Effect of pendant arm position and length on the structure and properties of nickel aromatic dicarboxylate coordination polymers incorporating a kinked organodiimine

Hydrothermal synthesis has afforded three nickel coordination polymers incorporating both aromatic dicarboxylates and the kinked and hydrogen bonding capable organodiimine 4,4′-dipyridylamine (dpa). These were characterized by single-crystal X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis. [Ni(1,2-phda)(dpa)(H₂O)]_n (1,2-phda = 1,2-phenylenediacetate, 1) displays (4,4) rhomboid grid-like 2D layers that aggregate into 3D through O–H?O hydrogen bonding. Shortening one of the pendant arms of the dicarboxylate ligand resulted in a shift to (6,3) herringbone style 2D coordination layer motifs in {[Ni(hmph)(dpa)] · 1.33H₂O}_n (hmph = homophthalate, 2), which stack in an AA′B pattern. [Ni(1,3-phda)(dpa)(μ-H₂O)_0.5]_n (1,3-phda = 1,3-phenylenediacetate, 3) manifests a canted primitive cubic type coordination polymer lattice constructed from dinuclear {Ni₂(μ-H₂O)} kernels linked into 3D through tethering 1,3-phda and dpa ligands. Analysis of the variable temperature magnetic susceptibility of 3 indicated the presence of antiferromagnetic superexchange within its dinuclear units (g = 2.290(2), J = −4.21(2) cm⁻¹).     

Two-dimensional divalent metal/pimelate coordination polymers incorporating dipodal organodiimines: Crystal structures,thermal properties,and magnetic studies

Hydrothermal synthesis has afforded a series of 2-D coordination polymers incorporating the flexible α,ω-dicarboxylate pimelate ligand (pim) and either the kinked organodiimine 4,4′-dipyridylamine (dpa) or its conformationally flexible congener 1,3-di-4-pyridylpropane (dpp).     

Syntheses and characterizations of nine coordination polymers of transition metals with carboxylate anions and bis(imidazole) ligands

Nine new compounds, namely [CuL1(biim-6)] · H₂O (1), [ZnL1(biim-6)] · H₂O (2), [MnL1(biim-6)] · H₂O (3), [MnL1(biim-4)] (4), [Co₂(L2)₂(biim-5)₃ · 6H₂O] · 8H₂O (5), [ZnL3(biim-6)] (6), [ZnL3(biim-5)] (7), [CdL3(biim-5) · 1.5H₂O] · 0.5H₂O (8) and [CdL4(biim-6) · 2H₂O] (9) [where L1 = oxalate anion, L2 = fumarate anion, L3 = phthalate anion, L4 = p-phthalate anion, biim-4 = 1,1′-(1,4-butanediyl)bis(imidazole), biim-5 = 1,1′-(1,5-pentanedidyl)bis(imidazole) and biim-6 = 1,1′-(1,6-hexanedidyl)bis(imidazole)] were successfully synthesized. Compounds 1–3 are isostructural, and display 2D polymeric structures. Compound 4 shows a threefold interpenetrating diamondoid framework. In compound 5, the anions act as counterions, and the metal cations are bridged by bis(imidazole) ligands to form 1D polymeric chains. Compounds 6–9 show 2D polymeric structures. The magnetic properties for 1, 3 and 4 and luminescent properties for 2 and 6–9 are discussed. Thermogravimetric analyses (TGA) for these compounds are also discussed.     

Syntheses and structures of two copper coordination polymers with bis (1,2,4-triazol-1-ylmethyl)benzene and benzenedicarboxylate

Two copper coordination polymers [Cu(obtz)(bdc)] _n (1) and {[Cu(obtz)(phth)] · 2H₂O} _n (2) (obtz = 1,2-bis(1,2,4-triazol-1-ylmethyl)benzene, bdc = 1,3-benzenedicarboxylate, phth = 1,4-benzenedicarboxylate) were synthesized and characterized. Both 1 and 2 are 2-D networks constructed via the bridging ligands bdc and phth. The obtz ligands do not extend the dimension (2-D network) but add their thickness, 10.9 Å for 1 and 11.6 Å for 2. Complex 1 further constructs a 3-D network via π?π stacking interactions between the benzene rings of obtz ligands of adjacent 2-D networks. The thermal stabilities have been investigated.     

