Dipyridyl Coligands Research Articles

A structural study into halogenated derivatives of mandelic acid as building blocks of chiral coordination polymers

Mandelic acid and its derivatives are an excellent source of chirality for the construction of chiral coordination polymers (CPs) and metal-organic frameworks (MOFs) for enantioselective applications. To date, limited reports exist for the incorporation of mandelic acid derivatives with halogen substituents such as fluorine and chlorine despite the extra intermolecular interactions possible. The extra sites for hydrogen and halogen bonding in these mandelic acid derivatives may afford interesting modes of coordination and packing in 3 D space. Six CPs containing mandelic acid and its halogenated analogues, (R)-2-chloromandelic acid, 3,5-difluoromandelic acid, 4-trifluoromethylmandelic acid, together with linear dipyridyl co-ligands are reported. These structures consist of three 2 D sql sheets and three 1 D chains with a range of packing motifs influenced by the differing intermolecular interactions present.

Crystal Structures and Fluorescent Properties of Two Distinct 2D Ag(I)/Cd(II) Coordination Polymers Based on Isonicotinic Acid Derivative and Dipyridyl Coligand

Crystal Structures and Fluorescent Properties of Two Distinct 2D Ag(I)/Cd(II) Coordination Polymers Based on Isonicotinic Acid Derivative and Dipyridyl Coligand

Co(ii) coordination polymers constructed from a bent chiral linker: influencing framework topology using co-ligands

The reaction of a semi-rigid chiral ligand with Co(ii) and dipyridyl co-ligands of varying length yielded a series of 2D coordination frameworks, with the topology of the network mediated by the length of the co-ligands.

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.

Diverse 2D and 3D topologies in cobalt cyclohexyldicarboxylate coordination polymers with bis(4-pyridylmethyl)piperazine coligands

Hydrothermal reaction of cobalt nitrate, a cyclohexyldicarboxylic acid, and the long-spanning dipyridyl coligand bis(4-pyridylmethyl)piperazine (bpmp) produced four structurally diverse coordination polymers which were characterized by single-crystal X-ray diffraction. [Co(cis-12chedc)(bpmp)]n (1, cis-12chedc = cyclohex-4-ene-1,2-cis-dicarboxylate) possesses a 3D pcu network based on embedded {Co2(OCO)2} dimeric units. {[Co(cis-13cdc)(bpmp)(H2O)]·2H2O}n (2, cis-13cdc = cyclohexane-1,3-cis-dicarboxylate) exhibits (4,4) sawtooth coordination polymer layers polycatenated in a 2D + 2D → 3D parallel fashion. {[Co2(cis-14cdc)2(bpmp)]·2H2O}n (3, cis-14cdc = cyclohexane-1,4-cis-dicarboxylate) also shows (4,4) grid layer structures, but without any interpenetration. {Co2(OCO)4} paddlewheel dimers are seen in chain-like substructures in 3. The minor phase [Co(cis-14cdc)(bpmp)(H2O)2]n (4) was isolated along with 3 and manifests a non-interpenetrated 658 cds topology 3D network. Thermal properties of 1–3 were also investigated. Variable temperature magnetic susceptibility studies showed dimer-based antiferromagnetic behavior for 1 and 3.

Structural diversity and variable temperature magnetic properties in copper dimethylmalonate coordination polymers containing dipyridyl-type coligands

Four copper dimethylmalonate (dmmal) phases containing long-spanning dipyridyl coligands have been prepared and structurally characterized by single-crystal X-ray diffraction. {[Cu2(dmmal)2(edin)(H2O)2]·3H2O}n (1, edin = N,N′-(ethane-1,2-diyl)diisonicotinamide) and {[Cu2(dmmal)2(bdin)(H2O)2]·2H2O}n (2, bdin = N,N′-(butane-1,4-diyl)diisonicotinamide) both show (6,3) herringbone layers constructed from the edin pillaring of [Cu(H2O)(dmmal)]n chain motifs, that feature embedded equatorial-equatorial bridged {Cu(OCO)}n chains.[Cu2(dmmal)2(bpmp)]n (3, bpmp = bis(4-pyridylmethyl)piperazine) shows a decorated (4,4) grid topology built from bpmp pillared [Cu2(dmmal)2]n ribbon motifs, that feature embedded {Cu2(OCO)4} paddlewheel dimeric units. [Cu2(dmmal)2(bpfp)]n (4, bpfp = bis(4-pyridylformyl)piperazine) shows a 5-connected non-interpenetrated 3D 4466sqp topology, formed from the bpfp pillaring of rectangular equatorial-equatorial bridged [Cu2(dmmal)2]n layers. Variable temperature magnetic studies were carried out on 1, 2 and 4, indicating predominant ferromagnetic superexchange within their equatorial-equatorial {Cu(OCO)}n chain motifs.

