Liquid-crystalline coordination polymers based on tetra(alkoxybenzoato)dirhodium(II) complexes axially linked by tetrazine,phenazine and 4,4′-bipyridine

The reaction of dirhodium tetrakis(3,4,5-trialkoxy)benzoates Rh₂(B3OCn)₄ (n = 10, 14, and 18) with three different dinitrogenated axial ligands (L_ax), namely tetrazine (tz), phenazine (phz), and 4,4′-bipyridine (bpy), gave rise to three homologous series of mesogenic coordination polymers, [Rh₂(B3OCn)₄]L_ax. All of them exhibited thermotropic columnar mesophases that were of the hexagonal type for tz and phz and rectangular for bpy. The lighter n = 10 homologs of the three series are liquid crystals (LC) at room temperature. Their mesomorphic properties have been compared with those of the previously studied L_ax = pyrazine series. Models for the supramolecular organization of the three polymeric series in their Col LC phases are proposed on the basis of their structural parameters, as measured by XRD and SAXS. The differences are interpreted in terms of different coordination features of the axial ligands.     

Topological diversification of two new Cd(II) photoluminescent coordination polymers via auxiliary N-donor ligands

Two new cadmium(II) coordination polymers, [Cd₂(nda)₂(L₁)] _n (1) and [Cd(nda)(L₂)_0.5] _n (2), were hydrothermally synthesized with 1,4-naphthalenedicarboxylic acid (H₂nda) and auxiliary N-donor coligands [L₁?=?1,5-bis(2-methyl-imidazol-1-yl)pentane and L₂?=?4,4′-bis(2-methyl-imidazol-1-ylmethyl)biphenyl]. Single-crystal X-ray diffraction analyses showed that the topological networks are different when the N-donor ligands are changed. Compound 1 showed a (4¹⁶.6⁵) topology and 2 showed a twofold interpenetrating pcu topology.     

三个二羧酸配体配位聚合物的合成、结构表征和荧光性质

以羧酸配体2,2''-（1,4-亚苯基双（亚甲基））双（硫二基）二苯甲酸（H₂L¹）和2,2''-（2,3,5,6-四甲基-1,4-亚苯基）双（亚甲基）双（硫二基）二苯甲酸（H₂L²）分别与金属盐反应,通过溶剂热方法合成了3个配位聚合物：{[Ni（L¹）（H₂O）₄]·2H₂O}_n （1）、[Zn（L¹）（DMA）₂]_n （2）和[Co（L²）（DMF）₂]_n （3）,其中DMA=N,N-二甲基乙酰胺,DMF=N,N-二甲基甲酰胺。对配合物1~3进行了单晶X射线衍射、元素分析、红外光谱、热重分析、粉末X射线衍射和固体紫外可见光谱测试和表征。单晶X射线衍射表明：3个配合物均为一维锯齿形链状结构,并通过氢键作用形成三维骨架,且配体均表现为反式构象。此外,对配合物2固态荧光性质进行了研究。     

Structural characterization,thermal stability,and solvent de-/ad-sorption behavior of two d10 M(II) (M = Cd and Zn) coordination polymers constructed by 1,3,5-tris(4-pyridylsulfanyl-methyl)-2,4,6-trimethyl-benzene (L1)

Two d¹⁰ M(II) (M = Cd and Zn) coordination polymers (CPs) with chemical formulas, {[Cd(L¹)(NCS)₂(H₂O)]⋅C₂H₅OH}_n (1) , and {[Zn(L¹)(NCS)₂]⋅C₂H₅OH⋅0.5H₂O}_n (2) (L¹ = 1,3,5-tris(4-pyridylsulfanylmethyl)-2,4,6-trimethylbenzene) were synthesized and structurally characterized by single-crystal x-ray diffraction method. In compound 1 , the coordination environment of Cd(II) ion is distorted octahedral bonded to three nitrogen donors from three L¹ ligands located in a facial-position, two nitrogen donors from NCS⁻ and one water molecule. The L¹ acts as a bridge ligand with tris-monodentate coordination mode in a cis-cis-cis structural conformation, connecting the Cd(II) to form a two-dimensional (2D) zigzag-like layered metal-organic frameworks. Adjacent 2D layers are then arranged orderly in an ABAB manner to complete its three-dimensional (3D) supramolecular architecture. In compound 2 , the coordination environment of Zn(II) ion is distorted tetrahedral bonded to two nitrogen donors from two L¹ ligands and two nitrogen donors from two NCS⁻ ligands. The L¹ acts as a bridge ligand with bis-monodentate coordination mode in a cis-cis-cis structural conformation, connecting the Zn(II) ions to form a one-dimensional (1D) zigzag-like polymeric chain. Adjacent chains are arranged orderly in an alternate ABAB manner to generate a 2D framework and then further arranged in an AAA manner to complete its 3D supramolecular architecture. The structural characterization as well as thermal-stability and solvents de-/ad-sorption behavior of 1 and 2 are studied and discussed in details.     

