Synthetic two-dimensional polymers, or bottom-up nanosheets, are ultrathin polymeric frameworks with in-plane periodicity. They can be synthesized in a direct, bottom-up fashion using atomic, ionic, ...or molecular components. However, few are based on carbon–carbon bond formation, which means that there is a potential new field of investigation into these fundamentally important chemical bonds. Here, we describe the bottom-up synthesis of all-carbon, π-conjugated graphdiyne nanosheets. A liquid/liquid interfacial protocol involves layering a dichloromethane solution of hexaethynylbenzene on an aqueous layer containing a copper catalyst at room temperature. A multilayer graphdiyne (thickness, 24 nm; domain size, >25 μm) emerges through a successive alkyne–alkyne homocoupling reaction at the interface. A gas/liquid interfacial synthesis is more successful. Sprinkling a very small amount of hexaethynylbenzene in a mixture of dichloromethane and toluene onto the surface of the aqueous phase at room temperature generated single-crystalline graphdiyne nanosheets, which feature regular hexagonal domains, a lower degree of oxygenation, and uniform thickness (3.0 nm) and lateral size (1.5 μm).
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2.
The Accelerating World of Graphdiynes Sakamoto, Ryota; Fukui, Naoya; Maeda, Hiroaki ...
Advanced materials (Weinheim),
10/2019, Volume:
31, Issue:
42
Journal Article
Peer reviewed
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 family and the synthetic procedures are also described. Highly developed π‐conjugated electronic structures are common important features in GDY and graphene; however, the coexistence of sp and sp2 carbons differentiates GDY from graphene. This difference gives rise to unique physical properties, such as high conductivity and large carrier mobility. Next, the theoretical and experimental studies of these properties are described in detail. A wide variety of applications are proposed for GDYs, including electrocatalysts and energy devices, which exploit the carbon‐rich nature, porous framework, and expanded π‐electron system of these compounds. Finally, potential uses are discussed.
Graphdiynes are 2D carbon materials that may be synthesized from organic monomers, such as hexaethynylbenzene, and significant interest of researchers has recently been drawn to the new 2D nanomaterial series. This work assembles comprehensive knowledge on graphdiynes: history, variations, syntheses, theoretical and experimental approaches for physical properties, and the wide varieties of application.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Spin-correlated electronic and magnetic properties of organic radicals have been developed, but luminescence properties, based on interplay with spins, have rarely been reported. The effect of ...magnetic fields on luminescence (i.e., magnetoluminescence) is a rare example of such properties, observed to date only in radicals dispersed in host matrices. We now report a novel method for achieving radical magnetoluminescence involving radical-based coordination polymers (CPs). The luminescence properties of the bis(3,5-dichloro-4-pyridyl)(2,4,6-trichlorophenyl)methyl (bisPyTM) and tris(3,5-dichloro-4-pyridyl)methyl (trisPyM) radicals and their 1D and 2D ZnII CPs were investigated. Although solid-state emissions of bisPyTM and trisPyM were not affected significantly by external magnetic fields at 4.2 K, those of CPs were greatly modulated. Studies of the crystal structures, magnetic properties, and the temperature-dependence and time-resolved properties of the magnetoluminescence indicate that the reduction of radical–radical interactions in CPs would be a key method for achieving magnetoluminescence.
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In the vertebrate retina, neurites from distinct neuronal cell types are constrained within the plexiform layers, allowing for establishment of retinal lamination. However, the mechanisms by which ...retinal neurites are segregated within the inner or outer plexiform layers are not known. We find that the transmembrane semaphorins Sema5A and Sema5B constrain neurites from multiple retinal neuron subtypes within the inner plexiform layer (IPL). In
Sema5A
−/−
;
Sema5B
−/−
mice, retinal ganglion cells (RGCs) and amacrine and bipolar cells exhibit severe defects leading to neurite mistargeting into the outer portions of the retina. These targeting abnormalities are more prominent in the outer (OFF) layers of the IPL and result in functional defects in select RGC response properties. Sema5A and Sema5B inhibit retinal neurite outgrowth through PlexinA1 and PlexinA3 receptors both in vitro and in vivo. These findings define a set of ligands and receptors required for the establishment of inner retinal lamination and function.
► Sema5A/5B constrain neurites from multiple retinal neuron subtypes within the IPL ► Sema5A/5B direct anatomical and functional properties of the OFF retinal pathway ► PlexinA1 and PlexinA3 mediate Sema5A and Sema5B inhibition both in vitro and in vivo ► Class 5 semaphorin signaling separates the IPL from the outer retina
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A macrocyclic dipyrrin tetramer containing flexible m-phenylene linkages and its tetranuclear zinc(II) complex were synthesized. The obtained complex has an unsymmetrical figure-of-eight structure ...because of the conformational flexibility of the macrocyclic framework. The first μ-hydroxo- and μ-acetato-bridged dinuclear zinc(II) dipyrrin complex structure is realized in the twisted macrocyclic complex. Furthermore, the complex exhibited an efficient emission in toluene and chloroform.
