Magnetic semiconductor: Structural, magnetic, and conducting properties of the salts of the 6-oxoverdazyl radical cation with M(dmit)2 anions (M = Ni, Zn, Pd, and Pt, dmit = 1,3-dithiol-2-thione-4,5-dithiolate)

Article abstract of DOI:10.1021/ic020212s

Five kinds of (1:1), (1:3), and (2:1) salts of 3-[4-(diethylmethylammonio)phenyl]-1,5-diphenyl-6-oxoverdazyl radical cation [V]⁺ with M(dmit)₂ anions (M = Ni, Zn, Pd, and Pt, dmit = 1,3-dithiol-2-thione-4,5-dithiolate) ([V]⁺[Ni(dmit)₂]^- (1), [V]⁺[Ni(dmit)₂]₃^- (2), [V]⁺₂[Zn(dmit)₂]^2- (3), [V]⁺₂[Pd(dmit)₂]^2- (4), and [V]⁺₂[Pt(dmit)₂]^2- (5)) and an iodide salt of [V]⁺ ([V]⁺[I]^- (6)) have been prepared, and the magnetic susceptibilities (χ_M values) have been measured between 1.8 and 300 K. The χ_M of the (1:1) Ni salt (1) can be well reproduced by the sum of the contributions from (i) a Curie-Weiss system with a Curie constant (C) of 0.376 K emu/mol and a negative Weiss constant (θ) of -1.5 K and (ii) the one-dimensional Heisenberg antiferromagnetic alternating chain system with 2J_A-B/k_B = -274 K (alternation parameter α = J_A-C/J_A-B = 0.2). The χ_M of the (1:3) Ni salt (2) can be well explained by the two-term contributions from (i) the Curie-Weiss system with C = 0.376 K emu/mol and θ = -5.0 K and (ii) the dimer system with 2J/k_B = -258 K. The magnetic properties of 1 and 2 were discussed based on the results obtained by crystal structure analysis and ESR measurements of 1 and 2. The χ_M values of the (2:1) Zn, Pd, Pt salts 3, 4, and 5 and [V]⁺[I]^- salt 6 follow the Curie-Weiss law with C = 0.723, 0.713, 0.712, and 0.342 K emu/mol and θ = -2.8, -3.1, -2.6, and +0.02 K, respectively, indicating that only the spins of the verdazyl radical cation contribute to the magnetic property of these salts. The salts 1, 3, and 5 are insulators. On the other hand, the conductivity (σ) of the Ni salt 2 and Pd salt 4 at 20 °C was σ = 8.9 × 10^-2 and 1.3 × 10^-4 S cm^-1 with an activation energy E_A = 0.11 and 0.40 eV, respectively. The salts 2 and 4 are new molecular magnetic semiconductors.

Full text of DOI:10.1021/ic020212s

Inorg. Chem. 2002, 41, 5066−5074
Magnetic Semiconductor: Structural, Magnetic, and Conducting
Properties of the Salts of the 6-Oxoverdazyl Radical Cation with
M(dmit)2 Anions (M ) Ni, Zn, Pd, and Pt, dmit )
1,3-dithiol-2-thione-4,5-dithiolate)
K. Mukai,* T. Hatanaka, N. Senba, T. Nakayashiki,† Y. Misaki,† K. Tanaka,† K. Ueda,‡
T. Sugimoto,‡ and N. Azuma
Department of Chemistry, Faculty of Science, Ehime UniVersity, Matsuyama 790-8577, Japan,
Graduate School of Engineering, Kyoto UniVersity, Kyoto 606-8501, Japan, and Research
Institute for AdVanced Science and Technology, UniVersity of Osaka Prefecture, Sakai,
Osaka 599-8570, Japan
Received March 19, 2002
Five kinds of (1:1), (1:3), and (2:1) salts of 3-[4-(diethylmethylammonio)phenyl]-1,5-diphenyl-6-oxoverdazyl radical
cation [V]+ with M(dmit)2 anions (M ) Ni, Zn, Pd, and Pt, dmit ) 1,3-dithiol-2-thione-4,5-dithiolate) ([V]+[Ni(dmit)2]-
(1), [V]+[Ni(dmit)2]3- (2), [V]+ [Zn(dmit)2]2- (3), [V]+ [Pd(dmit)2]2- (4), and [V]+ [Pt(dmit)2]2- (5)) and an iodide salt
2
2
2
of [V]+ ([V]+[I]- (6)) have been prepared, and the magnetic susceptibilities (øM values) have been measured between
1.8 and 300 K. The øM of the (1:1) Ni salt (1) can be well reproduced by the sum of the contributions from (i) a
Curie−Weiss system with a Curie constant (C) of 0.376 K emu/mol and a negative Weiss constant (θ) of −1.5 K
and (ii) the one-dimensional Heisenberg antiferromagnetic alternating chain system with 2JA-B/kB ) −274 K (alternation
parameter R ) JA-C/JA-B ) 0.2). The øM of the (1:3) Ni salt (2) can be well explained by the two-term contributions
from (i) the Curie−Weiss system with C ) 0.376 K emu/mol and θ ) −5.0 K and (ii) the dimer system with 2J/kB
) −258 K. The magnetic properties of 1 and 2 were discussed based on the results obtained by crystal structure
analysis and ESR measurements of 1 and 2. The øM values of the (2:1) Zn, Pd, Pt salts 3, 4, and 5 and [V]+[I]-
salt 6 follow the Curie−Weiss law with C ) 0.723, 0.713, 0.712, and 0.342 K emu/mol and θ ) −2.8, −3.1, −2.6,
and +0.02 K, respectively, indicating that only the spins of the verdazyl radical cation contribute to the magnetic
property of these salts. The salts 1, 3, and 5 are insulators. On the other hand, the conductivity (σ) of the Ni salt
2 and Pd salt 4 at 20 °C was σ ) 8.9 × 10-2 and 1.3 × 10-4 S cm-1 with an activation energy EA ) 0.11 and
0.40 eV, respectively. The salts 2 and 4 are new molecular magnetic semiconductors.
Introduction
have long been considered incompatible to each other,
because Cooper pairs are destroyed both by external fields
and by the internal fields generated in ferromagnets. There-
fore, it is very important to establish superconductivity in a
composite system containing localized magnetic moments.
