Structural characterization of ferromagnetic bridged-acetato and -dichlorido copper(II) complexes based on bicompartmental 4-t-butylphenol

The reaction of Cu(II) salts with 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-t-butylphenol (L^t-Bu-OH) afforded two bridged-phenoxido/hydroxido complexes. The dinuclear bridged acetate species [Cu₂(μ-L^t-Bu-O)(μ-CH₃COO)](PF₆)₂ (1) and the 1D polymeric doubly-bridged-chlorido {[Cu₂(μ-L^t-Bu-OH)(μ-Cl)₂](ClO₄)₂·4H₂O}_n (2). The two complexes were structurally characterized. Both complexes revealed ferromagnetic interactions; moderate in complex 1 (J = + 30.8 cm^− 1) and very weak (J = + 2.25 cm⁻¹) in 2.     

An unprecedented (4, 8)-connected self-penetrating Cu(I)-MOF constructed from the rare [Cu4I2]2 + cationic cluster and in situ generated tetrazole ligand

The in situ hydrothermal reaction of CuI, NaN₃ and 4-(1H-imidazol-1-yl)benzonitrile leads to a new three-dimensional pillared-layer Cu(I)-MOF, [Cu₂(μ₃-I)(μ₅-IPT)]_n (1) (HIPT = 5-[4-(imidazol-1-yl)phenyl]tetrazolate). Interestingly, the structure of 1 exhibits an unprecedented binodal (4, 8)-connected three-dimensional self-penetrating framework first constructed from [Cu₄I₂]^2 + cationic clusters as 8-connected nodes and in situ generated IPT ligands as 4-connected nodes. Moreover, 1 is strongly luminescent with green emission (λ_em = 545 nm) in the solid-state.     

Cyanide-bridged mixed-valence copper(II/I) coordination polymers: Unique 7-connected sev-type 3D network versus anionic 2D host network encapsulated with cationic complex

Reactions of CuCl₂, K₂[Ni(CN)₄]/K₃[Co(CN)₆], and 5-amino-1H-tetrazole led to cyanide-bridged mixed-valence Cu(II/I) complexes, [Cu(H₂O)₃Cu₃(CN)₅] (1) and [Cu(H₂O)₄][Cu₄(CN)₆] (2).The uncommon semi-closed {Cu₂(CN)₃} dimmers in 1 are bridged by μ₃-C,C,N cyanide ligands to afford rare 1D centipedal-like chain motifs, which are further bridged by μ₂-C,N and metalloligand “CN–Cu(4)–CN” to finish sophisticated zeolite-like 3-D structure. Topologically, 1 is the first example of uninodal 7-connected sev-like cyanide-bridged network. Compound 2 consists of two-dimensional honeycomb-related anionic layers [Cu₄(CN)₆]^2 −, within which the [Cu(H₂O)₄]^2 + cations are intercalated into alternate interlamellar space. Compound 1 shows antiferromagnetic couple arising from pure ground-state configuration of Cu(II) mediated by diamagnetic bridges –CN–Cu^I–CN −. The inclusion compound 2 shows blue photoluminescence originated from Cu(I) center to the unoccupied π* orbital of the cyanide ligand (MLCT) charge transfer.     

The first complex of the pentameric phosphazane macrocycle [{P(μ-NtBu)}2(μ-NH)]5 with a neutral molecular guest: Synthesis and structure of [{P(μ-NtBu)}2(μ-NH)]5(CH2Cl2)2

The reaction of [{P(μ-N^tBu)}₂(μ-NH)}₅I]⁻[Li(thf)₄]⁺([1 · I]⁻[Li(thf)₄]⁺) with NaOMe in CH₂Cl₂ gives the title compound [{P(μ-N^tBu)}₂(μ-NH)]₅(CH₂Cl₂)₂ [1 · (CH₂Cl₂)₂] the first adduct containing this type of macrocyclic phosph(III)azane host and a neutral guest.     