三个二羧酸配体配位聚合物的合成、结构表征和荧光性质

以羧酸配体 2,2''-(1,4-亚苯基双(亚苯基))双(硫二基)二苯甲酸(H₂L¹)和 2,2''-(2,3,5,6-四甲基-1,4-亚苯基)双(亚甲基）双(硫二基)二苯甲酸(H₂L²)分别与金属盐反应,通过溶剂热方法合成了 3个配位聚合物：{[Ni(L¹)(H₂O)₄]·2H₂O}_n (1)、[Zn(L¹)(DMA)₂]_n(2)和[Co(L²)(DMF)₂]_n (3),其中DMA=N,N-二甲基乙酰胺,DMF=N,N-二甲基甲酰胺。对配合物1~3进行了单晶X射线衍射、元素分析、红外光谱、热重分析、粉末X射线衍射和固体紫外可见光谱测试和表征。单晶X射线衍射表明：3个配合物均为一维锯齿形链状结构,并通过氢键作用形成三维骨架,且配体均表现为反式构象。此外,对配合物2固态荧光性质进行了研究。     

Copper(II) Complexes of ω‐Hydroxy‐Functionalized N‐Salicylidenehydrazides show pH‐Controlled Switching between Dicationic Dimers and Neutral One‐Dimensional Coordination Polymers

New copper(II) complexes of the hydrazone ligands H₂salhyhb, H₂salhyhp, and H₂salhyhh, derived from salicylaldehyde and ω‐hydroxy carbonic acid hydrazides, have been synthesized and physically characterized. Two fundamental structures were found in solid state depending on the pH‐value of the reaction solution. Acidic conditions lead to the formation of the di‐μ‐phenoxo‐bridged dicationic complex dimers [{Cu(Hsalhyhb)}₂]²⁺ ( 1a ), [{Cu(Hsalhyhp)}₂]²⁺ ( 2a ), and [{Cu(Hsalhyhh)}₂]²⁺ ( 3a ), isolated as perchlorate salts. The dimeric complexes show strong antiferromagnetic coupling with J = ?399 ( 1a ), ?410 ( 2a ), and ?311 cm^?1 ( 3a ). Higher pH‐values resulted in the aggregation of neutral copper ligand fragments to the one‐dimensional coordination polymers [{Cu(salhyhb)}_n] ( 1b ), [{Cu(salhyhp)}_n] ( 2b ), and [{Cu(salhyhh)}_n] ( 3b ). 3b has been examined by means of X‐ray crystallography and represents the first example of a structurally characterized neutral copper(II) N‐salicylidenehydrazide complex without additional ligands. The magnetic interactions in the polymers are also antiferromagnetic with J = ?125 ( 1b ), ?136 ( 2b ), and ?148 cm^?1 ( 3b ), but strongly reduced compared to the corresponding dimeric complexes. The two basic structure types can be reversibly interconverted simply by pH‐control.     

