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Macrocycle- and metal-centered reduction of metal tetraphenylporphyrins where metal is copper(II), nickel(II) and iron(II)статья
Статья опубликована в высокорейтинговом журнале
Статья опубликована в журнале из списка Web of Science и/или Scopus- Авторы: Nazarov Dmitry I., Andronov Mikhail G., Kuzmin Aleksey V., Khasanov Salavat S., Yudanova Evgeniya I., Shestakov Alexander F., Otsuka Akihiro, Yamochi Hideki, Kitagawa Hiroshi, Konarev Dmitri V.
- Журнал: Dalton Transactions
- Том: 50
- Номер: 43
- Год издания: 2021
- Издательство: Royal Society of Chemistry
- Местоположение издательства: United Kingdom
- Первая страница: 15620
- Последняя страница: 15632
- DOI: 10.1039/d1dt02573b
- Аннотация: The reduction of metal(II) tetraphenylporphyrins, where metal(II) is copper, nickel or iron, has been performed in toluene solution in the presence of a cryptand. Cesium anthracenide was used as a reductant. Crystalline salts {cryptand(Cs+)}2 {Cu(II)(TPP4−)}(2−) (1) and {cryptand(Cs+)}{Ni(I)(TPP2−)}−·C6H5CH3 (2) have been obtained. The two-electron reduction of {Cu(II)(TPP2−)}(0) is centered on the macrocycle allowing oneto study for the first time the structure and properties of the TPP(4−) tetraanions in the solid state. Tetraanions have a diamagnetic state and show essential C–C(meso) bond alternation. New bands attributed to TPP(4−) appear at 670, 770 and 870 nm. Unpaired S = 1/2 spin is localized on Cu(II). The one-electron reduction of {Ni(II)(TPP2−)}(0) centered on nickel provides the formation of {Ni(I)(TPP2−)}− with unpaired S = 1/2 spin localized on Ni(I) at 100(2) K. The effective magnetic moment of 2 is 1.68(μB) at 120 K and a broad asymmetric EPR signal characteristic of Ni(I) is observed for 2 and also for (Bu3MeP+){Ni(I)(TPP(2−))}(−)·C6H5CH3 (3) in the 4.2–120 K range. Since dianionic TPP(2−) macrocycles are present at 100(2) K, no alternation ofC–C(meso) bonds is observed in 2. The excited quartet S = 3/2 state according to the calculations is positioned close to the ground S = 1/2 state. In the excited state, charge transfer from Ni(I) to the macrocycletakes place resulting in the formation of NiII with S = 1 and TPP•3− with S = 1/2 in the {NiII(TPP•3−)}−anions. Therefore, the increase in the magnetic moment of 2 above 150 K is attributed to the populationof the excited quartet state with a gap of 750 K. Salt 2 is EPR silent above 150 K and manifests absorptionbands characteristic of TPP•3− at RT. The reduction of NiII(TPP2−) and FeII(TPP2−) by cesium anthracenidein the presence of Bu3MeP+ yields crystals of 3 and (Bu3MeP+){FeI(TPP2−)}−·C6H5CH3 (4) whose crystalstructures and optical properties are also presented. DFT calculations have been carried out for{MII(TPP2−)} (M = Cu, Ni and Fe) and their anions to interpret the experimental results obtained for 1–4.
- Добавил в систему: Конарев Дмитрий Валентинович