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An Octanuclear Metallosupramolecular Cage Designed To Exhibit Spin‐Crossover Behavior
Author(s) -
Struch Niklas,
Bannwarth Christoph,
Ronson Tanya K.,
Lorenz Yvonne,
Mienert Bernd,
Wagner Norbert,
Engeser Marianne,
Bill Eckhard,
Puttreddy Rakesh,
Rissanen Kari,
Beck Johannes,
Grimme Stefan,
Nitschke Jonathan R.,
Lützen Arne
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201700832
Subject(s) - spin crossover , chemistry , zinc , crystallography , spin states , porphyrin , cage , spin transition , inorganic chemistry , photochemistry , organic chemistry , mathematics , combinatorics
By employing the subcomponent self‐assembly approach utilizing 5,10,15,20‐tetrakis(4‐aminophenyl)porphyrin or its zinc(II) complex, 1 H ‐4‐imidazolecarbaldehyde, and either zinc(II) or iron(II) salts, we were able to prepare O‐symmetric cages having a confined volume of ca. 1300 Å 3 . The use of iron(II) salts yielded coordination cages in the high‐spin state at room temperature, manifesting spin‐crossover in solution at low temperatures, whereas corresponding zinc(II) salts led to the corresponding diamagnetic analogues. The new cages were characterized by synchrotron X‐ray crystallography, high‐resolution mass spectrometry, and NMR, Mössbauer, IR, and UV/Vis spectroscopy. The cage structures and UV/Vis spectra were independently confirmed by state‐of‐the‐art DFT calculations. A remarkably high‐spin‐stabilizing effect through encapsulation of C 70 was observed. The spin‐transition temperature T 1/2 is lowered by 20 K in the host–guest complex.