A robust metallomacrocyclic motif for the formation interpenetrated coordination polymers

The reproducibility of an M2L2 metallomacrocyclic synthon containing L-alanine substituted naphthalene diimide ligands (AlaNDI), and its ability to form both catenane and rotaxane motifs, has been demonstrated in a series of nine homochiral coordination polymers. The planes of the NDIs that comprise the metallomacrocycle are ∼7 A apart, an ideal distance for an aromatic group to reside within the ring with multiple parallel π-interactions. The tendency for these systems to be dominated by π-interactions appears to be a driving force for interpenetration of these coordination polymers by either the formation of catenanes between two {M2(AlaNDI)2} metallomacrocycles or the formation of rotaxanes by dipyridyl coligands passing through metallomacrocycles (4,4′-bipyridine, dipyridylethene and dipyridylnaphthalenediimide). Due to both of these interpenetration motifs being facilitated by parallel π-interactions, the interpenetration of the individual networks does not typically lead to increased dimensionality in the structures, with the exception of one material in which a 1D chain interpenetrates in a 1D → 2D manner. Two of the reported coordination polymers, both containing dipyridylnaphthalenediimide (4PyNDI), are not interpenetrated with π-interactions present between the 4PyNDI ligands themselves rather than engaging with the macrocycles. Overall the reproducibility of the metallomacrocycle, and the relatively common occurrence of catenane and rotaxane motifs, suggests that this is a promising synthon for further crystal engineering applications.

Five water-soluble zwitterionic copper(II)-carboxylate polymers: role of dipyridyl coligands in enhancing the DNA-binding, cleaving and anticancer activities.

Five water-soluble zwitterionic copper-carboxylate polymers were prepared from the reaction of N-carboxymethyl-(3,5-dicarboxyl)pyridinium bromide (H3CmdcpBr) with Cu(NO3)2 in the presence of NaOH by modulating the temperature, solvent and ancillary dipyridyl ligands. These complexes include a 1D ladder-shaped polymer {[Cu3(Cmdcp)2(OH)2(H2O)2]·H2O}n () formed in H2O at room temperature, and a 2D network polymer {[Cu(Cmdcp) (H2O)2]·2H2O}n () isolated in H2O at 135 °C. At 100 °C in H2O/DMF, the same reaction in the presence of an additional 2,2'-bipyridine (bipy) gave a 2D zwitterionic complex {[Cu(Cmdcp)(bipy)]·3H2O}n () together with a 1D double-stranded polymer {[Cu(Cmdcp)(H2O)2]·H2O}n () as a minor product. The replacement of bipy with phenanthroline (phen) afforded a 1D zigzag polymer chain {[Cu(Cmdcp)(phen)(H2O)]2·9H2O}5 (). All these complexes were characterized by IR, elemental analyses and single crystal X-ray crystallography. Agarose gel electrophoresis (GE) and ethidium bromide (EB) displacement experiments indicated that complex exhibited the highest pBR322 DNA cleaving ability with the catalytic efficiency (kmax/KM) of 14.80 h(-1) mM(-1) and the highest binding affinity toward calf-thymus DNA. The MTT assay indicated that complex showed significant inhibitory activity toward the proliferation of several tumor cells. Its IC50 value was at micromolar level and lower than those of cisplatin and complexes , especially toward resistant lung adenocarcinoma cell A549.

Distinct 3D CdII Coordination Polymers with 1,2-Naphthalenedicarboxylate Regulated by Dipyridyl Co-Ligands with Different Spacers

Two distinct three-dimensional (3D) CdII coordination polymers with 1,2-naphthalenedicarboxylate (ndc2–) and dipyridyl co-ligands have been synthesized under hydrothermal conditions. Interestingly, the slight difference in the two 4,4′-dipyridyl building blocks, namely, 1,2-bi(4-pyridyl)ethane (bpp) and 1,2-bi(4-pyridyl)ethene (bpe) with C–C or C=C spacers, results in the significant structural divergence of the resultant coordination polymers. Structural analysis reveals that complexes [Cd(ndc)(bpp)(H2O)]n (1) and {[Cd5(ndc)4(bpe)2(OH)2](H2O)1.5}n (2) are constructed by discrete metal–carboxylate dimeric units and metal–carboxylate chains, respectively, which are further extended by bpp or bpe linkers to form the inclined interpenetrated two-dimensional (2D)→3D network for 1 and the 3D porous framework for 2. This result reveals that the flexibility of auxiliary ligands plays an important role in the structural assemblies of coordination networks. The thermal and luminescence properties of both complexes were also investigated in solid state.

