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Synthesis, X‐ray Single‐Crystal Structure Determination, and Magnetic Properties of [Rb(benzo[18]crown‐6)] + Salts Containing Well‐Ordered Fulleride Trianions C 60 3−
Author(s) -
Boeddinghaus M. Bele,
Salzinger Michael,
Fässler Thomas F.
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200801923
Subject(s) - chemistry , crystallography , crystal structure , x ray , single crystal , x ray crystallography , magnetic susceptibility , physics , diffraction , nuclear physics , optics
Finally, a structure with well‐resolved C 60 3− ions and S=1/2 spin system : The two novel title compounds have clearly S=1/2 and not S=3/2 electronic states, as expected for the occupation of the triply degenerate LUMO of C 60. These structures with well‐ordered fullerene trianions show that the expected Jahn–Teller distortion is not observable in X‐ray diffraction experiments.Crystals of the composition [Rb(benzo[18]crown‐6)] 3 [η 3 ‐C 60 ](C 7 H 8 )(C 3 H 7 NO) 4.5 ( 1 ) and [Rb(benzo[18]crown‐6)] 3 [C 60 ](C 3 H 7 NO) 5.33 (C 4 H 8 O) 1.66 ( 2 ) were synthesized by reduction of C 60 with elemental rubidium in a mixture of dimethylformamide/tetrahydrofuran in the presence of benzo[18]crown‐6. X‐ray single‐crystal structure determinations reveal well‐ordered C 60 trianions in both compounds. In contrast to previously reported structures of compounds containing C 60 3− ions the present structure refinements allow the description of the buckyballs with good resolution ( R 1 / wR 2 for I >2σ( I ) (all data) are 0.030/0.069 (0.051/0.071) and 0.042/0.101 (0.076/0.108) for 1 and 2 , respectively). In 1 the C 60 3− unit coordinates in an η 3 ‐fashion to one Rb atom, whose coordination sphere is completed by one benzo[18]crown‐6 and one dimethylformamide molecule. In 2 no coordination of the alkali metal atom to the C 60 trianion is observed. Magnetic measurements for 1 reveal a magnetic moment of 1.74 μ B , as expected for an isolated S=1/2 spin system. The high‐quality data of the present studies allowed a comparison of structural details of C 60 3− ions with other C 60 n− units ( n =0, 2, 3) and a discussion of the structural Jahn–Teller distortions.