Hydrogen-bonded systems between monocarboxylic acids and the trinuclear cluster cation [H3Ru3(C6H6) (C6Me6)2(O)]+: cold-spray ionisation mass spectroscopic and X-ray crystallographic studies

Article abstract of DOI:10.1016/j.jorganchem.2004.06.021

The hydrogen-bonded systems formed between monocarboxylic acid derivatives and the trinuclear arene-ruthenium cluster cation [H₃Ru₃(C₆H₆)(C₆ Me₆)₂(O)]⁺ (1) have been studied in solution by cold-spray ionisation mass spectroscopy (CSI-MS) and in the solid state by single-crystal X-ray structure analysis of the tetrafluoroborate salts. The presence of 1:1 (acid:cluster) adducts in acetone solution has been clearly demonstrated by CSI-MS. Single-crystal X-ray structure analyses of selected acid-cluster complexes show that in every case the hydroxyl of the acid function interacts strongly with the μ₃-oxo ligand of cation 1, the O...O distance ranging from 2.499(9) to 2.595(11) A?.

Full text of DOI:10.1016/j.jorganchem.2004.06.021

Journal of Organometallic Chemistry 689 (2004) 2820–2826
www.elsevier.com/locate/jorganchem
Hydrogen-bonded systems between monocarboxylic acids
and the trinuclear cluster cation [H3Ru3(C6H6)(C6Me6)2(O)]+:
cold-spray ionisation mass spectroscopic and
X-ray crystallographic studies
a,
a
a
Bruno Therrien *, Ludovic Vieille-Petit , Georg Suss-Fink ,
¨
b
Yoshihisa Sei , Kentaro Yamaguchi
b
a
´ ˆ ˆ
Institut de Chimie, Universite de Neuchatel, Case postale 2, CH-2007 Neuchatel, Switzerland
Laboratory of Analytical Chemistry, Tokushima Bunri University, Shido, Sanuki-city, Kagawa 769-2193, Japan
b
Received 21 April 2004; accepted 9 June 2004
Available online 15 July 2004
Abstract
The hydrogen-bonded systems formed between monocarboxylic acid derivatives and the trinuclear arene-ruthenium cluster cat-
ion [H3Ru3(C6H6)(C6Me6)2(O)]+ (1) have been studied in solution by cold-spray ionisation mass spectroscopy (CSI-MS) and in the
solid state by single-crystal X-ray structure analysis of the tetrafluoroborate salts. The presence of 1:1 (acid:cluster) adducts in ace-
tone solution has been clearly demonstrated by CSI-MS. Single-crystal X-ray structure analyses of selected acid-cluster complexes
show that in every case the hydroxyl of the acid function interacts strongly with the l3-oxo ligand of cation 1, the OÁ Á ÁO distance
˚
ranging from 2.499(9) to 2.595(11) A.
ꢀ 2004 Elsevier B.V. All rights reserved.
Keywords: Arene ligands; Cluster complexes; Hydrogen bonds; Ruthenium; Mass spectroscopy
1. Introduction
esting host–guest properties [5–7]. Single-crystal X-ray
structure analyses show that the l3-oxo ligand is a
strong acceptor to form hydrogen bonds, and that the
hydrophobic pocket spanned by the three arene ligands
acts as a bowl to host different molecules in the solid
state. For example, in the presence of benzoic acid, the
phenyl group is incorporated in the hydrophobic pocket
of the cluster, whereas the hydroxyl group of the acid
function is hydrogen-bonded to the l3-oxo ligand of a
neighbouring molecule [7], see Scheme 1. However, little
is known if such interactions remain in solution.
Cold-spray ionisation mass spectroscopy (CSI-MS)
has been used to investigate the solution structure of pri-
mary biomolecules [1], labile organic species [2], asym-
metric catalysts [3], and supramolecules [4]. The
method allows the rapid and precise characterisation
of compounds possessing non-covalent interactions such
as hydrogen-bonds.
Recently, we have shown the l3-oxo-capped cluster
cation [H3Ru3(C6H6)(C6Me6)2(O)]+ (1) to possess inter-
Therefore, we were interested to investigate the bind-
ing properties of 1 in solution with various monocarbox-
ylic acids by CSI-MS. In order to confirm l3-oxoÁ Á Á
acid hydrogen bonding, single-crystal X-ray structure
*
Corresponding author.
