Self-assembly Of Coordination Polymers Research Articles

Supramolecular Frameworks and a Luminescent Coordination Polymer from New β-Diketone/Tetrazole Ligands

Mixed multidentate linkers with donor groups of different types can be fruitfully exploited in the self-assembly of coordination polymers (CPs) and Metal-Organic Frameworks (MOFs). In this work we develop new ligands containing a β-diketone chelating functionality, to better control the stereochemistry at the metal center, and tetrazolyl multidentate bridging groups, a combination not yet explored for networking with metal ions. The new ligands, 1,3-bis(4-(1H-tetrazol-5-yl)phenyl)-1,3-propanedione (H3L1) and 1-phenyl-3-(4-(1H-tetrazol-5-yl)phenyl)-1,3-propanedione (H2L2), are synthesized from the corresponding nitrile precursors by [2+3] dipolar cycloaddition of azide under metal-free catalytic conditions. Crystal structure analysis evidences the involvement of tetrazolyl fragments in multiple hydrogen bonding giving 2D and 1D supramolecular frameworks. Reactivity of the new ligands with different metal salts indicates good coordinating ability, and we report the preparation and structural characterization of the tris–chelate complex [Fe(HL1)3]3− (1) and the homometallic 2D CP [ZnL2(DMSO)] (2). In compound 1 only the diketonate donor is used, whereas the partially deprotonated tetrazolyl groups are involved in hydrogen bonding, giving rise to a 2D supramolecular framework of (6,3)IIa topological type. In compound 2 the ligand is completely deprotonated and uses both the diketonate donor (chelating) and the tetrazolate fragment (bridging) to coordinate the Zn(II) ions. The resulting neutral 2D network of sql topology shows luminescence in the solid state, which is red shifted with respect to the free ligand. Interestingly, it can be easily exfoliated in water to give a luminescent colloidal solution.

Fine Tunable, Redox Active Octapalladium Chains Supported by Linear Tetraphosphines, Leading to Dynamically 1D Self-Assembled Coordination Polymers.

A series of the octapalladium chains supported by meso-Ph2 PCH2 P(Ph)CH2 P(Ph)CH2 PPh2 (meso-dpmppm) ligands, [Pd8 (meso-dpmppm)4 (L)2 ](BF4 )4 (L=none (1), solvents: CH3 CN (2 a), dmf (2 b), dmso (2 c), RN≡C: R=Xyl (3 a), Mes (3 b), Dip (3 c), t Bu (3 d), Cy (3 e), CH3 (CH2 )7 (3 f), CH3 (CH2 )11 (3 g), CH3 (CH2 )17 (3 h)) and [Pd8 (meso-dpmppm)4 (X)2 ](BF4 )2 (X=Cl (4 a), N3 (4 b), CN (4 c), SCN (4 d)), were synthesized by using 2 a as a stable good precursor, and characterized by spectroscopic (IR, 1 H and 31 P NMR, UV-vis-NIR, ESI-MS) measurements and X-ray crystallographic analyses (for 1, 2 a, b, 3 a, b, e, f, 4 a-d). On the basis of DFT calculations on the X-ray determined structure of 2 b ([2b-Pd8 ]4+ ) and the optimized models [Pd8 (meso-Ph2 PCH2 P(H)CH2 P(H)CH2 PH2 )4 (CH3 CN)2 ]4+ ([Pd8 Ph8 ]4+ ) and [Pd8 (meso-H2 PCH2 P(H)CH2 P(H)CH2 PH2 )4 (CH3 CN)2 ]4+ ([Pd8 H8 ]4+ ), with and without empirically calculating dispersion force stabilization energy (B3LYP-D3, B3LYP), the formation energy between the two Pd4 fragments is assumed to involve mainly noncovalent interactions (ca. -70 kcal/mol) with four sets of interligand C-H/π interactions and Pd⋅⋅⋅Pd metallophilic one, while electron shared covalent interactions are almost canceled out within the Pd8 chain. All the compounds isolated are stable in solution and exhibit characteristic absorption at ∼900 nm, which is assignable to a spin allowed HOMO to LUMO transition, and shows temperature dependent intensity change with variable absorption coefficients presumably due to coupling with some thermal vibrations. The structures and electronic states of the Pd8 chains are found finely tunable by varying the terminal capping ligands. In particular, theoretical calculations elucidated that the HOMO-LUMO energy gap is systematically related to the central Pd-Pd distance (2.7319(6)-2.7575(6) Å) by two ways with neutral ligands L (1, 2, 3) and with anionic ligands X (4), which are reflected on the NIR absorption energy of 867-954 nm. The isocyanide terminated Pd8 complexes (3) further reacted with excess of RNC (6 eq) to afford the Pd4 complexes, [Pd4 (meso-dpmppm)2 (RNC)2 ](BF4 )2 (13), and the cyclic voltammograms of 2 a (L=CH3 CN), 3, and 13 (R=Xyl, Mes, t Bu, Cy) demonstrated wide range redox behaviors from 2{Pd4 }4+ to 2{Pd4 }0 through 2{Pd4 }2+ ↔{Pd8 }4+ , {Pd8 }3+ , and {Pd8 }2+ strings. The oxidized complexes, [Pd4 (meso-dpmppm)2 (RNC)3 ](BF4 )4 (16), were characterized by X-ray analyses, and the two-electron reduced chain of [Pd8 (meso-dpmppm)4 ](BF4 )2 (7) was analyzed by spectroscopic and electrochemical techniques and DFT calculations. Reactions of 2 a with 1 equiv. of aromatic linear bisisocyanide (BI) in CH2 Cl2 deposited insoluble coordination polymers, {[Pd8 (meso-dpmppm)4 (BI)](BF4 )4 }n (5), and interestingly, they were soluble in acetonitrile, 31 P{1 H} and 1 H DOSY NMR spectra as well as SAXS curves suggesting that the coordination polymers may exist in acetonitrile as dynamically 1D self-assembled coordination polymers comprising ca. 50 units of the Pd8 rod averaged within the timescale.

