Structurally characterised new twisted conformer for cyclen, controlled by metal ion complexation as seen in NiII and CuII complexes with halides and pseudohalides

Conformational flexibility of cyclen controlled by complexation with Ni(ii) and Cu(ii) as evidenced by structural studies.

Crystal structure and characterization of a new copper(II) chloride dimer with methyl(pyridin-2-ylmethylidene)amine

The new copper(II) complex [CuLCl₂]₂, where L is a product of Schiff base condensation between methyl­amine and 2-pyridine­carbaldehyde, is built of discrete centrosymmetric dimers.

The new copper(II) complex, namely, di-μ-chlorido-bis­{chlorido­[meth­yl(pyri­din-2-yl­methyl­idene)amine-κ²N,N′]copper(II)}, [Cu₂Cl₄(C₇H₈N₂)₂], (I), with the ligand 2-pyridyl­methyl-N-methyl­imine (L, a product of Schiff base condensation between methyl­amine and 2-pyridine­carbaldehyde) is built of discrete centrosymmetric dimers. The coordination about the Cu^II ion can be described as distorted square pyramidal. The base of the pyramid consists of two nitro­gen atoms from the bidentate chelate L [Cu—N = 2.0241 (9), 2.0374 (8) Å] and two chlorine atoms [Cu—Cl = 2.2500 (3), 2.2835 (3) Å]. The apical position is occupied by another Cl atom with the apical bond being significantly elongated at 2.6112 (3) Å. The trans angles of the base are 155.16 (3) and 173.79 (2)°. The Cu⋯Cu separation in the dimer is 3.4346 (3) Å. In the crystal structure, the loosely packed dimers are arranged in stacks propagating along the a axis. The X-band polycrystalline 77 K EPR spectrum of (I) demonstrates a typical axial pattern characteristic of mononuclear Cu^II complexes. Compound (I) is redox active and shows a cyclic voltammetric response with E_1/2 = −0.037 V versus silver–silver chloride electrode (SSCE) assignable to the reduction peak of Cu^II/Cu^I in methanol as solvent.

A thermoelectric copper-iodide composite from the pyrolysis of a well-defined coordination polymer

Coordination polymer 1 was prepared from CuI and a flexible [SNS] ligand L in acetonitrile. The thermal decomposition of 1 yielded a CuI-rich thermoelectric carbon composite 2, which is relatively light, thermally stable and robust. Composite 2 possesses high Seebeck coefficients (700-950 μV K-1) from rt to 204 °C after an optimization cycle.

A One-Dimensional Coordination Polymer Containing Cyclic [Ag4] Clusters Supported by a Hybrid Pyridine and Thioether Functionalized 1,2,3-Triazole

A pyridine and thioether co-supported triazole ligand L (L = 2-((4-(3-(cyclopentylthio)propyl)-1H-1,2,3-triazol-1-yl)methyl)pyridine) has been synthesized using the CuAAC click reaction. This ligand supports the formation of a thermally stable, one-dimensional coordination polymer [L2Ag4]n·4n(BF4) (1) possessing a cationic polymeric structure with [Ag4] metallomacrocycles, in which the ligand L displays chelate/bridging coordination modes using all four potential donors of nitrogen (N) and thioether (S). The dominant direction of the prism crystals of 1 aligns with the propagation of the chain in the lattice.

Reversible crystal-to-amorphous structural transformations and magnetic variations in single end-on azide-bridged MII (M = Mn, Ni) coordination polymers

Azide-bridged coordination polymers undergo reversible crystal-to-amorphous phase transformations during the hydration–dehydration process.

Cross-linking of cyanide magnetic coordination polymers by rational insertion of formate, cyanide or azide

Anionic bridging ligands formate, cyanide and azide have been used to form cross-links in a ferrimagnetic coordination framework, resulting in competing magnetic interactions that decrease the magnetic ordering temperature and result in peculiar magnetic properties.

Hydrogen-Bonding Interactions in Luminescent Quinoline-Triazoles with Dominant 1D Crystals

Quinoline-triazoles 2-((4-(diethoxymethyl)-1H-1,2,3-triazol-1-yl)methyl)quinoline (1), 2-((4-(m-tolyl)-1H-1,2,3-triazol-1-yl)methyl)quinoline (2) and 2-((4-(p-tolyl)-1H-1,2,3-triazol-1-yl)methyl)quinoline (3) have been prepared with CuAAC click reactions and used as a model series to probe the relationship between lattice H-bonding interaction and crystal direction of growth. Crystals of 1-3 are 1D tape and prism shapes that correlate with their intermolecular and solvent 1D lattice H-bonding interactions. All compounds were thermally stable up to about 200 C and blue-green emissive in solution.

