N-methyl-4,4′-bipyridinium and n-methyl-n′-oxide-4,4′- bipyridinium bismuth complexes - Photochromism and photoluminescence in the solid state

Article abstract of DOI:10.1002/ejic.201201233

Three bismuth complexes based on N-methyl-4,4′-bipyridinium (hMV ⁺), (hMV)[Bi(hMV)Cl₅] (1), and N-methyl-N′-oxide-4, 4′-bipyridinium (MVO⁺), [Bi(MVO)X₄(dmso)] ·dmso [X = Cl (2), Br (3)], are reported. All three compounds show luminescence in the solid state with maxima at 545 nm (yellow for 1) and 560 nm (orange for 2 and 3) with quantum yields up to 10 %. Upon UV irradiation, 1 undergoes a color change from white to blue accompanied by a reduction of the photoluminescence intensity. The analysis of the crystal structure of the three complexes points to a photoinduced charge-transfer (PICT) process at the origin of the photochromism in 1. Three bismuth complexes based on N-methyl-4,4′- bipyridinium (hMV⁺), (hMV)[Bi(hMV)Cl₅] (1), and N-methyl-N′-oxide-4,4′-bipyridinium (MVO⁺), [Bi(MVO)X₄(dmso)]·dmso [X = Cl (2), Br (3)], show strong photoluminescence in the solid state. Upon UV irradiation, 1 undergoes a photoinduced charge-transfer (PICT) process resulting in a color change from white to blue. Copyright

Full text of DOI:10.1002/ejic.201201233

SHORT COMMUNICATION
DOI:10.1002/ejic.201201233
N-Methyl-4,4Ј-bipyridinium and N-Methyl-NЈ-oxide-4,4Ј-
bipyridinium Bismuth Complexes – Photochromism and
Photoluminescence in the Solid State
Oksana Toma,[a] Nicolas Mercier,*[a] and Chiara Botta[b]
Keywords: Photochromism / Luminescence / Bismuth / Viologens / N ligands
Three bismuth complexes based on N-methyl-4,4Ј-bipyrid-
inium (hMV+), (hMV)[Bi(hMV)Cl5] (1), and N-methyl-NЈ-ox-
ide-4,4Ј-bipyridinium (MVO+), [Bi(MVO)X4(dmso)]·dmso [X
= Cl (2), Br (3)], are reported. All three compounds show lu-
minescence in the solid state with maxima at 545 nm (yellow
for 1) and 560 nm (orange for 2 and 3) with quantum yields
up to 10%. Upon UV irradiation, 1 undergoes a color change
from white to blue accompanied by a reduction of the photo-
luminescence intensity. The analysis of the crystal structure
of the three complexes points to a photoinduced charge-
transfer (PICT) process at the origin of the photochromism in
1.
molecules for the development of mechanically interlocked
molecules.[8] Hybrid complexes with N atoms coordinated
to Bi3+ centers are not so common, and only nine structures
based on 4,4-bipyridine (bipy) and Bi3+ and two based on
N-alkyl-4,4Ј-bipyridinium (hRV+), with N–Bi bonds, are re-
ported in the Cambridge Structural Database (CSD – No-
vember 2011). These last two Bi3+ complexes were not ob-
tained as pure phases,[9] and we noted that no luminescence
properties had been reported for these compounds as well
as for the nine Bi/bipy complexes mentioned above, in con-
trast with the report on the luminescence of the coordina-
tion polymer based on bismuth and pyridine-2,5-dicarb-
oxylate, for instance.[10] We have also considered the use of
the N-methyl-NЈ-oxide-4,4Ј-bipyridinium (MVO+), thus re-
placing the N site of the pyridyl ring of hMV+ by the O– site
of the pyridine N-oxide part. Surprisingly, while the neutral
N,NЈ-dioxide-4,4Ј-bipyridine has afforded a lot of coordina-
tion polymers, mainly associated with lanthanides[11] but
also with 3d elements,[12] to the best of our knowledge, no
compound based on Bi has been reported with the simple
pyridine N-oxide ligand (CSD – November 2011). Finally,
with regard to RVO+ linking metal centers, only four struc-
tures have been described.[13] Here, we report on complexes
(hMV)[Bi(hMV)Cl5] (1) and [Bi(MVO)X4(dmso)]·dmso [X
= Cl (2), Br (3)] exhibiting strong yellow (for 1) or orange
(for 2 and 3) luminescence in the solid state, and we show
that the PICT process occurring in 1 induces photochromic
properties that are able to modulate its luminescence.
