Chiral conducting salts of nickel dithiolene complexes

Article abstract of DOI:10.1021/ic300146s

Conducting and chiral [Ni(dmit)₂] dithiolene salts were obtained by electrocrystallization of the radical [n-Bu₄N][Ni(dmit) ₂] salt in the presence of chiral, enantiopure trimethylammonium cations. Three different cations were investigated, namely, (R)-Ph(Me)HC- NMe₃⁺, (S)-(^tBu)(Me)HC-NMe₃ ⁺, and (S)-(1-Napht)MeHC-NMe₃⁺, noted (R)-1, (S)-2, and (S)-3. Salts of 1:3 stoichiometry were obtained with (R)-1 and (S)-2, formulated as [(R)-1][Ni(dmit)₂]₃ and [(S)-2][Ni(dmit)₂]₃?(CH₃CN)₂. They both crystallize in the P2₁2₁2₁ chiral space group, with three crystallographically independent complexes exhibiting different oxidation degrees. Another salt with 2:5 stoichiometry was isolated with (S)-3. The semiconducting character of the three salts (σ _RT = 20-30 × 10^-3 S cm^-1) finds its origin in a strong electron localization, favored by the large number of crystallographically independent [Ni(dmit)₂] complexes in these chiral structures and their association into weakly interacting dimeric or trimeric motifs. Racemic salts with the same cations, obtained only with difficulties with the tert-butyl-containing (rac)-2 cation, afforded similar trimerized structures. The observed unusual stoichiometry and strong charge localization is tentatively assigned to the size and anisotropic charge distribution of the cations.

Full text of DOI:10.1021/ic300146s

Article
pubs.acs.org/IC
Chiral Conducting Salts of Nickel Dithiolene Complexes
Julien Lieffrig,† Olivier Jeannin,† Pascale Auban-Senzier,‡ and Marc Fourmigue*,†
́
†Sciences Chimiques de Rennes, Universite
́
Rennes 1 and CNRS UMR 6226, Campus de Beaulieu, 35042 Rennes, France
‡Laboratoire de Physique des Solides, Universite
́
Paris Sud, CNRS, UMR 8502, 91405 Orsay, France
S
* Supporting Information
ABSTRACT: Conducting and chiral [Ni(dmit)2] dithiolene
salts were obtained by electrocrystallization of the radical [n-
Bu4N][Ni(dmit)2] salt in the presence of chiral, enantiopure
trimethylammonium cations. Three different cations were
+
investigated, namely, (R)-Ph(Me)HC*-NMe3 , (S)-(tBu)-
+
+
(Me)HC*-NMe3 , and (S)-(1-Napht)MeHC*-NMe3 , noted
(R)-1, (S)-2, and (S)-3. Salts of 1:3 stoichiometry were
obtained with (R)-1 and (S)-2, formulated as [(R)-1][Ni(dmit)2]3 and [(S)-2][Ni(dmit)2]3·(CH3CN)2. They both crystallize in
the P212121 chiral space group, with three crystallographically independent complexes exhibiting different oxidation degrees.
Another salt with 2:5 stoichiometry was isolated with (S)-3. The semiconducting character of the three salts (σRT = 20−30 ×
10−3 S cm−1) finds its origin in a strong electron localization, favored by the large number of crystallographically independent
[Ni(dmit)2] complexes in these chiral structures and their association into weakly interacting dimeric or trimeric motifs. Racemic
salts with the same cations, obtained only with difficulties with the tert-butyl-containing (rac)-2 cation, afforded similar trimerized
structures. The observed unusual stoichiometry and strong charge localization is tentatively assigned to the size and anisotropic
charge distribution of the cations.
M = Ni, Pd, Pt.18 Indeed, electrocrystallization of the radical
INTRODUCTION
■
anion species [M(dithiolene)2]− can afford mixed-valence salts
formulated as C[M(dithiolene)2]2, where C+ can be a closed- or
open-shell radical. Examples of superconducting salts are found
with [Ni(dmit)2]− together with TTF+•,19 or EDT-TTF+•
radical cations,20 or [Pd(dmit)2]− with small closed-shell
cations such as Me4N+, Me4As+, and Me4Sb+ or larger
Et2Me2N+ and Et2Me2P+.21 Another remarkable result within
these series is identification of a quantum spin liquid (QSL)
ground state within the series of stibonium salts.22 Introduction
of chirality within such dithiole-based conducting salts has
never been considered, albeit it can potentially be done in two
ways as illustrated above with TTFs, that is, (i) dithiolene
complexes with chiral substituents and (ii) electrocrystallization
of achiral dithiolene complexes such as [M(dmit)2]− in the
presence of chiral cations. Only a few examples of dithiolene
complexes with chiral substituents were reported to date, a
radical anion cocrystallized with chiral viologens,23 several
neutral nickel dithiolene complexes capable of inducing a chiral
nematic phase when dissolved into a nematic liquid crystal
host,24 and, more recently, Ni and Au dithiolene complexes
derived from camphordione.25 The second route based on
achiral dithiolene complexes partially oxidized in the presence
of chiral cations was not investigated so far.
The combination of conductivity and chirality is currently being
investigated by several groups around the world, particularly
aiming at observation of so-called magneto-chiral effects of the
conductivity, as predicted and already observed by Rikken in
chiral nanotubes.1 Molecular conductors are particularly
attractive for controlled introduction of chirality, and several
strategies were considered to reach this goal. As the broadest
family of organic conductors is based on cation radical salts of
donor molecules such as tetrathiafulvalenes, the chirality was
effectively introduced in those salts,2,3 either on the TTF core
itself or on the counterion. The first approach already started in
1986 with methyl derivatives of BEDT-TTF,4,5 and several
conducting salts were successfully obtained.6,7 Tetrathiafulva-
lenes substituted with chiral oxazolines were also investigated8
and afforded several series of (R)-, (S)-, and racemic salts with
metallic conductivity.9 This concept was recently extended to
TTF derivatives with axial chirality introduced by binaphthol
moieties.10 The second approach involving chiral counterions
was investigated with MIII(oxalate)3,11 Fe(croconate)3,12
[MIII(S,S-EDDS)] (EDDS = ethylenediaminedisuccinato),13
Sb2(L-tartrate)2,14 TRISPHAT,15 or organic anions such as D-
camphorsulfonate16 in electrocrystallization experiments. A
third original approach to chiral cation radical salts involves
use of a neutral chiral solvent molecule able to either
intersperse within the anionic layer and/or favor one
enantiomer within a racemic mixture.17
We report here the first examples of conducting chiral salts of
[Ni(dmit)2]− dithiolene complexes with, as counterions, chiral
26
+
cations such as (R)-Ph(Me)HC*-NMe3 , (S)-(tBu)(Me)-
+
+
HC*-NMe3 , and (S)-(1-Napht)MeHC*-NMe3 . We describe
All examples reported above involve exclusively cation radical
salts derived from TTF-based donor molecules. However,
another broad family of molecular conductors is also found
among the partially oxidized [M(dithiolene)2]− complexes with
Received: January 19, 2012
Published: February 29, 2012
© 2012 American Chemical Society
7144
dx.doi.org/10.1021/ic300146s | Inorg. Chem. 2012, 51, 7144−7152

Inorganic Chemistry
Article
their syntheses, X-ray crystal structures, and transport proper-
ties in relationship with the chiral nature of the counterion. Of
particular interest is the unusual stoichiometries obtained
recurrently within these series with a cation to complex ratio of
1:3 and 2:5, at variance with the most common 1:2
stoichiometry, associated with a recurrent charge localization.
