Hybrid Structures Formed by Lead 1,3-Cyclohexanedicarboxylates

Solvo-thermal synthesis of a unique alkaline earth-transition Ba-Cd micro-porous coordination framework as hetero-metallic luminescent sensor for Cu2+ and real-time detection of benzaldehyde

In this work a unique hetero-metallic alkaline earth-transition Ba-Cd luminescent micro-porous metal-organic framework {[BaCd(μ₆-tp)_1.5(μ₂-Cl)(H₂O) (DMF)₂]·0.75H₂O}_n (H₂tp=terephthalic acid) (1) has been prepared under solvo-thermal conditions. In 1 infinite 1D {Ba-X-Cd} (X=O, Cl) inorganic chains are linked via these full de-pronated tp^2- ligands forming a unique 3D I¹O² type micro-porous coordination framework. PXRD patterns of 1 have been determined confirming pure phases of 1. Luminescence investigations suggested that 1 exhibits highly selective and sensitive sensing for trace amounts of benzaldehyde in ethanol, which provides a facile method for real-time detection of benzaldehyde. Meanwhile 1 also exhibits highly selective and sensitive sensing for Cu²⁺ over other cations with high quenching efficiency K_sv value 1.15×10⁴L·mol^-1. As far as we know, 1 represents the first example of alkaline earth-transition hetero-metallic Ba-Cd micro-porous coordination framework as bi-functional luminescent probes for Cu²⁺ and benzaldehyde.

Heterometallic Alkaline Earth-Lanthanide Ba(II)-La(III) Microporous Metal-Organic Framework as Bifunctional Luminescent Probes of Al(3+) and MnO4(.)

In this work a rigid asymmetrical tricarboxylate ligand p-terphenyl-3,4″,5-tricarboxylic acid (H3L) has been employed, and a unique heterometallic alkaline earth-lanthanide microporous luminescent metal-organic framework (MOF) {[Ba3La0.5(μ3-L)2.5(H2O)3(DMF)]·(3DMF)}n (1·3DMF) (DMF = dimethylformamide) has been isolated under solvothermal conditions. Single-crystal X-ray structural analysis demonstrates that 2D inorganic Ba-O-La connectivity can be observed in 1, which are further bridged via rigid terphenyl backbones of L(3-), forming a unique I(2)O(1)-type microporous luminescent framework. A 1D microporous channel with dimensionality of 9.151(3) Å × 10.098(1) Å can be observed along the crystallographic a axis. PXRD patterns have been investigated indicating pure phases of 1. The luminescence explorations demonstrated that 1 exhibits highly selective and sensitive sensing for Al(3+) over other cations with high quenching efficiency Ksv value of 1.445 × 10(4) L·mol(-1) and low detection limit (1.11 μM (S/N = 3)). Meanwhile 1 also exhibits highly selective and sensitive sensing for MnO4(-) over other anions with quenching efficiency Ksv = 7.73 × 10(3) L·mol(-1) and low detection limit (0.28 μM (S/N = 3)). It is noted that, when different concentrations of MnO4(-) solutions (0.5 to 100 μM) were dropped into the suspension of 1, the bright blue luminescence of the suspension observed under UV light can gradually change into pink color, indicating visually luminescent sensing, which makes the detection process of MnO4(-) more convenient in practical. The result also reveals that 1 represents the first example of bifunctional heterometallic alkaline earth-lanthanide MOF-based luminescent probes for selectively detecting Al(3+) and MnO4(-) in the water solutions.

Inorganic–organic hybrid materials based on PbBr2 and pyridine–hydrazone blocks – structural and theoretical study

A new series of lead(ii) coordination polymers was generated from PbBr₂ and various pyridine–hydrazone blocks; their detailed structural, topological and theoretical analysis was performed.

Synthesis, structure and catalytic application of lead(II) complexes in cyanosilylation reactions

