Structures and photoluminescence of coordination polymers assembled from bifunctional ligand containing both tetrazole and imidazole groups

Three new coordination polymers, namely, {[Cu₂(IPT)(SO₄)(OH)(H₂O)]·H₂O}_n (HIPT = 5-(4-(1H-imidazol-1-yl)phenyl)- 1H-tetrazolate, 1), {[Cd₂(IPT)(NPA)(OH)]·H₂O}_n (H₂NPA = 5-nitroisophthalic acid, 2), and {[Zn₂(IPT)(IDC)(H₂O)]·3H₂O}_n (H₃IDC = 1H-imidazole-4,5-dicarboxylic acid, 3), were assembled from a bifunctional organic ligand containing both tetrazole and imidazole groups with/without the aid of carboxylate coligands. Compound 1 possesses 2D structure built by 1D [Cu₂(IPT)(SO₄)(OH)]_n secondary building blocks and IPT⁻ linkers. The 2D networks are linked into 3D supramolecular framework via water chains in helical conformation. Compound 2 displays 3D pillar-layer framework with 2D layers based on tetranuclear Cd(II) SBUs and NPA^2 − pillars. Compound 3 exhibits a 3D framework constructed from the interconnection of 1D [Zn-IDC]_n chains and binuclear Zn₂(IPT)₂ rings. The thermal stabilities of porous compound 3 and luminescent properties of compounds 2 and 3 have also been studied in detail. They exhibit intense solid-state fluorescent emissions at room temperature.     

Syntheses and structures of cadmium(II) and cobalt(II) coordination polymers based on 1,1′-(2,2′-oxybis(ethane-2,1-diyl))bis(1H-imidazole) and carboxylate ligands

Two novel coordination polymers containing Cd(II) and Co(II) metals, connected via 1,1′-(2,2′-oxybis(ethane-2,1-diyl))bis(1H-imidazole) (L) ligand, have been synthesized. Compound [Cd(L)₂(p-BDC)] · 2H₂O (1) (p-BDC = 1,4-benzenedicarboxylate anion) is a three-dimensional interdigitated supramolecular architecture. Compound [Co(L)(BTCA)_0.5] (2) (BTCA = 1,2,3,4-butanetetracarboxylate anion) possesses a unique (3,4)-connected 3D framework with (8³)₂(8⁵ · 10) topology.     

Inorganic anion-induced structural diversity and structural transformation in a metal-negative ligand system containing Cd(II) ion and naphthalene diimide ligand

The coordination of a new 1,4,5,8-naphthalenediimides-based ligand N,N-di-(5-tetrazol)-1,4,5,8-naphthalenetetracarboxydiimide (H₂dtNDI) with CdSO₄ afforded mixtures containing {[Cd(dtNDI)(DMF)_2.5]·DMAc}_n (1) and {[Cd₂(dtNDI)₂(DMAc)₂]·DMAc}_n (2) as components. Whereas the coordination of H₂dtNDI with CdX₂ (x = ClO₄⁻, NO₃⁻ and I⁻) afforded pure coordination polymer, namely, {[Cd(dtNDI)(H₂O)_2.5]·DMAc}_n (3). All the compounds contain binuclear M₂L₂ ring as secondary building block (SBU). Compound 1 is a 1D chain composed of the binuclear SBUs and dimeric Cd(II) MBBs. Compound 2 exhibit a 2D network with (4·8²) topology based on a binuclear SBUs. Compound 3 possess a five-fold interpenetrating 3D dia framework with tetrameric Cd(II) MBBs as nodes and binuclear SBUs as linkers. Although the inorganic anions are not appeared in the final frameworks of compounds 1–3, they play an important role in the structural formation during assembly process. In addition, the mixtures composed of compounds 1–2 can transfer to pure compounds 3 via solvent-mediated process.     

