V-shaped Ligand Research Articles

Turn helical motifs from pair to single entangled double helixes in a cobalt-vanadate system via introduction of a V-shaped ligand.

Two novel helical compounds based on polyoxovanadates, [Co(H2O)2V2O6] (1) and [Co(bimb)V2O6] (2) (bimb = 1,3-bis(1-imidazoly)benzene), have been synthesized under identical hydrothermal conditions, providing two structurally different helical motifs due to introduction of a V-shaped bimb ligand in 2. Compound 1 possesses a pair of entanglement double helixes in a 3D inorganic framework, whereas compound 2 shows a single entangled double helix in a 3D inorganic-organic network owing to the influences of steric hindrance of ligands as well as coordination geometries of metal cations. The electrocatalytic and photocatalytic properties of 1 and 2 were also investigated in details.

A Six-Coordinate Picrate Nickel(II) Complex Based on the V-Shaped Ligand 1,3-Bis (1-Benzylbenzimidazol-2-yl)-2-Thiapropane: Synthesis, Crystal Structure, Biological Activities

A six-coordinate picrate nickel(II) complex based on the V-shaped ligand 1,3-bis(1-benzylbenzimidazol-2-yl)-2-thiapropane (L), with the composition [Ni(L)2](pic)2, has been synthesized and characterized systematically. The crystal structure of the Ni(II) complex is a six-coordinated octahedron, which is considerably close to ideal octahedral geometry with N4S2 donors of the two ligands. Biological activities of compounds were investigated using electronic absorption spectroscopy, fluorescence spectroscopy, and viscosity measurements. The results suggested that both ligand L and Ni(II) complex bind to DNA in an intercalative binding mode, and DNA-binding affinity of the Ni(II) complex is stronger than that of ligand L. [Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional figures.]

Syntheses, crystal structures, and optical properties of five metal complexes constructed from a V-shaped thiophene-containing ligand and different dicarboxylate ligands.

Five new metal complexes, {[Ni(DIDP)(m-bdc)(H2O)]·5H2O}n (1), {[Zn(DIDP)(hfipbb)]·2DMA}n (2), {[Zn(DIDP)(4,4'-sdb)]·H2O}n (3), {[Co(DIDP)(p-bdc)]}n (4), and {[Co2(DIDP)(hfipbb)2]·H2O}n (5), have been synthesized by reactions of the corresponding metal ions with a V-shaped ligand 2,8-di(1H-imidazol-1-yl)dibenzothiophene (DIDP) and different aromatic dicarboxylic acids, namely isophthalic acid (m-H2bdc), terephthalic acid (p-H2bdc), 4,4'-(hexafluoroisopropylidene)bis(benzoic acid) (H2hfipbb), and 4,4'-sulfonyldicarboxylic acid (4,4'-H2sdb), respectively. The structures of the complexes were determined by X-ray single-crystal diffraction. Complex 1 is a 1D chain structure containing a one-dimensional channel along the a direction and is further extended via O-H···S hydrogen bonds and C-H···π stacking interactions into a 3D framework. Complex 2 exhibits a quasi 2D + 2D → 2D with parallel polycatenation of 2D (4, 4) nets. Complex 3 displays an unusual 2D + 2D → 3D parallel polycatenated framework based on a 2D 6(3)-hcb network. Complex 4 shows a 2D 4-connected {4(4)·6(2)}-sql network containing a one-dimensional channel along the b direction. The adjacent 2D networks are further extended via C-H···O hydrogen bonds into a 3D supramolecular framework. Complex 5 features a 2-fold interpenetrating 3D framework with a 6-connected {4(12)·6(3)} pcu topology. Furthermore, the thermal stability for 1-5 and luminescence properties of 2 and 3 have been studied. Moreover, the solid-state UV-visible spectroscopy experiments show that complexes 1-5 are all optical semiconductors with band gaps of 3.06, 3.18, 3.23, 2.98, and 3.17 eV, respectively.

The coexistence of interconnected and interweaved double helices in an octamolybdate-based compound: synthesis, structure, and photocatalytic properties.

