1D Ladder-Like Structure Motif Assembled from Edge-Sharing Rhombic Squares of Sm2Mo2 Based on [Mo(CN)8]4− and Sm3+ Ions as Building Blocks

Novel bimetallic 4d–4f complex, {Cs[Sm(MeOH)₃(DMF)(H₂O)Mo(CN)₈] · H₂O} _n (1) (DMF = N,N′-dimethylformamide) has been synthesized and structurally characterized. The crystal analyses shown that 1 exhibit a one-dimension (1D) infinite chain structure, which adopts a 1D ladder-like structure motif assembled from edge-sharing rhombic squares of Sm₂Mo₂, and that is the first structurally characterized example of a 1D ladder structure based on the [Mo(CN)₈]^4? and Sm³⁺ building blocks. The complex 1 crystallizes in triclinic, space group P-1, with a = 9.905(2), b = 10.333(2), c = 13.562(3) Å, α = 82.00(3)°, β = 86.62(3)°, γ = 65.76(3)°, V = 1253.5(4) Å³ and Z = 2. The magnetic behavior of 1 has also been studied in this paper.     

A Novel Bimetallic Chain Based on [Mo(CN)<Subscript>8</Subscript>]<Superscript>3−</Superscript> and Yb<Superscript>3+</Superscript> Ions as Building Blocks in Which Containing Many Intriguing Structural Features

A novel Mo^V–Yb^III bimetallic chain, {[Yb^III(bpy)₂(DMF)(H₂O)][Mo^V(CN)₈]·0.5bpy·4.5H₂O}_n (1) (DMF = N,N′-dimethylformamide; bpy = 2,2′-bipyridine), has been constructed by the reaction of [Mo(CN)₈]³⁻ with Yb³⁺ and 2,2′-bipyridine. Complex 1 is confirmed as a host–guest supramolecular structure by X-ray structural analysis. The neighboring chains interact with each other with two types of hydrogen bonds and two types of π···π interactions. Thus complex 1 has a unique 3D network. Magnetic analysis of 1 indicates the presence of a strong Yb^III single-ion effect owing to spin–orbital coupling within this system.     

Molecular Spin Ladders Constructed from [Ni(dmit)2]− Building Blocks: Synthesis, Structure and Physical Properties

Abstract  A new ion-pair complex [1-(4-bromobenzyl)-3-methylpyridinium][Ni(dmit)₂] (1), in which dmit = 4,5-dimercapto-1,3-dithiole-2-thione, has been synthesized and structurally characterized. The anions of [Ni(dmit)₂]⁻ stack into dimers, which further construct into a two-leg ladder through lateral S···S interactions. The weak H-bonding interactions of C–H···S and van de Waals interactions between anion and cations were observed. The magnetic susceptibilities measured from 2–300 K indicate an AFM exchange interaction domination and an AFM ordering below ~8 K. The best fit to magnetic susceptibility above 40 K, using a dimer model with s = ?, gives rise to Δ/k_B = 29.8 K, zJ′ = −0.72 K, C = 3.40 × 10⁻³ emu K mol⁻¹ and χ ₀ = −5.8 × 10⁻⁶ emu mol⁻¹ with a fixed g = 2.0. Cyclovoltammetry revealed two quasi-reversible one-electron steps, which are attributed to Ni(IV/III) and Ni(III/II) redox couples. Graphical Abstract  [A novel complex [1-(4-bromobenzyl)-3-methylpyridinium][Ni(dmit)₂] has been synthesized and structurally characterized. The anions of [Ni(dmit)₂]⁻ stack into dimers, which further construct into two-leg ladder through lateral S···S interactions. The weak H–bonding interactions of C–H···S and van de Waals interactions between anion and cations were observed. Moreover, its magnetic property and electrochemical property have been investigated] .     