Syntheses,crystal structures and luminescent investigations of cobalt(II) and zinc(II) complexes with 2-propyl-4,5-dicarboxylate-imidazole (H3PIDC)

Presented in this communication are four metal complexes based on 2-propyl-4,5-dicarboxylate-imidazole (H₃PIDC), including two Co(II) coordination compounds, [Co(H₂PIDC)₂(H₂O)₂] · 4H₂O (1) and 2[Co(H₂PIDC)₂(H₂O)₂] · 5H₂O (2), as well as two Zn(II) coordination compounds, [Zn(H₂PIDC)₂(H₂O)₂] · 4H₂O (3) and 2[Zn(H₂PIDC)₂(H₂O)₂] · 7H₂O (4). They contain the same coordinated unit of [M(H₂PIDC)₂(H₂O)₂] (M = Zn or Co). Interestingly, among these four complexes, 1 and 2, or 3 and 4 crystallized in different space group, which may be related with the number of the crystallized H₂O molecules.     

Hydrothermal syntheses and crystal structures of PbII coordination polymers based on a N,O-donor ligand

In this article, four new lead(II) coordination polymers based on a N,O-donor ligand 2′-(1 H-1,3,7,8-tetraaza-cyclopenta[l]phenanthren-2-yl)biphenyl-2-carboxylic acid (HL) have been hydrothermally synthesized, namely, [PbL₂]·2H₂O (1), [PbL₂]·2H₂O·CH₃CH₂OH (2), [Pb₅L₂(m-BDC)₄]·3H₂O (3) and [Pb₂L₂(p-BDC)] (4), where m-BDC = 1,3-benzenedicarboxylate and p-BDC = 1,4-benzenedicarboxylate. Compound 1 shows a 2D bilayer structure, which is further extended into a 3D supramolecular structure through π–π stacking interactions. Compound 2 shows a 3D supramolecular structure based on a zero-dimensional molecule by π–π stacking interactions of neighboring molecules. Compound 3 shows a 2D layer structure. Compound 4 displays a 1D chain-like structure, which is then stacked by π–π interactions to result in a 2D supramolecular structure. Solid-state luminescent spectra of four lead(II) complexes indicate intense fluorescent emissions.     

Syntheses,crystal structures,and magnetic studies of two cobalt(II) coordination polymers based on concurrent ligand extension

An ether bridged tetracarboxylic acid ligand, 5-(3′,4′-Dicarboxylphenoxy)-isophthalic acid (H₄L) was used to construct two Co(II) coordination polymers in presence of different nitrogen donor ligands such as 4,4′-bipyridine (4,4′-bpy) and 4,4′-bis(pyrid-4-yl)biphenyl (bpbp). The products formed under hydrothermal conditions are formulated as [Co₂L(4,4′-bpy)₂(H₂O)₃]_n (1) and {[Co(bpbp)₂(H₂L)]·H₂O}_n (2). The compounds were characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis, and powder X-ray diffraction (PXRD) measurement. Compound 1 shows an intriguing (3,4,5)-connected 3D framework with a point symbol of (4² · 6² · 8²)(4² · 6⁵ · 8³)(6² · 8). Compound 2 is an unusual 3D supramolecular framework generated by the one-dimensional [Co(bpbp)(H₂L)]_n polymer chain. The magnetic properties of compounds 1 and 2 were examined, indicating antiferromagnetic interactions between the cobalt(II) ions in the temperature range of 2–300 K.     

Construction of three new mixed-ligand Zn(II) coordination polymers based on nitrogen-containing heterotopic ligands and carboxylate co-ligands

Reactions of Zn(II) salts, presynthesized 5-(4-(1H-imidazol-1-yl)phenyl)-1H-tetrazolate (HIPT) and various carboxylate ligands result to three new coordination polymers (CPs), namely, [Zn₂[(IPT)₂(ox)]}_n (H₂ox = oxalic acid, 1), [Zn₂(IPT)₂(mNBDC)]_n (H₂mNBDC = 5-nitroisophthalic acid, 2), and [Zn₂(IPT)(CA)(H₂O)]_n (H₃CA = citric acid, 3). Compound 1 can be seen as constructed from 2D [Zn(IPT)]_n layers with (6,3) topology and pillared by ox^2 −. It is a 3D (3,4)-connected framework with InS topology. Compound 2 has 2D bilayer structure based on 2D [Zn(IPT)]_n single layer and mNBDC^2 − linkers. Compound 3 is a 3D pillar-layer framework built by Zn–CA bilayers and IPT⁻ pillars. The results showed that the coordination modes, configurations of IPT⁻, and the structure of carboxylate co-ligands have great influence on the structures of the final network. The choice of carboxylate can decide the result of CPs in Zn–IPT chains/net subunits plus carboxyl linkers or Zn–carboxylate chains/net subunits plus IPT⁻ linkers. The thermal stabilities and luminescent properties of selected compounds have also been studied.     