Variations of structures on changing the ratios of metal ions in rare Ca(II)–Zn(II) hetero-metallic self-assembled coordination polymers of hexamethylenetetramine and benzoate

Two rare hetero-metallic calcium(II)-zinc(II) complexes [CaZn4(OBz)10(μ2-hmt)2]n (1) and [Ca2Zn4(OBz)12(μ2-hmt)2]n (2) have been synthesized using basic zinc carbonate, benzoic acid (HOBz), hydrated calcium chloride and hexamethylenetetramine (hmt) by varying the molar ratio of the reactants. Both the complexes have been analyzed by elemental analysis, IR spectroscopy and X-ray crystallography. The complex 1 is a 1D polymer which contains one calcium ion and four zinc atoms in the asymmetric unit together with ten benzoates and two hmts. The polymer has been constructed by the alternate joining of paddle-wheel Zn2(OBz)4 units and Zn2Ca trinuclear species by μ2-hmt bridging molecules connecting Zn2+ ions. Zinc atoms have five coordinate square pyramidal geometries and four coordinate tetrahedral geometries in Zn2(OBz)4 and Zn2Ca moieties, respectively, whereas calcium atoms have six-coordinate distorted octahedral geometry. Complex 2 is also a 1D polymer but unlike complex 1, it contains four independent zinc and two independent calcium atoms in the asymmetric unit together with twelve benzoates and two hmts. By contrast, the polymeric structure of complex 2 has been formed by the connection of Zn2Ca trinuclear species via μ2 hmt bridging molecules at Zn centers. Complex 2 is also a 1D polymer but unlike complex 1, it contains four independent zinc and three independent calcium atoms in the asymmetric unit together with twelve benzoates and two hmts. All four zinc atoms are four coordinate with tetrahedral environments and the calcium atoms are six coordinated (two are located on a center of symmetry) exhibiting a distorted octahedral geometry.