Introduction
Photochromism, or long-lived charge separation, is an
interesting phenomenon that can lead to a variety of appli-
cations ranging from clean energy to photo- or electro-
chromic devices.[1] An important class of photochromic ma-
terials are viologen-based compounds.[2–5] Viologens, which
are 1,1Ј-disubstituted 4,4Ј-bipyridinium dications (V2+), are
attractive because of their electron-acceptor nature, the sta-
bility and the color of their first reduced form, and the re-
versibility of the reduction step.[6] Crystallized photochro-
mic viologen compounds are mainly zeolite materials,[2] po-
lycyano polycadmate clathrates,[3] and halometalate hy-
brids.[4–5] Recently, we have been paying particular attention
to the last category to show that the photoinduced charge-
transfer (PICT) process leading to photochromism only oc-
curs when the inorganic anion is a chlorobismuthate and
that the efficiency of the color change increases with the
ratio Cl/V2+ [5]
However, the reversibility of the process
.
(from MV·+ to MV2+), which can be achieved by heating,
is partial in these systems, and after a few cycles, the PICT
process stops. It is therefore interesting to explore the pos-
sibility of having Bi3+ centers directly linked to viologen-
type molecular entities such as the N-substituted 4,4Ј-bi-
pyridinium cation (hRV+). Such ligands have often been
used with electron-donor metal ions (Re2+, Ru2+) to obtain
push-pull systems[7] or in the field of rotaxane or catenane
[a] Laboratoire MOLTECH-Anjou, UMR-CNRS 6200, Université
d’Angers,
2 Bd Lavoisier, 49045 Angers, France
Fax: +33-2-41735405
Results and Discussion
E-mail: nicolas.mercier@univ-angers.fr
[b] Istituto per lo Studio delle Macromolecole (ISMAC), CNR,
Via Bassini 15, 20133 Milano, Italy
Crystals of 1–3 were synthesized by the slow liquid–gas
diffusion method: a pillbox containing the viologen salt,
(hMV)(CH3SO4) or (MVO)(BF4), the bismuth(III) chloride
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.201201233.
Eur. J. Inorg. Chem. 2013, 1113–1117
1113
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjic.org
SHORT COMMUNICATION
(for 1 and 2) or bromide (for 3) salt, and tetrabutylammo- mation). We note that the emission spectra (shape, λmax) of
nium chloride (for 1 and 2) or bromide (for 3) dissolved in compounds 2 and 3 are different from that of compound 1,
dimethyl sulfoxide (dmso) was placed in a sealed jar filled suggesting that emission of this class of complexes is not
with ethyl acetate. After a few days, crystals were formed. associated to a purely MC (Bi3+) process. The luminescence
The thermogravimetric analysis of crystals of 2 and 3 may come from a LMCT process involving the pyridine N-
clearly shows that the first observed weight loss corre- oxide part and Bi3+ ions, as in other bismuth complexes, or
sponds to the departure of all dmso molecules leading to from an IL process facilitated by the heavy atom effect.[16]
the desolvated hybrids [Bi(MVO)X4] (X = Cl, Br) (Support-
ing Information).
The white powders of complex 1 exhibit bright yellow
photoluminescence (PL) with a broad emission centered at
545 nm (Figure 1) and a PL quantum yield (QY) of 10%.
