pH-dependent Co(II) assemblies from achiral 2-benzothiazolylthioacetic acid: crystal structures,symmetry breaking,and magnetic properties

Based on an achiral 2-benzothiazolylthioacetic acid (HL) ligand, three Co(II) coordination compounds, {[Co(L)₂(H₂O)₃]·H₂O}_n (1), [Co(L)₂(H₂O)₂]_n (2), and [Co(L)₂(H₂O)₄]·2H₂O (3), were obtained under different pH environments. Compound 1 possessing an interesting chiral 1-D helical double chain was synthesized with pH of 5.0~6.5, and the chiral symmetry breaking has been probed by single-crystal X-ray diffraction and circular dichroism spectroscopy. Switching pH to 4.0~5.0 and 3.0~4.0 resulted in achiral 2 and 3, respectively. Compound 2 has a 1-D chain structure and 3 is mononuclear.     

Construction of a magnetic chiral coordination polymer based on a semi-rigid carboxylic acid

A 2-D chiral entangled coordination polymer, {Mn₃(2,2′-bpy)₂(3-cpta)₂·H₂O}_n (1) (3-H₃cpta=3-(3′-carboxyphenoxy)phthalic acid, 2,2′-bpy=2,2′-bipyridine), has been synthesized via the solvothermal method. X-ray diffraction analysis reveals that 1 consists of one right-handed helical chain and one wavelike 2-D plane, which are connected with each other through hydrogen bonds and π···π interactions to generate a 3-D supra-molecule. Thermal gravimetric analysis shows that 1 possesses good thermal stability. Temperature dependent magnetic susceptibilities have also been measured from 1.8 to 300 K, which shows 1 to be anti-ferromagnetic.     

Synthesis,Structures, and Photocatalytic Properties of Zinc(II) and Cobalt(II) Supramolecular Complexes Constructed with Flexible Bis(thiabendazole) and Dicarboxylate Linkers

Three coordination complexes, namely, [Zn(btbp)(3‐npa)]_n ( 1 ), [Co(btbh)(3‐npa)]_n ( 2 ), and {[Co(btbb)(5‐nipa)(H₂O)] · H₂O}_n ( 3 ) (btbp = 1,3‐bis(thiabendazole)propane, btbh = 1,6‐bis(thiabendazole)hexane, btbb = 1,4‐bis(thiabendazole)butane, 3‐H₂npa = 3‐nitrophthalic acid and 5‐H₂nipa = 5‐nitroisophthalic acid) were synthesized under hydrothermal conditions and characterized by physicochemical and spectroscopic methods as well as by single‐crystal X‐ray diffraction. Complex 1 features a fascinating meso‐helical chain, which is further extended into a 2D supramolecular framework involving π ··· π stacking interactions. Complexes 2 and 3 show dinuclear structures. Complex 2 is further connected through C–H ··· O hydrogen bonding interactions to afford a 2D supramolecular layer, whereas complex 3 is further extended to a rare 2‐nodal (3,4)‐connected supramolecular sheet with a point symbol of {3.4².5.6.7}₂{3.8²} by O–H ··· O hydrogen bonding interactions. The electrochemical behaviors of the two cobalt complexes 2 and 3 were reported. Moreover, the luminescent properties for 1 and the photocatalytic properties for the complexes were investigated.     

Hydrothermal synthesis,crystal structure and characterization of a 1D neodymium(III) coordination polymer containing the pyridine-2,6-dicarboxylate and oxalate ligands

The reaction of 2,6-pyridinedicarboxylic acid (H₂Pydc) and ammonium oxalate with neodymium(III) nitrate affords the one-dimensional (1D) neodymium coordination polymer formulated as {[Nd₂(Pydc)₂(μ₂-C₂O₄) · 6H₂O] · 2H₂O} _n (I), and characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. The complex presents 1D stair-like chain array bridged through oxalate, and these 1D chains are further linked into 3D supramolecular architecture by extensive intra- and intermolecular hydrogen-bonding interactions. Preliminary magnetic studies reveal the presence of weak antiferromagnetic couplings with the two adjacent magnetic centers bridged through the pyridine dicarboxylate oxygen atom in the complex.     