Synthesis,crystal structure and magnetic properties of a new cyanide-bridged mixed-valence copper(I)/copper(II) clathrate

A unique cyanide-bridge mixed-valence Cu^I/Cu^II clathrate of formula [Cu^I₂(CN)₃][{Cu^II(tren)}₂(μ-CN)](CF₃SO₃)₂ [tren = tris(2-aminoethyl)amine] containing cyanide-bridged [{Cu^II(tren)}₂(μ-CN)]^3 + binuclear cations stacked between anionic honeycomb layered copper(I) cyanide networks, was synthesized and structurally characterized by single crystal X-ray diffraction. Variable-temperature magnetic susceptibility studies showed that the cyanide bridge mediates a strong antiferromagnetic interaction between the copper(II) centers (J = − 160 cm^− 1, the spin Hamiltonian being defined as H = −J S_A⋅S_B).     

Constructing two new crystalline metal–organic frameworks based on a mixed-donor ligand

The self-assembly of a prominent ligand, 5-(4-(1H-tetrazolyl)phen)isophthalic acid (H₃TZPI), with Zn^2 +/Cu^2 + centres generates two new MOFs, [Zn₂(TZPI)(μ₃-OH)(H₂O)₂]·2H₂O (JUC-161) and [Cu(HTZPI)(μ₂-H₂O)_0.5(H₂O)_1.5]·5(H₂O) (JUC-162). JUC-161 exhibits fascinating three-dimensional structures containing rectangular channels with dimensions of 6.5 × 3.0 Å², and JUC-162 displays 3D supramolecular structures with 12.5 × 14.6 Å² hexagonal channels. The observed structural diversity in these frameworks is due to the two distinct coordinating moieties of the H₃TZPI ligand. The photoluminescence of JUC-161 and the magnetic properties of JUC-162 are also measured at room temperature. Photoluminescence investigations reveal that JUC-161 displays a strong main emission spectrum peak at 388 nm. JUC-162 is found to exhibit an antiferromagnetic interaction between Cu^2 + ions.     

A 3D (3,8)-connected net based on the tetranuclear Cu4 units constructed from mixed organic ligands

Under hydrothermal conditions, a new polynuclear Cu(II) complex, [Cu₂(nip)(ina)(μ₃-OH)]₂·H₂O (1) (H₂nip = 5-nitroisophthalic acid, Hina = isonicotinic acid) has been synthesized with mixed organic ligands. Single crystal X-ray analysis reveals that complex 1 displays a three-dimensional (3D) structure based on the tetranuclear Cu₄ units. In the structure of 1, two pairs of symmetry-related Cu(II) ions are connected by six carboxyl and two μ₃-OH groups to generate the tetranuclear Cu₄ units, which are connected by the mixed ligands into a 3D framework. Topology analysis reveals a (3,8)-connected tfz-d net for 1. Magnetic studies display antiferromagnetic behavior for 1. And thermogravimetric analysis of 1 has also been investigated.     

{[Cu(phen)]3Cl4}2[GeMo12O40]: Synthesis,crystal structure and magnetic property of a new trinuclear copper complex based on germanomolybdate

A new trinuclear copper complex based on germanomolybdate, {[Cu(phen)]₃(μ₂-Cl)₄}₂[GeMo₁₂O₄₀] (1) (phen = 1,10-phenanthroline), has been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy, TG analysis, X-ray powder diffraction (XRPD) and single-crystal X-ray diffraction. Single crystal X-ray analysis reveals that the structural unit of 1 consists of two coordination cations {[Cu(phen)]₃(μ₂-Cl)₄}²⁺ (1a) and a saturated Keggin-type germanomolybdate polyoxoanion [GeMo₁₂O₄₀]^4?. In 1, the most intriguing feature is that each trinuclear copper cation {[Cu(phen)]₃(μ₂-Cl)₄}²⁺ is constructed from three [Cu(phen)]²⁺ cations bridged by four μ₂-Cl atoms. Magnetic measurements indicate 1 shows the ferromagnetic exchange interactions within Cu^II centers.     