Cobalt(II)‐Terephthalate Frameworks Containing Bis(benz­imidazole) Derivative Co‐ligands: Syntheses,Crystal Structures,Catalytic and Fluorescence Properties

Two metal‐organic coordination polymers of Co^II with the molecular formulae [Co(L₁)(tp)(H₂O)₂]_n ( 1 ) and [Co(L₂)(tp) · H₂O]_n ( 2 ) [L₁ = 1, 4‐bis(benzimidazole‐1‐ylmethyl)‐ benzene; L₂ = 1, 1‐(1, 4‐butanediyl)bis(5, 6‐dimethylbenzimidazole); tp = terephthalate] were synthesized and characterized by single‐crystal X‐ray diffraction studies, infrared spectroscopy (IR), thermogravimetric analysis (TGA), X‐ray powder diffraction (XRPD), and elemental analysis. The structure determination of complex 1 reveals a 2D layer with (4, 4) topology, with Co^II ions at the nodes connected through tp and L₁ co‐ligands. Complex 2 is the first example of a four‐connected SrAl₂ structure type ( sra , 4²6³8 topology) with threefold interpenetration in Co^II coordination frameworks, forming by bridging L₂ and tp co‐ligands. In addition, the fluorescence and catalytic performances of the complexes for the degradation of methyl orange were investigated.     

柔性配体构筑的三个构象多样的镧系羧酸配位聚合物:合成,结构和荧光性质

利用2,2''-(1,4-亚苯基)二(亚苯基)二(硫基)苯二羧酸(H₂L¹)和2,2''-(2,3,5,6-四甲基-1,4-亚苯基)二(亚甲基)二(硫基)苯二甲酸(H₂L²)2个柔性二羧酸分别与镧系金属盐反应,通过溶剂热方法合成了3个配位聚合物:{[(NH₂(CH₃)₂][Nd(L¹)₂(DMF)]·2DMF}_n(1)和{[Ln(L²)_1.5(H₂O)(DMF)₂]·2DMF}_n[Ln=Ce(2),Pr(3)]。利用元素分析、红外、粉末X射线衍射、热重分析等对配合物进行了表征。X射线单晶衍射分析表明:3个配合物均为二维的层状结构,并且2个配体在配合物中表现出不同的构象。(L¹)^2-在配合物1中表现出顺式和反式2种构象,(L2²)^2-在配合物2和3中仅表现出反式构象。此外,对配合物的热稳定性和荧光性质也进行了研究。     

Two zinc (II) coordination polymers based on aliphatic ether Schiff base: Synthesis,crystal structure,antioxidation and fluorescence

The synthesis of two 1D coordination polymers [Zn₂L¹₂]_n 1 and [Zn₂L²₂]_n 2 , based on the H₂L¹ (bis (salicylidene)‐3‐oxapentane‐1,5‐diamine) and the H₂L² (bis (5‐methylsalicylaldehyde)‐3‐oxapentane‐1,5‐diamine) ligands, have been described and characterized by IR, elemental analysis and X‐ray single crystal analyses. In coordination polymer 1 , each Zn²⁺ ion is five‐coordinated by three oxygen atoms and two nitrogen atoms from deprotonated ligand forming a square pyramidal configuration. It is worth noting that phenolic oxygens of the deprotonated H₂L¹ adapt monodentate and monoatomic bridging coordinated modes resulting in one‐dimensional linear chain structure in which macro rings alternately connect small rings. The coordination polymer 2 is a four‐coordinated one‐dimensional zigzag chain in which geometric structure around the Zn (II) atom can be described as distorted tetrahedron. The antioxidant activity of the coordination polymers 1 – 2 and the ligands were determined by superoxide and hydroxyl radical scavenging method in vitro. The results demonstrated that the coordination polymers exhibit more effective antioxidant activity than the ligands. Moreover, compared with emissive bands of the free ligands in the solid state and DMF solvent, the photoluminescent transition of the Zn (II) coordination polymer 1 – 2 may be attributed to ligand‐to‐ligand charge‐transfer regulated by Zn (II) ion.     

Effect of pH on the construction of CdII coordination polymers involving the 1,1′‐[1,4‐phenylenebis(methylene)]bis(3,5‐dicarboxylatopyridinium) ligand