The starting salt (hMV)(CH3SO4) is nonemissive, while the
luminescence of pyridine or pyridinium derivatives is often
weak and appears in the blue region; for example, 4,4Ј-bi-
pyridine emits at 438 nm, and [(hMV)ZnCl3] emits at
418 nm [this is attributed to the intraligand (IL) lumines-
cence of hMV+].[14] Moreover, according to our experience
in the field of chlorobismuthate hybrid salts and to the best
of our knowledge, no luminescence from the inorganic
anion has been reported. The photoluminescence of 1
might originate from a ligand-to-metal charge transfer
(LMCT) process, as observed for instance in bismuth com-
Figure 2. Solid-state photoluminescence (λexc = 380 nm) and pho-
toluminescence excitation (λem = 560 nm) spectra of 3 (red) and 2
plexes of pyridine-2,5-dicarboxylate.[10] However, the shape
of the emission band and the Stokes shift observed for 1 (blue). The spectra are normalized to the same intensity and shifted
vertically for clarity.
are typical of a luminescence originating from a MC (metal-
centered) sp excited state involving ns2 electrons of Bi3+ or
Pb2+ ions,[15] which is very much in favor of a MC emission
Among the three complexes, the most interesting is 1,
because it possesses photochromic properties. When irradi-
ated with a 150 W Hg UV lamp, the white crystalline sam-
ple becomes blue after a few minutes, the development of
the color being completed approximately after half an hour
(Figure 3). The initial state can be recovered by heating the
sample at 120 °C for a few minutes or after one day at room
temperature. However, as in the majority of such viologen
compounds, the reversibility is limited to several cycles.
Three photochromic materials based on N-substituted 4,4Ј-
bipyridinium have been reported recently,[4b,17] one includ-
ing the hMV·+ ion [(hMV)ZnCl3].[4b] However, in the study
dealing with its photochromic properties, this compound
is reported to have yellow crystals (changing to blue upon
irradiation), while it is reported to be colorless in the article
dealing with its synthesis.[14]
in 1.
Figure 1. Solid-state photoluminescence (λexc = 370 nm, black line)
and photoluminescence excitation (λem = 545 nm, red line) spectra
of 1, and photos of a powder sample of 1 taken under ambient
white light (bottom) and UV light (top).
As known in the field of viologen chlorobismuthates, the
color change is due to a PICT from the chlorides towards
the acceptor pyridinium parts, involving the presence of or-
ganic radicals, in this case hMV· which absorbs light in the
visible region (broad absorption band centered near
The yellow powders of 2 and 3 exhibit good PL proper- 600 nm),[4–6] and certainly neutral chlorine atoms.[18] Fig-
ties, in contrast to the starting salt (MOV)(BF4). When ex- ure 3b illustrates the evolution of the luminescence with the
cited at 380 nm, they both emit orange light, the similarly duration of UV irradiation. The intensity of luminescence
acentric shape of their emission spectra having a peak at decreases as the PICT process goes on (Figure 3c) to reach
560 nm with a shoulder at 600 nm (Figure 2). Their solid- approximately 2/3 of the initial value after UV irradiation
state PL QYs are 10% (for 3) and 5% (for 2). This clearly for 25 min. This reduction in emission intensity is expected
shows that changing the halide has an influence only on the and is also due to re-absorption processes (the broad ab-
luminescence intensity. We also note that desolvated hybrids sorption band at 600 nm overlaps with the emission – Fig-
[Bi(MVO)X4] show a kind of luminescence that is different ure 3a). It is interesting to note that both processes, PICT
from that of the solvated compounds (Supporting Infor- and luminescence, are triggered by the same excitation
Eur. J. Inorg. Chem. 2013, 1113–1117
1114
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjic.org
SHORT COMMUNICATION
mately above the pyridinium rings at the N atom in the case
of the Cl1···N2 and Cl5···N4 contacts, the angles between
the normal to the plane and the N···Cl vector being 3.5°
and 10.9°, respectively. This angle is 28.1° in the case of the
Cl1···N4 contact. Finally, we also note, as found in photo-
chromic viologen halobismuthates, that some N···Cl–Bi
bond angles are close to 110° (106.9° and 114.5° for
N2···Cl1–Bi and N4···Cl1–Bi, respectively).
