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Metallic conductivity versus charge disproportionation in C 60 complexes with noninteger average charges on fullerene
Author(s) -
Konarev Dmitri V.,
Khasanov Salavat S.,
Ishikawa Manabu,
Yudanova Evgeniya I.,
Shevchun Artem F.,
Mikhailov Maksim S.,
Stuzhin Pavel A.,
Otsuka Akihiro,
Yamochi Hideki,
Saito Gunzi,
Lyubovskaya Rimma N.
Publication year - 2016
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201500021
Subject(s) - cryptand , fullerene , disproportionation , conductivity , metal , crystallography , molecule , dication , charge (physics) , chemistry , materials science , ion , organic chemistry , physics , quantum mechanics , catalysis
Oxidation of {cryptand(Na + )}(C 60 •‐ ) and {cryptand(Na + )} 2 (C 60 2− ), which display integer −1 and −2 charges on the fullerene unit, by iron(II) octaethyltetrapyrazinoporphyrazine allowed the crystallization of complexes with noninteger average charges on C 60 . The complex {cryptand(Na + )}(C 60 ) 3 ‐ ⋅2C 6 H 4 Cl 2 ( 1 ), with a partial charge of ‐0.33 on C 60 , exhibits a closely‐packed 3D structure formed by fragments of hexagonal fullerene layers. Complex 1 shows high conductivity in the 295–120 K range: conductivities of 50–60 and 100–250 S⋅cm −1 were measured using four‐probe and microwave techniques, respectively. Metallic behavior of 1 is observed down to 150–120 K. Metallic conductivity is still observed in 1 after one month of exposure to air. The complexes {cryptand(Na + )}(C 60 ) 2 − ( 2 ) and {cryptand (Na + )} 8 (C 60 ) 6 8− ( 3 ), which display average charges of −0.5 and −1.33, respectively, on C 60 , do not show metallic conductivity. This can be explained by charge disproportionation and the formation of neutral and −1‐charged C 60 in 2 , and −1‐ and −2‐charged C 60 in 3 . Despite the close packing of the fullerene molecules in crystal structures, no dimerization of C 60 is observed in 1 and 2 . On the contrary, diamagnetic, singly‐bonded (C 60 − ) 2 dimers are formed in {cryptand(Li + )} 2 (C 60 − ) 2 ⋅C 6 H 4 Cl 2 ⋅C 6 H 14 ( 4 ), which contains fullerene molecules bearing a full −1 charge.