3D Ln–Ag (Ln = Nd; Eu) coordination polymers based on isonicotinate and oxalate ligands: Synthesis, crystal structures and luminescence

The self-assembly of isonicotinic acid with metal salts under hydrothermal conditions obtained two new 4d–4f coordination polymers, LnAg(OX)(IN)₂·H₂O (Ln = Nd (1); Eu (2), OX = oxalic acid, IN = isonicotinic acid). The 3D isostructural complexes 1 and 2 are constructed by the assembly of 2D layers, which are built by carboxylate groups of isonicotinic acid and oxalate ligands coordinating to metal centers, with 1D linear linkers completed by silver ions. Furthermore, the luminescent property of complex 2 was investigated.     

Hydrothermal synthesis,crystal structure and strong blue fluorescence of a novel 3D coordination polymer containing copper and zinc centers linked by isonicotinic acid ligands

The first mixed metal Zn/Cu coordination polymer, [Zn₃Cu₂(IN)₈] (1) (HIN = isonicotinic acid) was synthesized under hydrothermal conditions. The three dimensional structure of 1 has a novel topological metal-organic framework, which is built up by Zn²⁺, Cu⁺ and ligands IN to generate an open-framework with an unusual helical [–Zn(Cu)-IN–]_n chains along the b axis. The very strong blue fluorescence for 1 can be observed in the solid state.     

Hexanuclear 4d–4f complexes [Ln2Ag4(ina)8(H2O)10][NO3]2 · 4H2O (Ln = Sm, Eu, Dy): Syntheses, structures and photoluminescent properties

Hexanuclear 4d–4f heterometallic complexes, [Ln₂Ag₄(ina)₈(H₂O)₁₀][NO₃] ₂ · 4H₂O [Ln = Sm (1), Eu (2), Dy (3) and Hina = isonicotinic acid], have been synthesized by the hydrothermal reaction of lanthanide oxides, Ag^I, and isonicotinic acid at a suitable temperature. Single-crystal X-ray diffraction studies indicate that these 4d–4f complexes consist of extended 1D zigzag chains structure built upon [Sm₂Ag₄(ina)₈(H₂O)₁₀] subunits connected by Ag–Ag interactions. Furthermore, the photoluminescent properties of the complex 2 were studied.     

Two novel lanthanide (Nd, Gd) coordination polymers with chromate anion as building block of the 2D metal oxide

Two novel lanthanide coordination polymers, [Nd(IN)CrO₄]_n (1) and [Gd(IN)CrO₄]_n (2) (HIN = isonicotinic acid), were obtained from the reaction of Ln₂O₃, HIN and K₂Cr₂O₇ under hydrothermal conditions. The single-crystal X-ray diffraction studies reveal that 1 and 2 are isostructural. Compounds 1 and 2 are three-dimensional frameworks consisting of inorganic layers of Ln and pillared by the organic IN. Each anion in the structure binds four Nd(III) ions in an η³,μ₄-pentadentate coordination mode. Measurements of magnetic susceptibilities for Compounds 1 and 2 indicate the presence of antiferromagnetic interactions.     

Construction of three-dimensional Ln–Ag (Ln = Eu; Tm) coordination polymers based on isonicotinate and oxalate ligands

Hexanuclear 4d–4f heterometallic coordination polymers, [Ln₂Ag₄(IN)₅(ox)₂(NO₃)(H₂O)₂ · 3H₂O] [Ln = Eu (1), Tm (2); IN = isonicotinate and ox = oxalate], have been synthesized by hydrothermal reaction of mixed organic ligands and metal salts. Both structures display the same unusual 3D heterometallic coordination frameworks based on rare zigzag lanthanide–oxalate–silver chains, Ag₂(IN)₃ units and IN linkers. The photoluminescent properties of complex 2 were studied.     

Hydrothermal Synthesis,Crystal Structure and Characterization of a Novel 3D Pillared-Layer 3d–4f Lanthanum-Copper Heterometallic Coordination Polymer

A novel three-dimensional (3D) pillared-layer 3d–4f lanthanum-copper heterometallic coordination polymer, {La₂Cu₇I₆(IN)₇(H₂O)₆·2H₂O} _n (1) (HIN = isonicotinic acid), has been synthesized by hydrothermal reaction of La₂O₃, CuI, HIN with HNO₃, and characterized by elemental analyses, IR, PXRD, and single-crystal X-ray diffraction. The structure determination reveals that the 3D framework of 1 is constructed upon [Cu₇I₆] _n ⁿ⁺ inorganic layers linked by dimeric La₂(IN)₆ pillars. Additionally, the thermogravimetric analysis and luminescent property of 1 were investigated and discussed.     