Cu(II) coordination polymers incorporating 3-aminopyridine and flexible aliphatic dicarboxylate ligands: Synthesis,structure and magnetic properties

The synthesis, structural chemistry and magnetic properties of a series of new Cu(II) polymers with α,ω-dicarboxylic acids (sebacic (H₂seb), suberic (H₂sub), succinic (H₂suc) and adipic (H₂adip)) and 3-aminopyridine (3-apy) are described: [Cu(Hsub)₂(3-apy)₂·2CH₃OH]_n (1); [Cu(Hseb)₂(3-apy)₂·4CH₃OH]_n (2); [Cu(Hsuc)₂(3-apy)₂]_n (3); [Cu(adip)(3-apy)₂]_n·n(H₂adip) (4). All four compounds feature a bis-monodentate bridging mode of the coordinated dicarboxylate moiety. Compounds 1 and 2 exhibit linear chains, whereas compound 3 shows two-dimensional structure. The 3-apy ligand acts as terminal ligand in 1–3. Compound 4 contains a doubly deprotonated adipate (adip²⁻) that connects Cu centers into linear chains. Additionally, 3-apy acts as a bridge in 4, resulting in the formation of parallel two-dimensional layers distant enough to host neutral molecules of adipic acid. Magnetic susceptibility measurements of compounds 1 and 3 show Curie law behavior indicating that the S = 1/2 Cu(II) spin carriers are magnetically well isolated by the dicarboxylate ligands.     

Alkyl group dependence on structure and magnetic properties in layered cobalt coordination polymers containing substituted glutarate ligands and 4,4′-bipyridine

Five two-dimensional divalent cobalt coordination polymers containing 4,4′-bipyridine (bpy) and substituted or unsubstituted glutarate ligands have been prepared hydrothermally and structurally characterized by single-crystal X-ray diffraction. [Co(mg)(bpy)]_n (1, mg=3-methylglutarate) forms a (4,4) rhomboid grid structure based on the connection of {Co₂(CO₂)₂} dimeric units. Using the more sterically encumbered ligands 3,3-dimethylglutarate (dmg) and 3-ethyl, 3-methylglutarate (emg) generated {[Co(dmg)(bpy)(H₂O)]·2H₂O}_n (2) and {[Co(emg)(bpy)(H₂O)]·H₂O}_n (3), respectively. These complexes manifest {Co(CO₂)}_n chains linked into 2-D by aliphatic dicarboxylate and bpy ligands. The “tied-back” substituted glutarate ligand 1,1-cyclopentanediacetate (cda) afforded [Co(cda)(bpy)]_n (4), and the unsubstituted glutarate (glu) generated [Co(glu)(bpy)]_n (5), both of which exhibit a topology similar to that of 1. The magnetic properties of complexes 1-4 were analyzed successfully with a recently developed phenomenological chain model accounting for both magnetic coupling (J) and zero-field splitting effects (D), even though 1 and 4 contain isolated, discrete {Co₂(CO₂)₂} dimers. The D parameter in this series varied between 21.8(8) and 48.0(9) cm⁻¹. However weak antiferromagnetic coupling was observed in 1 (J=-2.43(4) cm⁻¹) and 4 (J=−0.89(2) cm⁻¹), while weak ferromagnetic coupling appears to be operative in both 2 (J=0.324(5) cm⁻¹) and 3 (J=0.24(1) cm⁻¹).     