The first example of a molecular paramagnetic superconduc-
tor has been reported for (BEDT-TTF)4(H2O)[Fe(C2O4)3]-
(C6H5CN): [BEDT-TTF ) bis(ethylenedithio)tetrathiaful-
valene] (TC ) 7 K).1 Further, it has been found that
κ-BETS2FeBr4 (BETS ) bis(ethylenedithio)tetraselena-
fulvalene) undergoes the transition from antiferromagnetic
Development of the molecular ferromagnet and the
superconductor has attracted much attention in the field of
material science, and many studies have been performed with
great success in recent years. On the other hand, the examples
of magnetic superconductor where the superconducting state
and antiferromagnetic or ferromagnetic order coexist in a
system are very limited, because of the difficulty in molecular
design of the complexes. Superconductivity and magnetism
* Author to whom correspondence should be addressed at Ehime
Uiversity. E-mail: mukai@chem.sci.ehime-u.ac.jp. Phone: 81-89-927-9588.
Fax: 81-89-927-9590.
(1) Kurmoo, M.; Graham, A. W.; Day, P.; Coles, S. J.; Hursthouse, M.
B.; Caulfield, J. L.; Singleton, J.; Pratt, F. L.; Hayes, W.; Ducasse,
L.; Guionneau, P. J. Am. Chem. Soc. 1995, 117, 12209.
† Kyoto University.
‡ University of Osaka Prefecture.
5066 Inorganic Chemistry, Vol. 41, No. 20, 2002
10.1021/ic020212s CCC: $22.00 © 2002 American Chemical Society
Published on Web 08/29/2002

Syntheses and Properties of M(dmit)2 Salts
(AFM) metal phase to superconducting phase at 1.1 K.2,3
The coexistence of ferromagnetism and metallic conductivity
has been reported for a [BEDT-TTF]3[MnCr(C2O4)3] com-
pound.4
Scheme 1
Since the first molecular superconductor containing a
transition metal complex, (TTF)[M (dmit)2]2 (M ) Ni and
Pd, TTF ) tetrathiafulvalene, and dmit ) 1,3-dithiol-2-
thione-4,5-dithiolate), was found by Brossard et al.,5,6
extensive studies have been performed for the assembled
metal complexes of dmit and related compounds.7-9 It has
been reported that the complexes (Me4N)[M(dmit)2]2 (M )
Ni and Pd) exhibit insulating, metallic, and superconducting
phases at low temperature under high pressure, depending
on the countercation.7-10 The first example of molecular
magnetic semiconductors consisting of an open-shell radical
cation donor and a metal complex anion acceptor has been
reported for the (1:1) salt of [Ni(dmit)2]- with the p-EPYNN
(p-N-ethylpyridinium R-nitronyl nitroxide) radical cation.11
AFM spin-ladder-chain formation of Ni(dmit)2 was observed
for the salt. The salt showed the property as a semiconductor.
Recently, it has been reported that the salt of [Ni(dmit)2]-
with the Me3N+-TEMPO ()N,N,N-trimethyl(1-oxyl-2,2,6,6-
tetramethylpiperidine-4-yl)ammonium) radical cation has a
magnetic semiconductor property.12
these verdazyl radicals with high probability, because of a
very strong spin polarization effect in these verdazyl
radicals.21 Recently, as a first step to obtain a superconducting
magnet using verdazyl radical, we prepared the (1:1) and
(1:2) salts of N-ethylpyridinium-substituted verdazyl radical
cations with the TCNQ anion and studied the magnetic and
electric properties of these salts. The (1:2) salts were found
to be genuine organic magnetic semiconductors.22
In the present work, we prepared six kinds of M(dmit)2
(M ) Ni, Zn, Pd, and Pt) and iodide salts of the 3-[4-(dieth-
ylmethylammonio)phenyl]-1,5-diphenyl-6-oxoverdazyl radi-
cal cation [V]+ (see Scheme 1) and investigated the structural,
magnetic, and electric properties of these radical salts. The
present work provides the first example of molecular
magnetic semiconductors consisting of an open-shell verdazyl
radical cation donor and metal complex anion acceptor.
The magnetic properties of the 1,5-diphenyl-6-oxoverdazyl
radical crystals have been studied in recent years, and several
interesting magnetic properties such as ferromagnetism,13,14
weak ferromagnetism,15-17 antiferromagnetism,18 and spin-
Peierls transition19,20 have been found. Further, the intermo-
lecular ferromagnetic exchange interaction was observed for
Experimental Section
(2) Ojima, E.; Fujiwara, H.; Kato, K.; Kobayashi, H.; Tanaka, H.;
Kobayashi, A.; Tokumoto, M.; Cassoux, P. J. Am. Chem. Soc. 1999,
121, 5581.
(3) Fujiwara, H.; Fujiwara, E.; Nakazawa, Y.; Narymbetov, B. Z.; Kato,
K.; Kobayashi, H.; Kobayashi, A.; Tokumoto, M.; Cassoux, P. J. Am.
Chem. Soc. 2001, 123, 306.
Syntheses. 3-(4-Diethylaminophenyl)-1,5-diphenyl-6-oxover-
dazyl radical: The radical was prepared according to a procedure
similar to that used by Neugebauer et al.23 to prepare a 1,3,5-
triphenyl-6-oxoverdazyl (TOV) radical. Dark green needle crys-
tals: mp 176.0-177.0 °C; UV (dioxane) λmax (log ꢀ) 643 (2.95),
320 (4.62). Anal. Calcd for C24H24N5O: C, 72.31; H, 6.07; N, 17.57.
Found: C, 72.14; H, 6.11; N, 17.52.
(4) Coronado, E.; Galan-Mascaros, J. R.; Gomez-Garcia, C. J.; Laukhin,
V. Nature 2000, 408, 447.
(5) Brossard, L.; Ribault, M.; Valade, L.; Cassoux, P. Physica B+C
(Amsterdam) 1986, 143, 378.
[V]+[I]- (6) ([V]+ ) 3-[4-(diethylmethylammonio)phenyl]-1,5-
diphenyl-6-oxoverdazyl radical cation): The iodide salt (6) was
prepared by the N-methylation of 3-(4-diethylaminophenyl)-1,5-
diphenyl-6-oxoverdazyl radical in methyl iodide.11 Wine-red pris-
matic crystals: mp 207.0-208.0 °C; UV (CH3CN) λmax (log ꢀ)
535 (3.31), 424 (3.21), 314 (4.11), 250 (4.52). Anal. Calcd for
C25H27N5OI: C, 55.56; H, 5.04; N, 12.96. Found: C, 55.32; H,
5.03; N, 12.97.
(6) Brossard, L.; Ribault, M.; Valade, L.; Cassoux, P. J. Phys. France
1989, 50, 1521.