Homo and Dinuclear Heteroleptic Zn,Cd & Pb Complexes Derived from FcCOOH and DTBbpy Ligands: Structural,Luminescence and Electrochemical Studies

Mononuclear [Zn(FcCOO)(DTBbpy)₂]ClO4.(H₂O)₃ (1) and dinuclear [Cd₂(FcCOO)₂(DTBbpy)₄]ClO₄·(H₂O) (2), [Pb₂(FcCOO)₂(DTBbpy)₂(H₂O)₂]·ClO₄ (3) (FcCOO = ferrocenecarboxylate, DTBbpy = 4,4′-di-tert-butyl-bipyridyl) metal complexes have been synthesized and characterized by single crystal X-ray diffraction. It reveals that the Zn(II), Cd(II) and Pb(II) metal complexes have different coordination geometries [Zn and Pb = distorted octahedral, Cd = distorted pentagonal bipyramidal]. The compound 3 shows the hemidirected mode of coordination in the geometrical system due to the inert pair effect of the lone pair of an electron on Pb(II) metal atom. The molecules are further forms 2D & 3D framework structure via intermolecular hydrogen bonding. All the three compounds exhibit strong fluorescence emission bands in the liquid state at ambient temperature, of which the emission maxima show red-shifted and the solution-state electrochemistry of compounds 1–3 in CH₃CN has been investigated.     

Structure and luminescent property of one three-dimensional cadmium(II) polymer derived from mixed flexible and rigid ligands

One new three-dimensional Cd(II) polymer [Cd₃(MMA)₂(INA)₂]_n (1) was synthesized hydrothermally based on mixed flexible methylmalonic acid (H₂MMA) and rigid isonicotinic acid (HINA) ligands. Single-crystal X-ray diffraction analysis reveals that compound 1 has a 3D framework structure consisting of 2D {Cd₃} layer unit and INA⁻ connector, which bears a (3,8)-connected tfz-d topology with Schläfli symbol of {4³}₂{4⁶.6¹⁸.8⁴}. The solid-state luminescent property was studied and 1 exhibits strong emission centered at 429 nm.     

Syntheses,structures and properties of cobalt and manganese complexes based on pyridine-2,3,5,6-tetracarboxylic acid

Two new complexes based on pyridine-2,3,5,6-tetracarboxylic acid(H₄pdtc) as ligand, {[Co₂(pdtc)(H₂O)₄] · H₂O}_n (1) and {Mn₂(pdtc)(H₂O)₄}_n (2), have been obtained by hydrothermal syntheses and characterized by IR, elemental analysis, X-ray diffraction single crystal structure analysis, PXRD, thermal gravimetric analysis, and magnetic measurements. Complex 1 is 3D coordination polymer and complex 2 belongs to 2D grid structure by covalent bonds. In 1 and 2, the metal ions show antiferromagnetic interactions.     

Three unprecedented high-connected 3D lanthanide–organic frameworks based on benzene-1,2,4,5-tetracarboxylic acid

Three unprecedented high-connected 3D lanthanide coordination polymers based on benzene-1,2,4,5-tetracarboxylic acid (H₄bta), {[Ln₂(bta)_1.5(H₂O)₄] · 3H₂O}_n (Ln = La (1) and Ce (2)) and [Pr(bta)_0.5(H₂bta)_0.5(H₂O)]_n (3), have been synthesized under hydrothermal conditions. Complexes 1 and 2 show trinodal (4,4,10)-connected 3D network structures consisting of tetranuclear metal clusters bridged by bta^4 − ligands, and a chair conformation hexamer water cluster can be found within the cage enclosed by eight neighboring tetranuclear metal clusters in the two complexes. While 3 consists of 2D {Pr(bta)_0.5}_n layers linked by H₂bta^2 − ligands, resulting in an unprecedented trinodal (4,6,10)-connected 3D topological network. The organic ligand exhibits five kinds of coordination modes, in which one of them is reported for the first time. Moreover, the luminescent properties of 1–3 have also been investigated.     