Crystal Structures,Magnetism, and Dye Degradation Catalytic Properties of Copper 2‐Methoxycarboxybenzoate Coordination Complexes

Copper coordination complexes containing the 2‐methoxycarboxybenzoate (2‐mcob) ligand show different topologies depending on the nature of the dipyridyl coligand. [Cu₂(2‐mcob)₂(ebin)]_n ( 1 ) [ebin = ethanebis(isonicotinamide)] shows a ladder structure based on anti‐syn bridged [Cu(OCO)]_n chain motifs. [Cu₂(2‐mcob)₂(bbin)(H₂O)₂] ( 2 ) [bbin = butanebis(isonicotinamide)] displays a dimeric molecular structure. [Cu₂(2‐mcob)₂(hbin)]_n ( 3 ) [hbin = hexanebis(isonicotinamide)] manifests a ladder structure very similar to that of 1 . {[Cu(2‐mcob)(dpa)] · H₂O}_n ( 4 ) [dpa = bis(4‐pyridyl)amine] shows a chain coordination polymer structure. All four materials showed significant promise as heterogeneous degradation catalysts for Congo Red dye in aqueous suspension under ultraviolet irradiation. Variable temperature magnetic susceptibility experiments for 1 indicated the presence of weak antiferromagnetic exchange (g = 2.059(2), J = –0.84(2) cm^–1). Thermal degradation behavior is also discussed.     

Syntheses,structures, luminescent and magnetic properties of two coordination polymers based on a fl exible multidentate carboxylate ligand

Two coordination polymers,{[Cu_3(tci)_2(DMAc)_3]-6DMAc 2H_2O}_n(1) and {[Cu_3(tci)_2(tpt)_2(H_2O)_2].2DMAc-2H_2O}_n(2)(H_3tci = tris(2-carboxyethyI)isocyanurate,tpt = 2,4,6-tris(4-pyridyl)-l,3,5-triazine,DMAc = N,/V-dimethylacetamide),have been constructed under solvothermal conditions.Both polymers were structurally characterized by single crystal X-ray diffraction,elemental analyses,IR spectra,thermogravimetric(TG) analyses and powder X-ray diffraction(RXPD).1 shows a(3,4)-connected 2D layer structure comprising Cu_2(CO_2)4 paddle-wheel units,which are further bridged by C-H…O interactions to give a 3D supramolecular network.The introduction of tpt produces different framework for 2 that comprises a dinuclear and a mononuclear Cu(Ⅱ) building units,which are further bridged together by tci~(3-) and tpt ligands to give a 4-connected 2D topological net.Adjacent 2D layers are packed together via C-H…O interactions and π…π stacking interactions to form a 3D supramolecular structure.In addition,the luminescent properties and the solid-state UV-vis spectra of 1 and 2 were explored.Furthermore,antiferromagnetic exchange interactions were unveiled in the Cu_2(COO)_4 units of 1.     

Two new coordination polymers of Robson-type macrocycle bridged by perchlorate anions: Structure,electrochemistry and magnetism

Two new coordination polymers of Robson-type macrocycles, [Cu₂L¹(μ-ClO₄)₂]_∞ (1) and [Cu₂L²(μ-ClO₄)₂]_∞ (2) (where H₂L¹and H₂L² are the [2+2] condensation products of 2,6-diformyl-4-flurophenol with 1,3-diaminopropane and 2-hydroxy-1,3-diaminopropane, respectively), have been synthesized and characterized. The intriguing feature is that intermolecular perchlorato bridges occur between adjacent copper(II) centers. The cyclic voltammograms of the complexes show that each complex undergoes two pseudo-reversible processes with the half wave potentials, −0.361 V and −0.729 V for 1, and −0.372 V and −0.744 V for 2, respectively. Magnetic susceptibility was measured for 1 and 2 over a temperature range of 2–300 K. The optimized magnetic data were J = −359.6 cm⁻¹, j′ = −30 cm⁻¹ and R = 6.8 × 10⁻⁸ for 1 and J = −411 cm⁻¹, j′ = −26 cm⁻¹ and R = 2.4 × 10⁻⁷ for 2, respectively. The data reveal antiferromagnetic couplings between the copper(II) ions of intra- and intermolecular units.     