A CeIII–CuII Supramolecular Architecture Based on a Trinuclear [Ce(H2O)6(CuL)2] Unit: Synthesis, Crystal Structure and Magnetic Properties

A novel 3d–4f heterometallic coordination complex [Ce(H₂O)₆ (CuL)₂]·NO₂·7H₂O (1) (H₃L = glycylglycine, N-[1-(2-hydroxy, phenyl)-propylidene]) was synthesized and characterized by IR, elemental analysis, TGA and single crystal X-ray diffraction. An octameric water cluster consisting of a planar tetrameric water ring and four dangling water molecules were observed in 1. Variable-temperature magnetic data shows antiferromagnetic behavior for 1.     

Quantum chemical study of the addition effect on the geometry of the [Mo6S8(CN)6]6− cluster

The geometrical structure and bonding in adducts [Mo₆S₈(CN)₁₂ · Cr(CO)₄L]⁶⁻ (L = CO, PH₃, PF₃, P(OCH₃)₃) were studied on the base of quantum chemical calculations. The main attention was paid to the study of the changes in the cluster geometry under the influence of the attached Cr(CO)₄L group. The large deformations in the Mo₆ core were found and explained by the electrostatic interaction and the pseudo-Jhan–Teller effect. The high values of the calculated polarizabilities of the compounds under consideration are in accord with the obtained results.     

A unique 3D Co(II)-MOF based on [Co6(μ3-OH)4]8 +n chains: Synthesis,crystal structure,and magnetic property

A novel metal-organic framework, [Co₆(μ₃-OH)₄(ndc)₄(bip)₂(H₂O)₂]_n (1)[H₂ ndc = 1,4-naphthalenedicarboxylic acid, bip = 1,5-bis(imidazole-1-yl)pentane], constructed from unique [Co₆(μ₃-OH)₄]^8 +_n chains containing alternate [Co₄(OH)₂]^6 + and [Co₂(OH)₂]^2 + subunits, was reported, which has a new (3,3,8,12)-connected or 12-connented fcu/cubic network and shows weak antiferromagnetic interaction between the adjacent Co(II) ions mediated through the carboxylate and hydroxyl groups.     

Synthesis and structure of [{As(NtBu)3}2Li6] containing an [As(NtBu)3]3− trianion

Attempts to prepare the [As(N^tBu)₃]³⁻ trianion by the reaction of As(NMe₂)₃ with [^tBuNHLi]_n (1:3 monomer equiv.) proved unsuccessful. However, if the reaction is carried out with an excess of ^tBuNH₂ (3 equiv.) the target complex [{As(N^tBu)₃}₂Li₆] (1) is obtained. This is the first example of a complex containing an [As(NR)₃]³⁻ trianion.     

Structures and magnetism of bimetallic octacyanometallates: honeycomb-like [Mo(CN)8Ni2(pn)4]n·4nH2O and binuclear [Mo(CN)8Ni(en)2(H2O)][Ni(en)3]·2H2O (pn=1,3-diaminopropane,en=1,2-diaminoethane)

Bimetallic octacyanometallates [Mo(CN)₈Ni₂(pn)₄]_n·4nH₂O (1) and [Mo(CN)₈Ni(en)₂(H₂O)][Ni(en)₃]·2H₂O (2) based on [Mo(CN)₈]⁴⁻ were synthesized in aqueous solution, and their crystal and molecular structures have been determined. The complex [Mo(CN)₈Ni₂(pn)₄]_n·4nH₂O (1) consists of novel two-dimensional honeycomb-like layers. The complex [Mo(CN)₈Ni(en)₂(H₂O)][Ni(en)₃]·2H₂O (2) contains a binuclear anion [Mo(CN)₈Ni(en)₂(H₂O)]²⁻,[Ni(en)₃]²⁺ cation and two lattice water molecules. Magnetic studies suggest a possible weak antiferromagnetic interaction between Ni²⁺ ions in 1.     

