Synthesis and Structural Characterization of Copper(I), Silver(I) and Gold(I) Complexes with Pyrimidine-2-thionato Ligands and their Adducts with Phosphanes

Heteronuclear Complexes with Promising Anticancer Activity against Colon Cancer

This study investigates the activity of novel gold(I) and copper(I)/zinc(II) heteronuclear complexes against colon cancer. The synthesised heteronuclear Au(I)-Cu(I) and Au(I)-Zn(II) complexes were characterised and evaluated for their anticancer activity using human colon cancer cell lines (Caco-2). The complexes exhibited potent cytotoxicity, with IC50 values in the low micromolar range, and effectively induced apoptosis in cancer cells. In the case of complex [Cu{Au(Spy)(PTA)}2]PF6 (2), its cytotoxicity is ×10 higher than its mononuclear precursor, while showing low cytotoxicity towards differentiated healthy cells. Mechanistic studies revealed that complex 2 inhibits the activity of thioredoxin reductase, a key enzyme involved in redox regulation, leading to an increase in reactive oxygen species (ROS) levels and oxidative stress, in addition to an alteration in DNA's tertiary structure. Furthermore, the complexes demonstrated a strong binding affinity to bovine serum albumin (BSA), suggesting the potential for effective drug delivery and bioavailability. Collectively, these findings highlight the potential of the investigated heteronuclear Au(I)-Cu(I) and Au(I)-Zn(II) complexes as promising anticancer agents, particularly against colon cancer, through their ability to disrupt redox homeostasis and induce oxidative stress-mediated cell death.

Synthesis, Structural Studies, and Anticancer Properties of [CuBr(PPh3)2(4,6-Dimethyl-2-Thiopyrimidine-κS]

CuBr(PPh3)2(4,6-dimethylpyrimidine-2-thione) (Cu-L) was synthesized by stirring CuBr(PPh3)3 and 4,6-dimethylpyrimidine-2-thione in dichloromethane. The crystal structure of Cu-L was obtained, and indicated that the complex adopts a distorted tetrahedral structure with several intramolecular hydrogen bonds. Moreover, a centrosymmetric dimer is formed by the intermolecular hydrogen bonding of the bromine acceptor created by symmetry operation 1−x, 1−y, 1−z to the methyl group (D3 = C42) of the pyrimidine–thione ligand. HSA-binding of Cu-L and its ligand were evaluated, revealing that Cu-L binds to HSA differently than its ligand. The HSA-bindings were modeled by molecular docking, which suggested that Cu-L binds to the II A domain while L binds between the I B and II A domains. Anticancer activities toward OVCAR-3 and HeLa cell lines were tested and indicated the significance of the copper center in enhancing the cytotoxic effect; negligible toxicities for L and Cu-L were observed towards a non-cancer cell line. The current study highlights the potential of copper(I)-phosphine complexes containing thione ligands as therapeutic agents.

Four new Cu6S6 cluster-based coordination compounds: synthesis, crystal structures and fluorescence properties

A hexagonal prismatic Cu₆S₆ cluster exhibits excellent near-infrared fluorescence properties due to its short Cu-Cu bonds, however, the construction of Cu₆S₆ cluster-based compounds with extended structures is still a challenge. Here, four new Cu₆S₆ cluster-based coordination compounds, formulated as Cu₃(pymt)₃ (1), {(CuCN)₂[Cu₃(mpymt)₃]}_n (2), {(CuSCN)[Cu₃(mpymt)₃]}_n (3) and {(CuCN)₂[Cu₃(dmpymt)₃]·CH₃CN}_n (4) (Hpymt = pyrimidine-2-thiolate, Hmpymt = 4-methyl-pyrimidine-2-thione and Hdmpymt = 4,6-dimethylpyrimidine-2-thione), have been synthesized through the reactions of mercaptopyrimidine derivatives and CuCN or CuSCN under solvo-thermal conditions and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, IR spectroscopy, elemental analysis, and thermal gravimetric analysis. Single-crystal X-ray diffraction analysis reveals that compound 1 is a zero-dimensional Cu₆(pymt)₆ molecule containing a distorted pseudo-hexagonal prismatic Cu₆S₆ core. Compounds 2 and 4 with isomorphic frameworks but different organic linkers show a rare three-dimensional framework with nor topology constructed from Cu₆(mpymt)₆ units and one-dimensional chiral [Cu(CN)]_n chains; compared with compound 2, a more hydrophobic one-dimensional channel in compound 4 is observed due to the increase of the methyl groups on the pyrimidine ligand, in which acetonitrile molecules are filled in the channels of compound 4. Compound 3 shows a rare two-dimensional layer constructed from Cu₆(mpymt)₆ units and one-dimensional puckered (CuSCN)_n chains. For the first time, Cu₆S₆ clusters are connected to one-dimensional inorganic CuCN (or CuSCN) chains through mercaptopyrimidine derivatives to obtain extended arrays in compounds 2-4. The crystals of compounds 1-4 in the solid state all show apparent red light emission. Compound 4 shows sensitive luminescence quenching response to nitrobenzene (NB), and the corresponding quenching constant (K_sv) and detection limit are 2.06 × 10³ M^-1 and 9.27 ppm, respectively. This study provides a new strategy to construct Cu₆S₆ cluster-based coordination polymers that have great potential in various applications such as luminescence sensing.