Syntheses and Crystal Structures of a Series of Coordination Polymers Constructed From C2‐Symmetric Ligand 1,3‐Adamantanedicarboxylic Acid

This article systematically investigates the influence of the properties of inhomogeneous N‐auxiliary ligands and pH value on the helical structures of complexes based on C₂‐symmetric ligand 1,3‐adamantanedicarboxylic acid (H₂ADC). Five kinds of neutral ligands (phen=1,10‐phenanthroline, bipy=4,4′‐bipyridine, bpa=1,2‐bis(4‐pyridyl)ethane, bpe=1,2‐bis(4‐pyridyl)ethane, and bpp=1,3‐bis(4‐pyridyl)propane) were selected, and a series of new Zn^II/Co^II dicarboxylates have been synthesized by slow diffusion, namely, [Zn(phen)(ADC)(H₂O)]₂ ? CH₃OH ( 1 ), {[Zn(ADC)(bpe)] ? H₂O}_n ( 2 ), {[Zn(ADC)(bipy)] ? 2 H₂O}_n ( 3 ), {[Zn(ADC)(bpa)]₂ ? 5 H₂O}_n ( 4 ), {[Zn(ADC)(bpp)]₂ ? CH₃OH}_n ( 5 ), {[Zn(ADC)(bpp)]}_n ( 6 ), {[Co(ADC)(bpp)(CH₃OH)(H₂O)] ? CH₃OH ? 2 H₂O}_n ( 7 ), and {[Co(ADC)(bpp)]}_n ( 8 ). Single‐crystal X‐ray structural analysis shows that complex 1 forms a 0D dinuclear with closed‐loop unit. The complex 2 is a 2D layer framework. Compounds 3 and 4 are isomorphous with a small discrepancy and present one‐dimensional chainlike structures. It is interesting that the 2D organic–inorganic hybrid frameworks containing meso‐helical chains have been observed. Compound 5 is a 2D interpenetrated network with (4,4) topology, in which homochiral left‐handed helical chains are arranged in an ABAB sequence parallel to the plane defined by (a,c), and right‐handed helical chains running along the a axis are also observed in the solid state, resulting in a meso‐helical structure. Compounds 6 , 7 , and 8 crystallize in a chiral space group P212121. Highly dimensional 6 and 8 are essentially isostructural and present a threefold interpenetrated 3D diamondoid network containing three helical chains, whereas 7 exhibits a 2D grid layer with a left‐handed helical chain. Furthermore, thermal stability, X‐ray powder diffraction, and the luminescent properties of 1 , 2 , 3 , 4 , 5 , 6 are also discussed.     

Synthesis,Structures, and Properties of two Helical Structures from Rigid Carboxylate Ligand and Flexible N‐Bridging Ligands

Two novel coordination polymers based on mixed ligands, [Zn(dpb)(bdc)(H₂O)]_n ( 1 ) and [Cd(dpb)(bbdc)(H₂O)(DMF)]_n ( 2 ) [dpb = 1, 4‐bis(pyridin‐3‐ylmethoxy)benzene, H₂bdc = 1, 4‐benzenedicarboxylate, H₂bbdc = 4, 4′‐dibenzenedicarboxylate], were synthesized under hydrothermal conditions. Compound 1 forms meso‐helical chain and shows three fold interpenetrating architecture with 4‐connected net {6 6} diamond topology. Compound 2 is a left‐ and right‐handed helical layer, which are interacted by π–π stacking interactions to construct a 3D framework. The luminescent properties of the compounds are discussed.     

Synthesis,crystal structures,and magnetic properties of three isomorphous helical coordination polymers

Three isomorphous coordination polymers of general formula {[M(H₂bna)·(DMF)₂·(H₂O)₂]·DMF}_n (M = Co for 1, Mn for 2, Ni for 3, respectively, where H₄bna = 2,2′-dihydroxy-[1,1′]-binaphthalene-3,3′-dicarboxylate) were synthesized under solvothermal conditions and characterized by FTIR, single crystal X-ray diffraction, thermogravimetric analysis, and X-ray power diffraction analysis. All three polymers crystallize in the same monoclinic space group P2₁/n. The complexes are assembled into 1D helical chains, and each adjacent helical chain of the same chirality is further connected to form a chiral layer by hydrogen bond interactions. The layers are packed in alternating left-(M) and right-handed (P) chirality arrays. Magnetic studies reveal the presence of antiferromagnetic coupling interactions in complexes 1 and 2.     