By choosing V-shaped ligands, Cu2+ cations and isopolymolybdates as starting materials, a novel double helical compound [Cu(H2O)(bimb)]2[β-Mo8O26] (1) (bimb = 1,3-bis(1-imidazoly)benzene) was hydrothermally synthesized and characterized by elemental analyses, single-crystal X-ray diffraction, powder X-ray diffraction and IR spectroscopy. A structural feature is that compound 1 represents the first example of a helical compound based on polyoxometalates, which possesses an unprecedented helical disposition, namely the coexistence of both interconnected and interweaved double helices in one structure. The photocatalytic properties of compound 1 were also investigated in detail and the result of photocatalytic experiments shows that compound 1 can be used as a stable photocatalyst toward the decomposition of the organic pollutant methylene blue.

Synthesis, Crystal Structure, and DNA-Binding Properties of a Cadmium(II) Complex With the Bis(2-benzimidazolymethyl)amine Ligand

A V-shaped ligand Bis(2-benzimidazolymethyl)amine (bba) and its cadmium(II) picrate (pic) complex, with composition [Cd(bba)2](pic)2·4DMF, have been synthesized and characterized on the basis of elemental analyses, molar conductivities, IR spectra and UV-vis measurements. In the complex, the Cd(II) ion is six-coordinated with a N6 ligand set, resulting in a distorted octahedron coordination geometry. In addition, the DNA-binding properties of the Cd(II) complex have been investigated by electronic absorption, fluorescence and viscosity measurements. The experimental results suggest that the Cd(II) complex binds to DNA by partial intercalation binding mode.

Synthesis, Characterization, and DNA-Binding Properties of the Cadmium(II) Complex With 1,3-bis(1-methylbenzimidazol-2-yl)-2-oxopropane

A new complex of cadmium(II) picrate with V-shaped ligand 1,3-bis(1-methylbenzimidazol-2-yl)-2-oxopropane (Meobb), [Cd(Meobb)2](pic)2 ·2(C2H3N)·0.5(H2O), was synthesized and characterized by elemental analyses and electrical conductivity, and IR and UV/visible spectra. The crystal structure of the complex has been determined by the single-crystal X-ray diffraction. In the complex, the Cd(II) ion is six-coordinated with a N4O2 ligand set, resulting in a distorted octahedron. The interaction of the cadmium(II) complex with calf-thymus DNA (CT-DNA) has been investigated by electronic absorption, fluorescence, and viscosity measurements. The experimental results suggest that the cadmium(II) complex binds to DNA in an intercalation mode.

V-shaped ligand bis(2-benzimidazolylmethyl)amine containing three copper(ii) ternary complexes: synthesis, structure, DNA-binding properties and antioxidant activity

Three copper(II) ternary complexes with the V-shaped ligand bis(2-benzimidazolylmethyl)amine (bba), with composition [Cu(bba)(crotonate)]·ClO4 (1), [Cu(bba)(methacrylate)]·ClO4 (2) and [Cu(bba)(acrylate)(CH3OH)]·NO3·H2O (3), have been synthesized and characterized by elemental analyses, molecular conductivities, IR, UV spectra and X-ray single crystal diffraction. The copper ions in these three complexes have a similar coordination mode, which can be described as a five-coordinated tetragonal pyramid geometry. The interaction of the ligand bba and copper(II) complexes with calf thymus DNA was investigated by electronic absorption, fluorescence spectroscopy and viscosity measurements. The experimental results suggest that the ligand bba and copper(II) complexes bind to DNA in an intercalation mode, and their binding affinity for DNA follows the order 2 > 1 > 3 > bba. The main reason for the DNA-binding behaviors can be attributed to the large coplanar aromatic rings in the V-shaped ligand. Such a trend in the DNA-binding affinities of the bba ligand and copper(II) complexes binding to DNA can be reasonably explained by the change of the electron density, the V-shaped angle (αV) and the value of τ. Moreover, the antioxidant assay in vitro also shows that the copper(II) complexes possess significant antioxidant activities.

Comprehensive Study on Mutual Interplay of Multiple V-Shaped Ligands on the Helical Nature of a Series of Coordination Polymers and Their Properties

V-shaped ligands are commonly used for helical coordination polymer synthesis. However, employment of multiple V-shaped ligands does not always lead to a helical network. The mutual interplay of two V-shaped ligands, which is neither easily predictable nor well documented, plays a major role directing the self-assembly of the resultant network. We report here the construction of a series of novel coordination polymers {[Ni(OBA)(H2MDP)(H2O)]·(DMF)3}n (1),{[Ni(FBA)(H2MDP)]·(H2O)3·(DMF)}n (2),{[Ni2(IPA)2(H2MDP)2(H2O)]·(H2O)(DMF)}n (3),{[Ni(ADA)(H2MDP)]·(MeOH)}n (4),[Ni(TNBA)(H2MDP)2]n (5), {[Ni(PPA)(H2MDP)2]·(H2O)2}n (6), {[Ni(HDPA)2(H2MDP)2]}n (7), and [Ni(SBA)(H2MDP)]n (8) {where H2OBA = 4,4′-oxybis(benzoic acid), H2FBA = 4,4′-(hexafluoroisopropylidene)bis(benzoic acid), H2IPA = isophthalic acid, H2ADA =1,3-adamantanediacetic acid, H2TNBA = 5,5′-dithiobis(2-nitrobenzoic acid), H2PPA 1,4-phenylenedipropionic acid, H2DPA = diphenic acid H2SBA= 4,4′-sulfonyldibenzoic acid} using a combination of mixed V-shape...

Two sodium(I) coordination polymers constructed by the V-shaped ligands 2,2′-[isopropylidenebis(1,4-phenyleneoxy)]diacetic acid and 2,2′-[sulfonylbis(1,4-phenyleneoxy)]diacetic acid

Two new inorganic-organic coordination polymers, namely poly[[μ6-2-(4-{1-[4-(carboxymethoxy)phenyl]-1-methylethyl}phenoxy)acetato][μ4-2-(4-{1-[4-(carboxymethoxy)phenyl]-1-methylethyl}phenoxy)acetato]disodium(I)], [Na2(C19H19O6)2]n, (I), and poly[hexa-μ-aqua-diaquabis{μ3-2,2'-[sulfonylbis(1,4-phenyleneoxy)]diacetato}tetrasodium(I)], [Na4(C16H14O8)2(H2O)8]n, (II), have been prepared. In (I), the asymmetric unit contains two Na(I) cations and two 2-(4-{1-[4-(carboxymethoxy)phenyl]-1-methylethyl}phenoxy)acetate (HL1(-)) ligands. Each Na(I) cation is octahedrally coordinated by two ether O atoms and four carboxylate O atoms of three different HL1(-) ligands. The NaO6 polyhedra share edges to form an inorganic ribbon along the a axis. These inorganic ribbons are further connected by the HL1(-) ligands to generate two-dimensional layers parallel to the (001) plane. The structure of (II) consists of ribbons of four crystallographically independent Na atoms (three six- and one five-coordinate), which are bridged by carboxylate O atoms of 4,4'-[sulfonylbis(1,4-phenyleneoxy)]diacetate (L2(2-)) ligands and water molecules. These ribbons are interlinked by L2(2-) ligands through two different coordination modes to afford a three-dimensional network.

Solvothermal Synthesis, Structural Diversity, and Properties of Alkali Metal–Organic Frameworks Based on V-shaped Ligand

A series of four new metal–organic frameworks, [Na2(SBA)] (1 or CYCU-6), [K8(H2O)2(SBA)4(DMF)] (2), [Rb2(SBA)] (3), and [Cs(H2O)(HSBA)]·DMF (4), have been constructed under solvothermal conditions by using 4,4′-sulfonyldibenzoic acid (H2SBA) as ligand. The structure of the complexes has been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analyses, reflectance UV–vis, and IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). The single crystal X-ray structural studies showed that all the complexes display three-dimensional (3D) structures containing inorganic motifs with one-dimensional chains connected through organic linkers and forming 3D networks. Among the four complexes, the Na(I) complex (1) displays very high thermal stability, which was inferred from TGA and PXRD results. Moreover, the solid state luminescent properties of the new complexes have been investigated at room temperature. In addition, the gas sorption properties of 1 toward nitrogen, hydrogen, carbon dioxide, and methane are reported.

Synthesis, crystal structure, DNA-binding properties and antioxidant activity of zinc(II) complexes based on the V-shaped bis(2-benzimidazol-2-ylmethyl)benzylamine ligand and its derivative

Two V-shaped ligands, bis(2-benzimidazol-2-ylmethyl)benzylamine (L1) and its derivative bis(N-allylbenzimidazol-2-ylmethyl)benzylamine (L2) have been prepared. Reaction of two shaped-specific designed ligands with Zn(pic)2 (pic=picrate) afforded two novel complexes, namely, [ZnL12](pic)2·2MeCN·Et2O 1, and [ZnL22](pic)22. The ligands and Zn(II) complexes were characterized by elemental analysis, UV–Vis, IR spectroscopy. Single crystal X-ray diffraction revealed that two Zn(II) complexes have similar distorted octahedral coordination geometry, except that the degree of distortion is different. In order to explore the relationship between the structure and biological properties, the DNA-binding properties have been investigated by viscosity measurement, electronic absorption and fluorescence titration. The results suggested that the ligands and Zn(II) complexes bind to DNA via intercalative binding mode, and their binding affinity for DNA are also different. Moreover, two Zn(II) complexes also exhibited potential antioxidant properties in vitro studies, and the complex 1 reveal more effective than complex 2.

Metal and structure tuned in vitro antitumor activity of benzimidazole-based copper and zinc complexes

Four new complexes, Cu2(p-2-bmb)2Cl4 (1), Cu2(p-2-bmb)2Br4 (2), Zn2(p-3-bmb)2Cl4 (3), and [Cu3(p-3-bmb)2Cl4·(CH3OH)2] n (4), have been synthesized under solvothermal reactions based on V-shaped flexible ligands 1-((2-(pyridin-2-yl)-1H-benzoimidazol-1-yl)methyl)-1Hbenzotriazole (p-2-bmb) and 1-((2-(pyridin-3-yl)-1H-benzoimidazol-1-yl)methyl)-1Hbenzotriazole (p-3-bmb). Complexes 1–3 are binuclear, whereas 4 is an infinite chain with trimetallic units, and then these complexes are further extended into 3D supramolecular architectures by π…π interactions and hydrogen bonds. In vitro antitumor activities of these complexes on four human tumor cell lines (gastric tumor cell line, esophagus tumor cell line, liver tumor cell line, colon tumor cell line) were evaluated by MTT assay. The results exhibit that these complexes inhibit the growth of cancer cells by inducing apoptosis, and the inhibition effect shows time- and dose-effect relationship.

Two stacked 2Dchiral/2Dchiral→2Dachiral sheets based on V-shaped imidazolyl ligand and flexible aliphatic acids

Abstract Two new stacked 2D chiral /2D chiral → 2D achiral coordination polymers {[Cd(BIDPE)(pim)]·(H 2 O)} n ( 1 ) and {[Cd(BIDPE)(glu)]·(H 2 O)} n ( 2 ) were prepared under hydrothermal conditions based on V-shaped ligand 4,4′-bis(imidazol-1-yl)diphenyl ether (BIDPE) and flexible polycarboxylic acids. In addition, the solid-state photoluminescent spectra were measured at room temperature.

The V-shaped ligand bis(N-allylbenzimidazol-2-ylmethyl)benzylamine and its Ag(I) complex: Synthesis, crystal structure, DNA-binding properties and antioxidation

A novel dinuclear Ag(I) complex of the type, [Ag2L2](pic)2, was synthesized by the reaction of the V-shaped ligand bis(N-allylbenzimidazol-2-ylmethyl)benzylamine (L) with Ag(pic) (pic=picrate). Ligand L and Ag(I) complex were characterized on the basis of elemental analysis, UV–vis, IR, NMR spectroscopy and X-ray crystallography. Single-crystal X-ray revealed that two L coordinated to a central silver(I) cation in a near-linear fashion through their benzimidazol-1-yl nitrogen atoms, and a centrosymmetric dinuclear pore canal structure was constructed in the discrete [Ag2L22]2+ cation. The DNA-binding properties of the free ligand L and Ag(I) complex have been carried out by using electronic absorption, fluorescence, and viscosity measurements. The results support that ligand L and Ag(I) complex both bind to DNA via an intercalative binding mode, and the affinity for DNA is more strongly in case of Ag(I) complex when compared with ligand L. Moreover, Ag(I) complex also exhibited potential antioxidant properties in vitro studies.

Two new three-dimensional metal–organic frameworks constructed from a semirigid V-shaped ligand with luminescent and topology studies

Two new compounds [Zn2L(OH)H2O]n (1) and [Cd(HL)]n (2) have been assembled from a semirigid V-shape ligand under hydrothermal conditions. The two compounds were determined by single-crystal X-ray diffraction analyses and further characterized by solid state emission spectra, IR spectra, and thermogravimetric analyses. Single crystal X-ray diffraction analyses show that both of the two compounds crystallize in space group P1¯ and display a three-dimensional (3D) structure with different topologies of fluorite topology for 1 and Au4Ho topology for 2. It is noteworthing that 1 has a novel Zn2 dinuclear unit containing only one bridging oxygen atom between two Zn atoms. Studies of photophysical properties reveal that 1 and 2 present luminescence, which can be ascribed to the emission of intraligand transition.

An Unprecedented Homochiral Metal–Organic Framework Based on Achiral Nanosized Pyridine and V-Shaped Polycarboxylate Acid Ligand

A unique homochiral metal–organic framework has been successfully synthesized by solvothermal reaction of an achiral flexible V-shaped ligand and a nanosized π-electron-deficient pyridine ligand based on cobalt(II) salt, [Co(L)(DPNDI)0.5]n (1) (H2L = 4,4′-dicarboxydiphenylamine, DPNDI = N,N′-di-(4-pyridyl)-1,4,5,8-naphthalenediimide); the helixes assembled by H2L and cobalt(II) paddle-wheel centers are left-handed and transform the framework to chiral. Also, the inserting of the DPNDI transforms the original dia net constructed by H2L and cobalt(II) paddle-wheel centers to a 3-fold jsm net. This is the first example of interpenetrated jsm net. In addition, the chiral property of bulk products is confirmed by circular dichroism spectra (CD), and the thermal stability and the magnetic properties are also investigated.

An unusual highly connected 3D net with hydrophilic pore surface

An unusual highly connected 3D framework, [K2Cd3(OBA)4(H2O)2(DMF)2](H2O)2 (1) that contains three windows along separate dimensions, has been constructed from a flexible V-shaped ligand 4,4′-oxydibenzoic acid (H2OBA) and a infinite linear {K2Cd3(COO)8}n cluster under solvothermal conditions. Owing to the existence of a polar Ccarboxyl–Ocore–Ccarboxyl moiety in the ligand and the coordinated hydrophilic DMF molecule, a hydrophilic environment is generated at the pore surface. Compound 1 shows high adsorption capacity for polar molecules, such as methanol (7.83%), ethanol (7.13%) and water (13.37%), but exhibits very low uptake capacity for non-polar molecules like methane (0.49%) and cyclohexane (0.68%). Furthermore, its luminescent properties including the quantum yield and lifetime value have also been investigated.

A second-order nonlinear optical material with a hydrated homochiral helix obtained via spontaneous symmetric breaking crystallization from an achiral ligand

A unique supramolecular helix assisted by solvent molecules (water and DMF) is obtained from an achiral flexible V-shaped ligand, and spontaneous symmetry breaking occurs in crystallization. Notably, the compound displays strong second-harmonic generation (SHG) response.

Synthesis, crystal structure, DNA-binding properties, and antioxidant activity of a V-shaped ligand bis(N-methylbenzimidazol-2-ylmethyl)benzylamine and its zinc(II) complex

A V-shaped ligand bis(N-methylbenzimidazol-2-ylmethyl)benzylamine (L) and its zinc(II) complex, [ZnL 2](pic)2 · 2CH3CN (pic = picrate), have been synthesized and characterized by physico-chemical and spectroscopic methods. Single-crystal X-ray crystallographic analysis revealed that the Zn(II) complex possesses a distorted trigonal bipyramidal geometry. Supramolecular interactions arising from various intra- or intermolecular π···π stacking interactions contributed to the form of the multidimensional configuration. Interactions of L and Zn(II) complex with DNA were monitored using spectrophotometric methods and viscosity measurements. The results suggest that L and Zn(II) complex both bind to DNA via intercalation and Zn(II) complex binds to DNA more strongly than L. Moreover, the Zn(II) complex also exhibited potential antioxidant properties in vitro.

Assembly of a New Three-Dimensional Metal-Organic Framework With V-Shaped Carboxylate Ligand and Rigid N-Donor Ligand

A new inorganic-organic coordination polymer based on a “V” shape linking unit 3,3′,4,4′-oxydiphthalic acid (H4ODPA),1,2–bis (4-pyridyl)ethene(bpe) and Co(II) ions, [Co2(ODPA)(bpe)(μ2-H2O)]n (1), has been prepared and structurally characterized by single-crystal X-ray diffraction analysis. Compound 1 adopts a novel 3D CdSO4-type topological framework containing nanotube channels. Moreover, the coordination chemistry of ODPA ligand is also discussed.