We report a unique dynamic morphology transformation of a Ag +coordinated supramolecular nanostructure accompanying the conversion of complex structures in aqueous solution. In the presence of AgNO 3 (1.0 equiv), the achiral bipyridine-based ligand 1G, possessing hydrazine and glycine moieties, preferentially generated a 1D needle-like structure (nanostructure I) based on the 1GAgNO 3 complex (1G:Ag + = 1:1) as a metastable product. Nanostructure I was then transformed into nanostructure II, which was composed of the 1G 3 Ag 2 (NO 3 ) 2 complex (1G:Ag + = 3:2) as the thermodynamically stable product. This nanostructure exhibited a 1D helical tubular structure with a uniform diameter via a 2D ribbon as an intermediator, which led to the generation of a circular dichroism (CD) signal with right-handed (P-type) helicity. The observed dynamic transformation was attributed to formation of the thermodynamically favored helical 1G 3 Ag 2 (NO 3 ) 2 complex. In addition, the helical 1G 3 Ag 2 (NO 3 ) 2 complex acted as an initiator in the transformation from the 1D needle-like structure to the 1D helical tube via a 2D ribbon. The enhanced ΔG°value of nanostructure II compared to that of nanostructure I confirmed that nanostructure II is thermodynamically stable. More importantly, the transformation of supramolecular nanostructure I to nanostructure II occurred via an "on" pathway, even though the 1GAgNO 3 complex was converted to the 1G 3 Ag 2 (NO 3 ) 2 complex, which did not involve dissociation from nanostructure I into the monomeric 1GAgNO 3 complex species. In the kinetic study, the NO 3 − anion was found to act as an accelerator for the dynamic transformation from nanostructure I to nanostructure II. This result provides the first example of a dynamic transformation of a 1D needle-like structure into a 1D tubular structure via a 2D ribbon structure, accompanied by the conversion of a complex structure and the generation of a large CD signal for the metallosupramolecular nanostructure. This study may open up new avenues to the understanding of a dynamic morphology transformation process in biological systems.

A mononuclear cobalt(III)–bis(tert-butylperoxo) adduct (CoIII–(OOtBu)2) bearing a tetraazamacrocyclic ligand was synthesized and characterized by various physicochemical methods, such as X-ray, UV-vis, ESI-MS, EPR, and NMR analyses. The crystal structure of...

High-valent transition metal–hydroxide complexes have been proposed as essential intermediates in biological and synthetic catalytic reactions. In this work, we report the single-crystal X-ray structure and spectroscopic characteristics of a mononuclear nonporphyrinic MnIV–(OH) complex, [MnIV(Me3-TPADP)­(OH)­(OCH2CH3)]2+ (2), using various physicochemical methods. Likewise, [MnIV(Me3-TPADP)­(OH)­(OCH2CF3)]2+ (3), which is thermally stable at room temperature, was also synthesized and characterized spectroscopically. The MnIV–(OH) adducts are capable of performing oxidation reactions with external organic substrates such as C–H bond activation, sulfoxidation, and epoxidation. Kinetic studies, involving the Hammett correlation and kinetic isotope effect, and product analyses indicate that 2 and 3 exhibit electrophilic oxidative reactivity toward hydrocarbons. Density functional theory calculations support the assigned electronic structure and show that direct C–H bond activation of the MnIV–(OH) species is indeed possible.