Novel hetero-polynuclear metal complexes (CuL)3[Mn(NCS)5]2 and (NiL)3[Mn(NCS)5]2 containing trigonal bipyramidal geometric [Mn(NCS)5]3− as bridging ligand

Two thiocyanate-bridged hetero-pentanuclear complexes (CuL)₃[Mn(NCS)₅]₂ (1) and (NiL)₃[Mn(NCS)₅]₂ (2) have been successfully synthesized and characterized by X-ray single crystal diffraction, elemental analysis, IR, TGA and magnetic measurements. (L = N-dl-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene). Single crystal structure analysis indicates that complex 1 and 2 have similar structures in which the Mn(II) atom is five-coordinated in a trigonal bipyramidal geometry by five N atoms from five thiocyanate ligands. The Cu(II) and Ni(II) both show two different coordination environments, square pyramidal and distorted octahedron. Three Cu(II) (or Ni(II)) ions and two Mn(II) ions are bridged by the end-to-end thiocyanate ligands to form pentanuclear entities. The pentanuclear entities are further linked to 3D framework by the hydrogen bonds. The variable-temperature magnetic measurements for 1 indicated weak antiferromagnetic interaction between the Cu(II) and Mn(II) ions.     

Crystal Structure and Physicochemical Properties of Two Supramolecular Compounds: (C4H8NH2)4[Mo8O26] and (NH4)Na2[AsIIIMo6O21(O2CCH2NH3)3]·8H2O

Two inorganic–organic hybrid supramolecular compounds based on polyoxometalates formulated as (C₄H₈NH₂)₄[Mo₈O₂₆] (1) and (NH₄)Na₂[As^IIIMo₆O₂₁(O₂CCH₂NH₃)₃]·8H₂O (2) have been synthesized by conventional solution method and characterized by infrared, UV–Vis and single-crystal X-ray diffraction analyses. Thermal analysis was performed to study their thermal stability. The atomic arrangement in compound (1) can be described as inorganic layers built by [Mo₈O₂₆]^4?, pyrrolidinium cations are embedded into layers. The fascinating structural feature of compound (2) is that the glycine molecules are bounded to two edge-sharing Mo centers via their carboxylate functionality leading to functionalized heteropolymolybdate [As^IIIMo₆O₂₁(O₂CCH₂NH₃)₃]^3?, extensive net hydrogen bonds between cations and anions contribute to the crystal packing. The electrochemical behavior of compound (2) has been studied.     

Two novel three-dimensional coordination polymers with [Ag(CN)2]− as bridging ligands: synthesis and structural characterization of {KMn[Ag(CN)2]3(H2O) }n and {Mn[Ag(CN)2]2(bpy)2}n (bpy=4,4′-bipyridine)

Two novel three-dimensional coordination polymers {KMn[Ag(CN)₂]₃(H₂O)}_n 1 and {Mn[Ag(CN)₂(bpy)]₂}_n 2 have been prepared and structurally as well as magnetically characterized. In both compounds, the three-dimensional networks are constructed entirely by coordinative linkages with all the CN⁻ anions of [Ag(CN)₂]⁻, bpy and water ligands involved in bridging and the novel 3-D structure of 1 is unprecedented.     

Synthesis,crystal structure and magnetic properties of one-dimensional cyano-bridged bimetallic complex of [Mn(Me2-bipy)2]3[W(CN)8]2·9H2O

An octacyanotungstate(V)-manganese(II) bimetallic assembly [Mn(Me₂-bipy)₂]₃[W(CN)₈]₂·9H₂O (1) (Me₂-bipy = 4,4′-dimethyl-2,2′-bipyridine) was synthesized in methanol and characterized by X-ray crystallography. X-ray analysis shows that complex 1 is a neutral, one-dimensional (1D) infinite chain polymer. Magnetic data analysis demonstrates a long-range magnetic interaction and two different antiferromagnetic coupling constants obtained by fitting between Mn and W ions in 1.     

Three New Metal–Organic Polymers Based on Flexible 3-(4-(Carboxymethoxy) Phenyl) Propanoic Acid: Crystal Structures, Luminescent and Magnetic Properties

Three new metal–organic coordination complexes, [Zn₂L(bpp)₂Cl₂] _n (1), [ZnL(bipy)] _n (2), [NiL(bipy)(H₂O)] _n (3), have been synthesized through hydrothermal reactions of flexible 3-(4-(carboxymethoxy)phenyl) propanoic acid(H₂L) with different pyridyl-containing 1,3-bis(4-pyridyl)propane(bpp) or 4,4′-bipyridine(bipy) ligand, and they are characterized by elemetal analysis and single-crystal X-ray diffraction techniques. Complex 1 has a 2-D layer supramolecular network composed of 1-D distorted trapezoidal chains via C–H···π stacking interactions. Complex 2 displays a 2-D lattice-shaped layer structure. Complex 3 has three kinds of O–H···O intermolecular hydrogen bonds, exhibiting a 3-D supramolecular framework. The luminescent properties of complex 1 and 2 have indicated the mixture characteristic of intraligand and ligand-to-ligand charge transition. The magnetic property of 3 has shown the ferromagnetic coupling between Ni²⁺ ions.     

