Isolation of an Annulated 1,4‐Distibabenzene Diradicaloid DOI Creative Commons
Henric Steffenfauseweh, Dennis Rottschäfer, Yury V. Vishnevskiy

et al.

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(19)

Published: Jan. 4, 2023

The first 1,4-distibabenzene-1,4-diide compound [(ADC)Sb]2 (5) based on an anionic dicarbene (ADC) (ADC=PhC{N(Dipp)C}2 , Dipp=2,6-iPr2 C6 H3 ) is reported as a bordeaux-red solid. Compound 5, featuring central six-membered C4 Sb2 ring with formally SbI atoms may be regarded base-stabilized cyclic bis-stibinidene in which each of the Sb bears two lone-pairs electrons. 5 undergoes 2 e-oxidation Ph3 C[B(C6 F5 )4 ] to afford [B(C6 ]2 (6) brick-red Each 6 has unpaired electron and lone-pair. broken-symmetry open-shell singlet diradical solution for (6)2+ calculated 2.13 kcal mol-1 more stable than closed-shell singlet. character according SS-CASSCF (state-specific complete active space self-consistent field) UHF (unrestricted Hartree-Fock) methods amounts 36 % 39 %, respectively. Treatments (PhE)2 yield [(ADC)Sb(EPh)]2 (7-E) (E=S or Se). Reaction (cod)Mo(CO)4 affords Mo(CO)4 (8).

Language: Английский

Soot inception: Carbonaceous nanoparticle formation in flames DOI
Jacob W. Martin, Maurin Salamanca, Markus Kraft

et al.

Progress in Energy and Combustion Science, Journal Year: 2021, Volume and Issue: 88, P. 100956 - 100956

Published: Sept. 17, 2021

Language: Английский

Citations

192
Open-Shell Graphene Fragments DOI Creative Commons
Wangdong Zeng, Jishan Wu

Chem, Journal Year: 2020, Volume and Issue: 7(2), P. 358 - 386

Published: Nov. 20, 2020

Language: Английский

Citations

182
Unconventional singlet fission materials DOI
Tobias Ullrich, Dominik Munz, Dirk M. Guldi

et al.

Chemical Society Reviews, Journal Year: 2021, Volume and Issue: 50(5), P. 3485 - 3518

Published: Jan. 1, 2021

Singlet fission (SF) is a photophysical downconversion pathway, in which singlet excitation transforms into two triplet excited states.

Language: Английский

Citations

139
Recent advances in stable main group element radicals: preparation and characterization DOI
Zhongtao Feng, Shuxuan Tang, Yuanting Su

et al.

Chemical Society Reviews, Journal Year: 2022, Volume and Issue: 51(14), P. 5930 - 5973

Published: Jan. 1, 2022

Radical species are significant in modern chemistry. Their unique chemical bonding and novel physicochemical properties play roles not only fundamental chemistry, but also materials science. Main group element radicals usually transient due to their high reactivity. Highly stable often stabilized by π-delocalization, sterically demanding ligands, carbenes weakly coordinating anions recent years. This review presents the advances synthesis, characterization, reactivity physical of isolable main radicals.

Language: Английский

Citations

92
Aza-Triangulene: On-Surface Synthesis and Electronic and Magnetic Properties DOI Creative Commons
Tao Wang, Alejandro Berdonces‐Layunta, Niklas Friedrich

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(10), P. 4522 - 4529

Published: March 7, 2022

Nitrogen heteroatom doping into a triangulene molecule allows tuning its magnetic state. However, the synthesis of nitrogen-doped (aza-triangulene) has been challenging. Herein, we report successful aza-triangulene on Au(111) and Ag(111) surfaces, along with their characterizations by scanning tunneling microscopy spectroscopy in combination density functional theory (DFT) calculations. Aza-triangulenes were obtained reducing ketone-substituted precursors. Exposure to atomic hydrogen followed thermal annealing and, when necessary, manipulations probe afforded target product. We demonstrate that Au(111), donates an electron substrate exhibits open-shell triplet ground This is derived from different Kondo resonances final product series intermediates Au(111). Experimentally mapped molecular orbitals match DFT-calculated counterparts for positively charged aza-triangulene. In contrast, receives extra displays closed-shell character. Our study reveals electronic properties metal surfaces offers approach fabrication new hydrocarbon structures, including reactive molecules.