(7) Kobayashi, A.; Kim, H.; Sasaki, Y.; Murata, K.; Kato, R.; Kobayashi,
H. J. Chem. Soc., Faraday Trans. 1990, 86, 361.
(8) Cassoux, P.; Valade, L.; Kobayashi, H.; Kobayashi, A.; Clark, R. A.;
Underhill, A. E. Coord. Chem. ReV. 1991, 110, 115.
(9) Pullen, A. E.; Olk, R.-M. Coord. Chem. ReV. 1999, 188, 211 and
references cited therein.
(10) Kato, R.; You-Liang, L.; Hosokoshi, Y.; Aonuma, S.; Sawa, H. Mol.
Cryst. Liq. Cryst. 1997, 296, 217.
(11) Imai, H.; Otsuka, H.; Naito, T.; Awaga, K.; Inabe, T. J. Am. Chem.
Soc. 1999, 121, 8098.
(12) Aonuma, S.; Casellas, H.; Faulmann, C.; Garreau de Bonneval, B.;
Malfant, I.; Cassoux, P.; Lacroix, P. G.; Hosokoshi, Y.; Inoue, K. J.
Mater. Chem. 2001, 11, 337.
(13) Mukai, K.; Konishi, K.; Nedachi, K.; Takeda, K. J. Phys. Chem. 1996,
100, 9658.
Preparations of the [M(dmit)2] (M ) Ni, Zn, Pd, and Pt) salts
1-5 of the verdazyl radical cation were as follows.
[V]+[Ni(dmit)2]- Salt (1): To a solution of [V]+[I]- (20.8 mg,
0.0385 mmol) in acetonitrile (10 mL) was added slowly [n-Bu4N]+-
(14) Takeda, K.; Hamano, T.; Kawae, T.; Hidaka, M.; Takahashi, M.;
Kawasaki, S.; Mukai, K. J. Phys. Soc. Jpn. 1995, 64, 2343.
(15) Kremer, R. K.; Kanellakopulos, B.; Bele, P.; Brunner, H.; Neugebauer,
F. A. Chem. Phys. Lett. 1994, 230, 255.
(16) Tomiyoshi, S.; Yano, T.; Azuma, N.; Shoga, M.; Yamada, K.;
Yamauchi, J. Phys. ReV. B 1994, 49, 16031.
(17) Mito, M.; Nakano, H.; Kawae, T.; Hitaka, M.; Takagi, S.; Deguchi,
H.; Suzuki, K.; Mukai, K.; Takeda, K. J. Phys. Soc. Jpn. 1997, 66,
2147.
(19) Mukai, K.; Wada, N.; Jamali, J. B.; Achiwa, N.; Narumi, Y.; Kindo,
K.; Kobayashi, T.; Amaya, K. Chem. Phys. Lett. 1996, 257, 538.
(20) Mukai, K.; Shimobe, Y.; Jamali, J. B.; Achiwa, N. J. Phys. Chem. B
1999, 103, 10876.
(21) Mukai, K.; Nuwa, M.; Suzuki, K.; Nagaoka, S.; Achiwa, N.; Jamali,
J. B. J. Phys. Chem. B 1998, 102, 782.
(22) Mukai, K.; Jinno, S.; Shimobe, Y.; Azuma, N.; Hosokoshi, Y.; Inoue,
K.; Taniguchi, M.; Misaki, Y.; Tanaka, K. Polyhedron 2001, 20, 1537.
(23) Nakatsuji, S.; Kitamura, A.; Takai, A.; Nishikawa, K.; Morimoto, Y.;
Yasuoka, N.; Kawamura, H.; Anzai, H. Z. Naturforsch. 1998, 53b,
495.
(18) Mito, M.; Takeda, K.; Mukai, K.; Azuma, N.; Gleiter, M. R.; Krieger,
C.; Neugebauer, F. A. J. Phys. Chem. 1997, 101, 9517.
Inorganic Chemistry, Vol. 41, No. 20, 2002 5067

Mukai et al.
Table 1. Conductivities (σRT), Activation Energies (EA), Weiss Constant (θ), Curie Constant (C), and Pascal’s Diamagnetism (øDia) of Salts 1-6
salts
σ, S cm-1
EA, eV
θ, K
C, K emu mol-1
ø
dia, emu mol-1
[V]+[Ni(dmit)2]- (1)
[V]+[Ni(dmit)2]3- (2)
[V]+2[Zn(dmit)2]2- (3)
[V]+2[Pd(dmit)2]2- (4)
[V]+2[Pt(dmit)2]2- (5)
[V]+[I]- (6)
3.6 × 10-7 a, b
8.9 × 10-2 c
3.0 × 10-4 a,b
1.3 × 10-4 c
1.8 × 10-7 b
Curie-Weiss + 1D-alt. Chain
-0.440 × 10-3
-0.809 × 10-3
-0.696 × 10-3
-0.711 × 10-3
-0.725 × 10-3
-0.306 × 10-3
0.11
0.40
Curie-Weiss + S-T
-2.8
-3.1
-2.6
+0.02
0.723
0.713
0.712
0.342
a Single crystal. b Two-probe dc method. c Four-probe dc method.
Table 2. Crystal Data, Experimental Conditions, and Refinement
Details of [V]+[Ni(dmit)2]- Salt (1) and [V]+[I]- Salt (6)
[Ni(dmit)2]- (26.7 mg, 0.0385 mmol) in acetonitrile (20 mL) and
the reaction mixture was kept for one night at room temperature
under nitrogen atmosphere. The dark green crystals (15.0 mg, 45%)
that precipitated were filtered and recrystallized from acetonitrile.
Black prismatic crystals: mp 204.0-205.0 °C; UV (CH3CN) λmax
(log ꢀ) 618 (3.53), 573 (3.59), 541 (3.58), 440 (4.25), 393 (4.35),
314 (4.57), 238 (4.68). Anal. Calcd for C31H27N5OS10Ni‚CH3CN:
C, 43.74; H, 3.34; N, 9.28. Found: C, 43.45; H, 3.20; N, 8.87.
The following radical salts 4 and 5 were prepared similarly.
[V]+2[Pd(dmit)2]2- salt (4): Reddish brown needle crystals: mp
176.0-177.0 °C; UV (CH3CN) λmax (log ꢀ) 549 (4.20), 388 (4.13),
310 (4.78). Anal. Calcd for C56H54N10O2S10Pd: C, 50.71; H, 4.10;
N, 10.56. Found: C, 50.31; H, 4.18; N, 10.88.