Synthesis, crystal structure, and magnetic properties of two-dimensional divalent metal glutarate/dipyridylamine coordination polymers, with a single crystal-to-single crystal transformation in the copper derivative

Hydrothermal reaction of divalent metal chlorides with glutaric acid and 4,4′-dipyridylamine (dpa) has afforded an isostructural family of coordination polymers with formulation [M(glu)(dpa)]_n (M=Co (1), Ni (2), Cu (3); glu=glutarate). Square pyramidal coordination is seen in 1-3, with semi-ligation of a sixth donor to produce a “5+1” extended coordination sphere. Neighboring metal atoms are linked into 1D [M(glu)]_n neutral chains through chelating/monodentate bridging glutarate moieties with a syn-anti binding mode, and semi-chelation of the pendant carboxylate oxygen. These chains further connect into 2D layers through dipodal dpa ligands. Neighboring layers stack into the pseudo 3D crystal structure of 1-3 through supramolecular hydrogen bonding between dpa amine units and the semi-chelated glutarate oxygen atoms. The variable temperature magnetic behavior of 1-3 was explored and modeled as infinite 1D Heisenberg chains. Notably, complex 3 undergoes a thermally induced single crystal-to-single crystal transformation between centric and acentric space groups, with a conformationally disordered unilayer structure at 293 K and an ordered bilayer structure at 173 K. All materials were further characterized via infrared spectroscopy and elemental and thermogravimetric analyses.     

Rare configuration of tautomeric benzimidazolecarboxylate ligands in cadmium(II) and copper(II) coordination polymers

Two Cd(HBimc)-based isomers, [Cd(HBimc^N)(HBimc^T)(H₂O)]·3.5H₂O·EtOH (1a·3.5H₂O·EtOH, H₂Bimc=1H-benzimidazole-5-carboxylic acid) and [Cd(HBimc^N)(HBimc^T)(H₂O)] (1b), and two Cu(HMBimc)-based coordination polymers, [Cu(HMBimc^N)₂(H₂O)]·1/2H₂O (2·1/2H₂O, H₂MBimc=2-methyl-1H-benzimidazole-5-carboxylic acid) and [Cu(HMBimc^T)₂]·2THF·H₂O (3·2THF·H₂O), were self-assembled from Cd(ClO₄)₂·6H₂O/H₂Bimc and Cu(ClO₄)₂·6H₂O/H₂MBimc systems, respectively. Compound 1a adopts a ladder-like chain structure, comprised of a hydrogen-bond-stabilized Cd₂(HBimc^N)₂-metallocyclic stair and a 1D straight -(Cd-HBimc^T)_n- edge, whereas compound 1b exhibits a 2D (4,4)-rhombus layered structure, intercrossed by 1D -(Cd-HBimc^N)_n- chains and -(Cd-HBimc^T)_n- chains. Compound 2 shows a 1D double-stranded wave-like chain from two single-stranded wave-like -(Cu-HMBimc^N)_n- chains and compound 3 adopts a 2D (4,4)-topological layer structure, intercrossed by subunits of 1D -(Cu-HMBimc^T)_n- chains. Interestingly, a pair of tautomeric HBimc building blocks—normal (N or HBimc^N) and tautomer (T or HBimc^T)—is simultaneously included in the structures of 1a and 1b, whilst the N- and T-configured HMBimc building blocks are present as separate entities in Cu species, 2 and 3, respectively. The existence of only a tautomer (T) mode of the benzimidazolecarboxylate-based ligand in a Cu(II) network is observed for the first time.     

Dipyridylamide Donor Disposition and Isophthalate Substituent Steric Effect on the Dimensionality and Topology of Divalent Copper Coordination Polymers