Figure 4. Environment of one anionic complex [Bi(hMV)Cl5]– in 1
showing intermolecular interactions between chloride and nitrogen
atoms of pyridinium rings.
Starting from the N-methyl-NЈ-oxide-4,4Ј-bipyridinium
(MVO+) ligand, complexes [Bi(MVO)X4(dmso)]·dmso [X =
Cl (2), Br (3)] have been synthesized. They enlarge the tiny
family of hybrid complexes based on RVO+ ligands (four
structures with M = Sm3+, Yb3+, and Cd2+ have been de-
scribed).[13] The neutral complex is formed by one ligand
linked to one Bi3+, which is also surrounded by four halides
and one dmso molecule (Figure 5a, X = Cl). The Bi–Cl
Figure 3. UV/Vis spectra (a) and solid-state photoluminescence
(λexc = 370 nm) (b) of 1 before irradiation (black line) and after
5 min (red line), 10 min (blue line), and 25 min (green line) of UV
irradiation; (c) variations of the absorbance at 620 nm and of the
PL intensity of 1 after UV irradiation as a function of irradiation
time. To the right of the spectra in (a) are photos of sample 1 before
irradiation and after 25 min of UV irradiation.
wavelength, which means that there is a competition be- bond lengths are in the range 2.622(2) Å–2.748(3) Å,
tween them and also that the luminescence of the sample d[Bi–O(dmso)] = 2.477(2) Å, d[Bi–O(MVO)] = 2.482(2) Å,
could be auto-modulated during the process of irradiation. and Є(N–O–Bi) = 127.6°, Є[O–Bi–Cl(apical)] = 175.0°. In
The asymmetric unit of the crystal structure of 1 (C2/c the structure, which also includes disordered free dmso mo-
space group) consists of one anionic complex [Bi(hMV)- lecules, complexes are arranged in a head-to-tail manner in
Cl5]– and one cationic ligand (hMV)+. As in cholorobis- such a way that all dmso molecules, those linked to bismuth
muthate salts, the coordination of bismuth centers is six, centers and the others, appear segregated in (a, b) planes
here five chlorine atoms [range of Bi–Cl bond lengths: (Figure 5a).
2.629(2)–2.755(3) Å] and one nitrogen atom [d(Bi–N) =
These findings help in the understanding of the different
2.657(3) Å and Є(N–Bi–Clapical) = 172.6°). The dihedral photochromic properties displayed by the three complexes.
angles between the two pyridyl rings, in the hMV+ linked In fact, differently from complex 1, complexes 2 and 3 do
to BiIII and in the free hMV+, are 14 and 28.1°, respectively. not display any color change upon UV irradiation If photo-
As 1 undergoes a color change upon irradiation, the close chromism was not expected for 3 because of the presence
examination of the structural arrangement is of importance, of bromides, 2 could potentially undergo a color change
particularly the relative disposition of chlorides and pyrid- upon irradiation because, like 1 and several photochromic
inium rings. In fact, it has been demonstrated in viologen materials, it contains pyridinium rings and bismuth chloride
chlorobismuthate salts that the color change is due to a inorganic parts. However, a close analysis of its structure
PICT process from chlorides, which act as electron donors clearly shows that the required structural features, which
towards the electron-acceptor pyridinium rings, and that are short N+···Cl contacts (d ≈ 3.40 Å) and the (N+···Cl)
this process is favored when short N+···Cl contacts and a direction perpendicular to the pyridinium ring, are not
recurrent N+···Cl–Bi angle of 110–120° are present.[4a,5] reached in 2. In fact, the head-to-tail arrangement of com-
Figure 4 illustrates an anionic complex that interacts plexes leads to a packing of molecules along the a direction
through N+···Cl contacts with two other complexes and two (Figure 5b) with shorter N+···Cl contacts of 3.701(3) Å
free hMV+ cations. The shortest N+···Cl contacts are those (N1···Cl3) and 3.675(3) Å (N2···Cl1), while the angles be-
of the apical chloride Cl1 (opposite N) [d(N2···Cl1) = tween the normal to the pyridinium planes and the
3.345(3) Å, d(N4···Cl1) = 3.352(4) Å], while one equatorial (N+···Cl) vector are far from 0° (40.68° and 38.07° for the
chloride Cl5 interacts with the nitrogen atom of a free corresponding N1···Cl3 and N2···Cl1 contacts, respec-
hMV+ [d(N4···Cl5) = 3.327(3) Å]. Chlorides are approxi- tively – see Figure 5b).