When possible, comparison with the racemic salts will be also
conducted.
Table 1. Average Intramolecular Bond Distances Within the
[Ni(dmit)2] Metallacycles in the Different Salts and
Reference Compounds
Ni−S (Å)
S−C (Å)
CC (Å)
ref
reference compds
a
[Ni(dmit)2]−2
2.195(9)
2.166(10)
2.163(3)
2.143(3)
1.733(8)
1.715(10)
1.701(4)
1.698(5)
1.352(3)
1.360(6)
1.382(7)
1.393(10)
29
30
31
32
a
[Ni(dmit)2]−
b
[Ni(dmit)2]−0.5
[Ni(dmit)2]0
with (R)-1
Ni(1)
RESULTS AND DISCUSSION
■
Crystallization of the chiral mixed-valence conducting dithio-
lene salts of [Ni(dmit)2]− is based on the electrocrystallization
of its nBu4N+ salt, (nBu4N)[Ni(dmit)2], in the presence of a
large excess of the chiral cation as electrolyte. Under such
conditions, we hope to crystallize a salt incorporating the
desired cation rather than the only known mixed-valence salt
with nBu4N+, (nBu4N)2[Ni(dmit)2]7·(CH3CN)2.27 As de-
scribed by Lacour,28 the chiral cations were prepared by MeI
alkylation of the commercially available primary amines, (R)-
Ph(Me)C*H-NH2, (S)-(tBu)(Me)C*H-NH2, and (S)-(1-
Napht)MeC*H-NH2, affording the corresponding iodide
salts, (R)-Ph(Me)C*H-NMe3I, (S)-(tBu)(Me)C*H-NMe3I,
and (S)-(1-Napht)MeC*H-NMe3I. Metathesis with HPF6 in
water/MeOH allowed for isolation of the hexafluorophosphate
salts, noted, respectively, [(R)-1,PF6], [(S)-2,PF6], and [(S)-
3,PF6] in the following.
2.165(2)
2.162(2)
2.157(2)
1.717(6)
1.706(6)
1.693(6)
1.381(8)
1.392(8)
1.403(8)
this work
this work
this work
Ni(2)
Ni(3)
with (S)-2
Ni(1)
2.1575(10)
2.165(1)
2.158(1)
1.699(3)
1.712(3)
1.697(3)
1.391(0)
1.375(5)
1.393(5)
this work
this work
this work
Ni(2)
Ni(3)
with (S)-3
Ni(1)
2.1643(17)
2.1608(17)
2.1606(17)
2.1673(18)
2.1555(18)
1.709(8)
1.700(8)
1.702(8)
1.709(8)
1.697(8)
1.380(10)
1.377(10)
1.382(10)
1.368(10)
1.387(10)
this work
this work
this work
this work
this work
Ni(2)
Ni(3)
Ni(4)
Ni(5)
a
b
As n-Bu4N+ salt. As N,N-dimethylpyrrolidinium salt.
alternating along the b axis with essentially neutral oxidized
complex Ni(3).
The mixed-valence salt with the tBu cation, (S)-2, also adopts
a 1:3 stoichiometry with a formulation which includes two
solvent molecules, that is, [(S)-2][Ni(dmit)2]3·(CH3CN)2. It
crystallizes in the orthorhombic system, chiral space group
P212121, with three [Ni(dmit)2] complexes in general position,
together with one (S)-2 cation and two CH3CN molecules
(Figure 3).
Electrocrystallization of [nBu4N][Ni(dmit)2] in the presence
of the phenyl cationic derivative (R)-1 as electrolyte afforded a
salt formulated as [(R)-1][Ni(dmit)2]3 with 1:3 stoichiometry,
which crystallizes in the orthorhombic system, space group
(chiral) P212121, with one cation and three [Ni(dmit)2] species
in general position in the unit cell. Intramolecular bond lengths
within the three independent complexes are collected in Table
1 and indicate that the three complexes do not have the same
charge. Indeed, the HOMO of closed-shell reduced [Ni-
(dmit)2]2− has, within the metallacycles, a bonding character
for the CC bond and an antibonding character for the C−S
and Ni−S bond. As a consequence, more oxidized species
exhibit a lengthening of the CC bond with concomitant
shortening of the C−S and Ni−S bonds. Examination of Table
1 shows that complex Ni(3) is essentially neutral while the two
other share the −1 charge, with Ni(2) possibly slightly more
oxidized than Ni(1)
As shown in Figure 1, the partially oxidized dithiolene
complexes are organized into layers, separated from each other
by the chiral enantiopure cations. Note also a short S···S
interlayer contact (dotted lines in Figure 1) at 3.392(2) Å. The
complexes stack along the b axis (Figure 2), with three different
overlap interactions, an almost eclipsed one for Ni(1)−Ni(2)
and more distorted ones for the Ni(1)−Ni(3) and Ni(2)−
Ni(3) overlap. Calculations of the βLUMO−LUMO interaction
energies for the three Ni(1)−Ni(2), Ni(2)−Ni(3), and (Ni1)−
Ni(3) pairs of [Ni(dmit)2] complexes confirm this observation,
with β12 = 0.51 eV, while β23 = 0.09 and β13 = 0.005 eV.
Combined with the charge distribution detailed above, this salt
thus appears as mixed-valence [Ni(1)−Ni(2)]−1 dyads,
Note that specifically with this chiral cation the localization
of the NMe3 group is not straightforward, as the isosteric tert-
butyl and trimethylammonium groups can be confused during
structure resolution (Scheme 1). The choice was made to keep
the (S) chirality of the cation, affording a (S)-2 cation with, as
expected N+−Me bonds notably shorter than the C−Me bonds
t
in the Bu group. The cations organize together with the
acetonitrile molecules in the ab plane (Figure 4), with nitrile
groups pointing toward the activated hydrogen atoms of the
NMe3 substituents to form a N+−CH3···NC−CH3 hydro-
+
gen-bond network, while the methyl groups of the tBu
substituent are not engaged in any such interactions,
confirming the actual cation chirality.