Divalent copper coordination polymers containing an isophthalate ligand and a dipyridylamide ligand show different dimensionalities and topologies depending on pyridyl nitrogen donor disposition and the steric bulk of the substituent on the dicarboxylate aromatic ring. According to single‐crystal X‐ray diffraction, [Cu(ip)(3‐pna)]_n ( 1 , ip = isophthalate, 3‐pna = 3‐pyridylnicotinamide) shows a (4, 4) layered grid structure based on {Cu₂(OCO)₂} dimeric units. {[Cu(ip)(3‐pina)]·H₂O}_n ( 2 , 3‐pina = 3‐pyridylisonicotinamide) exhibits similar dimeric units, but in contrast to 1 these are connected into a non‐interpenetrated 3D 6⁵8 cds network. Both [Cu(mip)(3‐pina)]_n ( 3 , mip = 5‐methylisophthalate) and [Cu(meoip)(3‐pina)]_n ( 4 , mip = 5‐methoxyisophthalate) display dimer‐based 4¹²6³ pcu networks in contrast to 2 . Use of 5‐hydroxyisophthalate (H₂hip) as a precursor afforded a mixture of {[Cu₂(hip)₂(3‐pina)₄]·9.5H₂O}_n ( 5 ) and [Cu(hip)(3‐pina)]_n ( 6 ). Compound 5 shows a 2D interdigitated structure with [Cu(hip)]_n coordination polymer layers featuring {Cu₂(OCO)₂} dimeric units and pendant 3‐pina ligands, while 6 also showed a dimer‐based 4¹²6³ pcu network. Use of the very sterically bulky 5‐tert‐butylisophthalate (tbip) ligand afforded the 1D chain coordination polymer {[Cu(tbip)(3‐pina)₂(H₂O)]·H₂O}_n ( 7 ), which contains isolated copper ions in contrast to 1 – 6 , and has a curious “butterfly“ resemblance. Very weak antiferromagnetic coupling is seen within the {Cu₂(OCO)₂} dimeric units in 1 . Thermal decomposition behavior is also discussed.     

Tuning the topological net of two new copper(II) coordination polymers based on a paddle-wheel secondary building unit via altering the auxiliary ligands

Two new coordination polymers, [Cu(BDC)(L₁)_0.5]_n (1) and [Cu(BDC)(L₂)_0.5]_n (2) [H₂BDC=5-methyl-1,3-benzenedicarboxylic acid, L₁=1,4-bis(2-methyl-imidazol-1-yl) butane and L₂=1,4-bis(1-imidazol-yl)-2,5-dimethylbenzene], were synthesized from Cu(II), H₂BDC, and L₁/L₂. The carboxylate groups in 1 and 2 are bis-monodentate. By changing the N-donor ligands, 1 and 2 exhibit different topologies from a rob topological net to a twofold interpenetrating pcu net; however, they possess the same paddle-wheel secondary building unit in which Cu(II) has square-pyramidal geometry. The thermal stabilities of 1 and 2 are investigated.     

Four distinctive 1-D lanthanide carboxylate coordination polymers: Synthesis,crystal structures and spectral properties

Four novel lanthanide coordination polymers [Pr(mal)(OH)(bipy) · 2H₂O]_n (1), {[Dy¹(SBA)₃(H₂O)₂][Dy²(SBA)₃(H₂O)₂] · 4H₂O}_n (2), {[Tb(OHnic)(Onic)(H₂O)₅ · (OHnicH)] · H₂O}_n (3) and {[Sm(OHnic)(Onic)(H₂O)₅ · (OHnicH)] · H₂O}_n (4) (Hmal = maleic acid, HSBA = 4-sulfobenzoic acid, OHnicH = 6-hydroxynicotinic acid and bipy = 2,2′-bipyridine) have been synthesized and determined by single crystal X-ray diffraction. Complex 1 is a 1-D helical chain with seven-coordinated praseodymium centers. Complex 2 forms 1-D chain-like molecular structure containing two crystallographically unique dysprosium centers, the Dy¹ center is seven-coordinated while Dy² is eight-coordinated. The isomorphous complexes 3 and 4 exhibit an unprecedented 1-D chain-like polymeric structure through hydroxyl oxygen atoms of bridging Onic²⁻ anions linking up the neighboring central ions, and there exist three types of 6-OHnicH ligands in the structural unit which is rare for lanthanide carboxylate complexes. The photophysical properties of these complexes were studied using ultraviolet absorption spectra, fluorescence excitation and emission spectra.     