Eur. J. Inorg. Chem. 2013, 1113–1117
1115
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjic.org
SHORT COMMUNICATION
and 3), BiX3 [X = Cl (for 1 and 2), Br (for 3)], and tetrabutylammo-
nium chloride (for 1 and 2) or bromide (for 3). The starting salts
based on hMV+ and MVO+ were first synthesized as described in
the Supporting Information. The starting materials were dissolved
in a minimum of dmso in a pillbox [for 1: (hMV)MeSO4 (26.5 mg,
0.094 mmol), BiCl3 (29.6 mg, 0.094 mmol), (tBuN)Cl (26.1 mg,
0.094 mmol); for 2: (MVO)BF4 (26.5 mg, 0.086 mmol), BiCl3
(27.0 mg, 0.086 mmol), (tBuN)Cl (71.5 mg, 0.260 mmol); for 3:
(MVO)BF4 (26.5 mg, 0.086 mmol), BiBr3 (38.3 mg, 0.086 mmol),
(tBuN)Br (55.2 mg, 0.170 mmol)]. The pillbox was then covered
with perforated aluminum paper and inserted in a jar filled with
ethyl acetate. The jar was then covered with a lid and sealed with
Parafilm. A few days later, crystals appeared. They were filtered,
washed with ethyl acetate, and dried in an oven at 50 °C [Yields:
19.6 mg (74%) for 1, 24.1 mg (91%) for 2, and 23.3 mg (88%) for
3]. Powder X-ray patterns of homogeneous samples of 1–3 showed
that all reflections are indexed in the unit cells obtained from
single-crystal X-ray diffraction studies (Supporting Information).
C22H22N4BiCl5 (1) (728.67): calcd. C 36.24, H 3.01, N 7.68; found
C 35.85, H 2.93, N 7.46. C15H23N2BiCl4O3S2 (2) (694.28): calcd. C
25.96, H 3.32, N 4.04, S 9.23, O 6.91; found C 26.35, H 3.20, N
4.18, S 8.90, O 6.73. C15H23N2BiBr4O3S2 (3) (872.09): calcd. C
20.66, H 2.64, N 3.21, S 7.34, O 5.50; found C 20.92, H 2.51, N
3.31, S 6.96, O 5.50. The IR spectrum of 1 after irradiation shows
a new band at 1050 cm–1 that was not present before irradiation,
which is close to the 1028 cm–1 band observed in a methylviologen
(MV2+) salt due to the presence of MV·+ radicals (vibration of the
C–C central bond).[3b]
Figure 5. (a) [Bi(MVO)Cl4(dmso)] complex in 2 (right) and general
view of the structure along a; (b) part of the structure showing the
packing of four complexes: space-filling representation (left) and
view along the long molecular axis showing the N+···Cl interac-
tions.
Thermal Analysis: Differential scanning calorimetry (DSC) and
thermogravimetric analysis (TGA) were performed with DSC-2010
and TGA2050 TA instruments in the temperature range 20–400 °C
and 20–800 °C, respectively (results given in the Supporting Infor-
mation). The TGA analysis of crystals of 2 and 3 clearly shows
that the first observed weight losses at 128 °C (for 2) and 135 °C
(for 3) well correspond to the departure of all dmso molecules
[theoretical/experimental weight loss: 22.48%/22.13% (for 2) and
17.89%/17.89%(for 3)] leading to the desolvated hybrids [Bi-
(MVO)X4]. C13H17N2BiCl4O2S (616.14): calcd. C 24.54, H 2.04, N
Conclusions
In summary, three unprecedented bismuth complexes
with a bright emission in the solid state have been prepared.
