Helical nanographenes with high quantum yields and strong chiroptical responses are pivotal for developing circularly polarized luminescence (CPL) materials. Here, we present the successful synthesis ...of novel π‐extended double 7helicenes (ED7Hs) where two helicene units are fused at the meta‐ or para‐position of the middle benzene ring, respectively, as the structural isomers of the reported ortho‐fused ED7H. The structural geometry of these ED7Hs is clearly characterized by single‐crystal X‐ray analysis. Notably, this class of ED7Hs exhibits bright luminescence with high quantum yields exceeding 40 %. Through geometric regulation of two embedded 7helicene units from ortho‐, meta‐ to para‐position, these ED7Hs display exceptional amplification in chiroptical responses. This enhancement is evident in a remarkable approximate fivefold increase in the absorbance and luminescence dissymmetry factors (gabs and glum), respectively, along with a boosted CPL brightness up to 176 M−1 cm−1, surpassing the performance of most helicene‐based chiral NGs. Furthermore, DFT calculations elucidate that the geometric adjustment of two 7helicene units allows the precise alignment of electric and magnetic transition dipole moments, leading to the observed enhancement of their chiroptical responses. This study offers an effective strategy for magnifying the CPL performance in chiral NGs, promoting their expanded application as CPL emitters.
π‐Extended helical nanographenes (ED7Hs) have been synthesized where the two embedded 7helicene units are fused at the ortho‐, meta‐ or para‐position of the middle benzene ring, respectively. The obtained ED7Hs display exceptional fivefold amplification in chiroptical responses with enhanced circularly polarized luminescence (CPL) brightness up to 176 M−1 cm−1.
The radial conjugated π‐system of cycloparaphenylenes (CPPs) makes them intriguing fluorophores and unique supramolecular hosts. However, the bright photoluminescence (PL) of CPPs was limited to the ...blue light and the supramolecular assembly behavior of large CPPs was rarely investigated. Here we present the synthesis of tetra‐benzothiadiazole‐based 12cycloparaphenylene (TB12CPP), which exhibits a lime to orange PL with an excellent quantum yield up to 82 % in solution. The PL quantum yield of TB12CPP can be further improved to 98 % in polymer matrix. Benefiting from its enlarged size, TB12CPP can accommodate a fullerene derivative or concave–convex complexes of fullerene and buckybowl through the combined π–π and C−H⋅⋅⋅π interactions. The latter demonstrates the first case of a ternary supramolecule of CPPs.
A benzothiadiazole‐based 12cycloparaphenylene (TB12CPP) is obtained and characterized. TB12CPP exhibits a lime to orange emission with a quantum yield up to 98 %, ranking it as one of the brightest CPPs. As a supramolecular host, TB12CPP is bright as well, showing adaptable ring structure. A ternary assembly between TB12CPP, fullerene, and buckybowl is realized.
Although heptagons are widely found in graphenic materials, the precise synthesis of nanocarbons containing heptagons remains a challenge, especially for the nanocarbons containing ...multiple‐heptagons. Herein, we show that photo‐induced radical cyclization (PIRC) can be used to synthesize multi‐heptagon‐embedded nanocarbons. Notably, a nanographene containing six heptagons (1) was obtained via a six‐fold cascade PIRC reaction. The structure of 1 was clearly validated and showed a Monkey‐saddle‐shaped conformation. Experimental bond analysis and theoretical calculations indicated that the heptagons in 1 were non‐aromatic, whereas the peripheral rings were highly aromatic. Compared to planar nanographene with the same number of π electrons, 1 had a similar optical gap due to a compromise between the decreased conjugation in the wrapped structure and enhanced electronic delocalization at the rim. Electrochemical studies showed that 1 had low‐lying oxidation potentials, which was attributed to the nitrogen‐doping.
Photo‐induced radical cyclization was used in the synthesis of nanocarbons with embedded heptagons, providing a new approach towards nanocarbons with novel topologies. The nanographene reported herein bears six heptagons, representing the nanocarbon containing the largest number of heptagons by organic synthesis reported to date. The embedded heptagons distort the graphene core into a Monkey‐saddle‐shaped conformation.
