Xiangru Meng

A series of novel metal-ferrocenedicarboxylate coordination polymers: crystal structures, magnetic and luminescence properties

Novel two-dimensional layered lanthanide(III)-ferrocenedicarboxylate coordination polymers {[M(η 2 -O 2 CFcCO 2 -η 2 )(μ 2 -η 2 -O 2 CFcCO 2 -η 2 -μ 2 ) 0.5 (H 2 O) 2 ]· m H 2 O} n (Fc=(η 5 -C 5 H 4 )Fe(η 5 -C 5 H 4 ), M=Tb 3+ , m =2, 1 ; M=Eu 3+ , m =2, 2 ; M=Y 3+ , m =1, 3 ) with trapezium-shaped units and one-dimensional wave-shaped Cd(II)-ferrocenedicarboxylate polymer {[Cd(η 2 -O 2 CFcCO 2 -η 2 )(H 2 O) 3 ]·4H 2 O} n ( 4 ) have been prepared and structurally characterized by single crystal diffraction. In polymers 1 – 3 , each central metal ion (Tb(III), or Eu(III) or Y(III)) is located in a pseudo-capped-tetragonal prism coordination geometry, and ferrocenedicarboxylate anion ligands have two coordination modes (bidentate-chelating mode and tridentate-bridging mode). The magnetic behaviors for 1 and 2 are studied in the temperature range of 5.0–300 K. The results show that the paramagnetic behavior of 2 is mainly due to the effective spin–orbital coupling between the ground and excited states through the Zeeman perturbation, and the weak magnetic interaction between Eu 3+ centers can be observed. In addition, compared with sodium ferrocenedicarboxylate, the fluorescent intensities of the polymers 1 – 4 are enhanced in the solid state.

Syntheses, structures, and properties of four Cu(II) complexes containing 2-(1H-imidazol-1-methyl)-1H-benzimidazole ligand

Four Cu(II)-containing complexes based on 2-(1H-imidazol-1-methyl)-1H-benzimidazole (imb), [Cu2(imb)2Cl4] · 2CH3OH (1), {[Cu(imb)(bdic2−)] · 1.5H2O · DMF} n (2), {[Cu(imb)(bdic2−)] · 2H2O} n (3), and {[Cu3(imb)2(Hbdc3−)2] · 2H2O} n (4), where H2bdic = 1,3-benzenedicarboxylic acid and H4bdc = 1,2,4,5-benzenetetracarboxylic acid, have been synthesized and characterized by single-crystal diffraction. Dinuclear 1 is isolated by the reaction of imb with CuCl2 · 2H2O. When H2bdic is added in the reaction with the other experimental conditions unchanged, 2 with a different structure is obtained. The [Cu2(imb)2] dinuclear units are linked through bdic2− groups to form a 2-D structure. The imb reacts with CuCl2 · 2H2O and H2bdic at 80°C to give 3, which exhibits a 2-D (4,4) network. With the replacement of H2bdic with H4bdc in the above reaction, 4 is formed featuring a 2-D structure in which Hbdc3− is a six-connecting group. Their IR spectra and thermogravimetric analyses are also investigated.

Novel zinc(II) coordination polymers constructed from ferrocenyl carboxylate ligands

Two novel ferrocene-containing Zn(II) coordination polymers, [Zn{μ2-OOCCH(CH3)CFc}2]n [1, Fc = (η5-C5H5)Fe(η5-C5H4)] and {[Zn2{μ2-OOCCH(CH3)CFc}4(bpa)]·2MeOH}n [2, bpa = 1,2-bis(4-pyridyl)ethane], have been prepared. The two polymers have been characterized by single-crystal X-ray crystallography. The Zn(II) ions in polymer 1 are bridged by μ2-coordinated FcC(CH3)CHCOO− anions, forming an infinite [Zn(μ2-OOCH(CH3)CFc}2]n chain. Polymer 2 is constructed from paddle-wheel shaped [Zn2{μ2-OOCCH(CH3)CFc}4] building units. The dimeric tetrabridged cores are connected by organic bridging ligands, leading to a linear [Zn2{μ2-OOCCH(CH3)CFc}4(bpa)]n chain. To the best of our knowledge, 2 is the first example of a Zn(II) polymer built up by ferrocene-based paddle-wheel building units. The electrochemical properties of both polymers were also investigated.