Insight understanding into influence of binding mode of carboxylate with metal ion on ligand-centered luminescence properties in Pb-based coordination polymers

In the crystal engineering area,it is important to clearly demonstrating the relationship of structure and certain functionality.Herein,we present the study of the relationship of structure with phosphorescent nature for two new room temperature phosphorescence(RTP) coordination polymers(CPs).[Pb(FDA)(H_2 O)](1) and [NH_3(CH_3)NH_2(CH_3)_2][Pb_4(FDA)_5](2),where H_2 FDA is 2,5-furandicarboxylic acid,have been synthesized by solvothermal method using different solvents and Pb~(2+) sources and characterized by microanalysis,powderX-ray diffraction(PXRD),thermogravimetric(TG),IR and UV-vis spectra.The Pb~(2+)ions adopt bicapped triangle prism coordination sphere in 1 and 2,which are connected together via FDA~(2-) ligands into bilayer structure in 1 while pillared-layer framework in 2.The FDA~(2-) ligands show different bridging modes in 1 and 2,leading to distinct coordination interactions between Pb~(2+) ion and FDA~(2-) ligand in both CPs.Both 1 and 2 emit ligand-centered RTP due to the heavy atom of Pb~(2+) ion,with a lifetime and quantum yield of 0.62 ms and 14.9% in 1 versus 1.69 ms and 15.7% in 2.The emission peak shows significant redshift(79 nm) in 2 regarding 1,which arises from their distinction of coordination interactions between Pb~(2+) ion and FDA~(2-) ligand in both CPs.     

Two fluorescent coordination polymers constructed from mixed rigid and flexible carboxylate ligands: Formation of cross-linking helical and zigzag chains

Two 3D coordination polymers with different structure motifs, [Zn₂(PCPA)₂(IN)₂]_n (1) and [Co(PCPA)(IN)]_n (2) (PCPA=p-chlorophenoxyacetate, IN=isonicotinate), first constructed from mixed rigid and flexible carboxylate ligands, have been obtained under hydrothermal condition and characterized by elemental analyses, IR spectra, thermogravimetric analysis, fluorescent spectra and single crystal X-ray diffraction analysis. The most intriguing structural feature is that each complex exhibits both infinite helical Zn(μ₂-carboxylate) or Co(μ₃-carboxylates) chain units with 2₁ helices and zigzag M₂(IN)₂ (M=zinc and cobalt) chain units by reason of two different carboxylate ligands coordinating to metal centers. Additionally, compounds 1 and 2 show similar blue fluorescence in the solid state at room temperature.     

Synthesis,crystal structure and magnetism of a two-dimensional Ni(II) coordination polymer with thiocyanate anion and dehydrogen-1,10-phenanthrolin-2-ol as bridging ligands

A two-dimensional coordination polymer [Ni(μ_1,3-SCN)(μ-Pheno)(CH₃OH)] _n (where Pheno = dehydrogen-1,10-phenanthrolin-2-ol) has been synthesized and its crystal structure determined by X-ray crystallography. Adjacent Ni(II) ions are coordinated by μ_1,3-SCN^? and μ-Pheno alternately forming a two-dimensional sheet structure. The fitting of the variable-temperature magnetic susceptibilities with a binuclear nickel(II) formula reveals that there is an anti-ferromagnetic interaction between the bridging Ni(II) ions with the magnetic coupling constant 2J = ?0.67 cm^?1.     

Three-dimensional acentric coordination polymers formed from the linkage of cobalt and nickel malonate quadratic layers through a kinked organodiimine: Synthesis,structure, thermal properties and magnetochemistry

Hydrothermal synthesis has afforded a pair of isostructural acentric three-dimensional coordination polymers {[M₂(malonate)₂(dpa)(H₂O)₂] · 2H₂O}_n (M = Co, 1; M = Ni, 2; dpa = 4,4′-dipyridylamine), which were structurally characterized via single-crystal X-ray diffraction and spectroscopically and thermally analyzed. Both materials exhibit exotridentate malonate ligands conjoining metal atoms into grid-like [M(malonate)(H₂O)]_n layers; in turn, these are connected into 3-D sqp lattices (4⁴6⁶ topology) through tethering dpa ligands. The central kink and inter-ring torsion within the dpa ligands enforces the acentric Aba2 space group of crystals of 1 and 2. Antiferromagnetic coupling (g = 2.08(2), J = –1.05(8) cm⁻³) was observed within the malonate-bridged layer motifs within the cobalt derivative 1. In contrast, the nickel congener 2 exhibited ferromagnetic coupling (g = 2.201(1), J = 0.289(1) cm⁻³).