1D lead(II) coordination chains with carboxylate containing ligands. A rare example of polyrotaxane 1D → 1D interpenetrated coordination polymer

The structural determination of two interesting lead(II) coordination polymers, namely [Pb(ind)₂(H₂O)]_n (1) and [Pb₂(dbsf)₂(bipy)]_n (2) (Hind = indane-2-carboxylic acid, H₂dbsf = 4,4′-sulfonyldibenzoic acid, and bipy 4,4′-bipyridine), reveals in the second an unexpected polyrotaxane 1D → 1D interpenetrated coordination polymer thanks to the hemidirected coordination geometry of the metal and the rings formed by the dicarboxybiphenyl sulfone ligands along the 1D chain.     

A Novel Co(II) Coordination Polymer Assembled from V-shaped 2,3,2’,3’-Thiodiphthalic Acid and N-donor Ancillary Ligand: Syntheses,Structure and Properties

A novel coordination polymer {[Co₂(tdpa)(bpe)_1.5(H₂O)]·(bpe)_0.5·(H₂O)} _n (1) has been hydrothermally synthesized through the reaction of 2,3,2’,3’-thiodiphthalic acid (H₄tdpa) with divalent cobalt salt in the presence of ancillary nitrogen ligand (bpe = trans-1,2-bis(4-pyridyl)ethene) and characterized by IR spectra, elemental analysis and single crystal X-ray diffraction. Due to various coordination modes and conformations of the versatile 2,3,2’,3’-thiodiphthalic acid ligand, the complex exhibits structural and dimensional novelty. In complex 1, metal–organic ribbons (Co-tdpa) are connected together through bpe ligands to generate a three-dimensional (3D) metal–organic framework. The structure of 1 can be described as a (3,6)-connected network with a Schläfli symbol of (4²·6)(4⁴·6¹⁰·8) topology. The thermal stability of the complex 1 was studied by thermal gravimetric analyses (TGA), and the UV?vis absorption property of complex 1 was also investigated.     

Synthesis,characterization and luminescence of two unusual 4d–4f Ln–Ag coordination compounds

Two novel Ln–Ag coordination compounds with the formula [LnAg₂(IN)₄(OAC) · 5H₂O] · 2H₂O (Ln = Gd 1, Eu 2; HIN = isonicotinic acid; HOAC = acetic acid) have been synthesized under hydrothermal condition and characterized by single-crystal X-ray diffraction, thermal analysis, IR absorption spectroscopy, ultraviolet excitation and emission spectrum. The two compounds show isostructural architectures and exhibit an unusual 1-D structure, which is formed by the linkages of Ag–Ag.     

A new 3D coordination framework with helical chains in mixed ligands system: Preparation,crystal structure and magnetic property

A new 3D coordination polymer [Ni₂(L)₂(bpp)₂(μ₂-H₂O)] (1) (H₂L = 2,4-dibenzoylisophthalic acid and bpp = 1,3-bis(4-pyridyl)propane) has been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectra, and thermogravimetric analysis. Further, it was determined by single crystal X-ray diffraction analysis. Compound 1 is a 3D network with (3⁶·4⁸·5⁷) topology, which comprises of two kinds of helical chains. Additionally, compound 1 shows ferromagnetic interactions among metal ions.     

Solvent-controlled synthesis and reversible dynamic structural conversions of a series of iron(II) coordination complexes

In this work, a versatile multi-dentate 1,2-bis(pyridin-4-ylmethylene)hydrazine (L) ligand has been employed to construct three novel iron(II) coordination complexes, [Fe(L)₂(NCS)₂(H₂O)₂]·2H₂O (1), [Fe(L)(NCS)₂(H₂O)₂] (2) and {[Fe(L)₂(NCS)₂]·2CH₃OH}_n (3) (NH₄NCS = ammonium thiocyanate), which can be isolated under similar synthetic conditions, only different molar ratio of metal/ligand or different solvent systems are used. 1 is a mono-nuclear iron(II) coordination complex, and 2 is a one-dimensional (1D) iron(II) coordination complex, while 3 is a 2D micro-porous iron(II) framework with the channel dimensionality of 13.936(3) Å × 13.936(3) Å. PXRD patterns also confirm the purity of the bulky samples of 1–3. For 1–3, it represents the first example of solvent-induced drastic reversible dynamic conformation between different dimensional iron(II) coordination complexes 1 (0D), 2 (1D) and 3 (2D) (for 1: water; for 2: benzene; for 3: methanol/acetone/acetonitrile), which are unambiguously confirmed by PXRD characterizations. Variable-temperature magnetic susceptibility data of 2–3 have been recorded in the 2–300 K temperature range, indicating weak antiferromagnetic interactions.     