Multi-dimensional copper(I) and silver (I) coordination polymers assembled with a pyridyl bis-urea macrocyclic ligand

We report the synthesis of a new flexible multimodal macrocyclic ligand, protected pyridyl bis-urea macrocycle 1, and two of its coordination polymers Cu2I2(1)2·(CH3CN)1.63 (2) and [Ag(1)](NO3).(H2O)2.49 (3). The ligand possesses conformational flexibility and adopts different conformations and binding modes depending on the metal ions. The crystal structure of 2 shows a 2D coordination network constructed from rhomboidal Cu2I2 dimer units and 1 as a bridging ligand binding through the pyridyl N atoms. 3 forms a sophisticated 3D structure with 1D chains formed by N-Ag-N links between pyridyl N atoms of two adjacent macrocyclic ligands and Ag(I) ions. These chains form 2D layers through longer Ag-O interactions and the chains are linked together into a 3D network by hydrogen bonding involving interstitial water molecules. These results indicate the potential of ligand 1 in the self-assembly of coordination polymers with diverse topology and functional applications.

Synthesis of carboxy-cyclobutane isomers combining an amide bond and self-assembly of coordination polymers in the solid state: controlling the reaction site of [2 + 2] cycloaddition by introducing a substituent group

Combining an amide bond and self-assembly of CPs by solid-state [2 + 2] cycloaddition reactions to synthesize stereoselectively carboxy-cyclobutane isomers.

Self-assembly of coordination polymers on plasmonic surfaces for computer vision decodable, unclonable and colorful security labels

An unclonable, colorful, and computer vision decodable anti-counterfeiting label is fabricated by self-assembly of coordination polymers on plasmonic surfaces. The physics behind the colors on the security label is surface plasmon enhanced optical interference.

A new twofold interpenetrated two-dimensional cadmium(II) coordination polymer constructed from 2,2'-(benzene-1,4-dicarboxamido)dipropionate.

In recent years, much initial interest and enthusiasm has focused on the self-assembly of coordination polymers due to the aesthetics of their crystalline architectures and their potential applications as new functional materials. As part of an exploration of chiral coordination polymers, a new twofold interpenetrated two-dimensional (2D) coordination polymer, namely, poly[[tetraaquabis[μ3-(2R,2'R)-2,2'-(benzene-1,4-dicarboxamido)dipropionato-κ5O,O':O'',O''':O'']dicadmium(II)] trihydrate], {[Cd2(C14H14N2O6)2(H2O)4]·3H2O}n, has been synthesized by the reaction of Cd(CH3COO)2·2H2O with the designed ligand (2R,2'R)-2,2'-(benzene-1,4-dicarboxamido)dipropionic acid (H2L). The compound has been structurally characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction and single-crystal X-ray diffraction analysis. In the crystal structure, each CdII cation binds to three carboxylate groups from two crystallographically independent L2- dianions. Four carboxylate groups link two crystallographically independent cadmium cations into a 4,4-connected secondary building unit (SBU). The resulting SBUs are extended into a two-dimensional folding sheet via the terephthalamide moiety of the ligand as a spacer, which can be simplified as a (4,4)-connected 4,4L15 net with the point symbol (3.53.62)(32.52.62). In the lattice, two independent folding sheets interpenetrate each other to yield a double-sheet layer. The resulting 2D layers pack in parallel arrays through intermolecular hydrogen bonds and interlayer π-π interactions. The thermal stability and photoluminescence properties of the title compound have been investigated and it exhibits an enhanced fluorescence emission and a longer lifetime compared with free H2L.

Self-assembled coordination polymers of Zn(II): Syntheses, structural diversity, luminescence properties and base catalysis