Hydrothermal synthesis,crystal structure and strong blue fluorescence of a novel 3D coordination polymer containing copper and zinc centers linked by isonicotinic acid ligands

The first mixed metal Zn/Cu coordination polymer, [Zn₃Cu₂(IN)₈] (1) (HIN = isonicotinic acid) was synthesized under hydrothermal conditions. The three dimensional structure of 1 has a novel topological metal-organic framework, which is built up by Zn²⁺, Cu⁺ and ligands IN to generate an open-framework with an unusual helical [–Zn(Cu)-IN–]_n chains along the b axis. The very strong blue fluorescence for 1 can be observed in the solid state.     

Alkoxo- and carboxylato-bridged hexanuclear copper(II) complex: Synthesis,structure and magnetic properties

Reaction of copper(II) nitrate trihydrate with N,N-dimethylethanolamine (dmea) and pivalic acid in methanol led to the hexanuclear copper(II) complex Cu₆(η¹:μ₂-C₄H₁₀NO)₄(η¹:η¹:μ₂-C₅H₉O₂)₄(η¹:μ₁-C₅H₉O₂)₂(μ₃-OH)₂ (1). The crystal structure of 1 indicates that hexametallic centers are bridged by the μ₃-alkoxo, dmea oxygens, and the μ₂-dicarboxylato oxygen atoms of pivalate ions. Furthermore, in the asymmetric unit, three types of copper ions have been found labeled as Cu₁, Cu₂ and Cu₃. The Cu₂ takes a distorted octahedral shape, whereas Cu₁ and Cu₃ adopt square pyramidal geometries. The complex 1 shows strong antiferromagnetic interactions through the oxo groups within the dimeric units (J = − 82.6 to − 25.8 cm^− 1) and weak antiferromagnetic couplings between the dimers (J = − 10.9 and 0.8 cm^− 1).     

Luminescence sensing of an unusual tetranodal 3-connected topology of Cu(I)-MOF

A new Cu(I)-based complex with chemical formulae [Cu₄Cl_0.24(CN)_3.76(L)] (1), (L = 1,3,5-tris(1-imidazolyl) benzene) has been synthesized and structurally characterized. Compound 1 shows an unusual tetranodal 3-connected topology and is self-penetrating – 0-membered shortest circuits. It shows that 1 can work as highly sensitive sensors to Cu^2 + and nitrobenzene (NB) explosive by luminescent quenching. This study shows that 1 could be a useful luminescent sensor for metal ions and organic small molecules.     

New μ-oxo-bridged tetranuclear Cu(II) complex with Schiff-base ligand: Synthesis,crystal structure and magnetic properties

A new μ-oxo-bridged Cu(II) complex with cubane-like tetranuclear copper(II) complex, [Cu₄(L¹)₄] · 4H₂O (1) (H₂L¹ = 2-(3-methoxy-salicylidene-amino)-benzyl-alcohol), has been prepared, and structurally characterized by X-ray crystallography. Complex 1 crystallized in the monoclinic space group P₂₁/n and has a tetranuclear core of Cu₄O₄. The temperature dependence of magnetic susceptibility measurements shown that complex 1 exhibits a strong antiferromagnetic interaction with J = −103.4 cm⁻¹.     

Hydrothermal syntheses and characterization of a series of mixed-ligand luminescent CdII frameworks with novel 2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl) acetate ligand and benzenedicarboxylate isomers