Modulating the DNA cleavage ability of copper(ii) Schiff bases through ternary complex formation

Copper(ii) Schiff-bases were electrochemically synthesized and characterized. The presence of co-ligands such as 2,2′-bpy or phen in the metal coordination environment increases the DNA cleavage efficiency.

Metal complexes of a novel heterocyclic benzimidazole ligand formed by rearrangement-cyclization of the corresponding Schiff base. Electrosynthesis, structural characterization and antimicrobial activity

One-pot electrochemical synthesis of metal complexes containing a novel heterocyclic benzimidazole ligand is reported and characterized.

Copper(i) 5-phenylpyrimidine-2-thiolate complexes showing unique optical properties and high visible light-directed catalytic performance

Copper(i) 5-phenylpyrimidine-2-thiolate complexes exhibit intriguing luminescence properties and excellent visible light-directed catalytic activity towards aerobic oxidative hydroxylation of arylboronic acids.

A three-dimensional metal-organic polymer: poly[bis(μ₂-pyrimidine-2-thiolato-κ⁴N¹,S:S,N³)lead(II)]

The title compound, [Pb(C4H3N2S)2]n, was prepared by the reaction of [Pb(OAc)2]·3H2O (OAc is acetate) with pyrimidine-2-thione in the presence of triethylamine in methanol. In the crystal structure, the Pb(II) atom has an N4S4 coordination environment with four ligands coordinated by N- and S-donor atoms. This compound shows that the pyrimidine-2-thiolate anion can lead to a three-dimensional network when the coordination number of the metal ion can be higher than 6, as is the case with the Pb(II) ion. This compound presents only covalent bonds, showing that despite the possibility of the hemidirected geometries of Pb(II), the eight-coordinated ion does not allow the formation of an isolated molecular structure with pyrimidine-2-thiolate as the ligand.

Synthesis, structures and DFT calculations of 2-(4,6-dimethyl pyrimidyl)selenolate complexes of Cu(i), Ag(i) and Au(i) and their conversion into metal selenide nanocrystals

Dimethyl pyrimidylselenolates of Cu(i), Ag(i) and Au(i) were synthesized and utilized as precursors for preparation of the respective metal selenide nanocrystals.

(4,6-Dimethyl-2-sulfanylidenepyrimidin-1-ium) trichlorido(thiourea-κS)zinc(II)

The title compound, (C6H9N2S)[ZnCl3{SC(NH2)2}], exists as a zincate where the zinc(II) centre is coordinated by three chloride ligands and a thiourea ligand to form the anion. The organic cation adopts the protonated 4,6-dimethyl-2-sulfanylidenepyrimidin-1-ium (L) form of 4,6-dimethylpyrimidine-2(1H)-thione. Two short N—H...Cl hydrogen bonds involving the pyrimidine H atoms and the [ZnCl3L]−anion form a crystallographically centrosymmetric dimeric unit consisting of two anions and two cations. The packing structure is completed by longer-range hydrogen bonds donated by the thiourea NH2groups to chloride ligand hydrogen-bond acceptors.