Syntheses, structures, and fluorescent properties of two new d10-metal coordination polymers containing 1-((benzotriazol-1-yl)methyl)-1-H-1,2,4-triazole ligand

Two new coordination polymers formulated as {[Zn(bdic)(bmt)H2O] · 0.5H2O} n (1) and {[Cd(bdic)(bmt)(H2O)2] · 2H2O} n (2) (H2bdic = 1,3-benzenedicarboxylic acid, bmt = 1-((benzotriazol-1-yl)methyl)-1-H-1,2,4-triazole) have been synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. Both coordination polymers exhibit 1-D chain structure where bmt is unidentate and bdic2− bridging. In 1, bmt hangs at two sides of the main chain, whereas bmt hangs at one side of the main chain in 2. Fluorescent properties have also been determined.

Self-assembly of three Cd(II) complexes: 0-D, 1-D, and 3-D structures based on 2-(1H-imidazol-1-methyl)-1 H-benzimidazole

Three new complexes, [Cd(L)I2]2 (1), {[Cd(L)I2] · DMF} n (2), and [Cd2(L)4(μ 2-I)I(H2O)] n (3), have been obtained through self-assembly of an unsymmetrical ligand 2-(1H-imidazol-1-methyl)-1H-benzimidazole (L) with Cd(II) salts. Single-crystal X-ray diffraction shows that 1 displays a dimeric structure in which two Cd(II) ions are bridged by two bidentate bridging L. Complex 2 exhibits a 1-D chain structure (···Cd–L–Cd–L···) constructed by L bridging Cd(II) ions. In 3, the Cd(II) ions are five-connected nodes and linked by L and iodide leading to the 3-D network. Complexes 2 and 3 are synthesized maintaining the same solvents and stoichiometric ratio of metal and ligand at different reaction temperature. The different structures of the complexes indicate that the temperature plays a significant role in construction of the complexes. Luminescent properties of 1–3 have been investigated in the solid state at room temperature.

Syntheses, structures, and properties of two 2-D Cd(II) complexes based on 2-(1H-imidazol-1-methyl)-1H-benzimidazole and polycarboxylate ligands

Two 2-D Cd(II) complexes, {[Cd(imb)(bdc)(H2O)]·CH3OH}n (1) and {[Cd(imb)(Hbtc)(CH3OH)]·2H2O·CH3OH}n (2), have been synthesized by reactions of CdCl2·2.5H2O with 2-(1H-imidazol-1-methyl)-1H-benzimidazole (imb) and 1,3-benzenedicarboxylic acid (H2bdc) or 1,3,5-benzenetricarboxylic acid (H3btc). Single-crystal X-ray diffraction shows that 1 possesses an infinite 2-D layered structure in which all the carboxylates chelate Cd(II) and imb bridge Cd(II) ions. Complex 2 also features an infinite 2-D layered structure and imb ligands also bridge Cd(II) ions, but two carboxylates of each 1,3,5-benzenetricarboxylate coordinate to Cd(II) in monodentate or chelating mode, leaving the third one, which is not deprotonated, uncoordinated. IR spectra, fluorescent properties, and thermogravimetric analyses of both complexes have been investigated. Two new 2-D Cd(II) complexes {[Cd(imb)(bdc)(H2O)]·CH3OH}n (1) and {[Cd(imb)(Hbtc)(CH3OH)]·2H2O·CH3OH}n (2) have been synthesized and characterized by single crystal X-ray diffraction. Their IR, TG and fluorescent properties have also been investigated.

