Phenalenyls, Cyclopentadienyls, and Other Carbon‐Centered Radicals

Nishida, Shinsuke

doi:10.1002/9780470666975.ch3

Cited by 83 publications

(55 citation statements)

References 103 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Phenalenyl (PNL) is a carbon-centered neutral π-radical with a delocalized spin structure. [12][13][14][15][16][17][18][19] Several PNL derivatives form π-dimers, and exhibit absorption bands around 600 nm. [15][16][17] In a few cases, 1D π-stacking columns are formed with large intermolecular separations of~3.78 (ref.…”

mentioning

confidence: 99%

Near-infrared absorption of π-stacking columns composed of trioxotriangulene neutral radicals

et al. 2017

Self Cite

View full text Add to dashboard Cite

A long-wavelength photoabsorption of organic molecules has been noticed because of the potential as materials. In addition to the extension of π conjugation, molecular aggregation has been utilized to realize the elongation of absorption wavelength. We report strong near-infrared absorptions of trioxotriangulene neutral radicals in the crystalline state and large-scale theoretical calculations of the radical assemblies interpreting the mechanism of optical properties. Polarized absorption spectra and X-ray diffraction of the crystals clarified that an unusual π-stacking column consisting of π-dimers is key for this absorption. Quantum chemical calculations based on time-dependent density functional theory revealed that the π-dimer shows an electronic transition between frontier orbitals generated by strong coupling of the delocalized singly occupied orbitals of monomers. The interdimer interaction of transition dipole moments, which are parallel to the column, elucidated the increase of absorption wavelength. The divide-andconquer Green function method enabled the large-scale time-dependent density functional theory calculation up to a 60mer, where the maximum number of atoms is 4380, reproducing the near-infrared absorptions of trioxotriangulene crystals. The present method to investigate the mechanism of the long-wavelength photoabsorption is useful for developing organic materials consisting of stable neutral radicals.

show abstract

mentioning

confidence: 99%

Near-infrared absorption of π-stacking columns composed of trioxotriangulene neutral radicals

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…Following earlier work on the 6-oxophenalenoxyl neutral radical for its use as cathode-active materials for battery applications [14], Morita et al recently introduced the trioxytriangulene motif (denoted as TOT in the following), characterized by a SOMO and two degenerate LUMOs, arising from the topological symmetry of the π-system [15]. Among these series, the tribromo derivative, denoted as Br 3 TOT, forms a one-dimensional columnar structure stabilized by strong π-π stacking.…”

Section: Halogenated Trioxytriangulene Radicalmentioning

confidence: 99%

Organizing Radical Species in the Solid State with Halogen Bonding

Fourmigué

Lieffrig

2014

Topics in Current Chemistry

View full text Add to dashboard Cite

The electronic properties (conductivity, magnetism) of radical systems in the solid state essentially depend on (1) the extent of delocalization of the spin density in the molecule and (2) the intermolecular interactions between radicals. The halogen bond has proven very efficient in engineering such magnetic or conducting structures and recent advances along these lines are reviewed here. Three situations are considered: (1) halogenated radical species acting as halogen bond donors, as found in iodotetrathiafulvalene-based chiral conductors or bilayer systems, and in spin crossover (SCO) complexes with halogenated ligands, (2) radical species acting as halogen bond acceptors, such as neutral nitronyl species or anionic, mixed-valence dithiolene complexes, interacting with closed-shell halogen bond donors (iodoperfluoro alkanes and arenes, iodo- or bromo-pyridinium cations), and, finally, (3) charge transfer salts where both halogen bond donor and acceptor are radical species.

show abstract

“…1e5 It has attracted considerable interest since it has interesting magnetic, 6e10 optical, 8,11,12 and electronic properties. 13 The phenalenyl radical, the smallest open shell graphene, 14 was first prepared by Reid 6 and independently detected by Calvin. 15 It is a resonance-stabilised radical 16 that can be generated and observed at room temperature in solution, showing thermodynamic high stability but some kinetic instability.…”

Section: Introductionmentioning

confidence: 99%

“…15 It is a resonance-stabilised radical 16 that can be generated and observed at room temperature in solution, showing thermodynamic high stability but some kinetic instability. 7,14 Since then, a number of simple derivatives have been generated 17 and the literature reviewed. 18 In fact, the structure of 1H-phenalene and its 2H-and 3H-isomers, as well as the phenalenyl cation, neutral radical and anion have been theoretically investigated at different computational levels.…”

Section: Introductionmentioning

confidence: 99%