As observed with the first salt, analysis of intramolecular
bond lengths within the three independent complexes in [(S)-
2][Ni(dmit)2]3·(CH3CN)2 (Table 1) indicates that the three
complexes do not have the same charge, with Ni(1) and Ni(3)
comparable to the neutral [Ni(dmit)2]0 complex while Ni(2)
looks essentially as the monoanionic [Ni(dmit)2]− complex.
Within the layers, the molecules are organized onto trimerized
stacks (Figure 5), with the less oxidized radical anion Ni(2)
species interspersed between the two oxidized, essentially
neutral complexes Ni(1) and Ni(3), giving rise to three
different overlap interactions, two essentially eclipsed ones for
Ni(1)−Ni(2) and Ni(2) −Ni(3) defining the trimer, a more
distorted one for the Ni(1)−Ni(3) overlap. Calculations of the
βLUMO−LUMO interaction energies for the three Ni(1)−Ni(2),
Ni(2)−Ni(3), and Ni(1)−Ni(3) pairs of [Ni(dmit)2] com-
7145
dx.doi.org/10.1021/ic300146s | Inorg. Chem. 2012, 51, 7144−7152

Inorganic Chemistry
Article
Figure 1. Projection view along the b axis of the unit cell of [(R)-1][Ni(dmit)2]3.
Figure 2. View of the stacks of [Ni(dmit)2] species (left) together with the intermolecular overlap pattern (right).
t
Figure 3. Projection view along the b axis of the unit cell of the Bu salt, [(S)-2][Ni(dmit)2]·(CH3CN)2.
Scheme 1
2][Ni(dmit)2]·(CH3CN)2. This structural analysis is reinforced
by the temperature dependence of the magnetic susceptibility
of both salts (Figures S1 and S2, Supporting Information), well
fitted in the whole temperature range with a Curie−Weiss law
for one S = 1/2 species, χ = χ0 + Ng2β2/3k(T − θ) with for
[(R)-1][Ni(dmit)2]3 χ0 = 2.139(8) × 10−3 cm3 mol−1, g =
2.139(9), and θ = −1.89(4) K and for [(S)-2][Ni-
(dmit)2]·(CH3CN)2 χ0 = 0.75(4) × 10−3 cm3 mol−1, g =
2.131(4), and θ = −2.41(2) K. This behavior indicates that the
radical species in both salts are essentially localized, with
negligible interactions between trimers. As a consequence, the
two salts are semiconducting with a similar room-temperature
conductivity, σRT, of 0.02 S cm−1 (Figure 7) together with large
activation energies, 0.13 and 0.17 eV for [(R)-1][Ni(dmit)2]3
and [(S)-2][Ni(dmit)2]·(CH3CN)2, respectively.
plexes confirm this observation with β12 = −0.51, β23 = −0.53,
and β13 = −0.03 eV, respectively.
A side view of dithiolene slabs for both complexes with (R)-1
and (S)-2, taking into account the charge distribution discussed
above, is shown in Figure 6, demonstrating that the radical
species are only weakly interacting with each other along the a
direction in [(R)-1][Ni(dmit)2]3, while they are fully isolated
from each other by essentially neutral complexes in [(S)-
A more complex structure is found with the larger naphthyl
cation (S)-3, which affords a salt with a rare 2:5 stoichiometry,
7146
dx.doi.org/10.1021/ic300146s | Inorg. Chem. 2012, 51, 7144−7152

Inorganic Chemistry
Article
Figure 4. Weak N+−CH3···NC−CH3 hydrogen-bond network
between the (S)-2 cation and CH3CN molecules in [(S)-2][Ni-
(dmit)2]3·(CH3CN)2.
Figure 6. View of the slab built out of [Ni(dmit)2] species in [(R)-
1][Ni(dmit)2]3 (left) and [(S)-2][Ni(dmit)2]·(CH3CN)2 (right) with
charge repartition deduced from comparison of intramolecular bond
distances.
[(S)-3]2[Ni(dmit)2]5·(CH3CN)4. It crystallizes in the triclinic
system, space group P1, with now five crystallographically
independent [Ni(dmit)2] complexes, two cations, and four
solvent (CH3CN) molecules (Figure 8). Among the five
dithiolene complexes, Ni(1) and Ni(4) appear as the less
oxidized ones, while Ni(2), Ni(3), and Ni(5) are closer to
neutral [Ni(dmit)2]0. A side view of the stacks (Figure 9) shows
an alternation of Ni(1)−Ni(3) dimers and Ni(2)−Ni(4)−
Ni(5) trimers along b. Again, the charge localization deduced
from comparison of intramolecular bond lengths leads to a
charge localization illustrated in Figure 9c and confirmed by the
temperature dependence of the magnetic susceptibility (Figure
S3, Supporting Information). It is well fitted with a Curie−
Weiss law for two S = 1/2 species, χ = χ0 + 2Ng2β2/3k(T − θ),
with χ0 = 4.3(1) × 10−3 cm3 mol−1, g = 2.004(6), and θ = −0.95
K. This strong localization leads to a semiconducting behavior
(σRT = 0.028 S cm−1, Eact = 0.12 eV, Figure 7) comparable to
that observed in the other two salts.
Figure 7. Temperature dependence of the resistivity of the three salts.
Red line is a model in the high-temperature regime with ρ = ρ0
exp(Eact/kT).
A recurrent behavior is found for those three chiral salts, all
characterized with formation of dimers or trimers with two
recurrent overlap interactions, described as mode A (small
lateral shift with large overlap interaction) and mode B (long
longitudinal displacement with small associated overlap
interaction) in many solid crossing column structures, as
found in the prototypical (NMe4)[Ni(dmit)2]2.33 The main
difference with the reported conducting salts is the unusual
stoichiometries (1:3, 2:5) encountered here which can
potentially be attributed to the larger size of the cation and,
most importantly, the large number of crystallographically
Figure 5. Detail of the trimerized stacks (left) and overlap patterns within stacks (right) in [(S)-2][Ni(dmit)2]·(CH3CN)2.