1-D wave-like chain,twofold 2-D layer,and chiral 3-D open framework based on multidentate ligand: structural diversities,thermal properties,and photoluminescence

From 1-D to 3-D zinc coordination polymers based on multifunctional flexible 4-(1,2,4-triazole-methylene)-benzonitrile (tzbt), {[Zn(tzbt)₂(bdc)]·2H₂O}_n (1), [Zn(tzbc)₂]_n (2), and [Zn(bpdc)(H₂O)]_n (3) (bdc = 1,4-benzenedicarboxylic acid, tzbc = 4-(1,2,4-triazole-methylene)-benzoic acid, bpdc = 4,4′-biphenyldicarboxylic acid), were synthesized under hydrothermal conditions. The tzbt was synthesized by N-alkylation and hydrolyzed in situ to produce tzbc (in 2). Single-crystal X-ray diffraction analysis reveals that 1 displays 1-D wave-like chains based on [Zn(bdc)]_n. 2 is a chiral twofold interpenetrating 2-D architecture constructed with “V”-shaped tzbc. 3 is a 3-D chiral compound constructed from achiral H₂bpdc with right-handed helical chains. 1–3 display stable blue-emitting luminescence with emission maxima ranging from 383 to 410 nm, depending on ligand-centered π*→π transitions. The effects of different polarity solvents and temperature on luminescence are discussed. TGA and VT-XPRD reveal that 2 has thermal stability to 360 °C.     

Syntheses,structures, and properties of CdII and CoII complexes with 5-(pyridin-4-yl)isophthalate

A N-donor containing carboxylic ligand, 5-(pyridin-4-yl)isophthalic acid (H₂L), was applied to construct two new coordination polymers [Cd(L)(DMF)] _n (1, DMF?=?N,N-dimethylformamide) and {[Co(L)(H₂O)₂]?·?0.5CH₃OH?·?1.5H₂O} _n (2) under different conditions. The complexes were characterized by IR, elemental, and thermogravimetric analyses, powder and single crystal X-ray diffraction. In 1 each L^2? links four Cd^II to form a 3-D framework, while in 2 each L^2? connects three metals to form a 2-D layer structure, which is further connected together by hydrogen bonds to form a 3-D architecture. The thermal stability of the complexes and the photoluminescence of 1 were investigated.     

Three double- or triple-stranded chains constructed from different cobalt(II) salts and a flexible bis-triazole ligand

Three coordination compounds, {[Co(btrp)₂(H₂O)₂]?·?NO₃?·?H₂O} _n (1), {[Co(btrp)₂(H₂O)₂]?·?H₂O?·?2H₂btc} _n (2), and {[Co(btrp)₃]?·?2ClO₄} _n (3) (btrp?=?1,3-bis(1,2,4-triazol-1-yl)propane; H₃btc?=?benzene-1,3,5-tricarboxylic acid), have been prepared via solvothermal method and characterized by single-crystal X-ray diffraction and elemental analyses. Compound 1 possesses a 1-D double-stranded chain composed of ribbons of 20-membered cycles. Binuclear water clusters link adjacent nitrate anions to form a 1-D supramolecular helix in the structure. Compound 2 has a 1-D double-stranded chain wherein free H₂btc ligands constitute 1-D negative chains through classical hydrogen-bonding interactions (O–H?···?O). Compound 3 exhibits a triple-stranded 1-D chain. For 1–3, 3-D supramolecular structures are consolidated by interchain weak hydrogen-bonding interactions as well as electrostatic interactions.     