Varied Layer Topologies in Luminescent Zinc Coordination Polymers with Flexible Aromatic ortho‐Dicarboxylate and Dipyridyl Ligands

AbstractHydrothermal synthesis has afforded four divalent zinc flexible‐arm aromatic ortho‐dicarboxylate coordination polymers containing dipyridyl coligands. According to X‐ray crystallography, all four show layered coordination polymer structures. Nevertheless there is significant ligand influence on the nature of zinc atom aggregation and overall topology. In both {[Zn2(hmph)2(dpa)2]·2H2O}n (1) (hmph = homophthalate, dpa = 4, 4′‐dipyridylamine), and {[Zn2(hmph)2(dpe)2](ClO4)2·H2dpe·4H2O}n (2) [dpe = bis(4‐pyridyl)ethane], large {Zn2(hmph)2} dimeric units are evident, along with an overall herringbone (6, 3) layer topology. The longer span of the dpe ligands results in larger incipient channels, which can accommodate protonated dpe dications and perchlorate counterions. In {[Zn2(hmph)2(3‐pna)]·H2O}n (3) (3‐pna = 3‐pyridylnicotinamide), {Zn2(OCO)2} anti‐syn bridged dimers and {Zn2(OCO)4} syn‐syn paddlewheel dimers coexist and are linked together by hmph and 3‐pna ligands into decorated (4, 4) grid coordination polymer layers. {[Zn(1, 2‐phda)(3‐pina)]·2H2O}n (4) (1, 2‐phda = 1, 2‐phenylenediacetate, 3‐pina = 3‐pyridylisonicotinamide) manifests an undulating (4, 4) grid structure with isolated zinc atoms; the “wavelength” of the layers measures over 40 Å. Luminescent properties of these materials are also reported.

Synthesis, Crystal Structure and Magnetic Properties of a Porous Manganese Coordination Polymer with N-[(4-Carboxyphenyl)-sulfonyl]glycine and 4,4′-dipyridyl

A new Mn coordination polymer, [Mn(cbsglyH)(bipy) (H2O)] n ·nH2O (1) (cbsglyH3 = N-[(4-carboxyphenyl)-sulfonyl] glycine], bipy = 4,4′-dipyridyl), was prepared by aqueous reactions of Mn(II) acetate with cbsglyH3 in the presence of 4,4′-dipyridyl co-ligand. Its crystal structure was determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses and IR spectra. In 1, cbsglyH3 link the Mn(II) ions to form 2D layers that are held together through 4,4′-dipyridyl molecules in a double-pillar supporting fashion to give a 3D porous framework. Moreover, the magnetic properties of the title complex were investigated and are discussed in detail.

Luminescent cadmium phenylenedipropionate coordination polymers with long-spanning dipyridine ligands

Hydrothermal synthesis has generated oxoanion-free divalent cadmium 1,4-phenylenedipropionate (phdp) coordination polymers containing either bis(4-pyridylmethyl)piperazine (bpmp) or bis(4-pyridylformyl)piperazine (bpfp) ligands. The coordination environment at cadmium appears to dictate the overall dimensionality of the resulting coordination polymer crystal structure. {[Cd(phdp)(bpfp)(H 2O)]·4H 2O} n ( 1) possesses pentagonal bipyramidal coordination at cadmium with trans pyridyl donors and displays a simple 2-D (4,4) grid network. {[Cd(phdp)(bpmp)]·5H 2O} n ( 2) exhibits distorted octahedral coordination with cis pyridyl donors, resulting in a 3-D 3-fold interpenetrated diamondoid network. Both 1 and 2 show visible-light luminescence upon ultraviolet excitation, with the emission maximum depending on the nature of the dipyridyl coligand.

Tether Length Control of Topology in Cadmium 4-Methylphthalate Two-Dimensional Coordination Polymers: An Acentric Buckled Grid and a Rare Self-Catenated Layer

Hydrothermal synthesis has afforded a pair of dual-ligand divalent cadmium 4-methylphthalate (mph) two-dimensional (2-D) coordination polymers, wherein the length of the dipyridyl co-ligand plays a...

