Tetrabutylammonium Salts of Aluminum(III) and Gallium(III) Phthalocyanine Radical Anions Bonded with Fluoren-9-olato- Anions and Indium(III) Phthalocyanine Bromide Radical Anions

Dmitri V Konarev; Salavat S Khasanov; Manabu Ishikawa; Yoshiaki Nakano; Akihiro Otsuka; Hideki Yamochi; Gunzi Saito; Rimma N Lyubovskaya

doi:10.1002/asia.201700138

Tetrabutylammonium Salts of Aluminum(III) and Gallium(III) Phthalocyanine Radical Anions Bonded with Fluoren-9-olato^- Anions and Indium(III) Phthalocyanine Bromide Radical Anions

Chem Asian J. 2017 Apr 18;12(8):910-919. doi: 10.1002/asia.201700138. Epub 2017 Mar 24.

Authors

Dmitri V Konarev¹, Salavat S Khasanov², Manabu Ishikawa³, Yoshiaki Nakano^{3

4}, Akihiro Otsuka^{3

4}, Hideki Yamochi^{3

4}, Gunzi Saito^{5

6}, Rimma N Lyubovskaya¹

Affiliations

¹ Institute of Problems of Chemical Physics RAS, Chernogolovka, Moscow region, 142432, Russia.
² Institute of Solid State Physics RAS, Chernogolovka, Moscow region, 142432, Russia.
³ Research Center for Low Temperature and Materials Sciences, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan.
⁴ Division of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
⁵ Faculty of Agriculture, Meijo University, 1-501 Shiogamaguchi, Tempaku-ku, Nagoya, 468-8502, Japan.
⁶ Toyota Physical and Chemical Research Institute, 41-1, Yokomichi, Nagakute, Aichi, 480-1192, Japan.

PMID: 28205420
DOI: 10.1002/asia.201700138

Abstract

Reduction of aluminum(III), gallium(III), and indium(III) phthalocyanine chlorides by sodium fluorenone ketyl in the presence of tetrabutylammonium cations yielded crystalline salts of the type (Bu₄ N⁺ )₂ [M^III (HFl-O^- )(Pc^.3- )]^.- (Br^- )⋅1.5 C₆ H₄ Cl₂ [M=Al (1), Ga (2); HFl-O^- =fluoren-9-olato^- anion; Pc=phthalocyanine] and (Bu₄ N⁺ ) [In^III Br(Pc^.3- )]^.- ⋅0.875 C₆ H₄ Cl₂ ⋅0.125 C₆ H₁₄ (3). The salts were found to contain Pc^.3- radical anions with negatively charged phthalocyanine macrocycles, as evidenced by the presence of intense bands of Pc^.3- in the near-IR region and a noticeable blueshift in both the Q and Soret bands of phthalocyanine. The metal(III) atoms coordinate HFl-O^- anions in 1 and 2 with short Al-O and Ga-O bond lengths of 1.749(2) and 1.836(6) Å, respectively. The C-O bonds [1.402(3) and 1.391(11) Å in 1 and 2, respectively] in the HFl-O^- anions are longer than the same bond in the fluorenone ketyl (1.27-1.31 Å). Salts 1-3 show effective magnetic moments of 1.72, 1.66, and 1.79 μ_B at 300 K, respectively, owing to the presence of unpaired S=1/2 spins on Pc^.3- . These spins are coupled antiferromagnetically with Weiss temperatures of -22, -14, and -30 K for 1-3, respectively. Coupling can occur in the corrugated two-dimensional phthalocyanine layers of 1 and 2 with an exchange interaction of J/k_B =-0.9 and -1.1 K, respectively, and in the π-stacking {[In^III Br(Pc^.3- )]^.- }₂ dimers of 3 with an exchange interaction of J/k_B =-10.8 K. The salts show intense electron paramagnetic resonance (EPR) signals attributed to Pc^.3- . It was found that increasing the size of the central metal atom strongly broadened these EPR signals.

Keywords: aluminum; antiferromagnetic coupling; gallium; indium; magnetic properties; phthalocyanines; radical ions.