MPI für Festkörperforschung / FKF Publikationen 2004 |
|Ionic pair complexes with well-separated columnar stack structure based on [Pt(mnt)2]- ions showing unusual magnetic transition: Syntheses, crystal structures, and magnetic properties|
|Authors:||Ren, X.-M.; Okudera, H.; Kremer, R. K.; Song, Y.; He, C.; Meng, Q. J.; Wu, P. H.|
|Date of Publication (YYYY-MM-DD):||2004|
|Title of Journal:||Inorganic Chemistry|
|Issue / Number:||8|
|Review Status:||not specified|
|Abstract / Description:||Three ion pair complexes,
(abbreviated as [RBzPy]-[Pt(mnt)(2)]; R = Cl (1), Br (2), or NO2 (3)),
have been synthesized. The cations and anions stack into well-separated
columns in the solid state, and the Pt(III) ions form a 1-D zigzag
chain within a [Pt(mnt)(2)](-) column through Pt...S, S...S, and
Pt...S...Pt interactions. The chain is uniform in 1 and 2, while it
alternates in 3. Unusual magnetic phase transitions from paramagnetism
to diamagnetism were observed in these three complexes at similar to275
K for 1, similar to269 K for 2, and similar to184 K for 3. These phase
transitions were also found in DSC measurements for 1 and 2. The
overall magnetic behaviors for 1-3 indicate the presence of
antiferromagnetic exchange interactions in the high-temperature phase
and spin-gapped systems in the low-temperature phase. Below 50 K, 2
exhibits weak ferromagnetism. The spontaneous moments are nearly
repressed by a field of 1.0 T. The crystal structure of 2 at 173 K
reveals that there are two crystallographically independent
[Pt(mnt)(2)](-) entries in an asymmetric unit. These two
crystallographically independent [Pt(mnt)(2)](-) entries satisfy the
spin-canting condition, and the EPR spectra measured at room
temperature exhibit anisotropic character. Therefore, the weak
ferromagnetic behavior in the low-temperature region for 2 can be
attributed to the spin-canting phenomenon.
|External Publication Status:||published|
|Communicated by:||Michaela Asen-Palmer|
|Affiliations:||MPI für Festkörperforschung|
|External Affiliations:||Nanjing Univ, Inst Coordinat Chem, Nanjing 210093, Peoples R China.
; Nanjing Univ, State Key Lab, Nanjing 210093, Peoples R China.
; Nanjing Univ, Dept Elect Sci & Engn, Nanjing 210093, Peoples R China.
; Anqing Normal Coll, Dept Chem, Anqing 246011, Peoples R China.
; Peking Univ, State Key Lab Rare Earth Mat Chem & Appl, Beijing 100871, Peoples R China.
; Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany.
|Identifiers:||ISI:000220838400020 [ID No:1] |
ISSN:0020-1669 [ID No:2]
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