Bowl inversion is a unique property of buckybowls. The polarity and assembly configuration of buckybowls are reversed after bowl inversion. So far, this unique phenomenon has been studied in solution ...and on surface, but not in solid state due to spatial constraint. Now a series of exo‐type supramolecular assemblies of trithiasumanene and nanographene are investigated. Tuning the electron density of the nanogaphene component was found to directly affect the binding constant of the complex. Reversible bowl inversion in the solid state was then successfully achieved by subjecting the trithiasumanene–nanographene assembly with the weakest binding strength to repeated heating–cooling cycles, which was unambiguously observed by single crystal X‐ray diffraction.
Bowl inversion: A series of exo‐type buckybowl‐supramolecules are obtained using a concave nanographene acceptor. The reversible bowl inversion in the solid state is realized in the complex with the weakest binding strength by heating and cooling cycles and is unambiguously observed by single‐crystal X‐ray diffraction.
Well-studied cycloparaphenylenes (CPPs) correspond to the simplest segments of armchair CNTs, whereas the corresponding macrocyclic oligophenylene strip of zigzag CNTs is still missing. Herein, we ...present two series of conjugated macrocycles (CM2PP and CN2PP) containing two
meta
-phenylene or 2,7-naphthylene units facing each other in the strip. CM2PP and CN2PP can be regarded as the shortest cyclic primitive segments of zigzag CNTs. They were synthesized by gold-mediated dimerization and unambiguously characterized. They adopted the tubular structures and can further pack into one-dimensional supramolecular nanotubes. In particular, the supramolecular nanotube of CM2P4P mimics the CNT(9, 0) structure. Structural analysis and theoretical calculation accounted for the reduced ring strain in CM2PPs and CN2PPs. CM2PPs and CN2PPs exhibited a large optical extinction coefficient and high photoluminescence quantum yield. CN2P8P can accommodate fullerene C
60
, forming a Saturn-like C
60
@CN2P8P complex, a mimic structure of zigzag CNT peapods.
Two types of macrocycles were synthesized by gold-mediated dimerization, representing the phenylene cutouts of zigzag carbon nanotubes. These macrocycles showed intriguing optical and supramolecular assembly properties.
As the shortest segment of carbon nanotubes (CNTs), cycloparaphenylenes (CPPs) offer a well‐defined alternative for CNTs as the fluorophores in bioimaging. However, most of CPPs emit blue or yellow ...light, the bright red‐emitting CPP materials required by bioimaging, particularly in vivo imaging, are still lacking. Here, it is shown that a CPP (TB9CPP) with red emission up to 650 nm is successfully synthesized and characterized. The fluorescence quantum yields of TB9CPP are measured up to 44% in chloroform and 17% as nanodots in aqueous media. Meanwhile, the water‐soluble nanodots present outstanding three‐photon fluorescence performances, thereby are utilized for in vivo probing of brain vessels by three‐photon fluorescence microscopic imaging technique, exhibiting a high penetration depth, good resolution, and clear image contrast.
A bright red emissive segment of carbon nanotube TB9CPP is realized by a combined strategy of ring‐shrinking and D‐A conjugation. The water‐soluble nanodots of TB9CPP with an emission at 650 nm are used for three‐photon fluorescence bioimaging of mouse cerebrovascular, showing high penetration depth, resolution, and image contrast.
High-sensitivity C-reactive protein (hs-CRP) is a key inflammatory factor in atherosclerotic cardiovascular diseases. In Chinese patients with coronary heart disease (CHD), the changes in hs-CRP ...levels after a daily meal and the effect of statins on those were never explored. A total of 300 inpatients with CHD were included in this study. Hs-CRP levels were measured in the fasting and non-fasting states at 2 h and 4 h after a daily breakfast. All inpatients were divided into two groups according to fasting hs-CRP ≤ 3 mg/L or not. Group with fasting hs-CRP ≤ 3 mg/L had a significantly higher percentage of patients with statins using ≥ 1 month (m) before admission than that with fasting hs-CRP > 3 mg/L (51.4% vs. 23.9%, P < 0.05). Hs-CRP levels increased significantly in the non-fasting state in two groups (P < 0.05). About 32% of patients with non-fasting hs-CRP > 3 mg/L came from those with fasting hs-CRP ≤ 3 mg/L. In conclusion, hs-CRP levels increased significantly in CHD patients after a daily meal. It suggested that the non-fasting hs-CRP level could be a better parameter to evaluate the inflammation state of CHD patients rather than fasting hs-CRP level.
