Dianionic Titanyl and Vanadyl (Cation+ )2 [MIV O(Pc4- )]2- Phthalocyanine Salts Containing Pc4- Macrocycles

Dmitri V Konarev; Alexey V Kuzmin; Salavat S Khasanov; Alexey L Litvinov; Akihiro Otsuka; Hideki Yamochi; Hiroshi Kitagawa; Rimma N Lyubovskaya

doi:10.1002/asia.201701754

Dianionic Titanyl and Vanadyl (Cation⁺ )₂ [M^IV O(Pc^4- )]^2- Phthalocyanine Salts Containing Pc^4- Macrocycles

Chem Asian J. 2018 Jun 18;13(12):1552-1560. doi: 10.1002/asia.201701754. Epub 2018 May 17.

Authors

Dmitri V Konarev¹, Alexey V Kuzmin², Salavat S Khasanov², Alexey L Litvinov¹, Akihiro Otsuka^{3

4}, Hideki Yamochi^{3

4}, Hiroshi Kitagawa³, 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 Division of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
⁴ Research Center for Low Temperature and Materials Sciences, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan.

PMID: 29771008
DOI: 10.1002/asia.201701754

Abstract

In this study, the titanyl and vanadyl phthalocyanine (Pc) salts (Bu₄ N⁺ )₂ [M^IV O(Pc^4- )]^2- (M=Ti, V) and (Bu₃ MeP⁺ )₂ [M^IV O(Pc^4- )]^2- (M=Ti, V) with [M^IV O(Pc^4- )]^2- dianions were synthesized and characterized. Reduction of M^IV O(Pc^2- ) carried out with an excess of sodium fluorenone ketyl in the presence of Bu₄ N⁺ or Bu₃ MeP⁺ is exclusive to the phthalocyanine centers, forming Pc^4- species. During reduction, the metal +4 charge did not change, implying that Pc is an non-innocent ligand. The Pc negative charge increase caused the C-N(pyr) bonds to elongate and the C-N(imine) bonds to alternate, thus increasing the distortion of Pc. Jahn-Teller effects are significant in the [eg(π*)]² dianion ground state and can additionally distort the Pc macrocycles. Blueshifts of the Soret and Q-bands were observed in the UV/Vis/NIR when M^IV O(Pc^2- ) was reduced to [M^IV O(Pc^.^3- )]^.^- and [M^IV O(Pc^4- )]^2- . From magnetic measurements, [Ti^IV O(Pc^4- )]^2- was found to be diamagnetic and (Bu₄ N⁺ )₂ [V^IV O(Pc^4- )]^2- and (Bu₃ MeP⁺ )₂ [V^IV O(Pc^4- )]^2- were found to have magnetic moments of 1.72-1.78 μ_B corresponding to an S=1/2 spin state owing to V^IV electron spin. As a result, two latter salts show EPR signals with V^IV hyperfine coupling.

Keywords: Jahn-Teller distortion; crystal structure; dianionic salts of metal phthalocyanines; optical and magnetic properties; titanyl and vanadyl phthalocyanines.