Polymorphism in 2,6-dimethylpyridinium tetrachlorocuprate(II): Theoretical and crystallographic studies

Halogen bond and polymorphism in trans-bis(2-iodo-5-halopyridine)dihalocopper(ii) complexes: crystallographic, theoretical and magnetic studies

As the halogen atom on position 5 of the 2I5YP ligand gets heavier the probability of crystallizing the syn-conformer increases; 2I5Cl-Cl crystallizes as the anti-conformer whereas 2I5Br-Cl crystallizes as syn- and anti-conformers.

Stabilization of Tetrachloride with Mn (II) and Co (II)Complexes and 4-Tert-Butylpyridinium Organic Cation: Elaboration of the Structure and Hirshfeld Surface, Optical, Spectroscopic and Thermal Analyses

[C9H14N]2[MnCl4] (I) and [C9H14N]2[CoCl4] (II) are isostructural compounds produced via gradual evaporation at room temperature. Both compounds consolidate in the tetragonal space group I4¯2d (No. 122), as shown by single-crystal X-ray diffraction observations. A slightly deformed tetrahedral geometry is formed by four chloride atoms around each cation MII (M = Mn or Co). The [C9H14N]+ groups and the isolated [MCl4]2− units are connected via C–H…Cl and N–H…Cl H-bonds to form sheets parallel to the (101¯), (011), (01¯1) and (101) planes. The morphology and the chemical composition of compounds (I) and (II)were determined here using SEM and EDX. The functional groups contained in both compounds were determined using FT-IR spectroscopy. The study of the optical characteristics showed that the two compounds exhibited semiconductor behavior. The thermal analysis (TGA-DTA) was used to determine their thermal stability.

May halogen bonding interactions compete with Cu⋯Cl semi-coordinate bonds? Structural, magnetic and theoretical studies of two polymorphs of trans-bis(5-bromo-2-chloro pyridine)dichlorocopper(ii) and trans-bis(2,5-dichloropyridine)dichlorocopper(ii)

Interaction of the negative potential area from one molecule with the positive areas I and II from two different molecules produces polymorphs 1 and 2.

Evidence of promising biological-pharmacological activities of the sertraline-based copper complex: (SerH2)2[CuCl4]

In the current study the ability of copper complex to exert multiple biological activities is combined with the pharmacological action of sertraline (SerH₂Cl, antidepressant drug). The hydrated and anhydrous forms of the tetrachlorocuprate(II) salts, namely (SerH₂)₂[CuCl₄]·½H₂O and (SerH₂)₂[CuCl₄], were synthesized and characterized by physicochemical methods. The crystal structures were determined by X-ray diffraction methods. The hydrate complex crystallizes in the monoclinic P2₁ space group with a=8.0807(2) Å, b=36.2781(8) Å, c=12.6576(3) Å, β=95.665(2)°, and Z=4 molecules per unit cell and the un-hydrate in P2₁ with a=13.8727(6) Å, b=7.5090(3) Å, c=18.618(1) Å, β=104.563(6)°, and Z=2. It has been suggested that Cu(II) ions might be critical in the development of mood disorders, showed potent biocidal activity, and also acted as analgesic adjuvant. To improve sertraline efficiency, the antidepressant and analgesic activities of the complex have been assessed in rats denoting a marked synergistic effect. Antithyroid and antimicrobial activities were also evaluated. Because depressive disorders and hyperthyroidism diseases led to an oxidative stress state, antioxidant capability has also been tested. The complex behaved as a good superoxide radical scavenger (IC₅₀=6.3×10^-6M). The ability of the complex to act as bromoperoxidase mimic was assessed. A pseudo-first order constant of k=0.157±0.007min^-1 has been determined. The complex evidences promising biological-pharmacological activities and the albumin binding studies showed a K_b of 2.90×10³M^-1 showing an improvement in the uptake of sertraline by albumin at 8h incubation (time required for effective interaction of sertraline with the protein).

Crystal structure of bis-(N,N,N',N'-tetra-methyl-guanidinium) tetra-chlorido-cuprate(II)

In the structure of the title salt, (C5H14N3)2[CuCl4], the Cu(II) atom in the anion lies on a twofold rotation axis. The tetra-chlorido-cuprate(II) anion adopts a flattened tetra-hedral coordination environment and inter-acts electrostatically with the tetra-methyl-guanidinium cation. The crystal packing is additionally consolidated through N-H⋯Cl and C-H⋯Cl hydrogen bonds, resulting in a three-dimensional network structure.

The square-planar to flattened-tetrahedral CuX4(2-) (X = Cl, Br) structural phase transition in 1,2,6-trimethylpyridinium salts

The abrupt green-to-yellow thermochromism observed for certain A2CuCl4 compounds has long been attributed to the presence of strong N-H hydrogen bonding in the low-temperature phase that favors square-planar CuCl4(2-) (green in color) through reduction of ligand-ligand repulsion. Weakening of the hydrogen bonding at higher temperature results in the transformation to (far more common) flattened-tetrahedral geometry - the expected geometry for CuBr4(2-) complexes due to their greater ligand-ligand repulsion. The square-planar to flattened-tetrahedral transitions in (1,2,6-trimethylpyridinium)2CuX4 provide the first examples of this phase transformation in the absence of N-H hydrogen bonding and for a CuBr4(2-) complex. These results suggest that the square-planar to flattened-tetrahedral transformation in CuX4(2-) systems may be more common than previously thought.

A fluorescent sensor with a detection level of pM for Cd2+ and nM for Cu2+ based on different mechanisms

L showed excellent selectivity and sensitivity towards Cd²⁺ in acetonitrile–H₂O buffer solution and towards Cu²⁺ in pure water.

Synthesis, structural characterization and dielectric properties of (C6H9N2)2(Hg0.75Cd0.25)Cl4 compound

The present paper undertakes the study of a title compound whose structure is (C6H9N2)2(Hg0.75Cd0.25)Cl4. The centrosymmetric compound crystallizes in the triclinic space group P-1, with a=7.580(7) Å; b=8.572(8) Å; c=15.433(13) Å; α=84.49(5)°; β=89.13(5)°; γ=68.53(5)° and Z=2. The crystal structure was solved and refined to R (int)=0.0212 using 7932 independent reflections. The atomic arrangement shows an alternation of organic and inorganic layers. Between layers, the cohesion is performed via N-H⋯Cl hydrogen bonding, yet in the organic sheets, cations are further connected to classical π-π stacking. The Infrared and Raman spectra of this compound reported from 400 to 4000 cm(-1) confirmed the presence of the principal bands assigned to the internal modes of organic cation. Solid-state (13)C and (111)Cd CP-MAS-NMR spectra are reported. The dielectric study of this compound has been measured, in order to determine the σ(d.c) conductivity which is thermally activated with activation energy about 1.5 eV.