E-mail address: bruno.therrien@unine.ch (B. Therrien).
0022-328X/$ - see front matter ꢀ 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2004.06.021

B. Therrien et al. / Journal of Organometallic Chemistry 689 (2004) 2820–2826
2821
The monocarboxylic acid derivatives used for the pres-
ent study are presented in Scheme 2; benzoic acid (A),
4-bromobenzoic acid (B), 3-bromobenzoic acid (C),
2,5-dibromobenzoic acid (D), 3,5-dichlorobenzoic
acid (E), 4-methoxybenzoic acid (F), cyclohexanecarb-
oxylic acid (G), 2-naphtoic acid (H) and mandelic
acid (I).
O
Ru
Ru
H
H
O
H
O
O
Ru
H
H
Ru
H
H
Ru
Ru
2.1. Cold-spray ionisation mass spectroscopy
In order to optimise the signal of the ion peak of the
adduct products, we first measured in the full mass
range a 10:1 mixture of B and [1][BF4] in different sol-
vents such as acetone, chloroform, dichloromethane
and methanol. The strongest [1+B]+/[1]+ signal ratio
was found in acetone, whereas no adduct signal was de-
tected in methanol and only a very weak one in dichlo-
romethane. Interestingly, in chloroform a peak at m/z
845 was observed, corresponding to a [1+CHCl3]+ sys-
tem. This result is in agreement with the fact that crys-
tallisation of [1][BF4] in a mixed acetone–chloroform
solution gives the host–guest complex as the tetrafluo-
roborate salt [CHCl3ꢁ1][BF4] [7]. Therefore, we can
assume that the same weak interactions by means of
which the chloroform molecule is hosted in the hydro-
phobic pocket of 1, found in the solid state, persist also
in solution.
In a typical experiment, 1 lmol of [1][BF4] was dis-
solved in acetone (3 mL) with 10 lmol of the acid, after
complete dissolution of the products, the solution was
injected at -20 ꢂC by syringe pump in the cold-spray
ion source. The mass spectrum measurements were per-
formed with a sector (BE) mass spectrometer (JMS-700,
JEOL) equipped with a CSI source.
Scheme 1.
analyses of selected acid-cluster complexes have been
performed.
2. Results and discussion
The trinuclear cluster [H3Ru3(C6H6)(C6Me6)2(O)]+
(1) is accessible in aqueous solution from the dinuclear
precursor [H3Ru2(C6Me6)2]+ and the mononuclear
building block [Ru(C6H6)(H2O)3]2+ [5]. The tetrafluo-
roborate salt of 1 is well soluble in acetone, dimethyl-
sulfoxide, dichloromethane and ethanol, and sparingly
soluble in water, methanol and chloroform. The l3-
oxo ligand is capable of forming hydrogen bonds with
donor molecules as observed in the crystal structures
of [1][BF4]ÆH2O [5], [1][BF4]ÆH2OÆ0.5 C4H8O2,
[1][BF4]ÆH2OÆC6H5OH, and [C6H5COOHꢁ1][BF4]
[7]. However, in solution, the only evidence for inter-
actions between the complex and guest molecules was
an electrospray ionisation mass spectrometric study
which showed 1 to form an adduct with a benzene
molecule [8]. By NMR spectroscopy no interaction
could be observed between 1 and benzoic acid, even
at low temperature, the signals of the benzoic acid re-
maining unchanged in the presence of 1 [9]. Therefore,
we were interested to investigate the presence of hy-
drogen bond interactions in solution by CSI-MS. We
carried out a series of CSI-MS measurements of mix-
ture of monocarboxylic acids with [1][BF4] in acetone.
In all cases a major peak at m/z 725 corresponding to
[H3Ru3(C6H6)(C6Me6)2(O)]+ was observed. The adducts
[1+B]+, [1+C]+, [1 + D]+, [1+E]+, [1+F]+, [1+H]+ and
[1+I]+ have been clearly identified in the CSI-MS spec-
trum. The peaks have been assigned unambiguously on
the basis of their characteristic Ru3 isotope pattern. The
[1+acid]+ spectra are presented in Fig. 1.
