Atomic-resolution electron microscopy elucidated single-molecule conformations of polynuclear coordination compounds.

Ionic polymers are intriguing materials whose functionality arises from the synergy between ionic polymer backbones and counterions. A key method for enhancing their functionality is the post-synthetic ion-exchange reaction, which is instrumental in improving the chemical and physical properties of polymer backbones and introducing of the functionalities of the counterions. Electronic interaction between host polymer backbone and guest ions plays pivotal roles in property modulation. The current study highlights the modulation of responses to external electric field in cationic bis(terpyridine)cobalt(II) polymer nanofilms through anion-exchange reactions. Initially, as-prepared chloride-containing polymers exhibited supercapacitor behaviour. Introducing anionic metalladithiolenes into the polymers altered the behaviour to either conductive or insulative, depending on the valence of the metalladithiolenes. This modulation was accomplished by fine tuning of charge-transfer interactions between the bis(terpyridine)cobalt(II) complex moieties and redox-active anions. Our findings open up new avenue for ionic polymers, showcasing their potential as versatile platform in materials science.

Development of efficient electrocatalysts for hydrogen evolution reactions (HERs) is necessary to achieve environmentally friendly and sustainable hydrogen production. To reduce cost and to circumvent the scarcity of platinum, the most efficient catalyst for HER, it is essential to develop catalysts using ubiquitous base metals or minimal amounts of precious metals. Bis(diimino)metal (MDI) coordination nanosheets are potential HER catalysts because their electric conductivities, two‐dimensionality, and porous structures provide large surface areas and efficient mass and electron transfer. In addition, with sparse metal arrangements in their chemical structures, nanosheets can reduce the amount of metal needed. We synthesized bis(diimino)palladium coordination nanosheets (PdDI) as a coordination polymer composed of bis(diimino)palladium, with semiconducting characteristics, using gas‐liquid interfacial synthesis and electrochemical oxidation. These electrochemically synthesized PdDIs exhibit remarkable catalytic performance with overpotential reaching 10 mA cm ⁻² of 34 mV, a Tafel slope of 47 mV dec ⁻¹ , and an exchange current density of 2.1 mA cm ⁻² after appropriate activation. This performance is closely comparable to that of metallic platinum. An ex‐situ investigation of the activation process revealed that reduction of the divalent Pd center in bis(diimino)palladium produced a composite of Pd(0) species and PdDI, combining high catalytic activity with smooth electron transfer.

We report a novel functional bis(terpyridine)metal(II) complex coordination nanosheet (CONASH) comprising a three-armed terpyridine ligand and Ni²⁺ ion. The colourless Ni-terpyridine CONASH was synthesized by the method of interfacial coordination reaction at an interface of two immiscible liquids. The synthesized CONASH was characterized with various microscopic observations such as TEM, SEM, and AFM, and spectroscopic measurements such as XPS, IR, SEM/EDS, and UV–Vis spectroscopy. The bis(terpyridine)nickel(II) complex nanosheet demonstrated redox-activity stemming from terpyridine complexes without distinctive colour change. Thus, the bis(terpyridine)nickel(II) coordination nanosheet is a potential redox-active material with colourlessness and flexibility, necessary for future transparent electronics.

Heterostructures of two‐dimensional materials realise novel and enhanced physical phenomena, making them attractive research targets. Compared to inorganic materials, coordination nanosheets have virtually infinite combinations, leading to tunability of physical properties and are promising candidates for heterostructure fabrication. Although stacking of coordination materials into vertical heterostructures is widely reported, reports of lateral coordination material heterostructures are few. Here we show the successful fabrication of a seamless lateral heterojunction showing diode behaviour, by sequential and spatially limited immersion of a new metalladithiolene coordination nanosheet, Zn₃BHT, into aqueous Cu(II) and Fe(II) solutions. Upon immersion, the Zn centres in insulating Zn₃BHT are replaced by Cu or Fe ions, resulting in conductivity. The transmetallation is spatially confined, occurring only within the immersed area. We anticipate that our results will be a starting point towards exploring transmetallation of various two‐dimensional materials to produce lateral heterojunctions, by providing a new and facile synthetic route.