Conducting dimerized cobalt complexes with tetrathiafulvalene dithiolate ligands

Emiko Fujiwara; Kazumasa Hosoya; Akiko Kobayashi; Hisashi Tanaka; Madoka Tokumoto; Yoshinori Okano; Hideki Fujiwara; Hayao Kobayashi; Yuichi Fujishiro; Eiji Nishibori; Masaki Takata; Makoto Sakata

doi:10.1021/ic701100r

Conducting dimerized cobalt complexes with tetrathiafulvalene dithiolate ligands

Emiko Fujiwara, Kazumasa Hosoya, Akiko Kobayashi, Hisashi Tanaka, Madoka Tokumoto, Yoshinori Okano, Hideki Fujiwara, Hayao Kobayashi, Yuichi Fujishiro, Eiji Nishibori, Masaki Takata, Makoto Sakata

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Abstract

To obtain novel single-component molecular metals, we attempted to synthesize several cobalt complexes coordinated by TTF (tetrathiafulvalene)-type dithiolate ligands. We succeeded in the syntheses and structure determinations of (ⁿBu₄N)₂[Co(chdt)₂]₂ (1), (ⁿBu₄N)₂[Co(dmdt)₂]₂ (2), [Co(dmdt)₂]₂ (3), and [Co(dt)₂] ₂ (4) (chdt = cyclohexeno-TTF-dithiolate, dmdt = dimethyl-TTF- dithiolate, and dt = TTF-dithiolate). Structure analyses of complexes 1-4 revealed that two monomeric [Co(ligand)₂]^- or [Co(ligand)₂]⁰ units are connected by two Co-S bonds resulting in dimeric [Co(ligand)₂]₂^2- or [Co(ligand)₂]₂ molecules. Complex 1 has a cation-anion-intermingled structure and exhibited Curie-Weiss magnetic behavior with a large Curie constant (C - 2.02 K·emu·mol^-1) and weak antiferromagnetic interactions (θ = -8.3 K). Complex 2 also has a cation-anion-intermingled structure. However, the dimeric molecules are completely isolated by cations. Complexes 3 and 4 are single-component molecular crystals. The molecules of complex 3 form two-dimensional molecular stacking layers and exhibit a room-temperature conductivity of σ_rt = 1.2 × 10^-2 S·cm^-1 and an activation energy of E_a = 85 meV. The magnetic behavior is almost consistent with Curie-Weiss law, where the Curie constant and Weiss temperature are 8.7 × 10^-2 K·emu·mol^-1 and -0.85 K, respectively. Complex 4 has a rare chair form of the dimeric structure. The electrical conductivity was fairly large (σ_rt = 19 S·cm ^-1), and its temperature dependence was very small (σ_0.55K/σ_rt = ca. 1:10), although the measurements were performed on the compressed pellet sample. Complex 4 showed an almost constant paramagnetic susceptibility (χ_{300 K} = 3.5 × 10^-4 emu·mol^-1) from 300 to 50 K. The band structure calculation of complex 4 suggested the metallic nature of the system. Complex 4 is a novel single-component molecular conductor with a dimeric molecular structure and essentially metallic properties down to very low temperatures.

Original language	English
Pages (from-to)	863-874
Number of pages	12
Journal	Inorganic chemistry
Volume	47
Issue number	3
DOIs	https://doi.org/10.1021/ic701100r
Publication status	Published - 2008 Feb 4
Externally published	Yes

ASJC Scopus subject areas

Physical and Theoretical Chemistry
Inorganic Chemistry

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@article{ec4c19775afc456783b04d3d7b8eea2a,

title = "Conducting dimerized cobalt complexes with tetrathiafulvalene dithiolate ligands",

abstract = "To obtain novel single-component molecular metals, we attempted to synthesize several cobalt complexes coordinated by TTF (tetrathiafulvalene)-type dithiolate ligands. We succeeded in the syntheses and structure determinations of (nBu4N)2[Co(chdt)2]2 (1), (nBu4N)2[Co(dmdt)2]2 (2), [Co(dmdt)2]2 (3), and [Co(dt)2] 2 (4) (chdt = cyclohexeno-TTF-dithiolate, dmdt = dimethyl-TTF- dithiolate, and dt = TTF-dithiolate). Structure analyses of complexes 1-4 revealed that two monomeric [Co(ligand)2]- or [Co(ligand)2]0 units are connected by two Co-S bonds resulting in dimeric [Co(ligand)2]22- or [Co(ligand)2]2 molecules. Complex 1 has a cation-anion-intermingled structure and exhibited Curie-Weiss magnetic behavior with a large Curie constant (C - 2.02 K·emu·mol-1) and weak antiferromagnetic interactions (θ = -8.3 K). Complex 2 also has a cation-anion-intermingled structure. However, the dimeric molecules are completely isolated by cations. Complexes 3 and 4 are single-component molecular crystals. The molecules of complex 3 form two-dimensional molecular stacking layers and exhibit a room-temperature conductivity of σrt = 1.2 × 10-2 S·cm-1 and an activation energy of Ea = 85 meV. The magnetic behavior is almost consistent with Curie-Weiss law, where the Curie constant and Weiss temperature are 8.7 × 10-2 K·emu·mol-1 and -0.85 K, respectively. Complex 4 has a rare chair form of the dimeric structure. The electrical conductivity was fairly large (σrt = 19 S·cm -1), and its temperature dependence was very small (σ0.55K/σrt = ca. 1:10), although the measurements were performed on the compressed pellet sample. Complex 4 showed an almost constant paramagnetic susceptibility (χ300 K = 3.5 × 10-4 emu·mol-1) from 300 to 50 K. The band structure calculation of complex 4 suggested the metallic nature of the system. Complex 4 is a novel single-component molecular conductor with a dimeric molecular structure and essentially metallic properties down to very low temperatures.",

author = "Emiko Fujiwara and Kazumasa Hosoya and Akiko Kobayashi and Hisashi Tanaka and Madoka Tokumoto and Yoshinori Okano and Hideki Fujiwara and Hayao Kobayashi and Yuichi Fujishiro and Eiji Nishibori and Masaki Takata and Makoto Sakata",

year = "2008",

month = feb,

day = "4",

doi = "10.1021/ic701100r",

language = "English",

volume = "47",

pages = "863--874",

journal = "Inorganic Chemistry",

issn = "0020-1669",

publisher = "American Chemical Society",

number = "3",

}

TY - JOUR

T1 - Conducting dimerized cobalt complexes with tetrathiafulvalene dithiolate ligands