Language: Английский

Citations

90
Conceptual Density Functional Theory DOI
Frank De Proft, Paul Geerlings, Farnaz Heidar‐Zadeh

et al.

Elsevier eBooks, Journal Year: 2022, Volume and Issue: unknown, P. 306 - 321

Published: Oct. 31, 2022

Language: Английский

Citations

78
Oxygen hole formation controls stability in LiNiO2 cathodes DOI Creative Commons
Annalena R. Genreith‐Schriever, Hrishit Banerjee, Ashok S. Menon

et al.

Joule, Journal Year: 2023, Volume and Issue: 7(7), P. 1623 - 1640

Published: July 1, 2023

Ni-rich lithium-ion cathode materials achieve both high voltages and capacities but are prone to structural instabilities oxygen loss. The origin of the instability lies in pronounced oxidation O during delithiation: for LiNiO2, NiO2, rock salt NiO, density functional theory dynamical mean-field calculations based on maximally localized Wannier functions yield a Ni charge state ca. +2, with varying between −2 (NiO), −1.5 (LiNiO2), −1 (NiO2). Calculated X-ray spectroscopy K K-edge spectra agree well experimental spectra. Using ab initio molecular dynamics simulations, we observe loss from (012) surface delithiated two O⋅− radicals combining form peroxide ion, ion being oxidized O2, leaving behind vacancies O2− ions. Preferential release 1O2 is dictated via singlet ground spin conservation.

Language: Английский

Citations

72
From Stable Radicals to Thermally Robust High-Spin Diradicals and Triradicals DOI

Chan Shu,

Zhimin Yang⌈,

Andrzej Rajca

et al.

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(20), P. 11954 - 12003

Published: Oct. 13, 2023

Stable radicals and thermally robust high-spin di- triradicals have emerged as important organic materials due to their promising applications in diverse fields. New fundamental properties, such SOMO/HOMO inversion of orbital energies, are explored for the design new stable radicals, including highly luminescent ones with good photostability. A relation singlet–triplet energy gap corresponding diradicals is proposed. Thermally triradicals, gaps that comparable or greater than a thermal at room temperature, more challenging synthesize but rewarding. We summarize number based on nitronyl nitroxides provide between experimental pairwise exchange coupling constant J/k species vs hyperfine constants monoradicals. This allows us identify outliers, which may correspond where not measured sufficient accuracy. Double helical diradicals, spin density delocalized over chiral π-system, been barely explored, sole example diradical possessing alternant π-system Kekulé resonance form. Finally, we discuss electrical conductivity derivatives triangulene diradicals.

Language: Английский

Citations

70
Heteroatom-Based Diradical(oid)s DOI
Alexander Hinz, Jonas Bresien, Frank Breher

et al.

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(16), P. 10468 - 10526

Published: Aug. 9, 2023

Heteroatom-centered diradical(oid)s have been in the focus of molecular main group chemistry for nearly 30 years. During this time, diradical concept has evolved and shifted to rational design specific applications. This review article begins with some important theoretical considerations tetraradical concept. Based on these considerations, terms ligand choice, steric, symmetry, electronic situation, element reactivity is highlighted examples. In particular, heteroatom-centered reactions are discussed compared closed-shell such as pericyclic additions. The comparison between reactivity, which proceeds a concerted manner, open-shell stepwise fashion, along diradical(oid) design, provides understanding interesting unusual class compounds. application diradical(oid)s, example small molecule activation or switches, also highlighted. final part application-related details spectroscopy followed by an update tetraradical(oid)s published last 10 years since 2013.

Language: Английский

Citations

50
Endogenous Photosensitizers in Human Skin DOI
E. L. Bastos, Frank H. Quina, Maurı́cio S. Baptista

et al.

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(16), P. 9720 - 9785

Published: July 17, 2023

Endogenous photosensitizers play a critical role in both beneficial and harmful light-induced transformations biological systems. Understanding their mode of action is essential for advancing fields such as photomedicine, photoredox catalysis, environmental science, the development sun care products. This review offers comprehensive analysis endogenous human skin, investigating connections between electronic excitation subsequent activation or damage organic biomolecules. We gather physicochemical photochemical properties key examine relationships chemical reactivity, location within primary biochemical events following solar radiation exposure, along with influence on skin physiology pathology. An important take-home message this that photosensitization allows visible light UV-A to have large effects skin. The presented here unveils potential causes continuous increase global cancer cases emphasizes limitations current protection approaches.

Language: Английский

Citations

48