Two new Zn(II) metal–organic networks, {[Zn(µ1-muco)(4bpdh)(H2O)]·H2O} (1) and {[Zn2(µ3-muco)2(µ-3bpdb)2(H2O)]·6H2O}n (2) (where, muco = trans,trans-muconate dianion, 4bpdh = 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene and 3bpdb = 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene) were synthesized at room temperature. Single-crystal X-ray structural determination revealed that compound 1 possesses a 1D coordination polymeric chain extended to a 3D supramolecular framework via (HO⋯H and OH⋯N) hydrogen bonding interactions and compound 2 has a 3D pillar-layered framework with 7-connected, {33·47·58·63} net topology. Photoluminescence measurements of 1 and 2 showed ligand based emissions owing to intra ligand and/or ligand to ligand charge transfer {(π∗ → n and π∗ → π)} transitions. The thermal stabilities of the compounds 1 and 2 were also examined. Application of the compounds as heterogeneous catalysts for the Knoevenagel reaction showed higher catalytic activity of 2 over 1 which has been ascribed to the presence of exposed basic azine (CN) groups in the 1D channels of 2. The catalyst can be easily separated from the reaction mixture and reused for five cycles without significant loss in the catalytic activity. Herein, the influence of ancillary ligands on the structural and catalytic properties of two new Zn(II)–organic networks 1 and 2 has been presented.

Investigation of BINOL-3,3′-dicarboxylate as a ligand for the formation of extended coordination-based structures

We provide a structural study of the ability of BINOL-3,3′-dicarboxylate, an inexpensive and readily accessible 1,1′-binaphthol-based ligand, to form extended self-assembled coordination polymers and frameworks in combination with divalent zinc and copper ions. While the structural diversity of herein described materials illustrates the untapped potential of the BINOL-3,3′-dicarboxylate in forming coordination polymer structures, we also provide the first example of an open two-dimensional framework established using this ligand as the only anionic, metal-bridging constituent.

Controlled self-assembled coordination polymer and monomer by [Ni(mnt)2Cu4I4]2−

Controlled self-assembled coordination polymer and monomer by [Ni(mnt)₂Cu₄I₄]²⁻

Electron-Triggered Metamorphism in Porphyrin-Based Self-Assembled Coordination Polymers.

Viologen-centered electron transfer is used to trigger a complete dissociation of a porphyrin-based supramolecular architecture. In the oxidized state, self-assembly is induced by iterative association of individual porphyrin-based tectons. Dissociation of the self-assembled species is actuated upon changing the redox state of the bipyridium units involved in the tectons from their dicationic state to their radical cation state, the driving force of the disassembling process being the formation of an intramolecularly locked conformation partly stabilized by π-dimerization of both viologen cation radicals.

A new three-dimensional manganese(II) coordination polymer based on the 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene ligand.

The self-assembly of coordination polymers and the crystal engineering of metal-organic coordination frameworks have attracted great interest, but it is still a challenge to predict and control the compositions and structures of the complexes. Employing multidentate organic ligands and suitable metal ions to construct inorganic-organic hybrid materials through metal-ligand coordination and hydrogen-bonding interactions has become a major strategy. Recently, imidazole-containing multidentate ligands that contain an aromatic core have received much attention. A new three-dimensional MnII coordination polymer based on 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene, namely poly[(ethane-1,2-diol-κO)(μ-sulfato-κ2O:O'){μ3-1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene-κ3N:N':N''}manganese(II)], [Mn(SO4)(C18H18N6)(C2H6O2)]n, was synthesized and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Crystal structural analysis shows that there are two kinds of crystallographically independent MnII centres, each lying on a centrosymmetric position and having a similar six-coordinated octahedral structure. One is coordinated by four N atoms from four 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene (timb) ligands and two O atoms from two different bridging sulfate anions. The second is surrounded by two timb N atoms and four O atoms, two from sulfate anions and two from two ethane-1,2-diol ligands. The tripodal timb ligand bridges neighbouring MnII centres to generate a two-dimensional layered structure running parallel to the ab plane. Adjacent layers are further bridged by sulfate anions, resulting in a three-dimensional structure with 3,4,6-c topology. Thermogravimetric analysis of the title polymer shows that it is stable up to 533 K. The first weight loss between 533 and 573 K corresponds to the release of coordinated ethane-1,2-diol molecules, and further decomposition occurred at 648 K.