[V]+[Ni(dmit)2]-‚
CH3CN
[V]+[I]-
C25H27N5OI
empirical formula
fw
C33H30N6OS10Ni
905.94
540.43
cryst color
cryst syst
space group
a/Å
b/Å
c/Å
black, prismatic
monoclinic
P21/c (no. 14)
9.743(7)
20.385(9)
20.113(8)
94.85(5)
3980(3)
4
1.512
wine-red, prismatic
orthorhombic
P212121 (no. 19)
13.911(1) Å
18.100(2) Å
9.7552(9) Å
â/deg
V/Å3
2456.3(4)
4
1.461
104.42 (Cu KR)
0.300 × 0.120 ×
0.100
Z
Dx/g cm-3
µ/cm-1
cryst size/mm3
[V]+2[Pt(dmit)2]2- salt (5): Violet thin needle crystals: mp
172.5-173.5 °C; UV (CH3CN) λmax (log ꢀ) 570 (3.95), 396 (4.25),
315 (4.55), 237 (5.96). Anal. Calcd for C56H54N10O2S10Pt: C, 47.53;
H, 3.85; N, 9.90. Found: C, 47.30; H, 3.96; N, 10.12.
10.49 (Mo KR)
0.380 × 0.380 ×
0.150
Range of 2θ/°
4.7-50.0
4.7-123.1
-
no. of unique reflns (Rint
no. of reflns obsd
reflns/parameter ratio
R, Rw
)
7412 (0.080)
2186
[V]+[Ni(dmit)2]3 salt (2): For the preparation of [V]+[Ni-
7385 (I > -10.0σ(I)) 2186 (I > -10.0σ(I))
16.02
0.136, 0.252
1.36
0.003
-
(dmit)2]3 (2), the air oxidation of a solution containing [V]+[Ni-
7.54
0.070, 0.119
0.90
0.00
-0.77 to 0.65
(dmit)2]- (1) (39 mg), acetic acid (15 mL), and acetic anhydride
(15 mL) in acetone (150 mL) was carried out at room temperature.8,9
The black powder crystals obtained show high melting point and
are insoluble in the usual organic solvents. The result of the
elemental analysis indicates the formation of (1:3) salt, [V]+[Ni-
(dmit)2]3-.9 Mp > 300 °C. Anal. Calcd for C43H27N5OS30Ni3: C,
29.21; H, 1.54; N, 3.96. Found: C, 29.67; H, 1.83; N, 3.74.
[V]+2[Zn(dmit)2]2- salt (3): To stirred solution of [V]+[I]-
(104.7 mg, 0.194 mmol) in methanol (30 mL) was added slowly
[n-Bu4N]+2[Zn(dmit)2]2- (91.3 mg, 0.097 mmol) in methanol (20
mL) and stirring was continued for 1 h at room temperature under
nitrogen atmosphere. The dark-red solids precipitated were filtered
and washed with diethyl ether. Recrystallization of the residue from
acetonitrile-diethyl ether afforded the product as dark-red needle
crystals: mp 168.5-169.5 °C; UV (CH3CN) λmax (log ꢀ) 502 (4.33),
313 (4.68), 255 (4.72). Anal. Calcd for C56H54N10O2S10Zn: C,
52.33; H, 4.24; N, 10.90. Found: C, 52.24; H, 4.41; N, 10.69.
Susceptibility and Conductivity Measurements. The magnetic
susceptibility was measured in the temperature range of 1.8-300
K by a SQUID magnetometer. The susceptibility at low temperature
was measured at 0.1 T to avoid saturation effects. The susceptibility
of all samples has been corrected for the diamagnetic contribution
(ødia), calculated by Pascal’s method (see Table 1).
S (goodness of fit)
max shifts/error
residual electron
density/e- Å-3
-1.14 to 1.08
Results
UV and Visible Spectra of Salts 1-6. Absorption spectra
of [V]+[Ni(dmit)2]- (1), [V]+[I]- (6), and [n-Bu4N]+[Ni-
(dmit)2]- salts are measured in acetonitrile solvent. As shown
in Figure 1a, the absorption spectrum of 1 can be well
explained by the addition of [V]+[I]- and [n-Bu4N]+[Ni-
(dmit)2]-, suggesting the (1:1) complex formation between
the [V]+ cation and the [Ni(dmit)2]- anion. Further, the
absorption spectra of (2:1) salts [V]+ [Zn(dmit)2]2- (3),
2
[V]+ [Pd(dmit)2]2- (4), and [V]+ [Pt(dmit)2]2- (5) can be well
2
2
explained by an addition of iodide salt (6) (2 mol) and
[n-Bu4N]+ [M(dmit)2]2- (M ) Zn, Pd, and Pt) salts (1 mol),
2
-
respectively, as shown in Figure 1b. The [V]+[Ni(dmit)2]3
(2) crystals are insoluble in the usual organic solvents, such
as acetonitrile, methanol, acetone, and diethyl ether, and we
could not measure the optical spectrum of salt 2 in solution.
The conductivity measurements were performed for the single
crystals of salts 1 and 3 and the pressed pellet samples of salts 2,
4, and 5, using the standard two- or four-probe dc technique.
Electrical contacts were achieved with gold paste.
Structure Determination and Crystal Data. The X-ray mea-
surements of the Ni salt (1) and iodide salt (6) were carried out on
a Rigaku AFC5R diffractometer with graphite-monochromated Mo
KR (λ ) 0.71069 Å) and Cu KR (λ ) 1.54178 Å) radiations,
respectively. The structure was solved by the direct method. The
crystallographic data and the parameters of structure refinement
are given in Table 2.
Crystal Structures of Salts 1 and 6. The crystal structure
could be determined for the (1:1) [V]+[Ni(dmit)2] - salt (1)
and the [V]+[I]- salt (6). Our attempts, however, to determine
the crystal structures of salts 2, 3, 4, and 5 have as yet been
unsuccessful because of the inadequate quality of their
crystals. Crystal data obtained for salts 1 and 6 are listed in
Table 2. In Figures 2 and 3, we show the solid-state structure
of [V]+[Ni(dmit)2]-‚CH3CN (1) and [V]+[I]- (6), respec-
tively. Salt 1 includes the CH3CN molecule in the crystal
5068 Inorganic Chemistry, Vol. 41, No. 20, 2002

Syntheses and Properties of M(dmit)2 Salts
Figure 3. Molecular structure of the iodide salt (6) with the atom
numbering scheme.