Inorganic–organic hybrid material containing β-cage: {[H2(en)]Co2(ox)(V4O12)}n

By using an organic ligand, a new inorganic–organic hybrid compound of cobalt oxalate-vanadate, {[H₂(en)]Co₂(ox)(V₄O₁₂)}_n 1, where en = ethylenediamine, ox = oxalic acid, has been synthesized hydrothermally from V₂O₅,CoCl₂·6H₂O,H₂C₂O₄·2H₂O and en. Crystal data 1, orthorhombic, Cmcm space group, a=11.624(2), b=9.968(2), c=14.900(3) Å, R1=0.0298, wR2=0.1172. Compound 1 possesses a three-dimensional open-framework with β-cage and is an antiferromagnetic matter.     

Two highly connected frameworks and one polythreading architecture based on multidentate N-donor ligands: Syntheses,structures, characterizations and photoluminescent properties

Three coordination polymers based on multidentate N-donor ligands and polycarboxylate anions, namely, [Co₃(4,4′-tmbpt)₄(btc)₂]·9.5H₂O (1), [Ag₄(4,4′-tmbpt)(btec)(H₂O)₂]·H₂O (2) and [Zn(4,4′-tmbpt)(btec)_0.5(H₂O)]·0.5H₂O (3) (4,4′-tmbpt = 1-((1H-1,2,4-triazol-1-yl)methyl)-3,5-bis(4-pyridyl)-1,2,4-triazole, H₃btc = 1,3,5-benzenetricarboxylic acid, and H₄btec = 1,2,4,5-benzenetetracarboxylic acid) have been prepared under hydrothermal condition. Compound 1 displays a 3D (3,6,8)-connected framework with (4·6²)(4⁴·6¹⁰·8)(4¹⁴·6¹²·8²) topology. Compound 2 is a 3D (4,5,8)-connected framework with (4³·6²·8)(4³·6⁵·8²)(4⁸·6²)(4¹⁰·6¹⁰·8⁸) topology. Compound 3 exhibits a 2D → 3D polythreading architecture. The photoluminescent spectra indicate that at room temperature, compounds 2 and 3 emit green and blue luminescence, respectively.     

Unusual metal–organic network constructed from Zn(II), benzenetricarboxylate and bis(1,2,4-triazolyl)pyridine

Hydrothermal reaction of ZnSO₄ · 7H₂O with 1,3,5-benzenetricarboxylic acid (H₃btc) and 2,6-bis(1,2,4-triazolyl)pyridine (btp) afforded a novel metal–organic network {[Zn₃(btc)₂(btp)₂(H₂O)₂] · 4H₂O}_n (1) with a supramolecular cocrystal [H₃btc · btp · H₂O]_n (2). The complex 1 exhibits an unusual network containing two molecular squares and a rectangle. The networks interpenetrate to make a 3D metal–organic framework, which is quite thermal stable. Compound 2 shows a 2D supramolecular network assembled through strong hydrogen bonds.     

Two new pH-controlled coordination polymers constructed from an asymmetrical tricarboxylate ligand and Zn-based rod-shaped SBUs

Two new 3D coordination polymers, [Zn₃(L)₂(H₂O)₄]·H₂O (1) and [Zn₅(μ₃-OH)₄(L)₂(H₂O)₂] (2) (H₃L = 3-(2′,5′-dicarboxylphenyl)benzoic acid), have been synthesized under hydrothermal conditions by adding different amounts of NaOH. Structural analyses show that both of them contain 1D inorganic Zn(II)-chains as rod-shaped secondary building units (SBUs) but they are in different forms. The rod-shaped Zn(II)-chain of 1 is only Zn-carboxylate chain, while the one in 2 is formed by the independent Zn₅(COO)₆ clusters connected by hydroxyl oxygen. Furthermore, the thermal and luminescent properties of both compounds have been studied.     