Utilization of mixed ligands to construct diverse Ni(II)-coordination polymers based on terphenyl-2,2′,4,4′-tetracarboxylic acid and varied N-donor co-ligands

Three new coordination polymers, namely, {[Ni(H2L)(bix)(H2O)2]·2h2O}n (1), {[Ni(HL)(Hdpa)(H2O)2]·H2O}n (2), {[Ni(L)0.5(bpp)(H2O)]·H2O}n (3) (H4L=terphenyl-2,2′,4,4′-tetracarboxylic acid; bix=1,4-bis(imidazol-1-ylmethyl)benzene; dpa =4,4′-dipyridylamine; bpp=1,3-bis(4-pyridyl)propane), based on rigid H4L ligand and different N-donor co-ligands, have been synthesized under hydrothermal conditions. Compound 1 features a 3D 4-connected 66-dia-type framework with H4L ligand adopts a μ2-bridging mode with two symmetry-related carboxylate groups in μ1-η1:η0 monodentate mode. Compound 2 displays a 1D [Ni(HL)(Hdpa)]n ribbon chains motif, in which the H4L ligand adopts a μ2-bridging mode with two carboxylate groups in μ1-η1:η1 and μ1-η1:η0 monodentate modes, while 3 possesses a (4,4)-connected 3D frameworks with bbf topology, with H4L ligand displays a μ4-bridging coordination mode. The H4L ligand displays not only different deprotonated forms but also diverse coordination modes and conformations. The structural diversities among 1–3 have been carefully discussed, and the roles of N-donor co-ligands in the self-assembly of coordination polymers have been well documented.

Anion-dependent construction of a series of fluorescent coordination polymers based on 1D zinc∩4,4′-bis(imidazol-1-yl)-biphenyl substrates

In this work, the rod-like ligand 4,4′-bis(imidazol-1-yl)-biphenyl (bibp) has been utilized as a building block to carry out counterion effects on the structural diversities of coordination polymers. A series of new zinc complexes, [Zn(trans-bibp)Cl2]∞ (1), [Zn(trans-bibp)Br2]∞ (2), {[Zn(cis-bibp)(Ac)2]·(H2O)}∞ (3), [Zn(trans-bibp)SO4]∞ (4), {[Zn2(cis-bibp)2(ipa)2]·(H2O)}∞ (5, H2ipa=isophthalic acid) and {[Zn(trans-bibp)(cis-bibp)]·(ClO4)2(CHCl3)2(CH3OH)}∞ (6) have been successfully synthesized. Complexes 1 and 2 are iso-structural, which show a 1D W-type chain [Zn(trans-bibp)]∞. Complex 3 exhibits a 2D wave-like layer formed by the hydrogen bond among the 1D linear chain [Zn(cis-bibp)]∞. Complex 4 displays a 2D fish-bone lattice, which is generated from connecting the 1D W-type chain [Zn(trans-bibp)]∞ by the μ2-SO42-. Complex 5 presents an interesting 2D–3D 65·8 architecture, including two 1D chains [Zn(ipa)]∞ and [Zn(cis-bibp)]∞. Complex 6 demonstrates a 2D wave-like layer [Zn(trans-bibp)(cis-bibp)]∞. The structural diversities among 1–6 have been carefully discussed, and the role of counterion in the self-assembly of coordination polymer have also been well documented from the coordination affinity and bridging mode. Furthermore, the solid-state fluorescence properties of 1–6 at room temperature have been studied.

Anion effect on the topological frameworks of a series of manganese coordination polymers based on 1,4-bis(imidazol-1-yl)-benzene: Syntheses, crystal structures and magnetic properties