7147
dx.doi.org/10.1021/ic300146s | Inorg. Chem. 2012, 51, 7144−7152

Inorganic Chemistry
Article
stoichiometry (Figure 10), with two complexes [Ni(1) and
Ni(3)] on inversion centers and, on general positions, two
complexes [Ni(2) and Ni(4)] and one cation, with the (R)-2
and (S)-2 enantiomers disordered on the same site (See
scheme 1). Again, the complexes organize into trimers [Ni(2)−
Ni(1)−Ni(2)]−1 and [Ni(4)−Ni(3)−Ni(4)]−1 (Figure S4,
Supporting Information) with, based on intramolecular bond
lengths (Table S1, Supporting Information), central inversion-
centered radical anion complexes [Ni(1), Ni(3)] sandwiched
between two essentially neutral complexes. These trimers form
slabs separated by the cation layers.
Figure 8. Projection view along the a axis of the unit cell of [(S)-
3]2[Ni(dmit)2]5·(CH3CN)4.
In the room-temperature monoclinic phase with the same
formulation, [(rac)-2][Ni(dmit)2]3·(CH3CN)2, three crystallo-
graphically independent [Ni(dmit)2] moieties are located in a
general position, together with one cation and two disordered
CH3CN molecules (Figure 11). The [Ni(dmit)2] complexes
are associated into [Ni(1)−Ni(2)−Ni(3)] trimers (Figure S5,
Supporting Information), and intramolecular bond lengths
(Table S1) within the three complexes indicate that the central
Ni(2) complex is less oxidized than the two others, with this
radical anion sandwiched between two neutral complexes, as
already observed in the two different trimers of the triclinic
phases. Hence, the two racemic structures are closely related
and both characterized by formation of trimers with the radical
anion diluted between essentially neutral, oxidized [Ni(dmit)2]0
complexes (Figures S6 and S7, Supporting Information).
In conclusion, we described here the first examples of
conducting and chiral metal dithiolene salts. In such
compounds, chirality can be introduced either on the dithiolene
complex itself or on the counterion. We explored the second
possibility with introduction of chiral, enantiopure cations as
electrolyte in the electrocrystallization experiments. Partial
oxidation of the radical [Ni(dmit)2]− in the presence of three
different enantiopure cations derived from chiral primary
amines leads to formation of mixed-valence salts with unusual
stoichiometries and a cation/complex ratio of 1:3 or 2:5. Their
semiconducting character finds its origin in a strong electron
localization, favored by the large number of crystallographically
independent [Ni(dmit)2] complexes in these chiral structures
and their association into weakly interacting dimeric or trimeric
motifs. Because of their chiral character, the absence of
independent [Ni(dmit)2] complexes. Indeed, with 3 or even 5
different complexes we systematically observe a strong charge
localization of the radical anion species [Ni(dmit)2]−•,
interspersed with oxidized, essentially neutral complexes
[Ni(dmit)2]0. This recurrent charge localization is at the origin
of the systematic semiconducting behavior of the salts. In other
words, the main effect of introduction of chiral cations appears
here to be loss of inversion centers, favoring a large number of
crystallographically independent complexes with different redox
states and the associated charge localization.
A comparison with the analogous racemic [Ni(dmit)2] salts
would be particularly interesting to shed light on this point.
Our attempts to grow crystals by the same electrocrystallization
experiments with (rac)-1, (rac)-2, or (rac)-3 cation afforded
contrasted results. We were not able to grow a crystal of proper
quality with the [(rac)-1,PF6] mixture, while the [(rac)-3,PF6]
electrolyte afforded systematically the enantiopure salt
described above with either (R)-3 or (S)-3, a first and
remarkable example of racemic resolution in electrocrystalliza-
tion experiments.
t
On the other hand, the Bu derivative, as racemic mixture,
[(rac)-2,PF6], afforded two different phases, depending on the
temperature of the electrocrystallization experiment, a mono-
clinic phase (space group Pn) with electrocrystallizations
conducted at room temperature (∼20 °C) and a triclinic
phase (space group P−1) at higher temperatures (40 °C). In
the high-temperature triclinic phase (space group P−1) the salt
formulated as [(rac)-2][Ni(dmit)2]3·(CH3CN)2 adopts the 1:3
Figure 9. Structure of [(S)-3]2[Ni(dmit)2]5·(CH3CN)4 with (a) detail of the alternating dimer and trimer structure of the stack of [Ni(dmit)2]
moieties, (b) the overlap patterns between molecules, and (c) the charge repartition deduced from comparison of intramolecular bond distances.
7148
dx.doi.org/10.1021/ic300146s | Inorg. Chem. 2012, 51, 7144−7152

Inorganic Chemistry
Article
Figure 10. Projection view (along the a axis) of the unit cell of the triclinic phase of [(rac)-2][Ni(dmit)2]·(CH3CN)2. Solvent molecules were
omitted.
Figure 11. Projection view (along the a axis) of the unit cell of the monoclinic phase of [(rac)-2][Ni(dmit)2]·(CH3CN)2.
Table 3. Electrocrystallization Conditions
electrolyte nature electrolyte (mg) TBA[Ni(dmit)2] (mg) current (μA) T (°C)
phase obtained
[(R)-1]PF6
[(S)-2]PF6
[(S)-3]PF6
[rac-2]PF6
[rac-2]PF6
[rac-3]PF6
11.1
14.6
23.3
19.4
30.3
26.4
3.7
5.0
0.5
0.5
1
20(1)
20(1)
20(1)
20(1)
40(1)
20(2)
[(R)-1][Ni(dmit)2]3
[(S)-2][Ni(dmit)2]3·(CH3CN)2
[(S)-3]2[Ni(dmit)2]5·(CH3CN)4
[rac-2][Ni(dmit)2]3·(CH3CN)2 monoclinic phase (SG Pn)
[rac-2][Ni(dmit)2]3·(CH3CN)2 triclinic phase (SG P−1)
[(S)-3]2[Ni(dmit)2]5·(CH3CN)4 or [(R)-3]2[Ni(dmit)2]5·(CH3CN)4
5.9
5.5
0.5
0.5
0.5
10.7
4.5
−
the precipitated PF6 salt in hot MeOH leads to the hexafluor-
ophosphates as white crystals.
inversion centers in the chiral salts could be a rationale for this
behavior. Racemic salts with the same cations were obtained
only with difficulty, and those isolated with the tert-butyl-
containing (rac)-2 cation afforded similar trimerized structures.