Temperature-controlled structural diversity of two Cd(II) coordination polymers based on a flexible tripodal multicarboxylate ligand

Two new 3-D Cd(II) coordination polymers (CPs) with 3,5-bi(4-carboxyphenoxy)-benzoic acid (H₃L), namely [Cd₃(L)₂(H₂O)₄]·4H₂O (1) and [Cd₃(L)₂(H₂O)₃]·2H₂O (2), were successfully synthesized under hydrothermal condition at 140 °C and 180 °C, respectively. Complex 1 is constructed from 1-D (–Cd–O–)_∞ rod-shaped SBUs (secondary building units) and ‘Y’-shaped L ligands. In complex 2, the 3-D network is mediated by 2-D [Cd(COO)₂]_n layered motifs and ‘T’ and ‘Y’-shaped L ligands. The results show that the reaction temperature plays a key role on the final structures of the complexes. The luminescent properties of the complexes have also been investigated.     

A 3D Cu(II) coordination polymer constructed from BIBP (BIBP = 5,5′-bis(1H-imidazol-1-yl)-2,2′-bithiophene) ligand with semiconductive property

Hydrothermal reaction of Cu(NO₃)₂·3H₂O with BIBP and H₂hfipbb at 105 °C yielded a novel 3D Cu(II) coordination polymer, {[Cu₂(BIBP)_0.5(hfipbb)₂(CH₃CN)]·5H₂O}_n (1) [BIBP = 5,5′-bis(1H-imidazol-1-yl)-2,2′-bithiophene, H₂hfipbb = 4,4′-(hexafluoroisopropylidene)bis(benzoic acid)]. Compound 1 displays a 3D 2-fold interpenetrating framework with {4⁴.6⁶} sqp topology, containing interesting ⋯LRLR⋯ double helical chains. The compound 1 was characterized by IR spectra, elemental analysis, thermal analysis and single crystal X-ray diffraction. In addition, solid-state UV–vis spectra experiment shows that compound 1 exhibits semiconductive property with a band gap of 2.46 eV.     

Syntheses and characterizations of two-dimensional polymers based on tetraimidazole tetraphenylethylene ligand with aggregation-induced emission property

Two new coordination polymers [Co(TIPE)(H₂O)₂]·Hbtc·CH₃CN·3H₂O (1) and [Cd(TIPE)_0.5(m-bdc)(H₂O)]·CH₃OH·H₂O (2) (TIPE = tetra(3-imidazoylphenyl)ethylene, H₃btc = 1,3,5-benzenetricarboxylate, m-H₂bdc = 1,3-benzenedicarboxylate) have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, elemental analysis, IR, TGA, and PXRD. Furthermore, the luminescent properties of complexes 1, 2 and TIPE ligand have also been investigated in the solid at room temperature.     

Template-assisted self-assembly: Synthesis,structures, and magnetic properties of lanthanide(III)-cobalt(II) coordination complexes constructed with deprotonated 3,5-pyridinedicarboxylic acid ligand

Two new 3d-4f complexes, [LnCo(3,5-pdc)₂(3,5-Hpdc) (H₂O)₇]·H₂O (Ln = Gd 2, La 3; 3,5-pdcH₂ = pyridine-3,5-dicarboxylic acid), have been synthesized by the self-assembly of Ln(III) oxides, 3,5-pdcH₂ and the template molecule [Co(3,5-pdc)(H₂O)₅]·H₂O (1) under hydrothermal conditions. Heterometallic complexes 2 and 3 are isostructural with supracyclic units containing four Ln(III) ions and two Co(II) ions, in which Co(II) and Ln(III) are linked by the deprotonated 3,5-pdcH₂ ligands in three kinds of bridging modes. The weak antiferromagnetic coupling of complex 2 and 3 imply that the large 3,5-pdc bridges with the greater separation ( > 7 Å) cannot lead to long range magnetic ordering, the strength of d_n-f_n exchange coupling increasing with decreases the size of the lanthanide ion.     

A 3D cadmium(II) coordination polymer constructed from new β-diketone-functionalized pyridinecarboxylate and 4,4′-bipyridine ligands

A new cadmium(II) coordination polymer [Cd₂(L)₂(bpy)]_n·nCH₃OH (1) (H₂L = 2-(3-oxo-3-phenylpropionyl)-6-pyridinecarboxylic acid N-oxide, bpy = 4,4′-bipyridine), has been synthesized from the reaction of H₂L, 4,4′-bipyridine with CdSO₄·8/3H₂O. Compound 1 is an exceptional non-interpenetrating three-dimensional framework and contains double helical chains and rare cross bpy configuration. Interestingly, these helical chains can span two different directions on other alternate layers. Compound 1 shows intense photoluminescence at room temperature.     