In the case of complex 1, the closeness of the Cl atoms to
the N atoms of pyridyl groups provokes a photoinduced
charge-transfer (PICT) process that leads to the interesting
photochromic properties of this complex. As a conse-
quence, the color and intensity of the luminescence of 1 can
be modulated by UV exposure, which opens it to potential
application in photoactive devices such as optical memo-
ries, switches, or filters. In the future, it will be worth ex-
ploring new complexes of this class by substituting the
methyl group of the ligands with various functional groups
in order to see the influence of the N-substituted pyridin-
ium part on the luminescence and the PICT processes, as
well as investigating the effect of using other metal centers.
Another direction will be to use the simple ligand N-oxide-
4,4Ј-bipyridine, only considered recently in coordination
chemistry,[19] which has, like hMV+, a pyridyl part, and like
MOV+, a pyridyl N-oxide part.
5.20,
O 2.97; found C 25.33, H 2.18, N 5.33, O 3.11;
C13H17N2BiBr4O2S (793.95): calcd. C 18.45, H 1.54, N 3.91, O
2.23; found C 19.28, H 1.54, N 4.01, O 2.30.
X-ray Crystallography: X-ray diffraction data of selected single
crystals were collected by using a Bruker-Nonius KAPPA-CDD
diffractometer equipped with graphite-monochromated Mo-Kα ra-
diation (λ = 0.71073 Å). A summary of crystallographic data and
refinement results for both polymorphs is listed in Table 1. Struc-
tures were solved and refined with the SHELXL97 package. Posi-
tions and agitation parameters were refined by full-matrix least-
squares routines against F2. All hydrogen atoms were treated with
a riding model. In 2 and 3, the nonbonded dmso molecule is disor-
dered, which leads to sulfur atoms (and riding hydrogen atoms of
the methyl groups) located over two positions, S2A and S2B: their
occupation factors, τ(S2A) and τ(S2B), were first refined with
τ(S2A) + τ(S2B) = 1, the isotropic agitation parameters being con-
strained to be equal. Finally, refinements of positions and aniso-
tropic displacement parameters of all non-H atoms lead to R1 =
0.051 (for 1); R1 = 0.040, τ(S2A) = 0.644, τ(S2B) = 0.356 (for 2);
R1 = 0.047, and τ(S2A) = 0.622, τ(S2B) = 0.378 (for 3). A more
complete summary of the crystallographic data for 1–3 is given in
the Supporting Information. CCDC-893199 (for 1), -893200 (for
2), and -893201 (for 3) contain the supplementary crystallographic
data for this paper. These data can be obtained free of charge from
Experimental Section
Synthesis: Compounds 1–3 were obtained with a slow liquid–gas
diffusion method from (hMV)MeSO4 (for 1) or (MVO)BF4 (for 2 the Cambridge Data Centre via www.ccdc.ac.uk/data-request/cif.
Eur. J. Inorg. Chem. 2013, 1113–1117
1116
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjic.org
SHORT COMMUNICATION
[6] a) P. M. S. Monk, The Viologens: Physicochemical Properties,
Synthesis and Application of the Salt of 4,4Ј-Bipyridine, Wiley,
New York, 1998; b) Y. Chen, Z. Yang, C.-X. Guo, C.-Y. Ni,
Z.-G. Ren, H.-X. Li, J.-P. Lang, Eur. J. Inorg. Chem. 2010,
5326–5333.
[7] a) B. Coe, Acc. Chem. Res. 2006, 39, 383–393; b) B. Coe, J. L.
Harries, M. Helliwell, L. A. Jones, I. Asselberghs, K. Clays,
B. S. Brunschwig, J. A. Harris, J. Garin, J. Orduna, J. Am.
Chem. Soc. 2006, 128, 12192–12204; c) B. Coe, L. A. Jones,
J. A. Harris, B. S. Brunschwig, I. Asselberghs, K. Clays, A. Per-
soons, J. Garin, J. Orduna, J. Am. Chem. Soc. 2004, 126, 3880–
3891.
