Synthesis, Structure, Biological Activity, and Luminescence Properties of a "Butterfly"-Type Silver Cluster with 3-Benzyl-4-phenyl-1,2,4-triazol-5-thiol

A new silver(I) cluster [Ag8L4(Py)(Pype)]·4Py·11H2O (I) with 3-benzyl-4-phenyl-1,2,4-triazol-5-thiol (L) was synthesized via the direct reaction of AgNO3 and L in MeOH, followed by recrystallization from a pyridine-piperidine mixture. The compound I was isolated in a monocrystal form and its crystal structure was determined via single crystal X-ray diffraction. The complex forms a "butterfly" cluster with triazol-5-thioles. The purity of the silver complex and its stability in the solution was confirmed via NMR analysis. Excitation and emission of the free ligand and its silver complex were studied at room temperature for solid samples. The in vitro biological activity of the free ligand and its complex was studied in relation to the non-pathogenic Mycolicibacterium smegmatis strain. Complexation of the free ligand with silver increases the biological activity of the former by almost twenty times. For the newly obtained silver cluster, a bactericidal effect was established.

Microwave synthesis of a blue luminescent silver(I) coordination polymer with a rigid tris-triazole ligand

Microwave-assisted hydrothermal reaction of 2-fluoro-3,5,6-tri(1H-1,2,4-triazol-1-yl)-1,4-benzenedicarbonitrile (L1) with silver(I) nitrate yields a coordination polymer [Ag3(L2)2(NO3)] n (1), in which the L2 ligand (HL2 = 2-hydroxy-3,5,6-tri(1H-1,2,4-triazol-1-yl)terephthalonitrile) is obtained by in situ ligand transformation from the L1 precursor. HL2 monohydrate has also been isolated by the microwave-mediated hydrolysis of L1 and structurally characterized. Single-crystal X-ray diffraction reveals that HL2 monohydrate comprises a zwitterionic HL2 moiety, while complex 1 displays an infinite L2-bridged double-chain structure. Given that the HL2 molecule has a large conjugated π system, complex 1 exhibits strong blue luminescence in the solid state at room temperature.

Marigold Flower-Like Assemblies of Phosphorescent Iridium-Silver Coordination Polymers

Racemic and enantiopure phosphorescent iridium(III)-silver(I) coordination polymers are reported. The polymers rac-, Λ-, and Δ-IrAg were formed, respectively, by the assembly of the chiral iridium metalloligands rac-, Λ-, and Δ-[Ir(mesppy)₂ (qpy)]PF₆ (rac-, Λ- and Δ-Ir) where mesppy is 2-phenyl-4-mesitylpyridinato and qpy is 4,4':2',2'':4'',4'''-quaterpyridine, and Ag⁺ ions through N_py -Ag linear coordination. The polymers have been characterized in MeNO₂ solution by ¹ H and ¹ H DOSY NMR and CD spectroscopies and in the solid-state by scanning electron microscopy (SEM). The crystal structures of the racemic polymer rac-IrAg has been obtained by X-ray diffraction. The polymers rac-, Λ-, and Δ-IrAg exhibited orange/red emission in solution, in films and as crystals, with intensities comparable to those of the corresponding iridium metalloligands rac-, Λ-, and Δ-Ir. The morphology of the enantiopure polymers in the solid-state resembles marigold flower-like nano-porous assemblies while the racemic polymer possesses an irregular morphology formation.

Aluminum Dimer Containing Bulky 1,2,3-Triazolate Ligand

The first molecular aluminum 1,2,3-triazolato complex was synthesized bearing a bulky 1,2,3-triazolate ligand. Oligomers and polymers were avoided due to the bulkiness and noncoordinating nature of the substituents. The novel Al2N4ring formed contains symmetrical Al-N bond distances unexpectedly having asymmetric Al-N-N angles of 144.55(15)° and 115.83(14)°. This asymmetry demonstrates the effect of the steric hindrance of the ligand.

A three-dimensional chiral crystal structure constructed from a chiral triazolate ligand showing an SrSi2topology: poly[bis(μ3-3,5-diethyl-1,2,4-triazolato-κ3N1:N2:N4)trisilver nitrate]

In the title metal–organic framework (MOF), {[Ag3(C6H10N3)2]NO3}n, the AgIcation is coordinated by two N atoms from two different 3,5-diethyl-1,2,4-triazolate (detz) ligands in a linear configuration. Each AgIcation is then connected to two adjacent AgIcationsviaa μ3-N1:N2:N4-detrz ligand, resulting in a three-dimensional chiral silver–triazolate structure showing an SrSi2(srs) net with 103topology.

Radical-involved photosynthesis of AuCN oligomers from Au nanoparticles and acetonitrile

We show here the first radical route for the direct photosynthesis of AuCN oligomers with different sizes and shapes, as evidenced by TEM observations, from an Au nanoparticle/benzaldehyde/CH(3)CN ternary system in air under UV-light irradiation. This photochemical route is green, mild, and universal, which makes itself distinguishable from the common cyanidation process. Several elementary reaction steps, including the strong C-C bond dissociation of CH(3)CN and subsequent •CN radical addition to Au, have been suggested to be critical in the formation of AuCN oligomers based on the identification of •CN radical by in situ EPR and the radical trapping technique, and other reaction products by GC-MS and (1)H NMR, and DFT calculations. The resulting solid-state AuCN oligomers exhibit unique spectroscopic characters that may be a result of the shorter Au-Au distances (namely, aurophilicity) and/or special polymer-like structures as compared with gold cyanide derivatives in the aqueous phase. The nanosized AuCN oligomers supported on mesoporous silica showed relatively good catalytic activity on the homogeneous annulation of salicylaldehyde with phenylacetylene to afford isoflavanones employing PBu(3) as the cocatalyst under moderate conditions, which also serves as evidence for the successful production of AuCN oligomers.