Under similar hydrothermal synthetic conditions using a novel flexible ligand 2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl)acetonitrile (PPAN), benzenedicarboxylate isomers (H₂pa = phthalate, H₂ip = isophthalate, and H₂tp = terephthalate) and Cadmium(II) acetate, three novel mixed-ligand Cd(II) coordination polymers {[Cd₂(PPAA)₂(μ-pa)(H₂O)]·2H₂O}_n (1), {[Cd₄(PPAA)₄ (μ₄-ip)₂]·2H₂O}_n (2) and {[Cd₂(PPAA)₂(μ-tp)]·2H₂O}_n (3) (PPAA⁻ = 2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl) acetate) have been isolated, in 1–3 PPAN, and are also hydrolyzed into a novel PPAA⁻ ligand. Complex 1 is a 1D coordination polymer in which the tetra-nuclear [Cd₄(PPAA)₄]^4 + structural units are extended by tri-dentate μ-pa^2 − ligands. Complex 2 contains binuclear [Cd₂(PPAA)₂]^4 + structural units, which are extended by four tetra-dentate μ₄-ip^2 − ligands to link eight neighboring binuclear [Cd₂(PPAA)₂]^4 + units ultimately forming a 2D layered framework, while complex 3 contains 1D double chain containing [Cd(PPAA)]_n cation structural units, which are further extended by tetradentate μ-tp^2 − ligands to form a new 2D layered framework. All the complexes have been investigated by elemental analysis, FT-IR, thermal analysis and fluorescence characterization. The flexible coordination modes of PPAA⁻ are also briefly analyzed. The flexible coordination modes of PPAA⁻ and benzenedicarboxylate isomers also reveal great potential in the construction of these novel mixed-ligand luminescent frameworks with diverse structural motifs and unique functional properties.     

An unusual emissive and colorimetric copper (II) detection by a selective probe based on a pseudo-crown cysteine dye: Solution and gas phase studies

An off-on-off emissive and colorimetric probe L, based on a Pseudo-Crown cysteine dye was designed for Copper (II). Compound L was studied in solution and in gas-phase (MALDI-MS) over alkaline, alkaline, earth-alkaline and transition metal ions (Li⁺, Na⁺, K⁺, Ca^2 +, Mg^2 +, Zn^2 +, Cu^2 +, Co^2 +, Ni^2 +, Pb^2 +, and Hg^2 +) in organic media. The recognition of Cu^2 + by L lead to red/dark red colored complexes, one emissive L₂Cu and another LCu, less emissive. In regards to fluorescent quantum yield in both cases an increase respective to L was visualized (2 fold for LCu and 7 fold for L₂Cu). The paramagnetic nature of both complexes was proved by the synthesis of both complex species, as well as, through ¹H NMR and FTIR. Compound L demonstrate to be able to detect and quantify the minimal amounts of 1.3 μM/3.3 μM of Cu^2 +.     

Synthesis,structure and magnetic properties of a copper molybdate hybrid inorganic/organic solid with a novel 10-connected three-dimensional network topology

Hydrothermal reaction of CuCl₂, MoO₃, and 4,4′-dipyridylketone (4,4′-dpk) afforded green crystals of the mixed metal oxide phase {[Cu₂(MoO₄)₂(4,4′-dpk)(H₂O)]·H₂O}_n (1). According to single-crystal X-ray diffraction, {Cu₂O₂} dimers link into 1-D {Cu₂O₂(μ-H₂O)}_n chains via bridging aqua ligands. These chains form [Cu₂(MoO₄)₂(H₂O)]_n slabs via linkage through tetrahedral molybdate anions. In turn, the copper molybdate slabs are pillared through tethering 4,4′-dpk ligands into a 10-connected three-dimensional lattice with an unprecedented 3¹²4³⁰5²6 topology. Variable temperature magnetic data above 140 K were fit to the Curie–Weiss law, with C = 0.17 cm³ K/mol Cu and Θ = 70 K, indicating likely ferromagnetic coupling within the dinuclear kernels of 1; low temperature data points towards the possibility of interdimer antiferromagnetic interactions.     