Table 1. Crystallographic data for (hMV)[Bi(hMV)Cl5] (1) and
[Bi(MVO)X4(dmso)]·dmso [X = Cl (2), Br (3)].
1
2
3
FW (gmol–1)
Space group
a (Å)
b (Å)
c (Å)
728.67
C 2/c
31.157(4)
8.652(1)
20.230(3)
90
106.57(1)
90
5227(1)
8
694.28
P1
872.09
P1
¯
¯
8.3068(5)
8.8559(5)
16.459(1)
85.63(1)
76.43(1)
84.26(1)
1169.3(1)
2
8.6278(6)
8.921(1)
16.640(2)
91.58(1)
104.63(1)
95.16(1)
1232.5(2)
2
α (°)
β (°)
γ (°)
[8] a) V. Blanco, M. Chas, D. Abella, C. Peinador, J. M. Quintela,
J. Am. Chem. Soc. 2007, 129, 13978–13986; b) G. J. E. David-
son, S. J. Loeb, Angew. Chem. 2003, 115, 78; Angew. Chem. Int.
Ed. 2003, 42, 74–77.
V (Å3)
Z
Ind. obs refl.
[IϾ2σ(I)]
R1 [IϾ2σ(I)]
4558
289
0.051
4745
258
0.040
0.069
4735
257
0.047
0.123
[9] Y. Chen, Z. Yang, X.-Y. Wu, C.-Y. Ni, Z.-G. Ren, H.-F. Wang,
J.-P. Lang, Phys. Chem. Chem. Phys. 2011, 13, 5659–5667.
[10] a) A. Thirumurugan, W. Li, A. K. Cheetham, Dalton Trans.
2012, 41, 4126–4134; b) A. C. Wibowo, M. D. Smith, H.-C.
zur Loye, Chem. Commun. 2011, 47, 7371–7373; c) A. C.
Wibowo, M. D. Smith, H.-C. zur Loye, Cryst. Growth Des.
2011, 11, 4449–4757; d) A. C. Wibowo, S. A. Vaughn, M. D.
Smith, H.-C. zur Loye, Inorg. Chem. 2010, 49, 11001–11008.
[11] a) R. J. Hill, D.-L. Long, N. R. Champness, P. Hubberstey, M.
Schröder, Acc. Chem. Res. 2005, 38, 337–350; b) D.-L. Long,
A. J. Blake, N. R. Champness, C. Wilson, M. Schröder, J. Am.
Chem. Soc. 2001, 123, 3401–3402.
[12] a) J. Jia, A. J. Blake, N. R. Champness, P. Hubberstey, C. Wil-
son, M. Schröder, Inorg. Chem. 2008, 47, 8652–8664; b) A.-C.
Chamayou, C. Janiak, Inorg. Chim. Acta 2010, 363, 2193–2200.
[13] a) D. J. Hoffart, S. J. Loeb, Angew. Chem. 2005, 117, 923; An-
gew. Chem. Int. Ed. 2005, 44, 901–904; b) D. J. Hoffart, S. J.
Loeb, Supramol. Chem. 2007, 19, 89–93; c) S. J. Loeb, Chem.
Commun. 2005, 1511–1518.
wR2 (all data) 0.134
Photoluminescence: Photoluminescence quantum yield measure-
ments for the solid-state materials were carried out by using a
home-made integrating sphere according to the procedure already
described.[20]
Supporting Information (see footnote on the first page of this arti-
cle): Procedure for the preparation of the viologen salts, single-
crystal and powder X-ray diffraction structural analysis, thermal
analysis (TGA, DSC), UV/Vis spectra, and photoluminescence of
the desolvated compounds.
Acknowledgment
[14] W.-T. Chen, D.-S. Liu, S.-M. Ying, H.-L. Chen, Y.-P. Xu, Inorg.
Chem. Commun. 2008, 11, 1212–1214.
We thank the French Research Ministry for a PhD grant to O. T.
[15] a) G. Blasse, Prog. Solid State Chem. 1988, 18, 79–171; b) H. F.