We finally believe that the complex structures obtained here
with chiral cations could be primarily due to their larger size,
when compared with classical closed-shell cations as
(NHxMe4−x)+ (x = 0−3) or (MMexEt4−x)+ (M = N, P, As,
Sb; x = 0−4), which favor recurrent 1:2 stoichiometry and
highly conducting character.18 Other stoichiometries (1:3, 2:5)
were indeed reported only with much larger cations such as
(MePh3P)+,34 (BzMe3P)+,35 Ph4P+,36 acridinium,37 phenazi-
nium,38 or [(NH4)(18-crown-6)]+.39 On the basis of this
assumption, smaller and still chiral cations could be considered
in the future, such as N-methyl oxazolinium40 or N-methyl
thiazolinium cations.41 Besides, numerous possibilities are also
offered by a direct functionalization of the dithiolene complex
itself with chiral substituents.23−25
1
[(R)-1]PF6. Yield: 63%. H NMR (d6-DMSO, TMS, 300 MHz): δ
1.70 (3H, d, CH3), 2.96 (9H, s, CH3), 4.74 (1H, q, CH), 7.47−7.60
(5H, m, Ar). 13C NMR (d6-DMSO, TMS, 300 MHz): δ 14.27 (CH3),
50.22 (CH3), 72.34 (CH), 128.62 (CH Ar), 129.94 (CH Ar), 130.21
(CH Ar), 133.26 (C Ar). Anal. Calcd for C11H18NPF6: C, 42.8; H, 5.6;
N, 4.5. Found: C, 42.57; H, 5.86; N, 4.72.
1
[(S)-2]PF6. Yield: 20%. H NMR (d6-DMSO, TMS, 300 MHz): δ
1.13 (9H, s, CH3), 1.31−1.35 (3H, m, CH3), 3.09 (9H, s, CH3), 3.46
(1H, q, CH). 13C NMR (d6-DMSO, TMS, 300 MHz): δ 12.32 (CH3),
29.05 (CH3), 36.29 (CH2), 52.99 (CH3), 77.84 (CH). Anal. Calcd for
C9H12NPF6: C, 37.5; H, 7.3; N, 4.8. Found: C, 37.55; H, 7.60; N, 4.64.
1
[(S)-3]PF6. Yield: 72%. H NMR (d6-DMSO, TMS, 300 MHz): δ
1.83 (3H, d, CH3), 3.03 (9H, s, CH3), 5.74 (1H, q, CH), 7.59−7.71
(3H, m, Ar), 7.94 (1H, d, Ar), 8.05 (1H, d, Ar), 8.11 (1H, d, Ar), 8.56
(1H, d, Ar). 13C NMR (d6-DMSO, TMS, 300 MHz): δ 15.60 (CH3),
50.45 (CH3), 65.94 (CH), 123.13 (Ar), 125.14 (Ar), 126.07 (Ar),
127.22 (Ar), 128.29 (Ar), 129.06 (Ar), 129.63 (Ar), 130.68 (Ar),
132.02 (Ar), 133.36 (Ar). Anal. Calcd for C15H20NPF6: C, 50.3; H,
5.4; N, 3.9. Found: C, 48.79; H, 5.49; N, 3.86.
[(rac)-1]PF6. Yield: 81%. 1H NMR (d6-DMSO, TMS, 300 MHz): δ
1.70 (3H, d, CH3), 2.96 (9H, s, CH3), 4.74 (1H, q, CH), 7.47−7.60
(5H, m, Ar). 13C NMR (d6-DMSO, TMS, 300 MHz): δ 14.27 (CH3),
50.22 (CH3), 72.34 (CH), 128.62 (CH Ar), 129.94 (CH Ar), 130.21
(CH Ar), 133.26 (C Ar). Anal. Calcd for C11H18NPF6: C, 42.8; H, 5.6;
N, 4.5. Found: C, 42.71; H, 5.65; N, 4.48.
EXPERIMENTAL SECTION
■
Syntheses. The trimethylammonium salts were prepared as
previously described for the iodide [(S)-1,I].28 The enantiopure or
racemic amine is reacted in MeOH at reflux overnight in the presence
of MeI (7 equiv) and NaHCO3 (4 equiv). After cooling, the solvent is
evaporated under vacuum and the residue extracted with CH2Cl2. The
filtered solution of the iodide is evaporated; the residue redissolved in
MeOH and HPF6 (60% in H2O, 1 equiv) is added. Recrystallization of
[(rac)-2]PF6. Yield: 85%. 1H NMR (d6-DMSO, TMS, 300 MHz): δ
1.13 (9H, s, CH3), 1.31−1.35 (3H, m, CH3), 3.09 (9H, s, CH3), 3.46
(1H, q, CH). 13C NMR (d6-DMSO, TMS, 300 MHz): δ 12.32 (CH3),
7149
dx.doi.org/10.1021/ic300146s | Inorg. Chem. 2012, 51, 7144−7152

Inorganic Chemistry
Article
a
Table 4. Crystallographic Data
[(R)-1]
[Ni(dmit)2]3
[(S)-2][Ni(dmit)2]3
·(CH3CN)2
[(S)-3]2[Ni(dmit)2]5
·(CH3CN)4
[(rac)-2] [Ni(dmit)2]3·
[(rac)-2][Ni(dmit)2]3
·(CH3CN)2
compound
(CH3CN)2
formula
fw (g·mol−1
C29H18NNi3S30
1518.37
C31H28N3Ni3S30
1580.49
C68H52 N6Ni5S50
2849.71
C27H22NNi3S30
1498.39
C29H25N2Ni3S30
1539.44
)
cryst color
black
black
black
black
black
cryst size (mm)
0.27 × 0.10 ×
0.083
0.45 × 0.23 × 0.07
0.54 × 0.46 × 0.07
0.35 × 0.12 × 0.07
0.32 × 0.24 × 0.06
cryst syst
space group
T (K)
orthorhombic
P212121
150(2)
11.1810(7)
11.2057(8)
41.036(2)
90.0
orthorhombic
P212121
150(2)
11.2264(9)
11.5591(9)
43.063(3)
90.0
triclinic
P1
triclinic
P−1
150(2)
monoclinic
Pn
150(2)
150(2)
7.3491(6)
8.8399(7)
43.054(3)
90.0
a (Å)
8.8577(8)
12.8475(12)
23.445(2)
81.282(4)
82.505(4)
78.952(4)
2574.1(4)
1
7.3392(12)
8.8475(13)
43.122(7)
92.729(4)
91.442(5)
90.047(4)
2796.0(8)
2
b (Å)
c (Å)
α (deg)
β (deg)
γ (deg)
V (Å3)
Z
90.0
90.0
91.682(2)
90.0
90.0
90.0
5141.4(6)
4
5588.2(8)
4
2795.8(4)
2
Dcalcd (g·cm−3
μ (mm−1
)
1.962
1.879
1.838
1.779
1.829
)
2.337
2.155
1.957
2.147
2.150
total reflns
abs corr
37 826
33 566
44 874
43 976
21 049
multiscan
0.544, 0.879
10 950
0.0330
9408
multiscan
0.760, 0.824
11 463
multiscan
0.557, 0.860
12 550
multiscan
0.361, 0.872
18 808
multiscan
0.741, 0.860
12 753
Tmin, Tmax
unique reflns
Rint
0.0518
0.0375
0.0335
0.0409
unique reflns (I >
2σ(I))
8497
10 596
14 622
10 454
refined params
R1 (I > 2σ(I))
wR2 (all data)
goodness-of-fit
residual density
572
606
1174
554
572
0.0384
0.1239
1.027
0.0293
0.0927
1.107
0.0318
0.0495
0.1459
1.070
0.0524
0.1638
1.088
0.1184
1.102
0.831, −1.010
0.928, −0.979
0.542, −0.750
1.525, −0.924
0.806, −1.480
(e·Å−3
)
a
2
4
R1 = Σ∥Fo| − |Fc∥/Σ|Fo|. wR2 = [Σw(Fo − Fc2)2/ΣwFo ]1/2
.