Table 3. Selected Structural Data of 1,3,5-Triphenyl-6-oxoverdazyl
(TOV) and the [V]+[Ni(dmit)2]- Salt (1) and [V]+[I]- Salt (6)
[V]+[Ni(dmit)2]-‚
TOV
CH3CN
[V]+[I]-
O-C2/Å
1.208(2)
1.381(1)
1.368(1)
1.330(1)
1.215(10)
1.38(1)
1.381(9)
1.32(1)
1.503(10)
114.4(7)
128.7(7)
123.9(7)
114.5(7)
42.25
1.222(9)
1.383(9)
1.371(9)
1.331(9)
1.496(10)
115.0(6)
126.9(7)
124.6(6)
113.4(6)
50.15
N1-C2/Åa
N1-N2/Åb
N2-C1/Åc
N5-C12/Å
N1-N2-C1/(deg)d
N2-C1-N3/(deg)
N3-N4-C2/(deg)e
N4-C2-N1/(deg)
dihedral angle/(deg)
N1-C3-(phenyl)
dihedral angle/(deg)
N4-C20-(phenyl)
dihedral angle/(deg)
C1-C9-(phenyl)
115.3
127.0
124.0
114.4
34.5(1)
Figure 1. UV and visible spectra of (a) the (1:1) Ni salt (1) and (b) the
(2:1) Zn salt (3) in acetonitrile.
34.5(1)
12.3
38.58
40.36
54.84
12.15
a Mean value of N1-C2 and N4-C2. b Mean value of N1-N2 and
N3-N4. c Mean value of N2-C1 and N3-C1. d Mean value of N1-N2-
C1 and C1-N3-N4. e Mean value of N3-N4-C2 and C2-N1-N2.
triphenyl-6-oxo-verdazyl (TOV),24 indicating that the ver-
dazyl moieties in salts 1 and 6 are not oxidized. However,
the dihedral angle (40.36°) between least-squares planes of
the verdazyl ring and the C1-phenyl ring in the Ni salt (1) is
much larger than those of the iodide salt (6) (12.15°) and
TOV (12.3°). The dihedral angle between least-squares
planes of two dmit rings in salt 1 is 7.171°, indicating the
planarity of the Ni(dmit)2 moiety. The structure of the Ni-
(dmit)2 anion moiety in salt 1 is also similar to that in the
[n-Bu4N]+[Ni(dmit)2]- salt (data are not shown).25
Molecular packing of the Ni salt (1) is shown in Figure 4.
The unit cell of salt 1 contains four [Ni(dmit)2]- units and
four verdazyl cations [V]+. The structure of salt 1 consists
of chains of [Ni(dmit)2] (A)-[Ni(dmit)2] (B) dimers. The
dimers are connected to each other through short S-S
Figure 2. Molecular structure of the (1:1) Ni salt (1) with the atom
numbering scheme.
with the ratio of (1:1), as expected from the result of the
elemental analysis.
If the verdazyl moiety of the verdazyl radical is oxidized
forming verdazylium ion, the N-N distance becomes shorter
than that of the neutral one, as can be found in the case of
[TPV]+[TCNQF4]- salt (TPV ) 1,3,5-triphenylverdazyl).23
Table 3 shows that the bond lengths and bond angles of
verdazyl moieties (N1-N2-C1-N3-N4-C2) in salts 1 and
6 are similar to those of the corresponding neutral 1,3,5-
(24) Neugebauer, F. A.; Fischer, H.; Krieger, C. J. J. Chem. Soc., Perkin
Trans. 2 1993, 535.
(25) Lindqvist, O.; Anderson, L.; Sieler, J.; Steimecke, G.; Hoyer, E. Acta
Chem. Scand. Ser. A 1982, 36, 855.
Inorganic Chemistry, Vol. 41, No. 20, 2002 5069

Mukai et al.
pressure, salts 2 and 4 show semiconductive behavior with
activation energy values (EA values) of 0.11 and 0.40 eV at
the temperature range of 127-290 and 262-295 K, respec-
tively. The conductivity of salt 4 is rather high for an integral
oxidation state salt. However, the reason is not clear at
present, because the crystal structure of salt 4 is not known.
Magnetic Susceptibilities of Salts 1-6. Figure 6 shows
a plot of øMT versus T for the [V]+[Ni(dmit)2]- salt (1). The
value (0.663 K emu/mol) of øMT at 300 K observed for salt
1
1 is larger than that (0.376 K emu/mol) for the S ) /2 free
spin system, suggesting that both spins of the verdazyl cation
1
1
(S ) /2) and [Ni(dmit)2]- anion (S ) /2) contribute to the
magnetism of salt 1. The øMT value of the salt decreases by
lowering the temperature, indicating AFM interaction in the
salt. The susceptibility increases monotonically by decreasing
temperature from 300 K, and no peak was observed in the
susceptibility.
The magnetic susceptibility of the (1:3) Ni salt (2) showed
behavior similar to that of the (1:1) Ni salt (1), as shown in
Figure 7. The value (0.651 K emu/mol) of øMT at 300 K
observed for salt 2 also suggests that both spins of verdazyl
cation (S ) 1/2) and [Ni(dmit)2]3- anion (S ) 1/2) contribute
to the magnetism of salt 2. The susceptibility increases
monotonically by decreasing temperature from 300 K, and
any peak was not observed in the susceptibility.
Figure 4. A molecular arrangement of the Ni(dmit)2 anions in salt 1
showing the formation of 1D alternating-chain along the a-axis and their
relation to the verdazyl radical cations.
contacts (see Table 4), forming a 1D-alternating chain along
the a-axis. As listed in Table 2, the R and Rw values of Ni
salt 1 are very high, because the single crystal of salt 1 is
deteriorated by X-ray irradiation, and thus the reflection
intensity decreased by 55.5% over the course of data
collection. Therefore, the interatomic distances (nonbonded
contacts) obtained include large experimental error (see Table
4). However, the fact that the Ni(dmit)2 anions form the 1D-
alternating chain along the a-axis is correct.
In iodide salt 6, the interatomic distances between the
nitrogen atoms in the central hydrazidinyl moiety (N1-N2-
C1-N3-N4) having the large unpaired spin densities are
larger than 4.6 Å, indicating weak intermolecular exchange
interaction.26 In fact, the susceptibility of salt 6 follows the
Curie-Weiss law with a very small Weiss constant of θ )
+ 0.02 K, as described later. The iodide ion [I]- in salt 6 is
located at the near position of the N1, N4, and C2 atoms of
the verdazyl ring; the I-N1, I-N4, and I-C2 distances are
3.725(7), 3.889(7), and 3.653(7) Å, respectively. On the other
hand, the distances (I-N5 ) 4.621(7), 5.048(6), and
5.822(6) Å) between the I- ions and the neighboring nitrogen
atoms (N5) having positive charge are larger than the above
distances.
