Perchlorophenalenyl Radical

Abstract

We report the preparation and solid-state characterization of the perchlorophenalenyl radical (1). The radical is initially obtained as a yellow-green solid by reduction of the perchlorophenalenium salt (12(+)). This solid sublimes in a sealed tube to give black shiny hexagonal crystals of the perchlorophenalenyl radical (1). The structure consists of 1-dimensional stacks of the monomeric radical. The peri-chlorine atoms force the phenalenyl system to be strongly nonplanar leading to a large separation between adjacent molecules within the stacks (3.78 A), and the molecules adopt two distinct stacking motifs (quasisuperimposed and rotated by 60 degrees with respect to neighbors). Because of the packing frustration in the lattice and the large intermolecular spacing, the solid shows Curie paramagnetism in the temperature range 100-400 K, before antiferromagnetic coupling sets in at low temperatures. Due to the narrow bandwidth that results from the isolation of the individual molecules, the solid is a Mott-Hubbard insulator, with a room-temperature conductivity of rho(RT) = 10(-10) S/cm.

Chemistry of Single-Walled Carbon Nanotubes

“…7 Characterization of the functionalized species is a major difficulty in carbon nanotube chemistry, but in the case of wall chemistry, where the band electronic structure is disrupted, solution spectroscopy is a powerful tool; Raman spectroscopy has also been used to study the effects of sidewall functionalization. [93][94][95]109 Dichlorocarbene is an electrophilic reagent that will add to deactivated double bonds (Scheme 5) [103][104][105] and to fullerenes. 106,107 Electronic spectroscopy showed that the band-gap transitions in the semiconducting tubes were completely disrupted at a functionalization level of 2% of the available SWNT carbon atoms.…”

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

“…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.…”

“…[15][16][17] In a few cases, 1D π-stacking columns are formed with large intermolecular separations of~3.78 (ref. 13) and 3.65 Å, 19 due to bulky protection groups, the latter of which shows a band around 800 nm. 19 π-Stacked structures of π-conjugated PNL dimers (1/2 unpaired electron per PNL unit) [20][21][22] and those of singlet-diradical bisphenalenyls 23 (one unpaired electron per PNL unit) exhibit NIR absorption bands.…”

Synthesis, Structure and Solid State Properties of Cyclohexanemethylamine Substituted Phenalenyl Based Molecular Conductor

“…It was first proposed in 1975 that phenalenyl has the potential to serve as a building block for molecular conductors [13][14][15]. Since then synthetic efforts have led to the crystallization and characterization of several types of PLY derivatives by chemical modification [16][17][18][19][20][21][22][23]. Heteroatom functionalization of neutral radicals such as thio-substituted PLY [24][25][26], azaphenalenyls [12,27,28], and bisphenalenyl boron complexes [29,30] have played a crucial role in the recent progress in phenalenyl chemistry and the important developments in heterocyclic radicals [31][32][33][34][35].…”