Mn and Cu–Na coordination compounds containing the tetrazole-5-acetato anion (tza) ligands

Two novel coordination compounds [Mn(tza) · (H₂O)₂]_n (1) and [CuNa₂(tza)₂ · (H₂O)₄]_n (2) (tza = tetrazole-5-acetato) were synthesized by reaction of tetrazole-5-ethyl acetate with Mn(ClO₄)₂ · 6H₂O and CuCl₂ · 2H₂O in sodium hydroxide solution, respectively. Compound 1 has a one-dimensional (1D) polymeric chain that are bridged by tza linker, while compound 2 has two crystallographically independent metal centers (Cu and Na), that are bridged by tza into a 2D layer structure. The magnetic susceptibility study of 1 demonstrates the presence of antiferromagnetic interaction between two adjacent Mn(II) ions.     

Terminal ligand effect on the structure variation of Copper(II) complexes

Two copper(II)–poly(pyrazolyl)methane complexes [Cu₂(bpm)₄(ta)](ClO₄) ₂ · 2H₂O 1 and {[Cu₂(tpm)₂(ta)₂] · H₂O}_n 2 (bpm = bis(3,5-dimethylpyrazolyl)methane, tpm = tris(pyrazolyl)methane, H₂ta = terephthalic acid) were synthesized and characterized by elemental analysis, FT-IR and UV–vis spectra. 1 is a binuclear complex, while 2 exhibits as a 1D zigzag coordination polymer.     

A 2D helical coordination polymer based on Keggin-type polyoxoanion: Synthesis,crystal structure and luminescent properties

A novel two-dimensional helical coordination polymer [Ag(CH₃CN)₄][Ag₃(CH₃CN)₈(SiMo₁₂O₄₀)] (1) has been gained by the conventional self-assembly reaction, and characterized by IR, elemental analysis, UV, TG technique and X-ray single crystal diffraction. Each [SiMo₁₂O₄₀]^4? cluster interconnects with three bimetallic cation subunits through three Mo–O–Ag bridges, meanwhile, each bimetallic cation subunit is surrounded by three [SiMo₁₂O₄₀]^4? to form an unprecedented two-dimensional network structure. The metal–metal bonds between Ag(1) and Ag(2) atoms from the adjacent helical chains connects the chains together into a chiral 2D helical network. The 2D network structures are further interconnected with each other to form a 3D supramolecular network through multiform intermolecular hydrogen bonds. The luminescent properties of the coordination polymer in the solid state were investigated.     

Various metal-organic frameworks from 1D, 2D to 3D with 1,6-bis(1,2,4-triazol-1-yl)hexane

Using Zn(II) or Cd(II) salts and the flexible ligand 1,6-bis(1,2,4-triazol-1-yl)hexane(L), a series of novel coordination polymers, {[Zn(L)Cl₂]}_n (1), [Cd(L)₂(SCN)₂]_n (2), {[M(L)₃](ClO₄)₂}_n (M = Zn, 3; Cd, 4), varying from one- to three-dimensionality, have been prepared and their crystal structures determined via X-ray single-crystal diffraction analysis. 1 and 2 are 1D zigzag chain and 2D (4,4) network, respectively. Isostructural compounds 3 and 4 are 3D threefold interpenetrating frameworks. This work suggests that metal/ligand ratio and anion play an important role in the self-assembly of 1D, 2D and 3D coordination polymers based on L.     

Hetero-bimetallic 2D coordination network constructed by azacrown ether carboxylic acid with lanthanide(III) and sodium ions

Two lanthanide-based coordination polymers [Na₃La(L)Cl·(H₂O)₆]·NO₃ (La-L) and [Na₃Eu(L)Cl·(H₂O)₆]·NO₃ (Eu-L) were newly synthesized by reaction of an azacrown ether carboxylic acid ligand H₄L (4,7,13,16-tetracarboxymethyl-1,10-dioxa-4,7,13,16-tetraazacyclooctadecane) with La(III)/Eu(III). Complexes La-L and Eu-L exhibited two-dimensional (2D) coordination architectures built up by Ln–L coordinating subunits and one-dimensional (1D) Na–O bridging chains. Four versatile coordination modes of carboxyl groups and Na–O coordination bi-chains linked by novel μ-O bridges (μ2-O and μ3-O) were demonstrated in the structure. Photoluminescence spectra of Eu-L were investigated to reveal characteristic emissions of Eu(III). This is the first example of hetero-bimetallic complex of the tetraazacrown ether ligand with lanthanide and sodium ions.