Hydrothermal reactions of a lead(II) salt with 3-aminopyrazine-2-carboxylic acid (HL1) gave rise to a series of lead(II) coordination compounds (1–6) having zero, one, two and three dimensional structures. X-ray diffraction structural analyses reveal that complexes [Pb(L1)2]2 (1) and [Pb(L1)(OCHNH2)(η-OCHO)]2 (2) possess dinuclear structures, containing a centre of symmetry. Complexes [Pb2(L1)4(NHMeCHO)2]n (3) and [Pb2(L1)4]n·(H2O)n·(2.5DMF)n (4) have 1D chain like structures, and [Pb5(L1)7(η-NO3)(μ-HCOO)(η-HCOO)]n·(DMF)n·(MeOH)n (5) shows a 2D sheet like structure constructed by the [Pb5O5(HCOO)] cluster and 3-aminopyrazine-2-carboxylate anions. The hydrothermal reaction of lead(II) nitrate with HL1 in DMF led to in situ formation of 3,3′-(methylenebis(azanediyl))bis(pyrazine-2-carboxylic acid) [H2L2] which produces the 3D framework [Pb2(L2)2]n·(2DMF)n·(H2O)n (6). The L1(−) and L2(2−) ligands bind the metal cations by means of a pyrazine N-atom and one, or both, carboxylate O-atoms. The carboxylate group of L1(−) presents a diversity of coordination modes, viz., monodentate (1 and 3), bridging μ2 (3) and bridging μ3 (4), monodentate bridging μ2 (1, 2, 4, 5 and 6) and bridging chelate μ2 (5). The carboxylate moiety of L2(2−) in 6 binds the metal in a bridging μ2 fashion. The Pb(II) ions display coordination numbers from 5 to 8 with hemi- or holodirected coordination environments. The Pb(II) complexes act as heterogeneous catalysts for the cyanosilylation reaction, at 15 °C, of different aldehydes with trimethylsilyl cyanide (TMSCN) and can be recycled at least three times without losing activity.

A rare I2O3 hybrid organic–inorganic material with high connectivity and quadruple-stranded helices

A novel I²O³ hybrid material with one Cd–OH helix, two quadruple-stranded Cd–ligand helices and a (5,14-c) topological net was assembled.

A three-dimensional Pb(II) coordination framework: poly[[μ4-(E)-2,2'-(diazene-1,2-diyl)dibenzoato]dimethanollead(II)]

In the title coordination polymer, [Pb(C14H8N2O4)(CH3OH)2]n, the asymmetric unit contains half of a Pb(II) cation, half of a 2,2'-(diazene-1,2-diyl)dibenzoate dianionic ligand (denoted L(2-)) and one methanol ligand. Each Pb(II) centre is eight-coordinated by six O atoms of chelating/bridging carboxylate groups from four L(2-) ligands and two O atoms from two terminal methanol ligands, forming a distorted dodecahedron. The [PbL2(MeOH)2] subunits are interlinked via the sharing of two carboxylate O atoms to form a one-dimensional [PbL2(MeOH)2]n chain. Adjacent chains are further connected by L(2-) ligands, giving rise to a two-dimensional layer, and these layers are bridged by L(2-) linkers to afford a three-dimensional framework with a 4(12)6(3) topology.

Hybrid vanadates constructed from extended metal–organic arrays: crystal architectures and properties

Classification of inorganic–organic vanadates constructed from bridging ligands based on the metal–organic and inorganic substructures dimensionalities.

Synthesis, characterization and properties of a family of lead(ii)–organic frameworks based on a multi-functional ligand 2-amino-4-sulfobenzoic acid exhibiting auxiliary ligand-dependent dehydration–rehydration behaviours

A simplified representation of the architectures and auxiliary ligand-dependent dehydration–rehydration behaviours of 1–4.

Incorporation of spin-5/2 chain into 2D network with conformational pure e,a-cis-cyclohexane-1,4-dicarboxylato linker

A two-dimensional coordination network, (2)(∞)[Fe(III) (OH)(e,a-cis-1,4-chdc)] (1,4-chdc: cyclohexane-1,4-dicarboxylate), featuring one-dimensional iron(III)-hydroxy chains that are transversely bridged by 1,4-chdc in its pure e,a-cis conformation have been isolated. The magnetic study shows a typical spin-5/2 Heisenberg chain above 20 K, but canted antiferromagnetic ordering at lower temperatures.

catena-Poly[[diaquaterbium(III)]-tetrakis(μ2-pyridine-4-carboxylato-κ2O:O′)-[diaquaterbium(III)]-bis(μ2-pyridine-4-carboxylato-κ2O:O′)]

The title complex, [Tb₂(C₆H₄NO₂)₆(H₂O)₄]_n, was isolated under hydro­thermal conditions using the ligand pyridine-4-carb­oxy­lic acid (HL) and Tb₂O₃. The deprotonated L²⁻ ligands adopt bridging coordination modes. The central Tb^III atom is bridged by L²⁻ ligands, forming a polymeric chain parallel to the a axis. Supra­molecular O—H⋯N inter­actions link the chains, building up a layer parallel to (010). O—H⋯O hydrogen bonds also occur. Two of the pyridine rings are disordered by rotation around the central C—N direction with occupancy ratios of 0.53 (1):0.47 (1).