Noncoordinating Anions as Key Modulators of Supramolecular Structures, Optical and Electrical Properties in Nickel(II) Complexes

This study explores the synthesis, structural characterization, and examination of two nickel(II) complexes, [Ni(N 3 L 1 )2](NO3)2 (complex 1) and [Ni(N 3 L 1 )2](ClO4)2 (complex 2), using the newly synthesized organic heterocyclic chelating ligand N 3 L 1 [4-imidazole-2,6-di(pyrazinyl)pyridine]. Through single-crystal X-ray diffraction, we have detailed the crystal structures of these complexes, highlighting their distorted octahedral geometries and diverse supramolecular interactions including π···π stacking, anion···π, and hydrogen bonding. These interactions crucially influence the formation of distinct one- and two-dimensional supramolecular architectures. Density functional theory (DFT) calculations were utilized to probe these noncovalent interactions, revealing insights into their stereoelectronic influence and stability in the solid state. Additionally, the electronic properties of the complexes were explored through their electrical characterizations in Schottky diodes, which suggest the potential of these complexes in Schottky diode based electronic devices applications. Notably, complex 2, incorporating perchlorate anions, exhibited better electrical properties than complex 1. This work aims to elucidate the role of noncoordinating counteranions in the structural integrity and photophysical behavior of these complexes, while also providing a structure-function correlation through detailed theoretical analysis.

Synergizing Steric Hindrance and Stacking Interactions To Facilitate the Controlled Assembly of Multiple 41 Metalla-Knots and Pseudo-Solomon Links

In this work, a noncoplanar terphenyl served as a building block to synthesize a novel 3,3'-substituted bipyridyl ligand (L1) which further reacted with binuclear half-sandwich units A/B, giving rise to two aesthetic 41 metalla-knots in high yields via a coordination-driven self-assembly strategy. Furthermore, given the inherent compactness of the 41 metalla-knots, it creates favorable conditions for the emergence of steric repulsion. We focused on progressively introducing nitrogen atoms featuring a lone pair of electrons (LPEs) into ligand L1 to manipulate the balance of H⋅⋅⋅H/LPEs⋅⋅⋅LPEs steric repulsion during the assembly process, ultimately achieving controlled assembly from 41 metalla-knots to the pseudo-Solomon link and then to molecular tweezer-like assembly facilitated by stacking interactions. All the assemblies were well characterized by solution-state NMR techniques, ESI-TOF/MS, and single-crystal X-ray diffraction. The evolutionary process of the topological architectures is equivalent to visualizing the synergistic effect of steric hindrance and stacking interactions on structural assembly, providing a new avenue for achieving the controlled synthesis of different topologies.

Tunability of Photovoltaic Functions via Halogen Substitution [(Ade)2 CdX4](X = Cl, Br): A Class of Three-Dimensional Organic-Inorganic Hybrid Materials

Two new three-dimensional organic-inorganic hybrid crystalline materials, [(Ade)2 CdCl4] (1) and [(Ade)2 CdBr4] (2), were obtained by the slow evaporation of adenine (Ade) and cadmium chloride in aqueous solution at room temperature with hydrochloric acid and hydrobromic acid used as halogen sources. The structural, thermal, optical, and electrical properties were characterized by single-crystal X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, variable-temperature-variable-frequency dielectric constant analysis, and electrochemical tests. With increasing the substitution of Cl by Br, the composition of the material changed and the space group shifted from P-1 to P21/m, with a significant blue-shift in the fluorescence emission. Changing the temperature induced the deformation of the three-dimensional framework structure formed by hydrogen bonding interactions, leading to dielectric anomalies. Cyclic voltammetry tests showed the good reversibility of the electrolysis process. The structural diversity of the complexes was realized by modulating the halogen composition, and a new method for designing novel organic-inorganic hybrids with controllable photoelectric functionality was proposed.

Surfactant-induced disaggregation of a quinoxaline AIEgen scaffold: aggregation aptitude in the solid and solution states

We have designed five propellor-shaped molecules based on the quinoxaline scaffold with a functional group variation. They exhibit aggregation-induced emission, and the responses of these congeners regarding good solvents and poor solvents are investigated both spectroscopically and microscopically. Solid- as well as solution-state parallel analysis of the aggregation facet is laid out. Notably, L2 interacts specifically with a cationic surfactant, unlike other congeners where the mechanism proceeds via disaggregation. Real sample analysis was carried out on freshwater samples as well as waste effluent samples from domestic households and industries, thus projecting the analytical and environmental significance.