Premium
Electronic Communication between S= 1/2 Spins in Negatively‐charged Double‐caged Fullerene C 60 Derivative Bonded by Two Single Bonds and Pyrrolizidine Bridge
Author(s) -
Konarev Dmitri V.,
Kuzmin Alexey V.,
Khasanov Salavat S.,
Goryunkov Alexey A.,
Brotsman Victor A.,
Ioffe Ilya N.,
Otsuka Akihiro,
Yamochi Hideki,
Kitagawa Hiroshi,
Lyubovskaya Rimma N.
Publication year - 2019
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201900154
Subject(s) - fullerene , chemistry , spins , cyclobutane , moiety , crystallography , pyrrolizidine , diradical , singlet state , ground state , radical ion , exchange interaction , derivative (finance) , superexchange , ion , stereochemistry , ferromagnetism , atomic physics , condensed matter physics , physics , excited state , organic chemistry , ring (chemistry) , financial economics , economics
Radical anion salt {cryptand[2.2.2] (K + )} 2 (bispheroid) 2− ⋅3.5C 6 H 4 Cl 2 ( 1 ) of the double‐caged fullerene C 60 derivative, in which fullerene cages are linked by a cyclobutane bridging cycle and additionally by a pyrrolizidine moiety, was obtained. Each fullerene cage in this derivative accepts one electron on reduction, thus forming the (bispheroid) 2− dianions with two interacting S= 1/2 spins on the neighboring cages. Low‐temperature magnetic measurements reveal a singlet ground state of the bispheroid dianions whereas triplet contributions prevail at increased temperature. An estimated exchange interaction between two spins J / k B =−78 K in 1 indicates strong magnetic coupling between them, nearly two times higher than that ( J / k B =−44.7 K) in previously studied (C 60 − ) 2 dimers linked via a cyclobutane bridge only. The enhancement of magnetic coupling in 1 can be explained by a shorter distance between the fullerene cages and, possibly, an additional channel for the magnetic exchange provided by a pyrrolizidine bridge. Quantum‐chemical calculations of the lowest electronic state of the dianions by means of multi‐configuration quasi‐degenerate perturbation theory support the experimental findings.