Figure 8 shows a plot of øMT versus T for three kinds of
(2:1) salts [V]+ [Zn(dmit)2]2- (3), [V]+ [Pd(dmit)2]2- (4),
2
2
[V]+ [Pt(dmit)2]2- (5) and (1:1) salt [V]+[I]- (6). The
2
susceptibilities of salts 3-6 follow the Curie-Weiss law with
Curie constants of 0.730, 0.767, 0.735, and 0.342 K emu/
mol and Weiss constants of -2.8 ( 0.2, -3.1 ( 0.2, -2.6
( 0.2, and +0.02 K, respectively. The Curie constants of
salts 3, 4, and 5 are similar to that (0.752 K emu/mol) for
the two S ) 1/2 spin systems, suggesting that only the spins
of the verdazyl cation contribute to the magnetism of salts
3, 4, and 5. The [M(dmit)2]2- (M ) Zn, Pd, and Pt) anion
moieties have no unpaired electron. The small values of
negative Weiss constants in salts 3-5 indicate weak anti-
ferromagnetic interaction between the verdazyl radical cation
moieties. Salt 6 shows the small value of the Weiss constant
(θ ) +0.02 K). This agrees with the absence of short direct
distances between verdazyl moieties having high spin
density.26
ESR Measurements of the 1-6. The ESR measurements
were carried out in powder samples of salts 1-6 and
[n-Bu4N]+[Ni(dmit)]- in the temperature range of 77-300
K. The g-value and the peak-to-peak line width (∆HPP) of
the samples at 300 and 77 K are listed in Table 5. The ESR
spectra of salts 3, 4, and 5 show an exchange-narrowed,
Lorentz-type absorption located at g ) 2.0041, 2.0041, and
2.0041 with a line width (∆HPP) of 0.257, 0.611, and 1.01
mT, respectively. The g-values are nearly temperature
independent, while the line widths show a small increase
with decreasing temperature. These g-values are similar to
those of the TOV radical (g ) 2.0036) and [V]+[I]- (g )
2.0036) in ethanol. The g-value (g ) 2.0050) of the powder
sample of iodide salt 6 is a little bit larger than those of
salts 3-5. The I- ion having negative charge is located at
Conductivity of Salts 1-5. The room-temperature con-
ductivities (σRT values) for salts 1, 2, 3, 4, and 5 are 3.6 ×
10-7, 8.9 × 10-2, 3.0 × 10-4, 1.3 × 10-4, and 1.8 × 10-7
S cm-1, respectively, as listed in Table 1. Salts 1 and 5 are
insulators as expected for the (1:1) and (2:1) salts. The
(1:3) Ni salt (2) and (2:1) Pd salt (4) have higher conductivi-
ties than salts 1 and 5. Temperature dependencies of the resis-
tivity of salts 2 and 4 are shown in Figure 5. Under ambient
(26) Mukai, K.; Suzuki, K.; Ohara, K.; Jamali, J. B.; Achiwa, N. J. Phys.
Soc. Jpn. 1999, 68, 3078.
5070 Inorganic Chemistry, Vol. 41, No. 20, 2002

Syntheses and Properties of M(dmit)2 Salts
Table 4. Pertinent Intermolecular Contacts (r/Å) in [V]+[Ni(dmit)2]-‚CH3CN (1)
Ni (A)-Ni (B)a
Ni-Ni ) 4.147(3)
Ni(A)-Ni(C)a
Ni-Ni ) 6.619(5))
V (A) - V (B)b
N(i)-N(j) (i, j)1,2,3,4)
Ni (A)-V (A)a
Ni-S10
3.578(3)
3.733(9)
3.945(4)
3.814(4)
3.930(4)
3.545(9)
3.685(9)
3.836(9)
3.843(10)
3.81(1)
S1-S1
3.782(5)
3.801(4)
3.747(4)
3.816(4)
S4-N1
3.589(8)
3.992(8)
3.756(8)
3.890(7)
3.82(1)
N1-N3
7.60(1)
Ni-S31
S4-S8
S1-S6
S2-S6
S2-S7
S4-N2
S4-N4
S4-O
S5-S7
S6-S10
S5-C29
S5-C31
S9-C26
S9-C28
C28-C30
S5-C8
S5-C10
3.95(1)
a r < 4.00 Å. b r < 8.00 Å.
Figure 5. Temperature dependence of the resistivity (F) of salts 2 and 4
at ambient pressure.
Figure 7. Temperature dependence of the product øMT (O) for the (1:3)
Ni salt (2). The solid curve is the theoretical susceptibility calculated with
eq 3.
Figure 6. Temperature dependence of the product øMT (O) for the (1:1)
Ni salt (1). The solid curve is the theoretical susceptibility calculated with
eq 1.
Figure 8. Temperature dependence of the product øMT for salts 3, 4, 5,
and 6.
the near position of the verdazyl ring, as described above.
This negative charge may affect the increase of g-value of
salt 6. The observed g-values indicate that a paramagnetic
contribution from the [M(dmit)2]2- (M ) Zn, Pd, and Pt)
anions is almost negligible in these salts. The result corre-
sponds to that obtained by the susceptibility measurements
of salts 3-5.
The ESR absorption spectrum of the [n-Bu4N]+[Ni-
(dmit)2]- salt exhibits one symmetric broad line with a
Inorganic Chemistry, Vol. 41, No. 20, 2002 5071

Mukai et al.
Table 5. The g-Value and Peak-to-Peak Line Width (∆HPP) of Salts
1-6 and Related Compounds
300 K
∆HPP (mT)
77 K
salts
g-value
g-value ∆HPP (mT)
[V]+[Ni(dmit)2]- (1)
[V]+[Ni(dmit)2]3- (2)
2.0207a 29.3
2.0106a 14.4
2.0083
2.0179d
2.0042
2.0042
2.0040
2.0050
12.0
10.4d
0.338
0.694
1.04
[V]+2[Zn(dmit)2]2- (3) 2.0041b 0.257
[V]+2[Pd(dmit)2]2- (4) 2.0041b 0.611
[V]+2[Pt(dmit)2]2- (5) 2.0041b 1.01
[V]+[I]- (6) (powder)
2.0050b 3.44
1.20
[V]+[I]- (6) (in EtOH) 2.0036c aN ) 0.57 mT
TOV (in EtOH)
2.0036c aN ) 0.56 mT
[n-Bu4N]+[Ni(dmit)2]- 2.0472a 7.97
2.0474
7.94
a Experimental error: (0.0005. b Experimental error: (0.0002. c Ex-
perimental error: (0.0001. d The value at 203 K. At the temperature below
203 K, the signal due to Curie impurity overlaps to that of salt 2, and the
g-value and line width could not be determined.
