both crystallographic distinct Pb(1) and Pb(4) ions adopt six-coordination geometry, and the other two crystallographic distinct Pb(2) and Pb(3) ions display eight-coordination geometry under the condition of Pb–O bond length extended to 3.10 Å. A 3-D supramolecular network is also formed by hydrogen bonds (C–H···O). Result of photoluminescence measurement indicates an emission band at 385 nm (λ _excitation = 209 nm).     

The rigid isomeric 5-(x-pyridyl)-1H-tetrazole ligands-directed various isopolymolybdate-based compounds: assembly,structures, and properties

Two new isopolymolybdate-based metal–organic complexes, [Cu₂(2-ptz)₂(Mo₄O₁₄)_0.5] (1) and [Cu₃(OH)₂(3-ptz)₄(γ-H₄Mo₈O₂₆)(H₂O)₄]·10H₂O (2) (2-ptzH = 5-(2-pyridyl)-1H-tetrazole, 3-ptzH = 5-(3-pyridyl)-1H-tetrazole), constructed from isomeric ligands with different N-donor sites were synthesized under hydrothermal conditions. In 1, each [Mo₄O₁₄]^4? cluster connected with six neighboring [Mo₄O₁₄]^4? clusters through six binuclear [Cu₂(2-ptz)₂]²⁺ subunits to yield a 2-D layer. In 2, bidentate inorganic [Mo₈O₂₆]^4? anions link the trinuclear [Cu₃(OH)₂(3-ptz)₄] clusters to construct a 1-D chain. Adjacent chains connect through Mo–N bonds between the [Mo₈O₂₆]^4? anions and pyridyl groups from the trinuclear clusters to form a 2-D layer. The effect of the N-donor sites of the rigid isomeric ligands on the structures of 1 and 2 was discussed. The electrochemical properties and photocatalytic activities of 1 and 2 have also been studied.     

Structures and magnetism of two manganese crowns assembled with 2,4-dihydroxyacetophenone oxime

Reactions of 2,4-dihydroxyacetophenone oxime with manganese salts yielded two manganese crowns, [Mn₃(μ ₃-O)(4-OH-Me-sao)₃(HCOO)(MeOH)₅]·MeOH (1) and [Mn₃(μ ₃-O)(4-OH-Me-sao)₃(CH₃COO)(MeOH)₅]·MeOH (2) (4-OH-Me-saoH₂=2,4-dihydroxyacetophenone oxime). Both compounds possess [Mn^III ₃(μ ₃-O)]⁷⁺ cores which contain 9-MC-3 metallacrown (MC) rings with the repeating pattern [–Mn–N–O–]. However, the difference in the structures of both compounds is coordinated carboxylates. In 1 and 2, the MC molecules are connected with each other through intermolecular hydrogen bonds, generating similar 3-D supramolecular networks. Magnetic properties reveal that in 1 and 2 the metal ions exhibit ferromagnetic exchange coupling.     

Syntheses and structures of two new lithium-heptamolybdates

The synthesis, crystal structures, IR, UV–vis, ⁷Li NMR spectra, electrochemical investigations, and conductivity studies of two new lithium-heptamolybdates, (NH₄)₄[Li₂(H₂O)₇][Mo₇O₂₄]·H₂O (1) and (NH₄)₃[Li₃(H₂O)₄(μ₆-Mo₇O₂₄)]·2H₂O (2), are reported. In 1 the (NH₄)⁺ and [Li₂(H₂O)₇]²⁺, cations are charge balanced by the heptamolybdate anion. In 2, the [Mo₇O₂₄]^6? anion is coordinated to three unique Li⁺ ions via a μ₆-hexadentate-binding mode resulting in the formation of a two-dimensional (2-D) [Li₃(H₂O)₄(μ₆-Mo₇O₂₄)]^3? anionic complex, charge neutralized by three (NH₄)⁺ ions. The cations, anions, and the lattice water molecules in 1 and 2 are linked by weak H-bonding interactions.     