Changing the pH value of a reaction system can result in polymers with very different compositions and architectures. Two new coordination polymers based on 1,1′‐[1,4‐phenylenebis(methylene)]bis(3,5‐dicarboxylatopyridinium) (L^2?), namely catena‐poly[[[tetraaquacadmium(II)]‐μ₂‐1,1′‐[1,4‐phenylenebis(methylene)]bis(3,5‐dicarboxylatopyridinium)] 1.66‐hydrate], {[Cd(C₂₂H₁₄N₂O₈)(H₂O)₄]·1.66H₂O}_n, (I), and poly[{μ₆‐1,1′‐[1,4‐phenylenebis(methylene)]bis(3,5‐dicarboxylatopyridinium)}cadmium(II)], [Cd(C₂₂H₁₄N₂O₈)]_n, (II), have been prepared in the presence of NaOH or HNO₃ and structurally characterized by single‐crystal X‐ray diffraction. In polymer (I), each Cd^II ion is coordinated by two halves of independent L^2? ligands, forming a one‐dimensional chain structure. In the crystal, these chains are further connected through O—H…O hydrogen bonds, leading to a three‐dimensional hydrogen‐bonded network. In polymer (II), each hexadentate L^2? ligand coordinates to six Cd^II ions, resulting in a three‐dimensional network structure, in which all of the Cd^II ions and L^2? ligands are equivalent, respectively. The IR spectra, thermogravimetric analyses and fluorescence properties of both reported compounds were investigated.     

S,N‐Chelated organotin(IV) compounds containing 6‐phenylpyridazine‐3‐thiolate ligand—structural,antibacterial and antifungal study

A series of tri‐ and diorganotin(IV) compounds containing potentially chelating S,N‐ligand(s) (L^SN, where L^SN is 6‐phenylpyridazine‐3‐thiolate) were prepared and structurally characterized by multinuclear NMR spectroscopy. X‐ray diffraction techniques were used for determination of the structure of compounds containing one [(L^SN)Ph₂SnCl], two [(n‐Bu)₂Sn(L^SN)₂] and the combination of two L^SN and one L^CN [(L^CN)(n‐Bu)Sn(L^SN)₂] (where L^CN is {2‐[(CH₃)₂NCH₂]C₆H₄}‐) ligands. The coordination number of the tin atom varies from five to seven and is dependent on the number of chelating ligands present. The formation of the five‐membered azastanna heterocycle is favored over the formation of four‐membered azastannathia heterocycle in compounds containing both types of ligands. The di‐n‐butyl‐substituted compounds are the most efficient ones in inhibition of growth of yeasts, molds and G⁺ bacteria strains. Copyright © 2011 John Wiley & Sons, Ltd.     

柔性配体构筑的三个构象多样的镧系羧酸配位聚合物:合成,结构和荧光性质

利用2,2''-（1,4-亚苯基）二（亚苯基）二（硫基）苯二羧酸（H₂L¹）和2,2''-（2,3,5,6-四甲基-1,4-亚苯基）二（亚甲基）二（硫基）苯二甲酸（H₂L²）2个柔性二羧酸分别与镧系金属盐反应,通过溶剂热方法合成了3个配位聚合物：{[（NH₂（CH₃）₂][Nd（L¹）₂（DMF）]·2DMF}_n（1）和{[Ln（L²）_1.5（H₂O）（DMF）₂]·2DMF}_n[Ln=Ce（2）,Pr（3）]。利用元素分析、红外、粉末X射线衍射、热重分析等对配合物进行了表征。X射线单晶衍射分析表明：3个配合物均为二维的层状结构,并且2个配体在配合物中表现出不同的构象。（L¹）^2-在配合物1中表现出顺式和反式2种构象,（L²）^2-在配合物2和3中仅表现出反式构象。此外,对配合物的热稳定性和荧光性质也进行了研究。     

Influencing the Self-Sorting Behavior of [2.2]Paracyclophane-Based Ligands by Introducing Isostructural Binding Motifs

Two isostructural ligands with either nitrile ( L^nit ) or isonitrile ( L^iso ) moieties directly connected to a [2.2]paracyclophane backbone with pseudo-meta substitution pattern have been synthesized. The ligand itself ( L^nit ) or its precursors ( L^iso ) were resolved by HPLC on a chiral stationary phase and the absolute configuration of the isolated enantiomers was assigned by XRD analysis and/or by comparison of quantum-chemical simulated and experimental electronic circular dichroism (ECD) spectra. Surprisingly, the resulting metallosupramolecular aggregates formed in solution upon coordination of [(dppp)Pd(OTf)₂] differ in their composition: whereas L^nit forms dinuclear complexes, L^iso exclusively forms trinuclear ones. Furthermore, they also differ in their chiral self-sorting behavior as (rac)- L^iso undergoes exclusive social self-sorting leading to a heterochiral assembly, whereas (rac)- L^iso shows a twofold preference for the formation of homochiral complexes in a narcissistic self-sorting manner as proven by ESI mass spectrometry and NMR spectroscopy. Interestingly, upon crystallization, these discrete aggregates undergo structural transformation to coordination polymers, as evidenced by single-crystal X-ray diffraction.     