Figure 10. Temperature dependence of the g value (g(T)) (O) and the
line width (∆HPP(T)) (4) of the polycrystalline sample of salt 2.
mT) with a narrow line width that will be attributable to the
Curie impurity due to the verdazyl radical cation. The
integrated signal intensity of the Curie impurity was about
1.0% of that of salt 2. The g-value increased by decreasing
the temperature, differing from the case of salt 1, as shown
in Figure 10. At the temperature below 200 K, the signal
due to Curie impurity overlaps that of salt 2, and we could
not determine the g-value and line width of salt 2.
Discussion
The electronic spectra of the [V]+[Ni(dmit)2]- salt (1) in
CH3CN solution can be explained by the addition of those
of the [V]+[I]- salt (6) and [n-Bu4N]+[Ni(dmit)2]-, as
described above. The result indicates that the electronic
structures of the verdazyl radical cation moieties in iodide
salt 6 and Ni salt 1 are similar. In fact, as the results of the
X-ray structure analyses of these salts indicate, the bond
length and bond angle of the verdazyl cation part, that is,
the central hydrazidinyl ring and 4-(diethylmethylammonio)-
phenyl ring in salt 1, are similar to the corresponding values
in salt 6 in the crystal state.
Figure 9. Temperature dependence of the g value (g(T)) (O) and the line
width (∆HPP(T)) (4) of the polycrystalline sample of salt 1. The solid line
is the theoretical g(T) value calculated by using eq 2.
g-value of 2.0472 and a line width of 7.97 mT at 300 K.
Both the g-value and the line width are temperature
independent (see Table 5).
The ESR spectrum of salt 1 also shows a symmetric broad
line with a g-value of 2.0207 and a line width of 29.3 mT at
300 K. However, in addition to the broad ESR signal of salt
1, a symmetric single line (g ) 2.0044 and ∆HPP ) 0.889
mT) with narrow line width that will be attributable to the
Curie impurity due to the verdazyl radical cation was
observed at 300 K. The integrated signal intensity of the
Curie impurity was about 0.34% of that of salt 1. The g-value
and the line width of Ni salt 1 show notable temperature
dependence, as shown in Figure 9. By decreasing the
temperature, both the g-value and line width decrease from
g ) 2.0207 and ∆HPP ) 29.3 mT at 300 K to g ) 2.0083
and ∆HPP ) 12.0 mT at 77 K. Since relatively large g-value
and line width are characteristics of the [Ni(dmit)2]- anion
radical, the observed temperature dependence indicates that
a paramagnetic contribution from the [Ni(dmit)2]- anion
decreases by decreasing the temperature.11 The observation
is quite consistent with the interpretation of the temperature
dependence of the susceptibility, as described later.
As described in a previous section, the value of øMT at
300 K is 0.663 K emu/mol for the Ni salt (1), which
decreases by lowering the temperature, as shown in Figure
6. The susceptibility of salt 1 follows the Curie-Weiss law
with a Curie constant of 0.376 K emu/mol and a Weiss
constant of -1.5 K below 30 K. The observed Curie constant
just corresponds to that (0.376 K emu/mol) expected for a S
1
) /2 radical molecule. This can be readily understood by
considering that the spin of either the verdazyl radical cation
or [Ni(dmit)2]- anion apparently disappears as a result of
strong AFM interaction with the neighboring spin. It is
probable that the [Ni(dmit)2]- anions prefer to form a dimer
in the crystal lattice.9,11,12 Therefore, the susceptibility of salt
1 below 30 K will be due to the spins of the verdazyl cation
[V]+.
The susceptibility of salt 1 can be well reproduced by the
sum of the two contributions
The ESR signal of the (1:3) Ni salt 2 at 300 K consists of
(i) a slightly asymmetric broad line with a relatively large
g-value (g ) 2.0106) and line width (∆HPP ) 14.4 mT) and
(ii) a symmetric sharp line (g ) 2.0043 and ∆HPP ) 1.03
øM(T) ) øCurie-Weiss(T) + ø1D-Alt(T)
(1)
where the first and second terms represent the contributions
from (i) the Curie-Weiss system and (ii) the one-dimen-
5072 Inorganic Chemistry, Vol. 41, No. 20, 2002

Syntheses and Properties of M(dmit)2 Salts
-
sional (1D) Heisenberg AFM alternating-chain system,
respectively. The solid curve in Figure 6 is a theoretical curve
with (i) CCurie ) 0.376 K emu/mol and θ ) -1.5 K and (ii)
2JA-B/kB ) -274 K (alternation parameter R ) JA-C/JA-B
) 0.2).27
[n-Bu4N]+[Ni(dmit)2]- (gNi ) 2.0472), respectively. These
values are temperature independent, as listed in Table 5. The
temperature dependence of the effective g(T)-value calculated
by using eq 2 reproduces well the observed g(T) curve (77
K < T < 300 K), as shown in Figure 9. The result also
suggests that the spins of cation and anion moieties in salt 1
independently contribute to the magnetic susceptibility.
As described in a previous section, the value of øMT for
salt 2 is 0.651 K emu/mol at 300 K, and decreases by
lowering the temperature, as shown in Figure 7. The
magnetic behavior is similar to that of salt 1. The susceptibil-
ity of salt 2 can be explained by the two-term contributions
(eq 3)
As shown in Figure 4, the [Ni(dmit)2]- anions form one-
dimensional (1D) columns along the a-axis. The column is
built up by two kinds of spin pairs, [Ni(dmit)2]- (A)-[Ni-
(dmit)2]- (B) and [Ni(dmit)2]- (A)- Ni(dmit)2]- (C), sug-
gesting 1D-alternating magnetic properties. The Ni-Ni
distances of alternating Ni(dmit)2 anions are 4.147(3) Å for
Ni (A)-Ni (B) and 6.619(5) Å for Ni (A)-Ni (C). The short
Ni-S, S-S, S-C, and C-C distances were observed for
the [Ni(dmit)2]- (A)-[Ni(dmit)2]- (B) pair, as listed in Table
4. On the other hand, the short S-S distances were observed
for the [Ni(dmit)2]- (A)-[Ni(dmit)2]- (C) pair. There are
some comparatively short distances between the verdazyl
radical cation and the Ni(dmit)2 anion, as listed in Table 4.