In this work, the rod-like ligand 1,4-bis(imidazol-1-yl)-benzene (bib) has been utilized as a building block to perform counterion researches on the structural diversities of coordination polymers. A series of new manganese compounds, {[Mn(bib)3(ClO4)2](CHCl3)2}n (1), [Mn(bib)2(N3)2]n (2), [Mn(bib)2(HCO2)2]n (3), [Mn(bib)2(Ac)2]n (4), {[Mn(bib)2(CF3SO3)2](CH2Cl2)4}n (5), and [Mn(bib)2(SO4)]n (6) have been successfully synthesized. Compound 1 shows a 3D interpenetrating α-Po network only based on the bib linker. Compounds 2 and 3 exhibit a 2D (4,4) layer with parallel and incline interpenetration, respectively. Compounds 4 and 5 display a parallel-packing 2D (4,4) layer with the porosity of 23.4% and 61.4%, respectively. Compound 6 furnishes a 3D α-Po framework with a 2D (4,4) layer pillared by the μ2-SO42− ion. The structural diversities among 1–6 have been carefully discussed, and the roles of counterions (from coordination affinity and molecular size) in the self-assembly of coordination polymers have also been well documented. Furthermore, magnetic properties of 6 have been carefully studied.

Facile Deposition of Multicolored Electrochromic Metal–Organic Framework Thin Films

The construction of well-defined organic architectures on solid surfaces is a key step toward the development of more efficient and robust electronic devices. Indeed, a number of self-assembly strategies have been applied to building supramolecular structures for use in devices such as organic lightemitting diodes (OLEDs), organic transistors, and solar cells. Recently, self-assembled coordination polymers, namely crystalline, microporous metal-organic frameworks (MOFs), have received considerable attention for their potential in a number of applications, including electronic devices. The solvothermal methods used to synthesize MOF materials generally afford bulk single crystals or microcrystalline powders and, as a result, a number of methods have been developed to process MOFs as thin films, which are generally more desirable for use in devices. However, MOFs still face a number of challenges in this area, particularly with regard to their insulating nature. The incorporation of redox-active organic linkers represents one strategy toward improving the charge transport properties of MOF materials as well as imparting a response to electrochemical stimuli. In the latter case, the use of colorswitching, redox-active organic linkers might be considered for the design of new, color-tunable electrochromic materials. Inorganic materials such as metal oxides and Prussian blue analogs have been extensively studied for electrochromic applications. More recently, conducting organic polymers such as polythiophenes have received considerable attention owing to their greater color tunability and efficiency, and faster switching times. Despite significant advances, the need still exists for more easily synthesized and processable electrochromic materials with the same or greater degree of tunability. In this sense, the well-defined structures, selfassembly synthesis, and guest-accessible microporosity of MOFs might prove useful for their application in this field. Herein, we describe the solvothermal deposition and electrochemical properties of porous, micron-thick Zn-pyrazolate MOF films containing redox-active naphthalene diimide (NDI) linkers. NDIs have been extensively studied for their electron accepting properties which make them attractive as n-type semiconductors. Furthermore, core substitution of NDIs with electron donor groups results in the appearance of charge-transfer transitions in the visible spectrum, affording color-tunable and sometimes fluorescent dyes with applications in optoelectronics and sensing. A handful of MOFs containing NDI-based linkers have been reported and studied as gas sorption, photochromic, and fluorescent sensor materials. However, studies of their electrochemical properties remain scarce. Here, we show that processing them as homogeneously dispersed thin films enables their use as multicolored electrochromic devices. Our group has been concerned with developing modular syntheses for water-stable pyrazolate-based MOFs, and recently we described a series of core-substituted NDIbased materials. These MOFs (Zn(NDI-X), Figure 1) were obtained as microcrystalline powders by heating 1.1:1

Structural variations in self-assembled coordination polymers constructed by some carboxylate bridged di-copper(II) nodes and hexamethylenetetramine spacers

Four new copper(II)-hexamethylenetetramine (hmt) complexes [Cu3(2-nbz)6(μ2-hmt)]n (1), [Cu3(pa)6(μ3-hmt)]n (2), [Cu3(4-nbz)6(μ3-hmt)]n (3) and [Cu(3-nbz)2(μ4-hmt)·H2O]n (4) with three isomeric nitrobenzoates, [2-nbz=2-nitrobenzoate, 3-nbz=3-nitrobenzoate, 4-nbz=4-nitrobenzoate] and phenylacetate (pa) have been synthesized and structurally characterized by X-ray crystallography. Their identities have also been established by elemental analysis and IR studies. In all four complexes, the respective [Cu2(carboxylato)4] unit with four bridging carboxylate ligands in the familiar η1:η1:μ coordination mode acts as a linear node whereas the spacer hmt coordinates in different ways which result in the observed structural variations. Complex 1 is a 1D zigzag polymer where hmt acts as angular spacer. In complexes 2 and 3, μ3-hmt is pyramidal and the resulting structures are 2D polymers with fused hexagonal rings. Complex 4 is a very rare example of a 3D diamondoid polymer with μ4-hmt acting as a tetrahedral spacer. Various weak forces, i.e. lone pair–π, π–π and CH–π interactions, play a key role in stabilizing the observed structures.