Synthesis,Crystal Structures,and Fluorescent Properties of Two ZnII/CdII Coordination Polymers Constructed from Isomeric Ligands

The d¹⁰ coordination polymers (CPs), [Zn(L₁)(OH)]_n ( 1 ) and [Cd(L₂)₂]_n ( 2 ) were obtained from isomeric ligands 3‐(6‐aminpyridinium‐3‐yl) benzoic acid (L₁) and 4‐(6‐aminpyridinium‐3‐yl) benzoic acid (L₂), and characterized by elemental analyses, IR spectroscopy, single‐crystal and powder X‐ray diffraction. In compound 1 , a spiral chain structure connected by μ₂‐OH^– and the Zn^II ions, which are further linked by the L₁ ligands to give atwo‐dimensional layered structure. Classical hydrogen‐bonding interactions (O ··· H–N) between adjacent layers result in three‐dimensional supramolecular structure. Compound 2 features a three‐dimensional framework formed by linking [Cd₂(COO)₂] clusters in a bcu net. Thermal stabilities and fluorescent properties of 1 and 2 were also investigated.     

Effect of solvent on the construction of Co(II) coordination polymers containing a semi-rigid bis(benzimidazole) derivative: syntheses,structures, and properties

Two Co(II) coordination polymers, [CoL(npa)]·2H₂O (1) and [CoL(Hnpa)₂] (2) (L = 1,4-bis(5,6-dimethylbenzimidazole-1-yl)benzene, H₂npa = 5-nitroisophthalic acid), have been synthesized in different solvent systems and characterized by Infrared (IR) spectroscopy, elemental analysis, and powder and single crystal X-ray diffraction. Compound 1 was synthesized under solvothermal conditions with DMF as solvent and had a pair of L ligands adopting a μ₂-bridging mode and connecting two Co²⁺ cations to generate a 26-membered Co₂L₂ loop. The npa^2? link adjacent Co₂L₂ loops via a bis(monodentate) bridging mode to create a 1-D channel-like chain structure. Compound 2 was obtained under hydrothermal conditions, and the carboxylate of the monodeprotonated Hnpa^? adopt a μ₁-η^0?:?η¹ coordination to connect adjacent Co²⁺ cations into a 2-D polymeric layer. The μ₂-bridging L ligands connect adjacent 2-D [Co(Hnpa)]_n polymeric layers into a 3-D NaCl-like framework. The Co²⁺ cations and the L ligands in compounds 1 and 2 exhibit different coordination geometries and conformations. Effects of solvents on the construction of Co(II) coordination polymers were investigated. In addition, the electrochemical behavior of carbon paste electrodes containing 1 and 2 and the thermal stabilities of 1 and 2 were investigated.     

Three different structural lead(II) polymers constructed from newly designed chlorophenyl-imidazole dicarboxylate ligands

A 1-D coordination polymer, {[Pb(o-ClPhH₂IDC)₂]·H₂O}_n (o-ClPhH₃IDC = 2-(2-chlorophenyl)-1H-imidazole-4,5-dicarboxylic acid) (1), a 2-D coordination polymer, [Pb₃(p-ClPhIDC)₂(H₂O)]_n (p-ClPhH₃IDC = 2-(4-chlorophenyl)-1H-imidazole-4,5-dicarboxylic acid) (2), and a 3-D polymer, [Pb(p-ClPhH₂IDC)₂]_n (3), have been obtained solvothermally and structurally characterized by elemental analyses, IR, and single-crystal X-ray diffraction. Although they were prepared with similar ligands and Pb²⁺, polymers 1–3 show distinct structures. The X-ray powder diffraction and thermal properties of the polymers have been investigated. The influence of the reaction conditions to the final products and coordination of the organic ligands are discussed.     