COOH
COOH
COOH
COOH
Br
COOH
Br
Br
Br
Cl
Cl
A
B
C
D
E
COOH
COOH
COOH
OH
MeO
COOH
F
G
H
I
Scheme 2.

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B. Therrien et al. / Journal of Organometallic Chemistry 689 (2004) 2820–2826
Fig. 1. CSI-MS spectrum of [1+B]+, [1+D]+, [1+E]+, [1+F]+, [1 + H]+, and [1+I]+ in acetone solution.
Surprisingly, no adduct of 1 was observed with ben-
atoms numbering scheme of [4-BrC6H4COOHC1]+ is
presented in Fig. 2.
zoic acid (A) and cyclohexanecarboxylic acid (G), even
upon increasing the acid concentration. However, in
the mass spectrum of [1]+ with 4-bromobenzoic acid
(B) and 3-bromobenzoic acid (C), signals at m/z 926,
corresponding to the [1+ acid]+ adducts were observed.
Under the conditions used, it seems that the bromine po-
sition has no particular effect on the intensity of the sig-
nal. Similarly, adduct compounds were observed with
2,5-dibromobenzoic acid ([1+D]+ at m/z 1005), 3,5-di-
chlorobenzoic acid ([1 + E]+ at m/z 916), 4-methoxyben-
zoic acid ([1+F]+ at m/z 877), 2-naphtoic acid ([1 + H]+
at m/z 897) and mandelic acid ([1+I]+ at m/z 877),
respectively.
The geometry and packing arrangement in the crystal
is very similar to the one observed for
[C6H5COOHꢁ1][BF4] [7]. The p-bromobenzoic acid, like
the benzoic acid molecule, is incorporated inside the hy-
drophobic pocket. The phenyl ring interacts weakly with
the host molecule only by hydrophobic and van der Wa-
als contacts. The angle formed by the C6 plane and the
Ru3 plane is 82.03(7)ꢂ, the guest molecule being held al-
most upright in the hydrophobic pocket. On the other
hand, the acid function allows the guest molecule to form
hydrogen bonds. Indeed, in the solid state, a strong hy-
drogen bond with the l3-oxo ligand is observed. The
˚
OÁ Á ÁO distance is 2.541(3) A with an O–HÁ Á ÁO angle
2.2. Structural studies
of 167.7ꢂ, thus forming a host–guest–host infinite one-di-
mensional chain, see Fig. 3.
To gain further insight in the binding mode of 1 with
monocarboxylic acid, we attempted to crystallise
[1][BF4] with the same series of monocarboxylic acids.
In most cases no crystalline compounds were obtained.
However, with 4-bromobenzoic acid, 3,5-dichloroben-
zoic acid, 4-methoxybenzoic acid, and 2-naphtoic acid,
crystals containing a guest molecule were isolated. Crys-
tallographic details are summarised in Table 1. The crys-
tal structure of 1 with benzoic acid has been reported
previously [7].
The crystallisation of [1][BF4] with 4-bromobenzoic
acid (4-BrC6H4COOH) in an acetone solution gives
the host–guest complex [1][BF4]Æ4-BrC6H4COOH. The
phenyl ring acts as a guest molecule inside the hydro-
phobic pocket, while the carboxylic acid function
interacts with a l3-oxo ligand of a second cluster cation,
thus giving rise to a head-to-tail host–guest chain. The
In the crystals obtained with 3,5-dichlorobenzoic acid
(3,5-Cl2C6H3COOH), no guest molecule was observed
in the hydrophobic pocket of the cluster cation 1. In-
stead, a methyl group of symmetry related neighbouring
cluster cation is directed in the hydrophobic pocket of 1.
The distance between the methyl carbon and the Ru3
˚
plane is 3.991(9) A. The atoms numbering scheme of
[1]+ Æ3,5-Cl2C6H3COOH is presented in Fig. 4.