Synthesis and characterization of self-assembled coordination polymers of N-diaminomethylene-4-(3-formyl-4-hydroxy-phenylazo)-benzenesulfonamide

The azo dye ligand N-diaminomethylene-4-(3-formyl-4-hydroxy-phenylazo)-benzenesulfonamide (HL) and Cu(II), Co(II), and Mn(II) coordination polymers were synthesized in addition to a non-polymeric Pd(II) complex. In all complexes, the ligand bonds to the metal ion through the formyl and α-hydroxy oxygen atoms. The sulfonamide oxygen also coordinates to the metal. The complexes are formulated as [ML2] n , where M = Cu(II), Co(II), and Mn(II), and [ML(Cl)(H2O)], where M = Pd(II). On the basis of spectral studies and magnetic susceptibility measurements, an octahedral geometry was assigned to Co(II) and Mn(II) complexes, tetragonally elongated octahedral geometry for Cu(II) complex, while the Pd(II) complex was found to be square planar. Crystallization of Cu(II) complex from DMF afforded single crystals of general formula {[Cu(L)2] · 3DMF} n (2). X-ray structural analysis of 2 revealed that each Cu(II) adopts elongated octahedral geometry affording 1-D chains. The chains are connected by hydrogen bonds, resulting in the formation of 2-D supramolecular assemblies. The crystal structure of HL has also been determined and discussed. Cyclic voltammetric behavior of the ligand and some complexes are also discussed.

A self-assembled non-interpenetrating cubic diamondoid coordination polymer of hexamine with linear dicopper spacer: Structural and magnetic studies

Abstract Structural characterization of a new self assembled coordination polymer of CuII, hexamine (hmt) and benzoate (OBz), [Cu4(OBz)8(hmt)]n (1), reveals that it is a cubic non-interpenetrating diamondoid network formed by the coordination of the μ4-hmt ligand to a linear [Cu2(OBz)4] spacer. The magnetic study reveals that the Cu(II) ions are antiferromagnetically coupled (J = − 323.5 cm−1) through the syn–syn carboxylate bridges.

A Molecular Basketwork: Self-Assembly of Coordination Polymers from Zn(II) and Biphenyl-3,4′-dicarboxylate Regulated by Different Flexible Bridging and Chelating N-Donor Ancillary Ligands

Four low-dimensional coordination polymers, [Zn2(bpdc)2(dib)2]n·nH2O (1), [Zn(bpdc)(phen)]n·2nH2O (2), [Zn(bpdc)(bpy)]n·2nH2O (3), and [Zn(bpdc)(H2O)]n (4), (H2bpdc = biphenyl-3,4′-dicarboxylic acid, dib = 1,4-di(1H-imidazol-2-yl)butane, phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine), have been successfully prepared under hydrothermal conditions and characterized by IR, single crystal X-ray diffraction, thermogravimetric analysis (TGA), and luminescence analyses. Self-assembly behaviors of these polymers were entirely directed by N-donor ancillary coligands (bridging or chelating). Complex 1 displays an interesting novel two-dimensional (2D) basketwork, in which Zn(II) ions are knitted by both organic molecules, biphenyl-3,4′-dicarboxylic acid and 1,4-di(1H-imidazol-2-yl)butane, to form an infinite network. Polymers 2 and 3 are infinite zigzag helical chains, and both terminated ligands in 2 and 3 prevent self-assembly to higher dimensional polymers. In 4, a water molecule occupies one of four coordin...