Both end-on and end-to-end azide bridged tetranuclear ferromagnetic nickel(ii) Schiff base complexes

Variable temperature magnetic measurement of a tetranuclear nickel(ii) complex, consisting of two pseudo-dinuclear entities, indicates the presence of intra- and inter-dinuclear ferromagnetic interactions, corroborated by DFT calculations.

Green click synthesis of β-hydroxy-1,2,3-triazoles in water in the presence of a Cu(ii)–azide catalyst: a new function for Cu(ii)–azide complexes

A new method for preparing 1,2,3-triazols via a [3+2]-cycloaddition reaction is introduced. The effect of reaction temperature on the epoxide ring opening reactions is also investigated.

Hybrid 1,2,3-Triazole Supported CuII Complexes: Tuning Assembly and Weak Interaction-Driven Crystal Growth

Two new dinuclear CuII complexes [Cu2Cl4(L1)2] (1) and [Cu2Cl4(L2)2] (2) (L1 = 2-((4-(2-(cyclopentylthio)ethyl)-1H-1,2,3-triazol-1-yl)methyl)pyridine; L2 = 2-((4-(pyridin-2-yl)-1H-1,2,3-triazol-1-yl)methyl)benzonitrile) were synthesised and characterised by single-crystal X-ray diffraction (XRD), powder XRD, thermogravimetric analysis, elemental analysis and IR measurements. The picolyl-triazole ligand L1 coordinates in a chelate-bridging mode forming a dinuclear structure 1. The more rigid pyridyl-triazole ligand L2 chelates only, generating a chloride-bridged dinuclear complex 2. Both crystals of complexes 1 and 2 show dominant plate shapes that correlate with weak 2D H-bonding interactions in the lattice. A mononuclear structure (3, [CuCl2(L3)2]⋅6H2O, L3 = 3-((4-(pyridin-2-yl)-1H-1,2,3-triazol-1-yl)methyl)benzonitrile) yields block shape crystals that correlate with 3D H-bonding interactions. This study demonstrates tunable assembly at the molecular level and the relationship of crystal shape with weak lattice interactions.

Structural diversities and magnetic properties of azide-containing coordination polymers based on flexible tetra-pyridinate ligands

By utilizing two quadritopic ligands, four new azido-containing coordination polymers have been synthesized and structurally characterized.

Formation of a novel ferromagnetic end-to-end cyanate bridged homochiral helical copper(ii) Schiff base complex via spontaneous symmetry breaking

A homochiral helical coordination polymer of copper(ii) has been synthesized using achiral precursors. End-to-end cyanate bridges mediate ferromagnetic exchange interactions among copper(ii) centres.

Bis(4-pyridyl)mercury – a new linear tecton in crystal engineering: coordination polymers and co-crystallization processes

Three new coordination polymers have been obtained using bis(4-pyridyl)mercury (py₂Hg) as a spacer: [Cu(Hmea)₂(py₂Hg)](ClO₄)₂·2(py₂Hg) (1), [Cu₂(pa)₂(py₂Hg)(ClO₄)₂]·0.5(py₂Hg)·H₂O (2), and [Cu₂(pa)₂(py₂Hg)₂](BF₄)₂ (3) (Hmea = monoethanolamine; Hpa = propanolamine).

Effects of non covalent interactions in light emitting properties of bis-pyridyl-alkyl-di-imines

Crystallization induced emission is observed for bis-pyridyl-ethyl-di-imine and bis-pyridyl-butyl-di-imine. While in case of bis-pyridyl-di-imines, with no alkyl spacer, the quenching is observed in the solid state.

Synthesis, Structure, and Catalytic Epoxidation Property of a New Phenolato and μ1,1,3-Azido Co-Bridged Polynuclear Manganese(III) Complex Derived from N,N′-Bis(5-methylsalicylidene)ethane-1,2-diamine

A new phenolato and μ1,1,3-azido co-bridged polynuclear manganese(iii) complex has been synthesised and characterised. The structure of the complex has been confirmed by single crystal X-ray diffraction analyses. The ability of the complex to catalyse the epoxidation of styrene using PhIO or NaOCl as oxidant has been studied. Results show the catalysis to occur efficiently in the presence of PhIO and NaOCl.