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Photoluminescent coordination nanosheets (CONASHs) comprising three-way terpyridine (tpy) ligands and zinc(II) ions are created by allowing the two constitutive components to react with each other ...at a liquid/liquid interface. Taking advantage of bottom-up CONASHs, or flexibility in organic ligand design and coordination modes, we demonstrate the diversity of the tpy-zinc(II) CONASH in structures and photofunctions. A combination of 1,3,5-tris4-(4′-2,2′:6′,2″-terpyridyl)phenylbenzene (1) and Zn(BF4)2 affords a cationic CONASH featuring the bis(tpy)Zn complex motif (1-Zn), while substitution of the zinc source with ZnSO4 realizes a charge-neutral CONASH with the Zn2(μ-O2SO2)2(tpy)2 motif 1-Zn 2 (SO 4 ) 2 . The difference stems from the use of noncoordinating (BF4 –) or coordinating and bridging (SO4 2–) anions. The change in the coordination mode alters the luminescence (480 nm blue in 1-Zn; 552 nm yellow in 1-Zn 2 (SO 4 ) 2 ). The photophysical property also differs in that 1-Zn 2 (SO 4 ) 2 shows solvatoluminochromism, whereas 1-Zn does not. Photoluminescence is also modulated by the tpy ligand structure. 2-Zn contains triarylamine-centered terpyridine ligand 2 and features the bis(tpy)Zn motif; its emission is substantially red-shifted (590 nm orange) compared with that of 1-Zn. CONASHs 1-Zn and 2-Zn possess cationic nanosheet frameworks with counteranions (BF4 –), and thereby feature anion exchange capacities. Indeed, anionic xanthene dyes were taken up by these nanosheets, which undergo quasi-quantitative exciton migration from the host CONASH. This series of studies shows tpy-zinc(II) CONASHs as promising potential photofunctional nanomaterials.
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Vascular endothelial cells (vECs) in the brain exhibit structural and functional heterogeneity. Fenestrated, permeable brain vasculature mediates neuroendocrine function, body-fluid regulation, and ...neural immune responses; however, its vascular formation remains poorly understood. Here, we show that specific combinations of vascular endothelial growth factors (Vegfs) are required to selectively drive fenestrated vessel formation in the zebrafish myelencephalic choroid plexus (mCP). We found that the combined, but not individual, loss of Vegfab, Vegfc, and Vegfd causes severely impaired mCP vascularization with little effect on neighboring non-fenestrated brain vessel formation, demonstrating fenestrated-vEC-specific angiogenic requirements. This Vegfs-mediated vessel-selective patterning also involves Ccbe1. Expression analyses, cell-type-specific ablation, and paracrine activity-deficient
mutant characterization suggest that vEC-autonomous Vegfc and meningeal fibroblast-derived Vegfab and Vegfd are critical for mCP vascularization. These results define molecular cues and cell types critical for directing fenestrated CP vascularization and indicate that vECs' distinct molecular requirements for angiogenesis underlie brain vessel heterogeneity.
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 SnO2 electrode functions as a photoanode for a photoelectric conversion system. The photoresponse of N2 covers the whole visible wavelength range (400–650 nm), with a maximum quantum efficiency of more than twice that of a bis(dipyrrinato)zinc(II) complex nanosheet without porphyrin.
Sheet lighting: A liquid/liquid interfacial synthesis gives bis(dipyrrinato)zinc(II) complex micro‐ or nanosheets containing porphyrin. The nanosheet deposited on a SnO2 electrode functions as a photoanode. The photoresponse covers the whole visible wavelength range (400–650 nm), with a maximum quantum efficiency greater than that of the nanosheet without porphyrin.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The first mononuclear 1 : 1 complexes of heavy group 13 elements (Ga and In) and N2O2/N2O4-type dipyrrins were synthesized and characterized. The N2O2-type complexes showed efficient luminescent ...properties even in polar solvents. The N2O4-type complexes exhibited fluorometric responses to alkaline earth metal ions.
New magnetic metal complexes with organic radical ligands, M(hfac)2(PyBTM)2 (M = NiII, CoII; hfac = hexafluoroacetylacetonato, PyBTM = (3,5-dichloro-4-pyridyl)bis(2,4,6-trichlorophenyl)methyl ...radical), were prepared and their crystal structures, magnetic properties, and electronic structures were investigated. Metal ions in M(hfac)2(PyBTM)2 constructed distorted octahedral coordination geometry, where the two PyBTM molecules ligated in the trans configuration. Magnetic investigation using a SQUID magnetometer revealed that χT increased with decreasing temperature from 300 K in the two complexes, indicating an efficient intramolecular ferromagnetic exchange interaction taking place between the spins on PyBTM and M with J/kB of 21.8 K and 11.8 K for NiII(hfac)2(PyBTM)2 and CoII(hfac)2(PyBTM)2. The intramolecular ferromagnetic couplings in the two complexes could be explained by density functional theory calculations, and would be attributed to a nearly orthogonal relationship between the spin orbitals on PyBTM and the metal ions. These results demonstrate that pyridyl-containing triarylmethyl radicals are key building blocks for magnetic molecular materials with controllable/predictable magnetic interactions.
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