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Different types of interactions between fullerene C60 and C70 anions and meta tetraphenylporphyrins in the (PMDAE+)(MIITPP)(Fullerene−)Solvent complexes (M = Co, Mn, Zn) containing coordinating N, N, N, N‘, N‘-pentamethyldiaminoethane cationsстатья
- Авторы: Andronov Mikhail G., Kuzmin Alexey V., Shestakov Alexander F., Khasanov Salavat S., Konarev Dmitri V.
- Журнал: Inorganica Chimica Acta
- Том: 533
- Год издания: 2022
- Издательство: Elsevier BV
- Местоположение издательства: Netherlands
- Первая страница: 120789
- DOI: 10.1016/j.ica.2022.120789
- Аннотация: Series of anionic salts of fullerenes C60 and C70 with different metal tetraphenylporphyrins, MIITPP, where M = Co, Mn and Zn, and N, N, N, N‘, N‘-pentamethyldiaminoethane cations (PMDAE+) has been obtained in a crystalline form. Composition of the complexes is (PMDAE+)⋅(MIITPP)(C60−)⋅XC6H4Cl2 (M = Co, X = 1.25 (1), M = Mn, X = 0.75 (2) and M = Zn, X = 0.75 (3)) and {(PMDAE+)⋅ZnIITPP}2⋅(C70−)2⋅4C6H4Cl2 (4). Both fullerene anion and nitrogen-containing PMDAE+ cation can coordinate to metal porphyrin competing with each other. Weak Co-C(C60−) coordination bond of 2.426(7) Å length (120 K) is formed in 1 whereas PMDAE+ cation only weakly coordinates to CoIITPP. Dissociation of Co-C(C60−) bond observed at 90–310 K is accompanied by a transition of 1 from singlet to triplet state with an energy gap of 574 ± 3 K. According to the calculations negative charge on C60− is only −0.548 due to electron transfer to the macrocyclic ligand through the cobalt atom. Charge transfer bands are observed in {CoIITPP(C60)}− at 700 and 1240 nm. On the contrary, PMDAE+ cations coordinate to MnIITPP and ZnIITPP in 2 and 3, respectively, with short M−N(PMDAE+) bonds of 2.27–2.33 Å length. In these cases fullerenes are preserved in the non-coordinated radical anion state. Fullerenes are arranged in closely packed π-stacking {C60•−}2 dimers with short interfullerene center-to-center distances of 9.92–9.95 Å. Nevertheless, the C60•− radical anions do not form intercage Csingle bondC bonds down to 1.9 K. Strong antiferromagnetic coupling of spins is observed in the {C60•−}2 dimers of 3 with exchange interaction of J/kB = -21 K. Both {(PMDAE+)⋅MnIITPP} and C60•− species are paramagnetic in 2 having S = 5/2 and S = 1/2 spin states, respectively. These spins are coupled antiferromagnetically with Weiss temperature of −16 K. It is obvious that magnetic coupling occurs not only in the {C60•−}2 dimers but MnIITPP is also involved in this coupling. The C70•− radical anions are dimerized in 4 forming diamagnetic singly-bonded (C70−)2 dimers which manifest intense NIR absorption. As a result, complex 4 is EPR silent.
- Добавил в систему: Алдошин Сергей Михайлович