Tohoku University · Materials Science
Professor Ryota Sakamoto's research lab specializes in the design, synthesis, and application of molecule-based two-dimensional nanomaterials, with a focus on coordination nanosheets and functional polymeric nanosheets. The lab pioneers bottom-up approaches to create structurally diverse and functionally advanced nanosheets, particularly those incorporating photoactive metal complexes such as bis(dipyrrinato)zinc(II) and porphyrin-based systems. Key research directions include the development of nanosheets for optoelectronic and photocatalytic applications, leveraging their tunable electronic structures and high surface activity. The lab also explores advanced fabrication techniques like liquid/liquid interfacial synthesis and modified Langmuir-Schäfer methods to achieve large-area, highly ordered thin films.
Figures are computed from collected data and may differ slightly.
Two-dimensional polymeric nanosheets have recently gained much attention, particularly top-down nanosheets such as graphene and metal chalcogenides originating from bulk-layered mother materials. Although molecule-based bottom-up nanosheets manufactured directly from molecular components can exhibit greater structural diversity than top-down nanosheets, the bottom-up nanosheets reported thus far lack useful functionalities. Here we show the design and synthesis of a bottom-up nanosheet featuring
Nanosheets, which are two-dimensional polymeric materials, remain among the most actively researched areas of chemistry and physics this decade. Generally, nanosheets are inorganic materials created from bulk crystalline layered materials and have fascinating properties and functionalities. An emerging alternative is molecule-based nanosheets containing organic molecular components. Molecule-based nanosheets offer great diversity because their molecular, ionic, and atomic constituents can be sel
Bottom-up approaches have gained significant attention recently for the creation of nano-sized, ordered functional structures and materials. Stepwise coordination techniques, in which ligand molecules and metal sources are reacted alternatively, offer several advantages. Coordination bonds are stable, reversible, and self-assembling, and the resultant metal complex motifs may contain functionalities unique to their own characteristics. This review focuses on metal complex wire systems, specifica
Graphdiyne (GDY), a 2D allotrope of graphene, is first synthesized in 2010 and has attracted attention as a new low-dimensional carbon material. This work surveys the literature on GDYs. The history of GDYs is summarized, including their relationship with 2D graphyne carbons and yearly publication trends. GDY is a molecule-based nanosheet woven from a molecular monomer, hexaethynylbenzene; thus, it is synthesized by bottom-up approaches, which allow rich variation via monomer design. The GDY fam
This review summarizes recent progress in bis and tris(dipyrrinato)metal complexes, focusing on luminescence intensification, supramolecules and nanostructures, and materials applications.
New bis(dipyrrinato)zinc(II) complex micro- and nanosheets containing zinc(II) porphyrin (N2) are synthesized. A liquid/liquid interface method between dipyrrin porphyrin ligand L2 and zinc acetate produces N2 with a large domain size. N2 can be layered quantitatively onto a flat substrate by a modified Langmuir-Schäfer method. N2 deposited on a SnO<sub>2</sub> electrode functions as a photoanode for a photoelectric conversion system. The photoresponse of N2 covers the whole visible wavelength r
Graphdiyne (GDY) comprises an important class in functional covalent organic nanosheets based on carbon-carbon bond formation, and recent focus has collected in the expansion of its variations. Here we report on the synthesis of a GDY analogue, TP-GDY, which has triphenylene as the aromatic core. Our liquid/liquid interfacial synthesis for GDY ( J. Am. Chem. Soc. 2017, 139, 3145) was modified for hexaethynyltriphenylene monomer to afford a TP-GDY film with a free-standing morphology, a smooth te
Communicating better over a long distance: The bis(ferrocenylethynyl)ethene 1 undergoes E→Z photoisomerization upon excitation of a charge-transfer band with visible light (546 nm). This structural change leads to a decrease in the “through-bond” mixed-valence interaction between the two ferrocene units.
Heteroleptic zinc(II) complexes synthesized using achiral dipyrrinato and chiral bis(oxazoline) ligands show bright fluorescence with quantum efficiencies of up to 0.70. The fluorescence originates from the (1)π-π* photoexcited state localized exclusively on the dipyrrinato ligand. Furthermore, the luminescence is circularly polarized despite the achirality of the dipyrrinato ligand. Single-crystal X-ray structure analysis discloses that the chiral bis(oxazoline) ligand undergoes intramolecular
Let your light shine: The first example of a heteroleptic bis(dipyrrinato)zinc(II) complex, 7a, was synthesized from two types of dipyrrins prepared by a new deboration protocol for BODIPYs. Complex 7a showed a higher fluorescence quantum yield (0.76 in toluene) than the corresponding homoleptic complexes 5a and 6. The superiority of 7a as a luminophore was more prominent in more polar CH2Cl2 (see picture). Detailed facts of importance to specialist readers are published as ”Supporting Informati
Bis(dipyrrinato)metal(II) and tris(dipyrrinato)metal(III) complexes have been regarded as much less useful luminophores than their boron difluoride counterparts (4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes, BODIPYs), especially in polar solvent. We proposed previously that dissymmetry in such metal complexes (i.e., two different dipyrrinato ligands in one molecule) improves their fluorescence quantum efficiencies. In this work, we demonstrate the universality and utility of our methodology by sy
A new platinum complex with both an azo-bound dithiolato ligand and an azobenzene-bound bipyridine ligand exhibits tristability reversibly controllable using different energy lights.
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