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Double-Decker Paramagnetic {(K)(H3 Hhp)2 }⋅2- Radical Dianions Comprising Two
Dmitri V Konarev1, Salavat S Khasanov2, Mikhail K Islyaikin3
1Institute of Problems of Chemical Physics RAS, Chernogolovka, Moscow region, 142432, Russia.
Abstract:
Reduction of free-base [30]trithia-2,3,5,10,12,13,15,20,22,23,25,30-dodecaazahexaphyrin (H3 Hhp) yields {cryptand[2.2.2](K)}2 {(K)(H3 Hhp)2 }⋅4C6 H4 Cl2 (1) containing double-decker {(K)(H3 Hhp)2 }⋅2- radical dianions, whose structure was elucidated using X-ray diffraction. Potassium ion forms 12 short (K+ )⋅⋅⋅N(H3 Hhp) contacts with two H3 Hhp macrocycles in the 3.048-3.157 Å range. Dianions have S=1/2 spin state manifesting an effective magnetic moment of 1.64 μB at 300 K and a narrow Lorentzian electron paramagnetic resonance signal. Quantum chemical calculations support the ionic nature of the (K+ )-N(H3 Hhp) interactions and the nearly equal distribution of the -1.5 charge over each macrocycle. H3 Hhp takes the role of an aza-crown ether in free-base reduced state and forms a new type of double-decker complex.
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