Significant Positional Isomeric Effect on Structural Assemblies of Zn(II) and Cd(II) Coordination Polymers Based on Bromoisophthalic Acids and Various Dipyridyl-Type Coligands

Seven Zn(II) and Cd(II) coordination polymers, formulated as {[Zn2(5-Br-ip)2(bpy)(H2O)]·2H2O}n (1), {[Zn(5-Br-ip)(bpa)(H2O)]}n (2), {[Cd(5-Br-ip)(bpp)(H2O)]}n (3), {[Zn(5-Br-ip)(bpe)]}n (4), {[Zn2(4-Br-ip)2(bpy)]·H2O}n (5), {[Zn(4-Br-ip)(bpa)(H2O)]}n (6), and {[Cd(4-Br-ip)(bpp)]}n (7), were prepared by hydrothermal reactions based on 4-bromo- or 5-bromoisophthalic acid (4-Br-H2ip or 5-Br-H2ip) and different dipyridyl-type coligands 4,4′-bipyridyl (bpy), 1,2-bi(4-pyridyl)ethane (bpa), 1,3-di(4-pyridyl)propane (bpp), and 1,2-di(4-pyridyl)ethene (bpe). All complexes 1−7 were characterized by elemental analysis, IR spectra, and X-ray single-crystal diffraction. Complex 1 is a 2D (6,3) coordination network and further assembled into a 3D framework via π−π stacking interactions. Complex 2 shows a 1D coordination array and further forms a 2D supramolecular network via H-bonding interactions. Complex 3 has a 2-fold interpenetrating 3D diamond framework. Complex 4 is a 3-fold interpenetrating 3D network with CdSO4 topology, constructed from alternately left- and right-handed helical arrays. Complex 5 has a 3D (3,4)-connected network with (4·82)(4·82·103) topology. Complex 6 features a 1D coordination chain and further forms a 2D helical supramolecular pattern by H-bonding. Complex 7 exhibits a (3,5)-connected 2D layer with the Schläfli symbol of (42·6) (42·67·8). The results reveal that the diverse coordination networks of 1−7 can be adjusted by the different dispositions of the -Br substituent of isophthalate building blocks, as well as the metal ions and the dipyridyl coligands. Moreover, the luminescent properties of the complexes have been investigated.

Coordination Assemblies of CoII/CuII/ZnII/CdII with 2,5-Bipyridyl-1,3,4-Oxadiazole and Dicyanamide Anion: Structural Diversification and Properties

This work presents eight coordination assemblies based on divalent metal ions (M = CoII, CuII, ZnII, and CdII), dicyanamide anion (N(CN)2−, dca), and two isomeric bent dipyridyl coligands (L), namely, 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (3-bpo) and 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (4-bpo). In the resulting crystalline materials, both bpo and dca tectons generally display the bidentate bridging fashion (except in the mononuclear species 5), extending the metal centers to afford diverse one-, two-, and three-dimensional (1-D, 2-D, and 3-D) coordination networks that are not commonly observed in M−dca−L systems. Notably, the inclined polycatenated 2-D → 3-D framework and 3-D polyknotting network with the unique 6-connected (44.611) topology are formed for the CuII and CdII species with dca and 4-bpo. For the polymeric CoII and CuII complexes, very weak antiferromagnetic or ferromagnetic interactions are observed between the metal centers due to the μ1,5-bridging mode of dca, and their magneto-structural c...

Synthesis, structures, and physical properties of metal flexible dicarboxylate frameworks with dipyridyl coligand

Five new metal-organic frameworks [Zn(bct)(4,4′-bipy)] ( 1) (H 2bct = 2,5-bis(carboxymethylmercapto)-1,3,4-thiadiazole acid; 4,4′-bipy = 4,4′-bipyridine) [Cd(bct)(H 2O)(4,4′-bipy) 0.5] ( 2), as well as three isostructural compounds, [M(bct)(H 2O)(4,4′-bipy)] [M = Zn ( 3), Mn ( 4), Co ( 5)], were obtained by reactions of the corresponding metal salts with a flexible dicarboxylic acid, H 2bct and 4,4′-bipy, and their structures were determined by single-crystal X-ray diffraction. The results reveal that 1 features a two-dimensional (2-D) layer structure consisting of one-dimensional (1-D) Zn-bct chain and 4,4′-bipy, while 2 has 2-D rectangular-grid layers with the bct carboxylate groups adopting similar coordination mode in 1 but different conformations in ligating Cd(II) ions, which is inserted into 4,4′-bipy. Additionally, there exist π–π stacking and intermolecular hydrogen-bonding interactions in 1 and 2, respectively, forming 3-D supramolecular structures. In 3– 5, undulating 2-D metal-bct layer structures are formed with another coordination mode of bct carboxylate groups, which are further extended by 4,4′-bipy into 3-D structures. The luminescence properties of 1– 3 were investigated. Low-temperature magnetic data indicate weakly antiferromagnetic exchange in 4 and 5.