Oligocyanometallic cords as building blocks in luminescent three-dimensional coordination polymers: [Ag4Cd2(tren)2(CN)6.5][Ag(CN)1.5] and [Au2Cd(tren)(CN)4]·H2O

The syntheses, structures and luminescent properties of two unusual mixed-metal coordination polymers, namely [Ag₄Cd₂(tren)₂(CN)_7.5][Ag(CN)_1.5] 1 and [Au₂Cd(tren)(CN)₄]·H₂O 2 (tren = tris(2-aminoethyl)amine), are presented. Both compounds contain abnormal metal cords of oligocyanometallic anions as building blocks wherein the d¹⁰–d¹⁰ interaction plays a crucial role in the metal–metal assembly.     

Synthesis and Properties of Soluble 3,3′,4,4′-Benzophenonetetracarboxylic Dianhydride Copolyimides Based on 1,1-Bis[4-(4-aminophenoxy)phenyl]-1-phenylethane and Commercial Dianhydrides

1,1-Bis[4-(4-aminophenoxy)phenyl]-1-phenylethane (BAPPE) is a useful monomer for preparing soluble polyimides, but polyimide synthesized from BAPPE and 3,3,4,4-benzophenonetetracarboxylic dianhydride (BTDA) shows poor solubility. Insoluble BTDA/BAPPE polyimide can copolymerize with soluble polyimides at certain molar ratios (m₂/m₁) to produce arbitrarily soluble copolyimides. To prepare soluble copolyimides, the smallest m₂/m₁ ratio changes due to the matching dianhydrides, depending on the structure of the dianhydride component. When polymers contain the same m₂/m₁ ratio, copolyimides formed through thermal imidization show poorer solubility than these formed through chemical imidization, and copolyimide cyclized at 250°C has a better solubility than that cyclized at 300°C; this is due to the formation of intermolecular linkages during the high-temperature thermal cyclization. Additional, these copolyimides are characterized by good mechanical properties together with good thermal stability, and a comparative study on the properties of the homopolyimide and copolyimide are also presented.     

Four New Metal–Organic Supramolecular Networks Based on Aromatic Acid and Flexible Bis(imidazole) Ligand: Synthesis,Structures and Luminescent Properties

Four new metal–organic supramolecular networks, namely, [Zn(H₂pdc)₂(H₂O)₂]·2H₂O·bbi (1), {[Cd(Hpdc)₂]·2H₂O₂·H₂bbi}_n (2), [Zn(BA)₂(bbi)]_n (3), and {[Cd(BA)₂(bbi)]·H₂O}_n (4) (H₃pdc = 3,5-pyrazoledicarboxylic acid, HBA = 3-hydroxybenzoic acid and bbi = 1,1′-(1,4-butanediyl)bis(imidazole)) have been synthesized under hydrothermal conditions and characterized by IR spectra, elemental analyses, and single-crystal X-ray diffraction analyses. Compound 1 possesses zero-dimensional (0D) structure, which is finally extended into a two-dimensional (2D) supramolecular network via O–H···O and C–H···O hydrogen bonds. Complex 2 displays a 2D network structure built from Cd²⁺ atoms interconnected by Hpdc^2? ligands. The adjacent networks are further assembled into three-dimensional (3D) supramolecular structure through O–H···O hydrogen bonds. Compounds 3 and 4 show similar one-dimensional (1D) chains, in which four-coordinated Zn(II) atoms and six-coordinated Cd(II) atoms are bridged by bbi ligands. Through O–H···O and C-H···O hydrogen bonding interactions, the 1D chains are further packed into 2D and 3D supramolecular frameworks for 3 and 4, respectively. Obviously, the structural differences among compelxes 1–4 are attributed to the different central metal atoms and organic ligands. In addition, compounds 1–4 exhibit blue fluorescent emission in the solid state at room temperature.     