29.05 (CH3), 36.29 (CH2), 52.99 (CH3), 77.84 (CH). Anal. Calcd for
C9H12NPF6·(H2O)4: C, 30.78; H, 5.74; N, 3.99. Found: C, 29.97; H,
6.10; N, 3.90.
as well as for one of two CH3CN molecules in the monoclinic phase of
[(rac)-2][Ni(dmit)2]3.
Magnetic Properties. Magnetic susceptibility measurements were
obtained from a Quantum Design SQUID magnetometer MPMS-XL.
This magnetometer works between 1.8 and 400 K for dc applied fields
ranging from −5 to 5 T. Measurements were performed on
polycrystalline samples of [(R)-1][Ni(dmit)2]3 (4.7 mg), [(S)-
2][Ni(dmit)2]3·(CH3CN)2 (3.8 mg), and [(S)-3]2[Ni-
(dmit)2]5·(CH3CN)4 (4.6 mg). Magnetic data were corrected for
the sample holder and diamagnetic contributions.
[(rac)-3]PF6. Yield: 81%. 1H NMR (DMSO): δ 1.83 (3H, d, CH3),
3.03 (9H, s, CH3), 5.75 (1H, q, CH), 7.59−7.72 (3H, m, Ar), 7.94
(1H, d, Ar), 8.05 (1H, d, Ar), 8.11 (1H, d, Ar), 8.56 (1H, d, Ar). 13C
NMR (DMSO): δ 15.60 (CH3), 50.45 (CH3), 65.94 (CH), 123.13
(Ar), 125.14 (Ar), 126.07 (Ar), 127.22 (Ar), 128.29 (Ar), 129.06 (Ar),
129.63 (Ar), 130.68 (Ar), 132.02 (Ar), 133.36 (Ar). Anal. Calcd for
C15H20NPF6: C, 50.3; H, 5.4; N, 3.9. Found: C, 50.07; H, 5.53; N,
3.76.
Theoretical Calculations. βLUMO−LUMO interaction energies were
based upon the effective one-electron Hamiltonian of the extended
Huckel method,45 as implemented in the Caesar 1.0 chain of
Electrocrystallization Experiments. They were conducted in
two-compartment cells equipped with Pt electrodes (diameter 1 mm,
length 2 cm) with the hexafluorophosphate ammonium salt dissolved
in CH3CN (10 mL) as electrolyte and nBu4N[Ni(dmit)2] as
electroactive compound in the anodic compartment. Details are
collected in Table 3 for the different salts.
̈
programs.46 The off-diagonal matrix elements of the Hamiltonian
were calculated according to the modified Wolfsberg−Helmholz
formula.47 All valence electrons were explicitly taken into account in
the calculations, and the basis set consisted of double-ζ Slater-type
orbitals for C, S, and Ni and single-ζ Slater-type orbitals for H.
X-ray Diffraction Studies. Single crystals were taken in a loop in
oil and put directly under the N2 stream at 150 K to avoid solvent
losses. Data were collected on a Bruker SMART II diffractometer with
graphite-monochromated Mo Kα radiation (λ = 0.71073 Å).
Structures were solved by direct methods (SHELXS-97, SIR97)42
and refined (SHELXL-97) by full-matrix least-squares methods,43 as
implemented in the WinGX software package.44 Absorption
corrections were applied. Hydrogen atoms were introduced at
calculated positions (riding model), included in structure factor
calculations, and not refined. Crystallographic data are summarized in
Table 4. A SQUEEZE procedure for two disordered CH3CN
molecules was applied for the triclinic phase of [(rac)-2][Ni(dmit)2]3
ASSOCIATED CONTENT
■
S
* Supporting Information
CIF files for the five reported X-ray crystal structures.
Temperature dependence of the magnetic susceptibility of the
three chiral salts [(R)−1][Ni(dmit)2]3, [(S)−2][Ni-
(dmit)2]3·(CH3CN)2, and [(S)−3]2[Ni(dmit)2]5·(CH3CN)4.
Table of intramolecular bond distances and structural
descriptions for the two racemic salts [(rac)−2][Ni-
(dmit)2]3·(CH3CN)2. This material is available free of charge
via the Internet at http://pubs.acs.org.
7150
dx.doi.org/10.1021/ic300146s | Inorg. Chem. 2012, 51, 7144−7152

Inorganic Chemistry
Article
(17) (a) Martin, L.; Day, P.; Akutsu, H.; Yamada, J.-i.; Nakatsuji, S.-i.;
Clegg, W.; Harrington, R. W.; Horton, P. N.; Hursthouse, M. B.;
McMillan, P.; Firth, S. CrystEngComm 2007, 9, 865. (b) Martin, L.;
Day, P.; Horton, P.; Nakatsuji, S.-i.; Yamada, J.-i.; Akutsu, H. J. Mater.
Chem. 2010, 20, 2738.
AUTHOR INFORMATION
Corresponding Author
*E-mail: marc.fourmigue@univ-rennes1.fr.
Notes
■
(18) Kato, R. Chem. Rev. 2004, 104, 5319.
(19) Brossard, L.; Ribault, M.; Bousseau, M.; Valade, L.; Cassoux, P.
The authors declare no competing financial interest.
C. R. Acad. Sci. Ser. II 1986, 302, 205.
ACKNOWLEDGMENTS
■
(20) Kobayashi, A.; Kim, H.; Sasaki, Y.; Kato, R.; Kobayashi, H.;
Moriyama, S.; Noshio, Y.; Kajita, K.; Sasaki, W. Chem. Lett. 1987,
1819.