Synthesis,structural characterization and properties of a novel 1D helical chain arsenomolybdate {[Cu(en)2][Cu(en)(H2O)][(Cu(en)2(H2O)] [AsIIIAsVMo9O34)]} · 2H2O

An organic–inorganic hybrid 1D helical chain arsenomolybdate {[Cu(en)₂][Cu(en)(H₂O)][(Cu(en)₂(H₂O)] [As^IIIAs^VMo₉O₃₄)]} · 2H₂O (1) (en = ethylenediamine) has been hydrothermally synthesized and characterized by elemental analyses, IR, UV and CD spectrum, powder X-ray diffraction, TG-DTA and single-crystal X-ray diffraction. The asymmetric unit of 1 consists of a monocapped trivacant Keggin [As^IIIAs^VMo₉O₃₄]^6 − subunit, a pendant [Cu(en)₂(H₂O)]^2 + cation, a pendant [Cu(en)(H₂O)]^2 + cation, one bridging [Cu(en)₂]^2 + cation and two lattice water molecules. It should be noted that 1 illustrates a one-dimensional (1D) helical chain assembled by {[Cu(en)(H₂O)][(Cu(en)₂(H₂O)][As^IIIAs^VMo₉O₃₄)]}^2 − clusters and [Cu(en)₂]^2 + linkers.     

A novel hydroxo-bridged cyclic tetranuclear copper(II) complex using the guanazole ligand: Synthesis,crystal structure and thermal analysis

A novel hydroxo-bridged cyclic tetranuclear copper(II) complex with the guanazole ligand (3,5-diamino-1,2,4-triazole = Hdatrz), [Cu₄(datrz)₄(μ₂-OH)₂(NO₃) (H₂O)₆] · (NO₃) · 5(H₂O) (1) has been synthesised and characterised by X-ray crystallography. In 1, the four copper(II) centres are linked by hydroxo bridges and the N1,N2-coordination of the deprotonated guanazole ligands. The core has considerably short Cu⋯Cu distances in the range of 3.3550(4)–3.3611(4) Å. Thermal analysis of 1 reveals that the cyclic framework constructed with hydroxo and guanazole ligands is stable up to 285 °C.     

A new high-dimensional architecture constructed from paradodecatungstate and [Cu(2-Hpzc)]2+ complexes

A new compound, H₄{[Cu₃(2-Hpzc)₂(H₂O)₄](H₂W₁₂O₄₂)}·13H₂O (1) (2-Hpzc = 2-pyrazinecarboxylic acid), was synthesized in conventional condition and characterized by elemental analyses, IR spectroscopy, thermal gravimetric analysis, X-ray powder diffraction (XRPD) and single X-ray diffraction. In the structure of compound 1, each paradodecatungstate anion acts as a quadridentate ligand coordinating to four Cu²⁺ cations through its terminal oxygen atoms to form a two-dimensional (2D) layer. The infinite [Cu(2-Hpzc)]²⁺ chains connect adjacent layers forming a three-dimensional (3D) architecture. There exist two kinds of channels with sizes of ca. 5.737 × 4.628 Å² and 9.104 × 8.640 Å² along the b and c directions, respectively. The magnetic behavior of 1 exhibits antiferromagnetic interaction.     

The first macrocyclic “layer-to-layer” type tetranuclear copper(II) complex: structure,stability and unprecedented catalase-like activity

The macrocyclic tetranuclear copper(II) complex [L₂Cu₄(μ-CO₃)₂](ClO₄)₄·4H₂O is synthesized by [2 + 2] condensation of the organic ligand L and a rational [2 + 2] assembly of the polynuclear complex; the structure, stability and catalase-like activity are investigated.     

Sequential detection of copper(II) and cyanide by a simple colorimetric chemosensor

A simple colorimetric receptor 1 based on the combination of N-(5-nitro-2-pyridyl)-1,2-ethanediamine and 4-(diethylamino)-2-hydroxybenzaldehyde was synthesized for the sequential detection of Cu^2 + and CN⁻. The receptor 1 showed a distinct color change toward Cu^2 + from colorless to yellow. The detection limit of 1 for Cu^2 + (0.88 μM) was much lower than the World Health Organization guideline (31.5 μM) as the maximum allowable copper concentration in drinking water. In addition, 1-Cu^2 + complex could be used to detect cyanide by showing a color change from yellow to colorless, indicating the recovery of 1 from 1-Cu^2 +. Furthermore, the sensing mechanism of 1 for Cu^2 + was supported by theoretical calculations.