Folkerts, J. Zuidema, G. Blasse, Chem. Phys. Lett. 1996, 249,
59–63; c) H. Nikol, A. Vogler, J. Am. Chem. Soc. 1991, 113,
8988–8990; d) H. Nikol, A. Becht, A. Vogler, Inorg. Chem.
1992, 31, 3277–3279; e) K. Oldenburg, A. Vogler, Z. Natur-
forsch. B 1993, 48, 1519–1523.
[16] a) A. Strasser, A. Vogler, Inorg. Chem. Commun. 2004, 7, 528–
530; b) X. Zhu, X. Li, Q. Liu, J. Lü, Z. Guo, J. He, Y. Li, R.
Cao, J. Solid State Chem. 2007, 180, 2386–2392.
[17] a) X.-H. Jin, J.-K. Sun, X.-M. Xu, Z.-H. Li, J. Zhang, Chem.
Commun. 2010, 46, 4695–4697; b) Y. Tan, H. Chen, J. Zhang,
S. Liao, J. Dai, Z. Fu, CrystEngComm 2012, 14, 5137–5139.
[18] J. Zhang, M. M. Matsushita, X. A. Kong, J. Abe, T. Iyoda, J.
Am. Chem. Soc. 2001, 123, 12105–12106.
[19] a) O. Toma, N. Mercier, M. Bouilland, M. Allain, Crys-
tEngComm 2012, 14, 7844–7847; b) D. J. Hoffart, N. C. Ha-
bermehl, S. J. Loeb, Dalton Trans. 2007, 2870–2875.
[1] a) R. Pardo, M. Zayat, D. Levy, Chem. Soc. Rev. 2011, 40, 672–
687; b) M.-S. Wang, G. Xu, Z.-J. Zhang, G.-C. Guo, Chem.
Commun. 2010, 46, 361–376; c) S. Kobatake, M. Irie, Annu.
Rep. Prog. Chem. Sect. C 2003, 99, 277–313; d) C. Yun, J. You,
J. Kim, J. Huh, E. Kim, J. Photochem. Photobiol. C: Pho-
tochem. Rev. 2009, 10, 111–168.
[2] a) E. L. Clennan, Coord. Chem. Rev. 2004, 248, 477–492; b) M.
Alvaro, H. Garcia, S. Garcia, F. Marquez, J. C. Scaiano, J.
Phys. Chem. B 1997, 101, 3043–3051.
[3] a) H. Yoshikawa, S. Nishikiori, Dalton Trans. 2005, 3056–3064;
b) H. Yoshikawa, S. Nishikiori, T. Watanabe, T. Ishida, G. Wat-
anabe, M. Murakami, K. Suwinska, T. Luboradzki, J. Lipkow-
ski, J. Chem. Soc., Dalton Trans. 2002, 1907–1917.
[4] a) G. Xu, G.-C. Guo, M. Wang, Z. Zhang, W. Chen, J. Huang,
Angew. Chem. 2007, 119, 3313; Angew. Chem. Int. Ed. 2007,
46, 3249–3251; b) X.-Y. Lv, M.-S. Wang, G.-E. Yang, A.-H. [20] J. Moreau, U. Giovanella, J.-P. Bombenger, W. Porzio, V.
Wang, R.-G. Lin, G.-C. Guo, Inorg. Chem. 2012, 51, 4015–
Vohra, L. Spadacini, G. Di Silvestro, L. Barba, G. Arrighetti,
S. Destri, M. Pasini, M. Saba, F. Quochi, A. Mura, G. Bon-
giovanni, M. Fiorini, M. Uslenghi, C. Botta, ChemPhysChem
2009, 10, 647–653.
4019.
[5] a) N. Leblanc, W. Bi, N. Mercier, P. Auban-Senzier, C. Pasquier,
Inorg. Chem. 2010, 49, 5824–5833; b) N. Leblanc, M. Allain,
N. Mercier, L. Sanguinet, Cryst. Growth Des. 2011, 11, 2064–
2069.
Received: October 11, 2012
Published Online: January 10, 2013
Eur. J. Inorg. Chem. 2013, 1113–1117
1117
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim