scholarly journals CCCCC pentadentate chelates with planar Möbius aromaticity and unique properties

2016 ◽  
Vol 2 (8) ◽  
pp. e1601031 ◽  
Author(s):  
Congqing Zhu ◽  
Caixia Yang ◽  
Yongheng Wang ◽  
Gan Lin ◽  
Yuhui Yang ◽  
...  
Keyword(s):  
Photothermal Therapy ◽  
Density Functional ◽  
Near Infrared ◽  
Chelating Agent ◽  
Density Functional Theory Calculations ◽  
Infrared Region ◽  
Carbon Chain ◽  
Broad Absorption ◽  
Functional Theory ◽  
Potential Applications

The coordinating atoms in polydentate chelates are primarily heteroatoms. We present the first examples of pentadentate chelates with all binding atoms of the chelating agent being carbon atoms, denoted as CCCCC chelates. Having up to five metal-carbon bonds in the equatorial plane has not been previously observed in transition metal chemistry. Density functional theory calculations showed that the planar metallacycle has extended Craig-Möbius aromaticity arising from 12-center–12-electron dπ-pπ π-conjugation. These planar chelates have broad absorption in the ultraviolet-visible–near-infrared region and, thus, notable photothermal performance upon irradiation by an 808-nm laser, indicating that these chelates have potential applications in photothermal therapy. The combination of facile synthesis, high stability, and broad absorption of these complexes could make the polydentate carbon chain a novel building block in coordination chemistry.

Narrow bandgap covalent–organic frameworks with strong optical response in the visible and infrared

2015 ◽  
Vol 3 (10) ◽  
pp. 2244-2254 ◽  
Author(s):  
Li-Ming Yang ◽  
Eric Ganz ◽  
Song Wang ◽  
Xiao-Jun Li ◽  
Thomas Frauenheim
Keyword(s):  
Density Functional ◽  
Near Infrared ◽  
Density Functional Theory Calculations ◽  
Optical Response ◽  
Covalent Organic Frameworks ◽  
Functional Theory ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Narrow Bandgap ◽  
Potential Applications

We propose a new series of covalent–organic frameworks. These materials have narrow band gaps, leading to strong near infrared optical response. Density functional theory calculations are used to explore their properties. These novel infrared active materials may have potential applications in organic light-emitting devices, chemical and biological sensing, hybrid solar cells, or electroluminescence.

scholarly journals First principles DFT calculations of the optical properties of A4BX6 group crystals

2021 ◽  
Vol 22 (1) ◽  
pp. 117-122
Author(s):  
H. Ilchuk ◽  
M. Solovyov ◽  
I. Lopatynskyi ◽  
F. Honchar ◽  
F. Tsyupko
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Energy Band ◽  
Density Functional ◽  
Near Infrared ◽  
Infrared Region ◽  
Energy Structure ◽  
Generalized Gradient ◽  
Reflection Index ◽  
Functional Theory

The results of investigating of the electron band energy structure and optical properties of A4BX6 (Tl4HgI6 and Tl4CdI6) group crystals are presented. The energy band structures of Tl4HgI6 and Tl4CdI6 crystals are calculated from the first principles within generalized gradient approximation (GGA). The band structure and reflection index were calculated using a pseudopotential method in the framework of density functional theory. Optical absorption edge in Tl4HgI6 and Tl4CdI6 is formed by direct optical transitions. The spectral dependence of the reflection index was calculated on the basis of the energy band results with using the Kramers–Kronig method. The spectra show pronounced anisotropy in E||a(b) and E||c polarizations. It was found the anomalous by large values of the birefringence (Δn > 0.18 for Tl4HgI6 and Δn > 0.03 for Tl4CdI6) in the visible and near infrared region.

scholarly journals Access to tetracyclic aromatics with bridgehead metals via metalla-click reactions

2020 ◽  
Vol 6 (3) ◽  
pp. eaay2535 ◽  
Author(s):  
Zhengyu Lu ◽  
Qin Zhu ◽  
Yuanting Cai ◽  
Zhixin Chen ◽  
Kaiyue Zhuo ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Region ◽  
Metal Center ◽  
Polycyclic Aromatics ◽  
Aromatic Rings ◽  
Broad Absorption ◽  
Excellent Thermal Stability ◽  
Click Reactions ◽  
Potential Applications ◽  
Further Development

The never-ending pursuits for exploring aromatic molecular architectures result in the large libraries of aromatics with fascinating structures, which have greatly broadened the scope of aromaticity. Despite extensive efforts that have been paid to develop aromatic frameworks, the construction of polycyclic aromatics that share a bridgehead atom with more than three rings has never been accomplished. Here, an unprecedented family of aromatics, in which a metal center shared by 4 five-membered aromatic rings, has been achieved by using the metalla-click reactions with excellent yields and remarkable regioselectivity. The distinctive tetracyclic aromatics exhibit a broad absorption in the ultraviolet-visible near-infrared region and excellent thermal stability in air, enabling their potential applications in photoelectric materials and biomedicine. This study now makes it possible to incorporate four aromatic rings with one common sharing metal center by a straightforward strategy that would promote further development of previously unknown polycyclic complex motifs in aromatic chemistry.

Optical properties of Yb-doped LaB6 from first-principles calculation

2016 ◽  
Vol 30 (07) ◽  
pp. 1650091 ◽  
Author(s):  
Luomeng Chao ◽  
Lihong Bao ◽  
Wei Wei ◽  
O. Tegus
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Near Infrared ◽  
Infrared Region ◽  
Transmission Peak ◽  
First Principles Calculation ◽  
First Principles Calculations ◽  
Plasmon Energy ◽  
Functional Theory

The optical properties of Yb-doped LaB6 have been investigated by first-principles calculations within the framework of density functional theory. The results show that the Yb [Formula: see text] states at near Fermi surface affect their optical properties and the Yb-doping leads to a reduction of the plasmon energy of LaB6, i.e. a redshift of the position of transmission peak in the visible-near infrared region. This study offers a theoretical prediction for the design and application of Yb-doped LaB6 as an optoelectronic material.

Stable Molecular Complex of Squaric Acid with 2-(Quinuclidinium)propionate

2013 ◽  
Vol 66 (7) ◽  
pp. 836 ◽  
Author(s):  
Zofia Dega-Szafran ◽  
Andrzej Katrusiak ◽  
Miroslaw Szafran
Keyword(s):  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Squaric Acid ◽  
X Ray Diffraction ◽  
Broad Absorption ◽  
Functional Theory ◽  
X Ray ◽  
State Aggregation ◽  
Ir Frequencies ◽  
Nmr Techniques

Squaric acid (3,4-dihydroxy-3-cyclobuten-1,2-dione, H2SQ) forms a complex with 2-(quinuclidinium)propionate (QNPr). In crystals, the molecules of H2SQ and zwitterions of QNPr are bridged by two strong non-equivalent O–H⋯O hydrogen bonds of 2.476(2) and 2.482(1) Å. The complex is investigated by X-ray diffraction, FTIR, and NMR techniques, and the results are supported by density functional theory calculations. The solid-state aggregation is consistent with the NMR results, recorded for an aqueous solution, and is also reproduced for the structure optimized at the B3LYP/6-311++G(d,p) level of theory. The calculated IR frequencies for the optimized structure have been used for the assignment of the experimental FTIR spectrum, where the broad absorption at ~2400 cm–1 corresponds to the short asymmetric OH⋯O bonds.

scholarly journals Ultrasmall PEI-Decorated Bi2Se3 Nanodots as a Multifunctional Theranostic Nanoplatform for in vivo CT Imaging-Guided Cancer Photothermal Therapy

2021 ◽  
Vol 12 ◽  
Author(s):  
Peng Zhang ◽  
Lei Wang ◽  
Xiuying Chen ◽  
Xiang Li ◽  
Qinghai Yuan
Keyword(s):  
Photothermal Therapy ◽  
Room Temperature ◽  
Near Infrared ◽  
Infrared Region ◽  
Ct Imaging ◽  
Broad Absorption ◽  
Good Biocompatibility ◽  
Imaging Performance

Bi-based nanomaterials, such as Bi2Se3, play an important part in biomedicine, such as photothermal therapy (PTT) and computed tomography (CT) imaging. Polyethylenimine (PEI)-modified ultrasmall Bi2Se3 nanodots were prepared using an ultrafast synthetic method at room temperature (25°C). Bi2Se3 nanodots exhibited superior CT imaging performance, and could be used as effective photothermal reagents owing to their broad absorption in the ultraviolet–visible–near infrared region. Under irradiation at 808 nm, PEI-Bi2Se3 nanodots exhibited excellent photothermal-conversion efficiency of up to 41.3%. Good biocompatibility and significant tumor-ablation capabilities were demonstrated in vitro and in vivo. These results revealed that PEI-Bi2Se3 nanodots are safe and a good nanotheranostic platform for CT imaging-guided PTT of cancer.

scholarly journals Unravelling an oxygen-mediated reductive quenching pathway for photopolymerisation under long wavelengths

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chenyu Wu ◽  
Kenward Jung ◽  
Yongtao Ma ◽  
Wenjian Liu ◽  
Cyrille Boyer
Keyword(s):  
Density Functional ◽  
Near Infrared ◽  
Chain Transfer ◽  
Experimental Studies ◽  
Density Functional Theory Calculations ◽  
Ambient Air ◽  
Functional Theory ◽  
Reversible Addition ◽  
Reversible Deactivation ◽  
Limited Scope

AbstractPhotomediated-reversible-deactivation radical polymerisation (photo-RDRP) has a limited scope of available photocatalysts (PCs) due to multiple stringent requirements for PC properties, limiting options for performing efficient polymerisations under long wavelengths. Here we report an oxygen-mediated reductive quenching pathway (O-RQP) for photoinduced electron transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerisation. The highly efficient polymerisations that are performed in the presence of ambient air enable an expanded scope of available PCs covering a much-broadened absorption spectrum, where the oxygen tolerance of PET-RAFT allows high-quality polymerisation by preventing the existence of O2 in large amounts and efficient O-RQP is permitted due to its requirement for only catalytic amounts of O2. Initially, four different porphyrin dyes are investigated for their ability to catalyse PET-RAFT polymerisation via an oxidative quenching pathway (OQP), reductive quenching pathway (RQP) and O-RQP. Thermodynamic studies with the aid of (time-dependent) density functional theory calculations in combination with experimental studies, enable the identification of the thermodynamic constraints within the OQP, RQP and O-RQP frameworks. This knowledge enables the identification of four phthalocyanine photocatalysts, that were previously thought to be inert for PET-RAFT, to be successfully used for photopolymerisations via O-RQP. Well-controlled polymerisations displaying excellent livingness are performed at wavelengths in the red to near-infrared regions. The existence of this third pathway O-RQP provides an attractive pathway to further expand the scope of photocatalysts compatible with the PET-RAFT process and facile access to photopolymerisations under long wavelengths.

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