As expected, the acid function forms a hydrogen
bond with a l3-oxo ligand. The OÁ Á ÁO distance is
˚
2.499(9) A with an O–HÁ Á ÁO angle of 157.6ꢂ. The car-
bonyl group of the acid function interacts with a chloro-
˚
form molecule, the CÁ Á ÁO distance is 3.21(2) A with a
C–HÁ Á ÁO angle of 155.1ꢂ. In the crystal, two indepen-
dent slipped-parallel p-stacking interactions are
observed, one involving the phenyl ring of the
Cl2C6H3COOH and a hexamethyl benzene ligand

B. Therrien et al. / Journal of Organometallic Chemistry 689 (2004) 2820–2826
2823
Table 1
Crystallographic and selected experimental data for [1][BF4]Æ4-BrC6H4COOH, [1][BF4]Æ3,5-Cl2C6H3COOHÆacetoneÆCHCl3, [1][BF4]Æ24-
MeOC6H4COOHÆacetone, and [1][BF4]Æ2-C10H7COOH
[1][BF4]Æ4-BrC6H4COOH
[1][BF4]Æ3,5-Cl2C6H3
COOHÆacetoneÆCHCl3
[1][BF4]Æ24-MeOC6H4
COOHÆacetone
[1][BF4]Æ2-C10H7COOH
Chemical formula
Formula weight
Crystal system
C37H50BBrF4O3Ru3
1012.70
C41H56BCl5F4O4Ru3
1180.13
Triclinic
C49H67BF4O8Ru3
923.80
Triclinic
C38H52BF4O3Ru3
946.82
Monoclinic
Cc
Monoclinic
C2/c
ꢀ
ꢀ
Space group
Crystal colour and shape
Crystal size
P1
P1
Red block
0.33·0.29·0.18
17.369(2)
13.9097(17)
16.185(2)
90
Red block
0.23·0.18·0.12
10.692(4)
13.967(5)
15.785(5)
100.691(5)
96.146(6)
91.403(6)
2300.6(14)
2
Orange block
0.35·0.25·0.12
10.9909(15)
14.377(2)
15.945(2)
101.403(3)
96.800(3)
93.614(3)
2442.7(6)
2
Red block
0.22·0.19·0.11
31.811(6)
10.781(2)
23.007(4)
90
˚
a (A)
˚
b (A)
˚
c (A)
a (ꢂ)
b (ꢂ)
c (ꢂ)
103.845(2)
90
102.392(3)
90
7706(2)
3
˚
V (A )
3796.7(8)
4
100(2)
Z
T (K)
8
100(2)
173(2)
1.704
1.318
173(2)
1.596
0.982
Dc (gÆcmÀ3
)
1.772
2.285
1.632
1.215
l (mmÀ1
)
Scan range (ꢂ)
3.80<2h<57.10
8834
8264
2.64<2h<56.84
10500
6996
2.62<2h<57.12
9997
4319
2.62<2h<57.30
9342
5486
Unique reflections
Refl. used [I>2r(I)]
Rint
0.0558
0.0789
0.0979
0.1183
Final R indices [I>2r(I)]
R indices (all data)
Goodness-of-fit
0.0282, wR2 0.0540
0.0322, wR2 0.0555
1.023
0.0778, wR2 0.2218
0.1153, wR2 0.2512
1.073
0.0755, wR2 0.1574
0.1830, wR2 0.2234
0.881
0.0604, wR2 0.1289
0.1254, wR2 0.1513
1.009
À3
˚
Max, Min Dq/e (A
)
0.714, À0.481
6.034, À1.836
1.319, À1.436
1.579, À0.993
Fig. 3. Infinite host–guest chain of [4-BrC6H4COOHꢁ1]+.
Surprisingly, addition of 4-methoxybenzoic acid (4-
MeOC6H4COOH) to an acetone solution of [1][BF4]
gives rise to the formation of [1][BF4]Æ24-
MeOC6H4COOHÆacetone, in which one 4-MeOC6H4-
COOH participates in a hydrogen bond with the l3-
oxo ligand, whereas the second 4-MeOC6H4COOH
forms a dimer with a symmetry related 4-MeOC6H4-
COOH molecule, see Fig. 6. As observed in the crystal
structure of [1][BF4]Æ3,5-Cl2C6H3COOH, a methyl
group of a neighbouring cluster molecule is slightly in-
corporated in the hydrophobic pocket. The distance be-
Fig. 2. ORTEP drawing of [4-BrC6H4COOHꢁ1]+, displacement
ellipsoids are drawn at the 50% probability level, hydrogen atoms
and tetrafluoroborate molecule are omitted for clarity.
˚
(centroidÁ Á Ácentroid 3.92 A), the second between two
symmetry related hexamethyl benzene ligand of 1 (cen-
˚
troidÁ Á Ácentroid 4.11 A). These interactions are sum-
marised in Fig. 5. The distance observed between the
p-stacking interacting systems are slightly longer than
the theoretical value calculated for these stacking modes
[10].
˚
tween the methyl carbon and the Ru3 plane is 3.96(1) A.
Finally, with 2-naphtoic acid (2-C10H7COOH), the
l3-oxo ligand is also hydrogen-bonded to the acid

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B. Therrien et al. / Journal of Organometallic Chemistry 689 (2004) 2820–2826
Fig. 4. ORTEP drawing of [1][BF4]Æ3,5-Cl2C6H3COOHÆCHCl3 Æace-
tone, displacement ellipsoids are drawn at the 50% probability level,
hydrogen atoms, solvent molecules and tetrafluoroborate are omitted
for clarity.
˚
function, OÁ Á ÁO distance 2.583(7) A, O–HÁ Á ÁO angle of
161.1ꢂ, see Fig. 7.
Interestingly, the 2-naphtoic acid is nested between
four cluster molecules, see Fig. 8. The end of the 2-naph-
toic acid, opposite to the acid function, pointed in the
hydrophobic pocket of a cluster cation, the closest car-
Fig. 6. ORTEP drawing of [1]+ Æ4-MeOC6H4COOH (top), dimer of 4-
MeOC6H4COOH (bottom).
˚
bon–carbon distance being 3.660(9) A. Two closed par-
allel p-stacking interactions, with carbon–carbon
˚
distances as closed as 3.385(9) and 3.440(9) A, generate
a very compact packing within the crystal.
([1][BF4]) was prepared according to published methods
[5].
3. Experimental
3.2. CSI-MS
3.1. General remarks
Typical measurement conditions are as follows: accel-
eration voltage, 5.0 kV; needle voltage, 2.9 kV; needle
current, 0–1000 nA; orifice voltage, 54 kV; resolution
(10% valley definition), 1000; sample flow, 0.5 mL/h; sol-
Solvents (technical grade) and other reagents were
purchased (Aldrich, Fluka) and used as received. The
starting compound [H3Ru3(C6H6)(C6Me6)2(O)][BF4]
Fig. 5. Main interactions involved in the crystalline packing of [1][BF4]Æ3,5-Cl2C6H3COOHÆCHCl3.

B. Therrien et al. / Journal of Organometallic Chemistry 689 (2004) 2820–2826
2825
perature for several days, the test tube being slightly
open, until thin red blocks are observed.
Preparation of [1][BF4]Æ24-MeOC6H4COOHÆace-
tone : In a test tube, 1 mg of [1][BF4] is added to an ac-
etone solution (3 mL) of 4-MeOC6H4COOH (1 mg).
The solution is left at room temperature for two days,
the test tube being slightly open, until orange crystalline
blocks are observed.
Preparation of [1][BF4]Æ2-C10H7COOH: To an ace-
tone solution (3 mL) of [1][BF4] (1 mg) is added 2-naph-
toic acid (1 mg). The mixture is left slightly opened
overnight, and two days later small red blocks are
observed.
Fig. 7. ORTEP drawing of [1][BF4]Æ2-C10H7COOH, displacement
ellipsoids are drawn at the 50% probability level, hydrogen atoms and
tetrafluoroborate anion are omitted for clarity.
3.4. X-ray crystallographic study
The data were measured using a Bruker SMART
CCD diffractometer, using Mo Ka graphite monochro-
mated radiation (k=0.71073 A). The structures were
vent, acetone; spray temperature, À20 ꢂC; ion source
temperature, 25 ꢂC.
˚
solved by direct methods using the program SHELXS-97
[11]. The refinement and all further calculations were
carried out using SHELXL-97 [12]. The H-atoms were in-
cluded in calculated positions and treated as riding at-
oms using the SHELXL default parameters. The non-H
atoms were refined anisotropically, using weighted full-
matrix least-square on F2. In [1][BF4]Æ2-C10H7COOH
the fluor atoms were treated as disordered with partial
occupancy factors of 50:50. Figs. 2, 4, 6 and 7 were
drawn with ORTEP [13] and Figs. 3, 5 and 8 with MER-
CURY [14].
3.3. Crystallisations
Preparation of [1][BF4]Æ4-BrC6H4COOH: In a test
tube, 1 mg of [1][BF4] is added to an acetone solution
(3 mL) of 4-BrC6H4COOH (1 mg). The solution is left
at room temperature overnight, the test tube being
slightly open, until small red blocks are observed.
Preparation of [1][BF4]Æ3,5-Cl2C6H3COOHÆace-
toneÆCHCl3: In a test tube, 1 mg of [1][BF4] in acetone
is added to a chloroform solution (3 mL) of 3,5-
Cl2C6H3COOH (1 mg). The solution is left at room tem-
Fig. 8. Naphtoic acid environment in the crystal structure of [1][BF4]Æ2-C10H7COOH.

2826
B. Therrien et al. / Journal of Organometallic Chemistry 689 (2004) 2820–2826
(b) S. Sakamoto, M. Yoshizawa, T. Kusukawa, M. Fujita, K.
Yamaguchi, Org. Lett. 3 (2001) 1601;
4. Supplementary data
(c) Y. Yamanoi, Y. Sakamoto, T. Kusukawa, M. Fujita, S.
Sakamoto, K. Yamaguchi, J. Am. Chem. Soc. 123 (2001)
980;
CCDC-235053 [1][BF4]Æ4-BrC6H4COOH, 235054
[1][BF4]Æ3,5-Cl2C6H3COOHÆacetoneÆCHCl3,
[1][BF4]Æ4-MeOC6H4COOHÆacetone, and
235055
235056
(d) S. Sakamoto, T. Imamoto, K. Yamaguchi, Org. Lett. 3
(2001) 1793.
[1][BF4]Æ2-C10H7COOH contain the supplementary crys-
tallographic data for this paper. These data can be ob-
tained free of charge via http://www.ccdc.cam.ac.uk/
data_request/cif, by emailing data_request@ccdc.cam.
ac.uk, or by contacting The Cambridge Crystallographic
Data Centre, 12, Union Road, Cambridge CB2 1EZ, UK;
fax: +44-1223-336033.
[3] T. Suzuki, Y. Yamagiwa, Y. Matsuo, S. Sakamoto, K. Yamag-
uchi, M. Shibasaki, R. Noyori, Tetrahedron Lett. 42 (2001) 4669.
[4] (a) S. Sakamoto, M. Fujita, K. Kim, K. Yamaguchi, Tetrahedron
56 (2000) 955;
(b) A. Tsuda, T. Nakamura, S. Sakamoto, K. Yamaguchi, A.
Osuka, Angew. Chem. Intl. Ed. Engl. 41 (2002) 2817;
(c) M. Ikeda, M. Takeuchi, S. Shinkai, F. Tani, Y. Naruta, S.
Sakamoto, K. Yamaguchi, Chem. Eur. J. 8 (2002) 5541;
(d) M. Ochiai, T. Suefuji, K. Miyamoto, N. Tada, S. Goto, M.
Shiro, S. Sakamoto, K. Yamaguchi, J. Am. Chem. Soc. 125
(2003) 769.
Acknowledgements
[5] M. Faure, M. Jahncke, A. Neels, H. Stoeckli-Evans, G. Suss-
¨
Fink, Polyhedron 18 (1999) 2679.
This work was supported by the Swiss National Sci-
ence Foundation (Grant No. 20-67834-02). The authors
thank the Johnson Matthey Technology Centre for a
generous loan of ruthenium chloride. B. Therrien thanks
JSPS, Japan Society for the Promotion of Science, for a
fellowship.
[6] L. Vieille-Petit, B. Therrien, G. Suss-Fink, T.R. Ward, J.
¨
Organomet. Chem. 684 (2003) 117.
[7] B. Therrien, L. Vieille-Petit, G. Suss-Fink, Inorg. Chim. Acta, in
¨
press.
[8] G. Suss-Fink, M. Faure, T.R. Ward, Angew. Chem. 114 (2002)
¨
105;
Angew. Chem. Int. Ed. 41 (2002) 99.
[9] NMR conditions; 3.3 mg of benzoic acid, 20 mg of 1 in 0.7 mL of
acetone-D6, Bruker 400 MHz spectrometer, À20 ꢂC.
[10] S. Tsuzuki, K. Honda, T. Uchimura, M. Mikami, K. Tanabe, J.
Am. Chem. Soc. 124 (2002) 104.
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