Artificial electronic kagome lattices may emerge from electronic potential landscapes using customized structures with exotic supersymmetries, benefiting from the confinement of Shockley ...surface-state electrons on coinage metals, which offers a flexible approach to realizing intriguing quantum phases of matter that are highly desired but scarce in available kagome materials. Here, we devise a general strategy to construct varieties of electronic kagome lattices by utilizing the on-surface synthesis of halogen hydrogen-bonded organic frameworks (XHOFs). As a proof of concept, we demonstrate three XHOFs on Ag(111) and Au(111) surfaces, which correspondingly deliver regular, breathing, and chiral breathing diatomic-kagome lattices with patterned potential landscapes, showing evident topological edge states at the interfaces. The combination of scanning tunnelling microscopy and noncontact atomic force microscopy, complemented by density functional theory and tight-binding calculations, directly substantiates our method as a reliable and effective way to achieve electronic kagome lattices for engineering quantum states.
Depression is an established independent prognostic factor for mortality, readmission, and cardiac events after CABG surgery. However, limited data exist on whether depression influences functional ...outcomes after CABG.
We followed 963 patients who underwent first CABG between February 1999 and February 2001. At baseline and at 6 months after CABG, we interviewed patients to assess depressive symptoms using the Geriatric Depression Scale (GDS) and physical function using the Short Form-36 Physical Component Scale (PCS). The patient's physical function was considered improved if the PCS score increased > or =5 points at 6 months. Patients with high GDS scores were younger, were more often female, and had worse physical function and higher comorbidity than patients with low GDS scores. Rates of improvement in physical function were 60.1% for a GDS score <5 (below 75th percentile), 49.8% for a GDS score between 5 and 9 (75th to 90th percentile), and 39.7% for a GDS score > or =10 (> or =90th percentile; P=0.002 for the trend). Depressive symptoms remained a significant independent predictor of lack of functional improvement after adjustment for severity of coronary artery disease, angina class, baseline PCS score, and medical history. A GDS score > or =10 was a stronger inverse risk factor for functional improvement after CABG than such traditional measures of disease severity as previous myocardial infarction, heart failure on admission, history of diabetes, and left ventricular ejection fraction.
Higher levels of depressive symptoms at the time of CABG are a strong risk factor for lack of functional benefits 6 months after CABG.
The bottom-up approach through on-surface synthesis of porous graphene nanoribbons (GNRs) presents a controllable manner for implanting periodic nanostructures to tune the electronic properties of ...GNRs in addition to bandgap engineering by width and edge configurations. However, owing to the existing steric hindrance in small pores like divacancies, it is still difficult to embed periodic divacancies with a nonplanar configuration into GNRs. Here, we demonstrate the on-surface synthesis of atomically precise eight-carbon-wide armchair GNRs embedded with periodic divacancies (DV8-aGNRs) by utilizing the monatomic step edges on the Au(111) surface. From a single molecular precursor correspondingly following a trans- and cis-coupling, the DV8-aGNR and another porous nanographene are respectively formed at step edges and on terraces at 720 and 570 K. Combining scanning tunneling microscopy/spectroscopy, atomic force microscopy, and first-principles calculations, we determine the out-of-plane conformation, wide bandgap (∼3.36 eV), and wiggly shaped frontier orbitals of the DV8-aGNR. Nudged elastic band calculations further quantitatively reveal that the additional steric hindrance effect in the cyclodehydrogenative reactions has a higher barrier of 1.3 eV than that in the planar porous nanographene, which also unveils the important role played by the monatomic Au step and adatoms in reducing the energy barriers and enhancing the thermodynamic preference of the oxidative cyclodehydrogenation. Our results provide the first case of GNRs containing periodic pores as small as divacancies with a nonplanar configuration and demonstrate the strategy by utilizing the chemical heterogeneity of a substrate to promote the formation of novel carbon nanomaterials.
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