Tetranuclear Zn(II) complexes with compartmental and dicyanamido ligands: synthesis,structure, and luminescent properties

New tetranuclear compounds have been obtained by reacting binuclear complexes, [Zn₂L ⁿ (μ-OH)(H₂O)₂](ClO₄)₂, with sodium dicyanamide (HL ⁿ are end-off bicompartmental ligands resulting from condensation between 2,6-diformyl-p-cresol with N,N-dimethyl-ethylenediamine or 2-aminomethyl-pyridine). The complexes, [{L¹(μ-OH)Zn₂}(μ _1,5-dca)₂{Zn₂(μ-OH)L¹}](ClO₄)₂ (1) and [{Zn₂L²(μ ₃-OH)(dca)}₂](ClO₄)₂?·?2H₂O (2), have been characterized by single-crystal X-ray diffraction. The angular nature of the bridging dicyanamido induces the “M” shape of the tetranuclear cationic unit in 1. The tetranuclear cation, because of its particular shape, acts as a receptor toward one perchlorate ion, which is hydrogen bonded to the hydroxo groups. This tetranuclear unit in 2 has a defective heterocubane structure. The luminescence properties of the new tetranuclear complexes have been investigated.     

基于2-巯基苯甲酸及其原位氧化配体的两种金属配位聚合物的合成、结构及发光性质

由水热法得到2个新颖配位聚合物[Cd(2-mba)(bimb)]_n(1)和[Pb(2-sb)]_n(2)(H₂(2-mba)=2-巯基苯甲酸, bimb=4,4-双(1-咪唑基)联苯,sb^2-=2-亚磺基苯甲酸酯) 通过元素分析、红外光谱、X射线粉末衍射和单晶衍射对其进行了表征。配合物1为二维网状结构,由一维的[Cd(2-mba)]_n链与bimb连接形成。在配合物2中配体2-巯基苯甲酸在溶剂热的条件下通过原位反应被氧化成2-亚磺基苯甲酸酯,其结构为一种由配体2-亚磺基苯甲酸酯中的羧基与亚磺基桥联金属铅离子形成的二维(4,4)连接的层状结构。此外,2个配合物展示了良好的热稳定性和光致发光性能。     

Syntheses and structures of Cd(II) and Co(II) compounds of 4-[(3-pyridyl)methylamino]benzoate anion

Three coordination polymers containing Cd(II) and Co(II), connected via 4-[(3-pyridyl)methylamino]benzoate (L^?), have been synthesized in hydrothermal conditions. In [Cd(L)Cl] _n (1), adjacent Cd(II) cations are linked by carboxylates to give a dinuclear cluster. Pairs of L^? bridge the dinuclear cluster to form double helical chains, and these chains are further linked by Cl^? to produce a 4-connected net with (4²?·?6³?·?8) topology. [CdL₂] _n (2) contains 1-D ladder-like chains. The packing structure displays a 3-D supramolecular structure, with π?···?π interactions stabilizing the framework. [CoL₂] _n (3) has a 2-D extended supramolecular structure via π?···?π interactions of 1-D coordination polymers of 3. The crystal structures of 1–3 have been determined by single-crystal X-ray diffraction. Luminescent properties for 1 and 2 are discussed.     

Spin Crossover and Valence Tautomerism in Neutral Homoleptic Iron Complexes of Bis(pyridylimino)isoindolines

Homoleptic iron complexes of six bis(pyridylimino)isoindoline (bpi) ligands with different substituents (H, Me, Et, tBu, OMe, NMe₂) at the 4‐positions of the pyridine moieties have been prepared and studied with regard to temperature‐dependent spin and redox states by a combination of ⁵⁷Fe Mössbauer spectroscopy, SQUID magnetometry, single‐crystal X‐ray diffraction analysis, X‐band EPR, and ¹H NMR spectroscopy. While the H‐, methyl‐, and ethyl‐substituted complexes remain in a pure high‐spin state irrespective of the temperature, the 4‐tert‐butyl‐substituted derivative shows spin‐crossover behavior. The methoxy‐ and dimethylamino‐substituted compounds were found to easily undergo oxidation. In the crystalline state, valence tautomeric behavior was observed for the methoxy derivative as a thermally activated charge‐transfer transition, accompanied by a spin crossover above 200 K. The valence tautomerism leads to a chelate with one of the bpi ligands as a dianion radical L^2?. and with an effective spin of S=2.