两种3D微孔Zn-MOF对水溶液中Fe3+、Cr2O72-和丙酮分子的荧光传感

通过溶剂热法合成了2种三维微孔锌金属有机框架材料,其分子式为[Zn₃(DBA)(OH)(1,10-phen)₂]_n(1)和{[Zn₂(HDBA)(4,4''-bipy)_1.5]·H₂O}_n(2)(H₅DBA=3,5-二(2'',4''-对羧基苯基)苯甲酸;1,10-phen=1,10-菲咯啉;4,4''-bipy=4,4''-联吡啶)。结构分析表明,配合物1为三核锌基金属单元的三维微孔骨架,配合物2为双核锌基的微孔结构。与2相比,配合物1在水中具有较强的发光性能,可作为检测Fe³⁺、Cr₂O₇^2-和丙酮分子的发光传感器,具有较高的选择性和灵敏度。     

Three coordination polymers built from planar tetranuclear clusters and 5-sulfoisophthalic acid

Three coordination polymers built from planar tetranuclear clusters and H₃sip ligands, Pb₂Cl(sip)(bipy) (1), Pb₂Br(sip)(H₂O) (2), and Ni₄(sip)₂(pyz)₂(H₂O)₈(OH)₂·2H₂O (3) (H₃sip?=?5-sulfoisophthalic acid, bipy?=?2,2′-bipyridine, and pyz?=?pyrazine), have been hydrothermally synthesized and characterized by IR, TGA, and single-crystal X-ray diffraction. Compound 1 features a 2-D layer-like structure containing tetranuclear square [Pb₄(SO₃)₂] clusters. Complex 2 has a 3-D open framework architecture constructed from tetranuclear cluster [Pb₄Br₂(SO₃)₂] inorganic building blocks. The tetranuclear units, [Ni₄(OH)₂(COO)₄], in 3 are interlinked through carboxylates and µ₂-pyz ligands to generate a 2-D layer structure. The connecting modes between tetranuclear clusters and organic ligands in the three compounds are discussed in this article. In the solid state at room temperature, yellow photoluminescence in 1 and 2 are observed.     

Synthesis, Structure, and 31P NMR of Sulfur/Oxygen-Bridged Incomplete Cubane-Type Molybdenum and Tungsten Clusters with Triphenylphosphine Ligands

Sulfur/oxygen-bridged incomplete cubane-type triphenylphosphine molybdenum and tungsten-clusters [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃]·3THF (1A), [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃]·2THF (2A), [Mo₃OS₃Cl₄(H₂O)₂(PPh₃)₃]·2THF (1B), and [W₃S₄Cl₄(H₂O)₂(PPh₃)₃]·2THF (1C) were prepared from the corresponding aqua clusters and PPh₃ in THF/MeOH. On recrystallization from THF, procedures with and without addition of hexane to the solution gave 1A and 2A, respectively, while the procedures gave no effect on the formation of 1B and 1C. Crystallographic results obtained are as follows: 1A: monoclinic, P2₁/n, a=17.141(4) Å, b=22.579(5) Å, c=19.069(4) Å, =96.18(2)°, V=7337(3) ų, Z=4, R(R _w)=0.078(0.102); 1C: monoclinic, P2 ₁/c, a=12.635(1) Å, b=20.216(4) Å, c=27.815(3) Å, =96.16(1)°, V=7062(2) ų, Z=4, R(R _w)=0.071(0.083). If the phenyl groups are ignored, the molecule [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃] in 2A has idealized CS symmetry with the mirror plane perpendicular to the plane determined by the metal atoms, while the molecule in 1A does not have the symmetry. The tungsten compound 1C is isomorphous with the molybdenum compound 2A. ³¹P NMR spectra of 1A, 2A, and 1C were obtained and compared with similar clusters with dmpe (1,2-bis(dimethylphosphino)ethane) ligands.     

Synthesis,structures, and magnetic properties of two pyrazolato-bridged trinuclear copper(II) complexes

One nonlinear and one linear trinuclear copper(II) complex [Cu₃(dien)₂(pdc)₂CH₃OH]₂?·?6CH₃OH (1) and [Cu₃(pdc)₂(CH₃OH)₆(H₂O)₄] (2) were prepared and characterized structurally, where dien is diethylenetriamine and pdc^3? the trianion of 3,5-pyrazoledicarboxylic acid. Both complexes consist of 3,5-pyrazoledicarboxylato-bridged trinuclear copper(II) centers. In 1, copper(II) ions are five-coordinate in distorted square pyramids with bond angles 164.78° for Cu(1)–Cu(2)–Cu(3) and 164.51° for Cu(4)–Cu(5)–Cu(6). In 2, the three copper(II) ions are six-coordinate with elongated octahedral geometry. The trinuclear units of 1 and 2 interact through hydrogen bonds to form 3-D and 2-D supramolecular networks, respectively. Variable temperature magnetic susceptibility measurements show that 1 and 2 are antiferromagnetically coupled with J values of ?11.2 and ?13.3?cm^?1.     