However, the dihedral angle between least-squares planes
of the verdazyl ring and the Ni(dmit)2 ring is very large
(70-72°), suggesting weak exchange interaction between the
verdazyl radical spin and the Ni(dmit)2 anion spin. Further,
the N(i)-N(j) contacts (i, j ) 1, 2, 3, and 4) between the
nitrogen atoms in the central hydrazidinyl moiety (N1-N2-
C1-N3-N4), having large unpaired spin densities, are larger
than 7.6 Å, as listed in Table 4.26 The result indicates the
øM(T) ) øCurie-Weiss(T) + øS-T(T)
(3)
where the first and second terms represent the contributions
from the Curie-Weiss system and the singlet-triplet (S-
T) equilibrium system (dimer system), respectively. øS-T(T)
is given by eq 4.
ø
S-T(T) ) (Nog2µB /kBT) [1/(3 + e-2J/k T)]
(4)
2
B
In the low-temperature region (T < 40 K), the susceptibil-
ity for salt 2 can be well reproduced by the Curie-Weiss
law with the Curie constant of 0.376 K emu/mol and the
Weiss constant of -5.0 K. Above ca. 40 K, however, øMT
increases with increasing temperature. This increase indicates
that thermal magnetic excitation occurs in addition to the
Curie-Weiss spins. The experimental data are interpreted
by the S-T equilibrium model with the value of 2J/kB )
-1.61Tmax) -258 K (Tmax) 160 K). As shown in Figure 7,
the experimental curve can be well reproduced by eq 3.
The powder sample of the (1:3) Ni salt 2 shows a slightly
asymmetric Lorentz-type absorption line at 300 K, which
suggests the strong exchange interaction between the ver-
dazyl cation spin and the [Ni(dmit)]3- anion spin. The large
g-value (g ) 2.0106) and broad line width (∆HPP ) 14.4
mT) of salt 2 observed at 300 K show that both spins of
+-V+
weak intermolecular exchange interaction (JV
) between
verdazyl cation molecules. In fact, the susceptibility of salt
1 can be well described by the sum of the 1D AFM
alternating-chain model with 2JA-B/kB) -274 K and 2JA-C
/
kB) -54.8 K due to Ni(dmit)2 anions and the Curie-Weiss
law (θ ) -1.5 K) due to verdazyl cations, as shown in Figure
6. The small value of the alternation parameter, R ) JA-C
/
JA-B ) 0.2, indicates that the magnetic property is near that
of the dimer system (R ) 0).
The separate contributions of the verdazyl cation [V]+ and
[Ni(dmit)2]- anion subsystems to the total magnetic suscep-
tibility of the Ni salt (1) were ascertained by the measure-
ments of the temperature dependence of the g-value and ESR
line width. The Lorentzian shape of the single EPR absorp-
tion line, which suggests the strong magnetic exchange
interaction between the verdazyl cation and [Ni(dmit)2]-
anion spins, was observed for the Ni salt (1). In such a case,
the temperature dependence of the g-value of the Ni salt (1)
is given by eq 228,29
-
[V]+ and [Ni(dmit)2]3 contribute to the magnetism of salt
2. However, the g-value increases by lowering the temper-
ature, as shown in Figure 10. The temperature dependence
of the g(T)-values of salts 1 and 2 is quite different, although
that of the susceptibilities is similar. Consequently, the
temperature dependence of the g-value cannot be explained
by eq 2, if we use the relation øV (T) ) øCurie-Weiss(T) and
øNi (T) ) øS-T(T). The reason is not clear at present.
As described in a previous section, the three salts 1, 3,
and 5 are insulators, as expected for the (1:1) and (2:1)
complexes. On the other hand, the (1:3) Ni salt 2 and (2:1)
Pd salt 4 are semiconductors (σRT ) 8.9 × 10-2 S cm-1 and
EA ) 0.11 eV for 2 and σRT ) 1.3 × 10-4 S cm-1 and EA
) 0.40 eV for 4). However, to our regret, we cannot discuss
the mechanism of the conduction, because the crystal
structures of salts 2 and 4 are not clear at present.
+
-
g(T) ) [gV+øV+(T) + gNi-øNi-(T)]/[øV+(T) + øNi-(T)] (2)
+
-
where the gV and gNi are the g-values of the verdazyl cation
-
+
-
and [Ni(dmit)2] anion, respectively. øV (T) and øNi (T) will
correspond to øCurie-Weiss(T) and ø1D-Alt(T) in eq 1, respec-
tively. As the g-values of the cation and anion moieties, we
used the g-values of [V]+[I]- (gV ) 2.0036 in ethanol) and
+
(27) Bonner, J. C.; Blote, H. W. J.; Bray, J. W.; Jacobs, I. S. J. Appl. Phys.
1979, 50, 1810.
Summary
(28) Tomkiewicz, Y.; Taranko, A. R.; Torrance, J. B. Phys. ReV. Lett. 1976,
36, 751.
In the present work, five magnetic charge-transfer salts
1-5 consisting of 3-[4-(diethylmethylammonio)phenyl]-1,5-
(29) Simonyan, M.; Yonehara, Y.; Ding, Y.; Yakushi, K. Phys. ReV. B
2001, 63, 113103.
Inorganic Chemistry, Vol. 41, No. 20, 2002 5073

Mukai et al.
diphenyl-6-oxoverdazyl radical cation ([V]+) and [Ni(dmit)]-,
susceptibility of the salts. We are also grateful to Dr. M.
Taniguchi of Kyoto University for his kind help with the
measurement of conductivity. This work was partly supported
by the Grant-in-Aid for Scientific Research on Priority Areas
(B) of Molecular Conductors and Magnets (Area No. 730/
11224205) from the Ministry of Education, Science, Sports
and Culture, Japan.
-
[Ni(dmit)2]3 , [Zn(dmit)2]-, [Pd(dmit)2]-, and [Pt(dmit)2]2-
anions have been prepared, and their magnetic and electric
properties have been studied by measuring the magnetic
susceptibility, ESR, and electric conductivity and by analyz-
ing the crystal structure of the salts. The (1:3) [V]+[Ni-
(dmit)2]3- salt (2) and (2:1) [V]+ [Pd(dmit)]2- salt (4) were
2
found to be new molecular magnetic semiconductors. At
lower temperature, we can expect antiferromagnetic ordering
for salt 2.
Supporting Information Available: Tables listing detailed
crystallographic data, atomic positional parameters, and bond
lengths and angles in CIF format. This material is available free of
charge via the Internet at http://pubs.acs.org.
Acknowledgment. We are very grateful to Dr. Y.
Hosokoshi and Prof. K. Inoue of the Institute of Molecular
Science for their kind help in measuring the magnetic
IC020212S
5074 Inorganic Chemistry, Vol. 41, No. 20, 2002