Synthesis of cis- and trans-[M(CN)2(1-CH3-C6H10-NC)4] (M = Fe,Ru) and crystal structure of trans-[Ru(CN)2(1′-CH3-C6H10-NC)4]

The reaction of the metal carbonyls Fe₂(CO)₉ or Ru₃(CO)₁₂ with 1-isocyano-1-methyl-cyclohexane produces the octahedral metal(II) cyano complexes [M(CN)₂(1-CH₃-C₆H₁₀-NC)₄] in good yields. The cis-isomer is not isolated as a pure compound due to rearrangement processes that yield the sterically less crowded trans-isomer. The molecular structure of the trans-isomer of the ruthenium complex shows the expected almost ideal octahedral coordination of the central ruthenium ion with two cyanide and four isocyanide ligands. This reaction again indicates that isocyanides exhibiting quarternary carbon atoms in α-position with respect to the isocyano substituent in general react with di- or trinuclear metal carbonyls to yield cyano complexes with oxidized metal centres and concomitant reductive cleavage of the respective isocyanide.     

Two Novel Bimetallic Cyano-Bridged Coordination Polymers Containing the 2,2′-(Ethylenedioxy)bis (Ethylamine): Syntheses,Structural, Thermal and Magnetic Properties

Two new cyano bridged bimetallic polymeric complexes, [Ni(edbea)Ni(CN)₄]·1/2H₂O (1) and [Cu(μ-edbea)(μ-CN)₂ Ni(CN)₂]·H₂O (2) [edbea = 2,2′-(ethylenedioxy)bis(ethylamine)] have been synthesized by adding metal chloride (M = Ni^II and Cu^II), and edbea into [Ni(CN)₄]²⁻ in water–ethanol solution and then characterized by elemental analysis, infrared (IR) and electron paramagnetic resonance (EPR) (for only complex 2) spectra, variable temperature magnetic measurement, and thermal gravimetric analysis. The X-ray diffraction crystal structure of complex 2 shows a 2D polymeric chain –edbea(N5,O1)–Cu1–N1C1–Ni(CN)2–C4N6–Cu1–(N6,O2) edbea– in which the Cu^II centers are linked by two cyano and one edbea. The powder EPR spectrum of the complex 2 has shown that Cu^II ions are located in rhombically distorted octahedral sites. The magnetic properties of the coordination polymers have been studied in temperature range of 15–300 K. The magnetic behaviors investigation of complexes 1 and 2 indicated the presence of a very weak antiferromagnetic interaction.     

One-Dimensional Cd(II) and Co(II) Coordination Polymers with Dinuclear Secondary Building Units Constructed by 1,1′-Biphenyl-3,3′-Dicarboxylic Acid: Synthesis, Structures, Luminescent and Magnetic Properties

Bilayered diffusion and hydrothermal synthetic methods using pyridine (py) and 2,6-dimethylpyrazine (dmpz) as weak bases and small terminal ligands generated two Cd(II) and Co(II) 1D coordination polymers with dinuclear metal clusters as secondary building units (SBUs) from an organic bridging ligand, 1,1′-biphenyl-3,3′-dicarboxylic acid (H₂ L). They are {[Cd₂(L)₂(py)₄] (py)(CH₃OH)} _n (1) and [Co₂(L)₂(dmpz)₄(H₂O)] _n (2). Compounds 1 crystallizes in the monoclinic space group P2(1)/c, while 2 crystallizes in the triclinic space group P-1. Especially, compound 2 possesses the 1D chain structure that contains two linked left-handed and right-handed helices. Fluorescent measurements for 1 display strong blue light emissions with the maximum emission at 396 nm with the excitation of 320 nm. Magnetization study shows the existence of weak antiferromagnetic coupling for 1 with the negative −E ₂/k value of −1.3 K.