Metal complexes of indole-3-acetic acid: synthesis,crystal structures,and Pb2+ chemosensing by cation-exchange reaction

Two binuclear complexes [Cu₂(IA)₄(DMSO)₂]·CH₃OH (1), [Cd₂(IA)₂(phen)₂I₂] (2), and one 1-D {[Pb₂(IA)₄]·CH₃OH}_n (3) (IAH = indole-3-acetic acid, phen = 1,10-phenanthroline) have been prepared and characterized by single crystal X-ray diffraction. Both 1 and 2 are binuclear wherein the central Cu ions are bridged by IA in 1, while Cd ions are bridged by I^? in 2. Complex 3 has a 1-D chain structure based on secondary building units (SBUs) of [Pb₂(IA)₄]. The three complexes show strong fluorescence emissions, and chemosensor behaviors for metal cations are investigated in mixed DMF/H₂O (1?:?9 v/v) solvent. The results reveal that 2 shows effective sensing to Pb²⁺. The mechanism of the detection to Pb²⁺ can be attributed to cation-exchange reaction between cadmium and lead ions.     

Thermochemistry of NaRb[B4O5(OH)4]·4H2O

The enthalpies of solution of NaRb[B₄O₅(OH)₄]·4H₂O in approximately 1 mol dm⁻³ aqueous hydrochloric acid and of RbCl in aqueous (hydrochloric acid + boric acid + sodium chloride) were determined. From these results and the enthalpy of solution of H₃BO₃ in approximately 1 mol dm⁻³ HCl(aq) and of sodium chloride in aqueous (hydrochloric acid + boric acid), the standard molar enthalpy of formation of −(5128.02 ± 1.94) kJ mol⁻¹ for NaRb[B₄O₅(OH)₄]·4H₂O was obtained from the standard molar enthalpies of formation of NaCl(s), RbCl(s), H₃BO₃(s) and H₂O(l). The standard molar entropy of formation of NaRb[B₄O₅(OH)₄]·4H₂O was calculated from the Gibbs free energy of formation of NaRb[B₄O₅(OH)₄]·4H₂O computed from a group contribution method.     

Two new Pb(II) coordination polymers derived from fatty dicarboxylates and phenanthroline derivatives: syntheses,structures, and properties

Two new Pb(II) coordination polymers, [Pb(3-pdip)(L₁)]?·?0.5H₂O (1) and [Pb(4-pdip)(L₂)] (2) [L₁?=?heptane diacid, L₂?=?hexane diacid, 3-pdip?=?2?-(3-pyridyl)imidazo[4,5-f]1,10-phenanthroline, 4-pdip?=?2?-(4-pyridyl)imidazo[4,5-f]1,10-phenanthroline], have been obtained from hydrothermal reactions of Pb(II) nitrate with two flexible fatty carboxylic acids and two phenanthroline derivatives. Single-crystal X-ray diffraction analysis reveals that 1 is a 1-D staircase-like double chain coordination polymer extended by binuclear [Pb₂N₄O₈] subunits and pairs of L₁ ligands. Compound 2 exhibits a 2-D (4,4) network based on bi-metallic [Pb₂N₆O₈] units and (L₂)₂/(4-pdip)₂ double linkers. Furthermore, adjacent chains of 1 and layers of 2 are extended into 3-D supramolecular networks by π–π stacking interactions between aromatic rings of phenanthroline groups. The organic carboxylic acids with different lengths show great influence on the shapes of Pb(II)-carboxylate double chains. Phenanthroline derivatives possessing different sites of N-donors (3-pyridyl and 4-pyridyl) determine the final coordination frameworks of 1 and 2. Photoluminescence and thermal stabilities of 1 and 2 were also investigated.     

Studies on synthesis, characterization and thermochemistry of Mg2[B2O4(OH)2]·H2O

A new magnesium borate Mg₂[B₂O₄(OH)₂]·H₂O has been synthesized by the method of phase transformation of double salt at hydrothermal condition and characterized by XRD, IR, TG and DSC. The enthalpy of solution of Mg₂[B₂O₄(OH)₂]·H₂O in 0.9764 mol L^–1 HCl was determined. With the incorporation of the enthalpies of solution of H₃BO₃ in HCl (aq), of MgO in (HCl+H₃BO₃) (aq), and the standard molar enthalpies of formation of MgO(s), H₃BO₃(s), and H₂O(l), the standard molar enthalpy of formation of –(3185.78±1.91) kJ mol^–1 of Mg₂[B₂O₄(OH)₂]·H₂O was obtained.This revised version was published online in November 2005 with corrections to the Cover Date.