Synthesis and crystal structure of a novel zinc(II) coordination polymer with mixed ferrocenyl diketone and bipyridine ligands

Abstract A novel zinc(II) coordination polymer [Zn(fca)2(bpe)]n·2nH2O (bpe=1,2-bis(4-pyridyl)ethene, fca=C5H5FeC5H4C(OH)CHCOCH3) was obtained by the reaction of Zn(OAc)2·2H2O with bpe and 1-ferrocenylbutane-1,3-dione (ferrocenoylacetone, Hfca) in methanol solution. X-ray structural analysis reveals that the compound contains two kinds of ligands: one is the 1,2-bis(4-pyridyl)ethene ligand, directly bridging zinc(II) centers to form a one-dimensional chain [Zn(bpe)]n, the other is the enolized ferrocenylacetone chelating the central ion. The zinc(II) ion is in an elongated octahedral environment with four oxygen atoms from two distinct enolized ferrocenoylacetone, two nitrogen atoms of the bridging 1,2-bis(4-pyridyl)ethene ligands.

Syntheses, crystal structures, and fluorescent properties of two 2-D Cd(II) complexes based on 2-((1H-1,2,4-triazol-1-yl)methyl)-1H-benzimidazole and 1,2,4,5-benzenetetracarboxylate

Two complexes formulated as {[Cd(btec)0.5(tmb)H2O]·4H2O}n (1) and {[Cd(H2btec)(tmb)(H2O)]·2H2O}n (2) (H4btec = 1,2,4,5-benzenetetracarboxylic acid, tmb = 2-((1H-1,2,4-triazol-1-yl)methyl)-1H-benzimidazole) have been synthesized and characterized by elemental analysis, IR, and single crystal X-ray diffraction. Single crystal X-ray diffraction shows that 1 has a 2-D layer structure in which tmb bridges and all of the carboxylates from 1,2,4,5-benzenetetracarboxylate chelate. In 2 Cd(II) ions are bridged by monodentate carboxylates leading to a 2-D layer structure with all tmb ligands coordinated monodentate to Cd(II), hanging at two sides of the layers. Complexes 1 and 2 are further extended to 3-D supramolecular structures by hydrogen bonding interactions. Luminescent properties have been investigated in the solid state at room temperature.

Syntheses, crystal structures, and fluorescent properties of two d10 metal complexes based on 2-(benzoimidazol-yl)methyl)-1H-1,2,4-triazole and 1,3,5-benzenetricarboxylate

Two d10 metal complexes, {[Zn(Hbtc)(bmt)]·DMF·5H2O} n (1) and {[Cd(Hbtc)(bmt)]·0.5DMF·0.5H2O} n (2) (H3btc = 1,3,5-benzenetricarboxylic acid, bmt = 2-((benzoimidazol-yl)methyl)-1H-1,2,4-triazole), have been synthesized under solvothermal conditions by employing bmt and H3btc. Single-crystal X-ray diffraction shows that Zn(II) ions are connected by bmt with bidentate-bridging coordination and by 1,3,5-benzenetricarboxylate with bis-monodentate coordination leading to the 2D structure of 1. Complex 2 exhibits a 2D layer structure, in which bmt coordinate tridentate-bridging to Cd(II) and 1,3,5-benzenetricarboxylates coordinate to Cd(II) unidentate/chelating. Photoluminescence and thermogravimetric analyses of the two complexes are investigated.

Syntheses, structures, and fluorescent properties of two new Zn(II) coordination polymers containing 2-((benzoimidazol-yl)methyl)-1H-tetrazole

Two coordination polymers, {[Zn(bdc)(bimt)2] H2O}n (1) and {[Zn1.5(btc)(bimt)(H2O)3] H2O DMF}n (2), have been synthesized through reactions of 2-((benzoimidazol-yl)methyl)-1H-tetrazole (bimt) with Zn(NO3)2 6H2O in the presence of 1,4-benzenedicarboxylate (H2bdc) or 1,3,5-benzenetricarboxylate (H3btc). Single-crystal X-ray diffraction analyses show that 1 displays a 1-D zigzag chain structure constructed by 1,4-benzenedicarboxylates bridging adjacent Zn(II) ions. Solid 2 shows a 1-D ribbon-like molecular ladder in which three monodentate carboxylates link adjacent Zn1 ions along the crystallographic a-direction and connect Zn1 and Zn2 along the crystallographic c-axis. In the two polymers, all bimt are terminal ligands to complete the metal coordination sphere and help to assemble the low-dimensional coordination skeleton into high-dimensional ordered supramolecular architectures by N–H O or N–H N hydrogen-bonding. IR spectra, fluorescent properties and thermostabilities have been investigated.