(21) (a) Kobayashi, A.; Kobayashi, H.; Miyamoto, A.; Kato, R.; Clark,
R. A.; Underhill, A. E. Chem. Lett. 1991, 2163. (b) Kobayashi, H.; Bun,
K.; Naito, T.; Kato, R.; Kobayashi, A. Chem. Lett. 1992, 1909. (c) Kato,
R.; Kashimura, Y.; Aonuma, S.; Hanasaki, N.; Tajima, H. Solid State
Commun. 1998, 105, 561. (d) Kato, R.; Tajima, N.; Tamura, M.;
Yamaura, J.-I. Phys. Rev. B 2002, 66, 020508.
(22) (a) Itou, T.; Oyamada, A.; Maegawa, S.; Tamura, M.; Kato, R.
Phys. Rev. B 2008, 77, 104413. (b) Yamashita, M.; Nakata, N.; Senshu,
Y.; Nagata, M.; Yamamoto, H. M.; Kato, R.; Shibauchi, T.; Matsuda, Y.
Science 2010, 328, 1246. (c) Itou, T.; Oyamada, A.; Maegawa, S.; Kato,
R. Nature Physics 2010, 6, 673. (d) Yamashita, S.; Yamamoto, T.;
Nakazawa, Y.; Tamura, M.; Kato, R. Nat. Commun. 2011, 2, 275.
(e) Itou, T.; Yamashita, K.; Nishiyama, M.; Oyamada, A.; Maegawa, S.;
Kubo, K.; Kato, R. Phys. Rev. B 2011, 84, 094405.
We thank the CDIFX (Rennes) for access to the X-ray
diffraction facilities and the ANR (France) for financial support
through project no. ANR-08-BLAN-0140-02.
REFERENCES
■
(1) (a) Krstic, V.; Roth, S.; Burghard, M.; Kern, K.; Rikken. J. Chem.
Phys. 2002, 117, 11315. (b) Krstic, V.; Rikken, G. L. J. A. Chem. Phys.
Lett. 2002, 364, 51.
(2) Avarvari, N.; Wallis, J. D. J. Mater. Chem. 2009, 19, 4061.
́ ́
(3) (a) Coronado, E.; Galan-Mascaros, J. R. J. Mater. Chem. 2005, 15,
66. (b) Amabilino, D. B.; Veciana, J. Top. Curr. Chem. 2006, 265, 253.
(4) Dunitz, J. D.; Karrer, A.; Wallis, J. D. Helv. Chim. Acta 1986, 69,
69.
(5) (a) Yang, S.; Brooks, A. C.; Martin, L.; Day, P.; Li, H.; Horton,
P.; Male, L.; Wallis, J. D. CrystEngComm 2009, 11, 993. (b) Wallis, J.
D.; Griffiths, J. P. J. Mater. Chem. 2005, 15, 347. Brown, R. J.; Brooks,
A. C.; Griffiths, J.-P.; Vital, B.; Day, P.; Wallis, J. D. Org. Biomol. Chem.
2007, 5, 3172.
(6) (a) Karrer, A.; Wallis, J. D.; Dunitz, J. D.; Hilti, B.; Mayer, C. W.;
Burkle, M.; Pfeiffer, J. Helv. Chim. Acta 1987, 70, 942. (b) Matsumiya,
S.; Izuoka, A.; Sugawara, T.; Taruishi, T.; Kawada, Y.; Tokumoto, M.
Bull. Chem. Soc. Jpn. 1993, 66, 1949.
(23) Kisch, H.; Eisen, B.; Dinnebier, R.; Shankland, K.; David, W. I.
F.; Knoch, F. Chem.Eur. J. 2001, 7, 738.
(24) Marshall, K. L.; Schudel, S.; Lippa, I. A. Proc. SPIE. Int. Soc. Opt.
Eng. 2004, 52B, 201.
̈
(25) Perochon, R.; Poriel, C.; Jeannin, O.; Piekara-Sady, L.;
Fourmigue, M. Eur. J. Inorg. Chem. 2009, 5413.
́
(26) This chiral cation was recently used for chirality transfer:
(a) Clemente-Leon, M.; Coronado, E.; Dias, J. C.; Soriano-Portillo, A.;
Willett, R. D. Inorg. Chem. 2008, 47, 6458. (b) El-Hachemi, Z.;
Mancini, G.; Ribo, J. M.; Sorrenti, A. J. Am. Chem. Soc. 2008, 130,
15176.
(27) (a) Underhill, A. E.; Ahmad, M. M. J. Chem. Soc., Chem.
Commun. 1981, 67. (b) Valade, L.; Legros, J.-P.; Bousseau, M.;
Cassoux, P.; Garbauskas, M.; Interrante, L. V. J. Chem. Soc., Dalton
Trans. 1985, 783.
(28) Lacour, J.; Vial, L.; Herse, C. Org. Lett. 2002, 4, 1351.
(29) Fun, H.-K.; Sivakumar, K.; Zuo, J.-L.; Yao, T.-M.; You, X.-Z.
Acta Crystallogr., Sect.C: Cryst. Struct. Commun 1996, 52, 312.
(30) Mulder, M. J. J.; Kooijman, H.; Spek, A. L.; Haasnoot, J. G.;
Reedijk, J. J. Chem. Cryst. 2002, 32, 347.
(31) Cornelissen, J. P.; Loux, R. L.; Jansen, J.; Haasnoot, J. G.;
Reedijk, J.; Horn, E.; Speck, A. L.; Pomarede, B.; Legros, J.-P.;
Reefman, D. J. Chem. Soc., Dalton Trans. 1992, 2911.
(32) Kushch, N.; Faulmann, C.; Cassoux, P.; Valade, L.; Malfant, I.;
Legros, J.-P.; Bowlas, C.; Errami, A.; Kobayashi, A.; Kobayashi, H. Mol.
Cryst. Liq. Cryst. Sci. Technol., Sect. A 1996, 284, 247.
(7) Galan-Mascaros, J. R.; Coronado, E.; Goddard, P. A.; Singleton,
J.; Coldea, A. I.; Wallis, J. D.; Coles, S. J.; Alberola, A. J. Am. Chem. Soc.
2010, 132, 9271.
(8) (a) Ret
2004, 1384. (b) Ret
E.; Lopes, E.; Almeida, M.; Cler
31, 1468. (c) Rethore, C.; Fourmigue,
2005, 61, 10935.
(9) Rethore, C.; Avarvari, N.; Canadell, E.; Auban-Senzier, P.;
Fourmigue, M. J. Am. Chem. Soc. 2005, 127, 5748. Madalan, A. M.;
Rethore, C.; Fourmigue, M.; Canadell, E.; Lopes, E. B.; Almeida, M.;
Auban-Senzier, P.; Avarvari, N. Chem.Eur. J. 2010, 16, 528.