Syntheses,Structures, and Magnetic Properties of Two Novel Cobalt(II) Coordination Polymers Constructed from Pyridine‐2,6‐dicarboxylic Acid N‐oxide (PDCO)

Two new cobalt(II) coordination polymers, [Co(PDCO)(H₂O)₂]_n ( 1 ) and [Co(PDCO)(bix)(2H₂O)₂·H₂O]_n ( 2 ) ( PDCO= pyridine‐2,6‐dicarboxylic acid N‐oxide, bix = 1,4‐bis(imidazol‐1‐ylmethyl)‐benzene) have been synthesized under hydrothermal conditions. Single‐crystal X‐ray analyses show that compound 1 is a 1D helical chainlike structure with 4₁ screw axes parallel to the crystallographic c‐axis and interchain hydrogen‐bonding interactions further result in a 3D framework; for compound 2 , each bix ligand connects two Co1 atoms (or two Co2 atoms) to give a zigzag chain structure and these 1D chains are connected by offset face‐to‐face π···π and hydrogen bond interactions to generate a 3D architecture. The thermogravimetric analyses were investigated for 1 and 2 . The determination of variable temperature magnetic susceptibilities indicates an antiferromagnetic interaction between the metal atoms for 1 and 2 .     

Binuclear cobalt(II/II) and cobalt(II/III) chelates with O<Subscript>2</Subscript>N<Subscript>2</Subscript> ligands: synthesis,structure and magnetic studies

Abstract  The title complexes and have been synthesized in excellent yields by reacting Co(OAc)₂·4H₂O with H₂L¹ and H₂L², respectively, in acetonitrile solution. Here, [L¹]²⁻ and [L²]²⁻ are the deprotonated forms of N,N-bis(2-hydroxybenzyl)-N′,N′-dimethylethylenediamine and N,N-bis(2-hydroxybenzyl)-2-picolylamine, respectively. The crystal structures of and were determined by x-ray crystallography. In , each cobalt atom has distorted trigonal bipyramid geometry, while in , each cobalt atom has distorted octahedral geometry. Variable temperature magnetic moment measurements show weak antiferromagnetic interaction in . The magnetic characterization for is in agreement with the presence of Co(II) and Co(III) centers. Graphical Abstract  The title complexes and have been synthesized in excellent yields by reacting Co(OAc)₂·4H₂O with dianionic N₂O₂ coordinating ligands. In complex 1, each cobalt atom has distorted trigonal bipyramid geometry, while in complex 2, each cobalt atom has distorted octahedral geometry. Variable temperature magnetic moment measurements show weak antiferromagnetic interaction in complex 1. The magnetic characterization for complex 2 is in agreement with the presence of Co(II) and Co(III) centers. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Self-assembly of 1-D, 2-D,and 3-D transition-metal coordination polymers based on a T-shaped tripodal ligand 4-(4,5-dicarboxy-1H-imidazol-2-yl)pyridine 1-oxide

Three coordination polymers, {[Co(C₁₀H₅N₃O₅)(H₂O)₂]·H₂O}_n (1), {[Mn₃(C₁₀H₅N₃O₅)₂Cl₂(H₂O)₆]·2H₂O}_n (2), and {[Cu₃(C₁₀H₄N₃O₅)₂(H₂O)₃]·4H₂O}_n (3), based on a T-shaped tripodal ligand 4-(4,5-dicarboxy-1H-imidazol-2-yl)pyridine 1-oxide (H₃DCImPyO), were synthesized under hydrothermal conditions. The polymers showed diverse coordination modes, being characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray structure analysis. In 1, the HDCImPyO^2? generated a 1-D chain by adopting a μ₂-kN, O : kN′, O′ coordination mode to bridge two Co(II) ions in two bis-N,O-chelating modes. In 2, the HDCImPyO^2? adopted a μ₃-kN, O : kO′, O′′ : O′′′ coordination mode to bridge two crystallographically independent Mn(II) ions, forming a 2-D hcb network with {6³} topology. In 3, by adopting μ₄-kN, O : kO′, O′′ : kN′′, O′′′ : O′′′′ coordination, DCImPyO^3? bridged three crystallographically independent Cu(II) ions to form a 3-D framework having the stb topology.     

Structures and luminescent properties of four compounds based on binuclear metal-terpyridine building blocks

Four new coordination polymers, [Cd(3-TPTP)Cl]₂ (3-HTPTP = 4′-(3-tetrazolylphenyl)2,2′:6′2′′-terpyridine, 1), {[Cd(3-TPTP)(pBDC)_0.5]?4H₂O}_n (pH₂BDC = 1,4-benzenedicarboxylic acid, 2), {[Mn(3-TPTP)(mBDC)_0.5]?5H₂O}_n (mH₂BDC = 1,3-benzenedicarboxylic acid, 3), and [Pb(3-TPTP)(H₂O)₂]?OH (4), were obtained. Compounds 1–3 are composed of binuclear [M₂(3-TPTP)₂] ring as building unit. In 1, the binuclear rings pack into a 3-D supramolecular framework via various hydrogen bonds. In 2 and 3, the binuclear rings are connected by mBDC^2? and pBDC^2?, respectively, resulting in two types of 1-D chains. In 4, the mononuclear [Pb(3-TPTP)] units are connected by Pb?N weak interactions, giving a chiral 1-D coordination chain, which is further connected by O–H?N interaction to form a chiral 3-D supramolecular framework. The phase purity of 1–4 and luminescence properties of 1, 2, and 4 were also investigated.     

Coordination‐directed one‐dimensional coordination polymers generated from a new oxadiazole bridging ligand and HgX2 (X = Cl,Br and I)

A new 1,3,4‐oxadiazole bridging bent organic ligand, 2,5‐bis{5‐methyl‐2‐[(4‐pyridyl)methoxy]phenyl}‐1,3,4‐oxadiazole, C₂₈H₂₄N₄O₃, L, has been used to create three novel one‐dimensional isomorphic coordination polymers, viz. catena‐poly[[[dichloridomercury(II)]‐μ‐2,5‐bis{5‐methyl‐2‐[(4‐pyridyl)methoxy]phenyl}‐1,3,4‐oxadiazole] methanol monosolvate], {[HgCl₂(C₂₈H₂₄N₄O₃)]·CH₃OH}_n, catena‐poly[[[dibromidomercury(II)]‐μ‐2,5‐bis{5‐methyl‐2‐[(4‐pyridyl)methoxy]phenyl}‐1,3,4‐oxadiazole] methanol monosolvate], {[HgBr₂(C₂₈H₂₄N₄O₃)]·CH₃OH}_n, and catena‐poly[[[diiodidomercury(II)]‐μ‐2,5‐bis{5‐methyl‐2‐[(4‐pyridyl)methoxy]phenyl}‐1,3,4‐oxadiazole] methanol monosolvate], {[HgI₂(C₂₈H₂₄N₄O₃)]·CH₃OH}_n. The free L ligand itself adopts a cis conformation, with the two terminal pyridine rings and the central oxadiazole ring almost coplanar [dihedral angles = 5.994 (7) and 9.560 (6)°]. In the Hg^II complexes, however, one of the flexible pyridylmethyl arms of ligand L is markedly bent and helical chains are obtained. The Hg^II atom lies in a distorted tetrahedral geometry defined by two pyridine N‐atom donors from two L ligands and two halide ligands. The helical chains stack together via interchain π–π interactions that expand the dimensionality of the structure from one to two. The methanol solvent molecules link to the complex polymers through O—H...N and O—H...O hydrogen bonds.     

Syntheses and crystal structures of three pillared complexes based on H2AIP and triazole-bipyridine ligands

Three pillared polymeric complexes, {[Ni₂(AIP)₂(4,4′-bpt)(H₂O)₂]·4H₂O}_n (1), {[Co(AIP)(3,3′-bpt)]·H₂O}_n (2), and {[Ni(AIP)(3,3′-bpt)]·H₂O}_n (3) (H₂AIP = 5-aminoisophthalic, 4,4′-bpt = 1H-3,5–bis(4-pyridyl)-1,2,4-triazole and 3,3′-bpt = 1H-3,5-bis(3-pyridyl)-1,2,4-triazole), have been hydrothermally synthesized and characterized by X-ray diffraction analysis. Both 1 and 3 have 2-D (6,3) honeycomb layers, which are further interlinked by bent pillared triazole-bipyridine ligands to form a bilayer structure. The structures can be simpli?ed to a (3,4)- and (3,5)-connected geometrical topology, respectively. Compound 2 has a Co-AIP layer structure in which the layers are pillared by 3,3′-bpt spacers to form the 3-D CsCl net.     

Four Co(II)/Zn(II) coordination polymers with a multidentate ligand: syntheses,structures, thermal,and photoluminescent properties

Two pairs of isostructural transition metal coordination polymers, {[Co(L)(H₂O)]_n} (1) and {[Zn(L)(H₂O)]_n} (3), {[Co(L)(4,4′-bipy)(H₂O)]·H₂O}_n (2) and {[Zn(L)(4,4′-bipy)(H₂O)]·H₂O}_n (4) (H₂L = N-pyrazinesulfonyl-glycine acid and 4,4′-bipy = 4,4′-bipyridine), have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental and thermogravimetric analyses. The structures show that 1 and 3 display 2-D polymeric grid frameworks with a 3-connected (4, 8²) topology. 2 and 4 also exhibit a 2-D polymeric grid structure, but are constructed by a 4-connected (4, 4) topology. The adjacent 2-D polymeric grid frameworks for 1–4 are further linked by hydrogen bonding O–H?O interactions to form 3-D supramolecular interweaved orderly networks. The fluorescent properties of 3 and 4 were investigated in the solid state.     

Two new 2-D coordination polymers based on a purine-containing carboxylate

A purine-containing multifunctional ligand, 2-(6-oxo-6H-purin-1(9H)-yl)acetic acid (HL), and two new 2-D coordination polymers, [Co(L)₂(H₂O)₂] _n?·?2nH₂O (1) and [Ni(L)₂(H₂O)₂] _n?·?2nH₂O (2), were synthesized and characterized. Polymers 1 and 2 have isomorphous structures with (4,4)-connected topologies composed of left- and right-handed metal–organic helices sharing common metal centers. Two helical conformations in the same net are stabilized by strong π–π stacking interactions between purine groups. Through direct and water-mediated interlayer hydrogen-bond interactions those layers are assembled into stable 3-D supermolecules where slight differences in the strength of hydrogen bonds and coordination bonds result in their decomposition behaviors.     

Two Zinc(II) Coordination Polymers Based on the Ligand 1, 4‐Bis[(2‐methyl‐imidazol‐1‐yl)methyl]benzene: Syntheses,Crystal Structures and Properties

Two coordination polymers (CPs), {[Zn₂(BMB)(5‐AIPA)₂] · 2H₂O}_n( 1 ) and [Zn(BMB)(5‐NIPA)]_n( 2 ) {BMB = 1, 4‐bis[(2‐methyl‐imidazol‐1‐yl)methyl]benzene, 5‐AIPA = 5‐aminoisophthalic acid, 5‐NIPA = 5‐nitroisophthalic acid}, were synthesized under hydrothermal conditions. Compound 1 displays a 2D double‐layer structure, which is packed into a 3D supramolecule by interlayer hydrogen bonds and π–π stacking interactions. Compound 2 displays a threefold interpenetrating 3D network, which is composed of left‐handed helical chains and two types of meso‐helical chains along different directions.     

Cobalt 2-pyrazinephosphonates: syntheses,structures, and magnetic properties

Reactions of Co(ClO₄)₂·6H₂O with 2-pyrazinephosphonic acid (2-paPO₃H₂) under two different hydrothermal conditions gave two new cobalt 2-pyrazinephosphonates, Co(2-paPO₃H)₂ (1) and Co(2-paPO₃)(H₂O) (2). Compound 1 was obtained at 160 °C, while 2 was obtained at 180 °C. In 1, two Co(II) units are bridged by two O–P–O’s into a dimer and the dimers are linked by pyrazinyl groups into a 1-D double chain. In 2, the {CoO₄N₂} and {CPO₃} polyhedra are interconnected via edge and corner-sharing into a metal phosphonate layer, and the layers are pillared by pyrazinyl groups into a 3-D network. Variable-temperature magnetic susceptibility studies reveal that both complexes have weak antiferromagnetic coupling between Co(II) ions.