Two new carboxylate–oxygen bridged trinuclear M(II) (MMn and Co) compounds with zwitterionic dicarboxylate ligands: crystal structures and magnetism

Two new Mn(II) and Co(II) coordination polymers with azide and zwitterionic dicarboxylate ligands L¹ and L² (L¹ = [4-((1-carboxylatobenzyl)pyridimium-3-yl) benzoic acid] chloride, L² = [1,1′-bis(4-carboxylatobenzyl)-4,4′-bipyridinium] dichloride) were synthesized and structurally and magnetically characterized. They are formulated as [Mn₃(L¹)₄(N₃)(CH₃CH₂OH)(H₂O)]ClO₄·4H₂O (1) and [Co₃(L²)₄(N₃)₂(H₂O)₂]·4NO₃ (2). Compound 1 contains two different linear trinuclear [Mn₃(COO)₈(CH₃CH₂OH)₂]^2 − and [Mn₃(COO)₆(H₂O)₂(N₃)₂]^2 − units built from the mixed bridges of (μ-COO)₂(μ₂-O_carboxylate). The trinuclear units are alternately linked into 1D chains by L¹. Compound 2 contains linear trinuclear [Co₃(N₃)₂(COO)₄(H₂O)₂] units built from the mixed bridges (μ-COO)₂(μ-H₂O). Magnetic studies demonstrated that the mixed triple bridges are antiferromagnetic in compounds 1 and 2.     

Metal-organic fameworks based on multi-carboxylate ligands with threefold symmetries and luminescence properties

Three new metal–organic frameworks, namely, [Cd_1.5(tcpb)(DMF)(H₂O)] (1), [Co_1.5(tcpb)(DMF)₂]·3DMF (2) and [Zn(Htcpb)(4,4′-bpy)_0.5]·1.5H₂O (3) (tcpb = 1.3,5-tris(4-carbonylphenyloxy)benzene) have been synthesized by solvent-thermal method. The single-crystal X-ray diffraction analysis shows that compound 1 is 2D grid layers, with the trinuclear cadmium clusters acting as secondary building units (SBUs), and the tcpb ligand serveing as organic linkers. Compound 1 and Compound 2 are isomorphic structures containning similar connection modes of tcpb ligands with trinuclear metal clusters. Compound 3 is a 3D interpenetrated framework based on dinuclear Zn cluster with dia topology. The fluorescence properties for solid state compound 1 and 3 were examined at room temperature. Compared with free tcpb ligands, both of them display remarkable red-shift.     

A novel three-dimensional coordination polymer containing tetranuclear [Co4(μ3-OH)2] building blocks: Synthesis,crystal structure and magnetic behavior of {[Co2(btc)(μ3-OH)(H2O)2] · H2O}n

A cobalt coordination polymer {[Co₂(btc)(μ₃-OH)(H₂O)₂] · H₂O}_n 1 (btc = 1,2,4-benzenetricarboxylate) was synthesized hydrothermally and structurally characterized by single-crystal X-ray diffraction method. In 1, the six-coordinated Co(II) ions are held together by two bridging hydroxides to form a tetranuclear [Co₄(μ₃-OH)₂] unit, which are connected further through btc³⁻ ligands in a new μ₇-bridging mode to give a porous three dimensional framework. The study of magnetic properties indicated dominant antiferromagnetic coupling interactions between the adjacent Co(II) sites.     

Construction of two mixed-ligand coordination polymers presenting unusual polyrotaxane-like entanglements

Two novel polyrotaxane-like coordination polymers, [Ni₄(L)₄(H₂O)₃(bpp)₄]·3H₂O (1) and [Cd₄(L)₄(bpp)₃]·3H₂O (2) (H₂L = Me₂Si(p-C₆H₄COOH)₂, bpp = 1,3-bis(4-pyridyl)propane), have been synthesized and structurally characterized. Compound 1 features a 2D → 3D polyrotaxane array by the interlock of bilayer networks. Compound 2 exhibits an unusual 3D polyrotaxane-like self-threading framework. In addition, compound 2 shows an emission at 485 nm when it was excitated at 400 nm.