AU - Fujiwara, Emiko

AU - Hosoya, Kazumasa

AU - Kobayashi, Akiko

AU - Tanaka, Hisashi

AU - Tokumoto, Madoka

AU - Okano, Yoshinori

AU - Fujiwara, Hideki

AU - Kobayashi, Hayao

AU - Fujishiro, Yuichi

AU - Nishibori, Eiji

AU - Takata, Masaki

AU - Sakata, Makoto

PY - 2008/2/4

Y1 - 2008/2/4

N2 - To obtain novel single-component molecular metals, we attempted to synthesize several cobalt complexes coordinated by TTF (tetrathiafulvalene)-type dithiolate ligands. We succeeded in the syntheses and structure determinations of (nBu4N)2[Co(chdt)2]2 (1), (nBu4N)2[Co(dmdt)2]2 (2), [Co(dmdt)2]2 (3), and [Co(dt)2] 2 (4) (chdt = cyclohexeno-TTF-dithiolate, dmdt = dimethyl-TTF- dithiolate, and dt = TTF-dithiolate). Structure analyses of complexes 1-4 revealed that two monomeric [Co(ligand)2]- or [Co(ligand)2]0 units are connected by two Co-S bonds resulting in dimeric [Co(ligand)2]22- or [Co(ligand)2]2 molecules. Complex 1 has a cation-anion-intermingled structure and exhibited Curie-Weiss magnetic behavior with a large Curie constant (C - 2.02 K·emu·mol-1) and weak antiferromagnetic interactions (θ = -8.3 K). Complex 2 also has a cation-anion-intermingled structure. However, the dimeric molecules are completely isolated by cations. Complexes 3 and 4 are single-component molecular crystals. The molecules of complex 3 form two-dimensional molecular stacking layers and exhibit a room-temperature conductivity of σrt = 1.2 × 10-2 S·cm-1 and an activation energy of Ea = 85 meV. The magnetic behavior is almost consistent with Curie-Weiss law, where the Curie constant and Weiss temperature are 8.7 × 10-2 K·emu·mol-1 and -0.85 K, respectively. Complex 4 has a rare chair form of the dimeric structure. The electrical conductivity was fairly large (σrt = 19 S·cm -1), and its temperature dependence was very small (σ0.55K/σrt = ca. 1:10), although the measurements were performed on the compressed pellet sample. Complex 4 showed an almost constant paramagnetic susceptibility (χ300 K = 3.5 × 10-4 emu·mol-1) from 300 to 50 K. The band structure calculation of complex 4 suggested the metallic nature of the system. Complex 4 is a novel single-component molecular conductor with a dimeric molecular structure and essentially metallic properties down to very low temperatures.

AB - To obtain novel single-component molecular metals, we attempted to synthesize several cobalt complexes coordinated by TTF (tetrathiafulvalene)-type dithiolate ligands. We succeeded in the syntheses and structure determinations of (nBu4N)2[Co(chdt)2]2 (1), (nBu4N)2[Co(dmdt)2]2 (2), [Co(dmdt)2]2 (3), and [Co(dt)2] 2 (4) (chdt = cyclohexeno-TTF-dithiolate, dmdt = dimethyl-TTF- dithiolate, and dt = TTF-dithiolate). Structure analyses of complexes 1-4 revealed that two monomeric [Co(ligand)2]- or [Co(ligand)2]0 units are connected by two Co-S bonds resulting in dimeric [Co(ligand)2]22- or [Co(ligand)2]2 molecules. Complex 1 has a cation-anion-intermingled structure and exhibited Curie-Weiss magnetic behavior with a large Curie constant (C - 2.02 K·emu·mol-1) and weak antiferromagnetic interactions (θ = -8.3 K). Complex 2 also has a cation-anion-intermingled structure. However, the dimeric molecules are completely isolated by cations. Complexes 3 and 4 are single-component molecular crystals. The molecules of complex 3 form two-dimensional molecular stacking layers and exhibit a room-temperature conductivity of σrt = 1.2 × 10-2 S·cm-1 and an activation energy of Ea = 85 meV. The magnetic behavior is almost consistent with Curie-Weiss law, where the Curie constant and Weiss temperature are 8.7 × 10-2 K·emu·mol-1 and -0.85 K, respectively. Complex 4 has a rare chair form of the dimeric structure. The electrical conductivity was fairly large (σrt = 19 S·cm -1), and its temperature dependence was very small (σ0.55K/σrt = ca. 1:10), although the measurements were performed on the compressed pellet sample. Complex 4 showed an almost constant paramagnetic susceptibility (χ300 K = 3.5 × 10-4 emu·mol-1) from 300 to 50 K. The band structure calculation of complex 4 suggested the metallic nature of the system. Complex 4 is a novel single-component molecular conductor with a dimeric molecular structure and essentially metallic properties down to very low temperatures.

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U2 - 10.1021/ic701100r

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JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 3

ER -

Conducting dimerized cobalt complexes with tetrathiafulvalene dithiolate ligands

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