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Abstract We report on the largest open‐shell graphenic bilayer and also the first example of triply negatively charged radical π‐dimer. Upon three‐electron reduction, bilayer nanographene fragment molecule (C96H24Ar6)2(Ar=2,6‐dimethylphenyl) (12) was transformed to a triply negatively charged species123.−, which has been characterized by single‐crystal X‐ray diffraction, electron paramagnetic resonance (EPR) spectroscopy and magnetic properties on a superconducting quantum interference device (SQUID).123.−features a 96‐center‐3‐electron (96c/3e) pancake bond with a doublet ground state, which can be thermally excited to a quartet state. It consists of 34 π‐fused rings with 96 conjugatedsp2carbon atoms. Spin frustration is observed with the frustration parameterf>31.8 at low temperatures in123.−, which indicates graphene upon reduction doping may behave as a quantum spin liquid.
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A Complete Triad of Zero‐Valent 17‐Electron Monoradicals of Group 7 Elements Stabilized by m ‐Terphenyl Isocyanides
Abstract The first consistent series of mononuclear 17‐electron complexes of three Group 7 elements has been isolated in crystalline form and studied by X‐ray diffraction and spectroscopic methods. The paramagnetic compounds have a composition of [M0(CO)(CNp‐F‐ArDArF2)4] (M=Mn, Tc, Re; ArDArF2=2,6‐(3,5‐(CF3)2C6H3)2C6H2F) and are stabilized by four sterically encumbering isocyanides, which prevent the metalloradicals from dimerization. They have a square pyramidal structure with the carbonyl ligands as apexes. The frozen‐solution EPR spectra of the rhenium and technetium compounds are clearly anisotropic with large99Tc and185,187Re hyperfine interactions for one component. High‐field EPR (Q band and W band) has been applied for the elucidation of the EPR parameters of the manganese(0) complex.
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- PAR ID:
- 10408567
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 62
- Issue:
- 19
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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