(10) (a) Saad, A.; Barriere, F.; Levillain, E.; Vanthuyne, N.; Jeannin,
O.; Fourmigue,
Jeannin, O.; Fourmigue,
Jeannin, O.; Fourmigue,
Jeannin, O.; Fourmigue,
́
hore,
́
C.; Fourmigue,
hore, C.; Madalan, A.; Fourmigue,
ac, R.; Avarvari, N. New J. Chem. 2007,
M.; Avarvari, N. Tetrahedron
́
M.; Avarvari, N. Chem. Commun.
́
́
́
M.; Canadell,
́
́
́
́
́
́
́
́
́
́
̀
́
M. Chem.Eur. J. 2010, 16, 8020. (b) Saad, A.;
́
M. New J. Chem. 2011, 35, 1004. (c) Saad, A.;
M. Tetrahedron 2011, 67, 3820. (d) Saad, A.;
M. CrystEngCommun 2010, 12, 3866.
́
́
(11) (a) Martin, L.; Turner, S. S.; Day, P.; Mabbs, F. E.; McInnes, E.
J. L. Chem. Commun. 1997, 1367. (b) Martin, L.; Turner, S. S.; Day, P.;
Malik, K. M. A.; Coles, S. J.; Hursthouse, M. B. Chem. Commun. 1999,
513. (c) Martin, L.; Turner, S. S.; Day, P. Synth. Met. 1999, 102, 1638.
(12) (a) Gomez-Garcia, C. J.; Coronado, E.; Curreli, S.; Gimenez-
Saiz, C.; Deplano, P.; Mercuri, M. L.; Pilia, L.; Serpe, A.; Faulmann, C.;
Canadell, E. Chem. Commun. 2006, 4931. (b) Coronado, E.; Curreli,
S.; Gimenez-Saiz, C.; Gomez-García, C. J.; Deplano, P.; Mercuri, M.
́ ́
L.; Serpe, A.; Pilia, L.; Faulmann, C.; Canadell, E. Inorg. Chem. 2007,
46, 4444.
(33) (a) Kobayashi, A.; Kim, H.; Sasaki, Y.; Kato, R.; Kobayashi, H.;
Moriyama, S.; Nishio, Y.; Kajita, K.; Sasaki, W. Chem. Lett. 1987, 1819.
(b) Kim, H.; Kobayashi, A.; Sasaki, Y.; Kato, R.; Kobayashi, H. Chem.
Lett. 1987, 1799. (c) Kajita, K.; Nishio, Y.; Moriyama, S.; Kato, R.;
Kobayashi, H.; Sasaki, W.; Kobayashi, A.; Kim, H.; Sasaki, Y. Solid State
Commun. 1988, 65, 361.
(13) Chmel, N. P.; Clarkson, G. J.; Troisi, A.; Turner, S. S.; Scott, P.
Inorg. Chem. 2011, 50, 4039.
(34) Pullen, A. E.; Lui, H.-L.; Tanner, D. B.; Abboud, K. A.;
Reynolds, J. R. J. Mater. Chem. 1997, 7, 377.
(14) Coronado, E.; Galan-Mascaros, J. R.; Gomez-Garcia, C. J.;
Murcia-Martinez, A.; Canadell, E. Inorg. Chem. 2004, 43, 8072.
(15) Clemente-Leon, M.; Coronado, E.; Gomez-Garcıa, C. J.;
Soriano-Portillo, A.; Constant, S.; Frantz, R.; Lacour, J. Inorg. Chim.
Acta 2007, 360, 955.
(35) Faulmann, C.; Errami, A.; Donnadieu, B.; Malfant, I.; Legros, J.-
P.; Cassoux, P.; Rovira, C.; Canadell, E. Inorg. Chem. 1996, 35, 3856.
(36) (a) Nakamura, T.; Underhill, A. E.; Coomber, A. T.; Friend, R.
H.; Tajima, H.; Kobayashi, A.; Kobayashi, H. Synth. Met. 1995, 70,
1061. (b) Liu, H. L.; Tanner, D. B.; Pullen, A. E.; Abboud, K. A.;
Reynolds, J. R. Phys. Rev. B 1996, 53, 10557.
(16) (a) Brezgunova, M.; Shin, K. S.; Auban-Senzier, P.; Jeannin, O.;
Fourmigue,
Brezgunova, M.; Jeannin, O.; Roisnel, T.; Camerel, F.; Auban-
Senzier, P.; Fourmigue, M. Cryst. Growth Design 2011, 11, 5337.
́
M. Chem. Commun. 2010, 3226. (b) Shin, K.-S.;
(37) Veldhuizen, Y. S. J.; Haasnoot, J. G.; Reedijk, J. Synth. Met. 1997,
86, 1827.
́
7151
dx.doi.org/10.1021/ic300146s | Inorg. Chem. 2012, 51, 7144−7152

Inorganic Chemistry
Article
(38) Veldhuizen, Y. S. J.; Smeets, W. J. J.; Veldman, N.; Spek, A. L.;
́
Faulmann, C.; Auban-Senzier, P.; Jerome, D.; Paulus, P. M.; Haasnoot,
J. G.; Reedijk, J. Inorg. Chem. 1997, 36, 4930.
(39) Akutagawa, T.; Nakamura, T.; Inabe, T.; Underhill, A. E. Thin
Solid Films 1998, 331, 264.
(40) Wasserscheid, P.; Bosmann, A.; Bolm, C. Chem. Commun 2002,
̈
200.
(41) Levillain, J.; Dubant, G.; Abrunhosa, I.; Gulea, M.; Gaumont, A.-
C. Chem. Commun. 2003, 2914.
(42) Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, G.;
Giacovazzo, C.; Guagliardi, A.; Moliterni, A. G. G.; Polidori, G.;
Spagna, R. J. Appl. Crystallogr. 1999, 32, 115.
(43) Sheldrick, G. M. SHELX97-Programs for Crystal Structure
Analysis (Release 97-2); Institut fur Anorganische Chemie, Universitat
̈
̈
̈
Gottingen: Gottingen, Germany, 1998.
̈
̈
(44) Farrugia, L. J. J. Appl. Crystallogr. 1999, 32, 837.
(45) Whangbo, M.-H.; Hoffmann, H. J. Am. Chem. Soc. 1978, 100,
6093.
(46) Ren, J.; Liang, W.; Whangbo, M.-H. Crystal and Electronic
Structure Analysis Using CAESAR; PrimeColor Software, Inc.: Cary,
NC, 1998.
(47) Ammeter, J.; Burgi, H.-B.; Thibeault, J.; Hoffmann, R. J. Am.
̈
Chem. Soc. 1978, 100, 3686.
7152
dx.doi.org/10.1021/ic300146s | Inorg. Chem. 2012, 51, 7144−7152