Synthesis, Characterization, and Coordination Chemistry of the 2-Azaphenalenyl Radical

Abstract

The 2-azaphenalenyl radical 2 has been synthesized and characterized by ESR spectroscopy. Variable-temperature ESR measurements were carried out on both the phenalenyl (1) and the 2-azaphenalenyl (2) radicals. The phenalenyl radical 1 has the known propensity to dimerize at temperatures below 20 degrees C, but unexpectedly less so than originally reported. The first experimental measurement of bond dissociation enthalpy for the dimerization of the phenalenyl radical 1 was obtained in CCl(4) (11.34 +/- 0.11 kcal/mol) and toluene (9.8 +/- 0.7 kcal/mol). The 2-azaphenalenyl radical 2 does not show a propensity to dimerize over the measurable temperature range (220-330 K), but does so in the presence of Cu(hfac)(2) (hfac = hexafluoroacetylacetonate). The latter complex was characterized by X-ray crystallography.

Recent Advances in the Chemistry of Phenalenyl

“…The enthalpy and entropy changes for the σ dimerization of 5 were determined to be 64.0 kJ mol 1 and 135 J K 1 mol 1 , respectively, from the temperature dependency of the ESR signal intensity. The enthalpy change in 5 was larger than that in the parent phenalenyl radical ( 41 kJ mol 1 ), 26 indicating a higher propensity of 5 to σ dimerization. This can be attributed to a face to face attractive interaction between the C 6 F 5 group and phenalenyl ring, that is, per uoroarene arene interaction.…”

Phenalenyls, Cyclopentadienyls, and Other Carbon‐Centered Radicals

“…For the construction of 2-D and 3-D interactions used by the coordination of nitrogen atoms to metal ions, Rubin designed and synthesized the 2-azaphenalenyl (2APLY) 33 and perchloro-2,5,8-triazaphenalenyl (PTAZ) radicals. 34 Because the nitrogen atoms are incorporated into the β positions with very small coefficients of the SOMO, perturbations on their electronic structures are expected to be much smaller than those of α-type APLYs.…”

“…33 Reduction of the carbonyl groups of the 1,8-naphthalimide derivative and the following deprotection of the benzyl group give the amine derivative. N -Chlorination, dehydrochlorination and oxidation with oxygen give 2APLY as a yellow-green solution.…”

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].…”