Dihalogen-halogenomethyl complexes of indium(III) X2InCH2X (X = Br, I): Simultaneous coordination of soft and hard ligands

Article abstract of DOI:10.1016/j.jorganchem.2009.03.001

Halogenomethyl-dihalogen-indium(III) compounds X₂InCH₂X (X = Br, I) obtained from indium monohalides and methylene dihalides were reacted with the soft donor ligands dialkylsulfides, R₂S (R = CH₃, CH₂

Full text of DOI:10.1016/j.jorganchem.2009.03.001

Journal of Organometallic Chemistry 694 (2009) 2228–2233
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Journal of Organometallic Chemistry
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Dihalogen–halogenomethyl complexes of indium(III) X2InCH2X (X = Br, I):
Simultaneous coordination of soft and hard ligands
*
Clovis Peppe , Fabiano Molinos de Andrade, Jaqueline Pinto Vargas, Melina de Azevedo Mello,
Railander Alves Barcellos, Robert A. Burrow, Rubia Mara Siqueira da Silva
Laboratório de Materiais Inorgânicos, Departamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria-RS, Brazil
a r t i c l e i n f o
a b s t r a c t
Article history:
Halogenomethyl–dihalogen–indium(III) compounds X2InCH2X (X = Br, I) obtained from indium monoha-
lides and methylene dihalides were reacted with the soft donor ligands dialkylsulfides, R2S (R = CH3,
CH2Ph) to afford the corresponding dialkylsulfonium methylide complexes of InX3, X3InCH2SR2 (X = Br,
R = CH3, 1; X = I, R = CH3, 2; X= I, R = CH2Ph, 3). Compound 1 was reacted with the hard donor ligands
dimethylsulfoxide or triphenylphosphine oxide to give the corresponding 1:1 adduct, Br3(L)InCH2S(CH3)2
(L = (CH3)2SO, 4; L = (C6H5)3PO, 5). Compounds 1–5 were fully characterized in solution by NMR spectros-
copy and in the solid state by X-ray methods.
Received 6 February 2009
Received in revised form 26 February 2009
Accepted 2 March 2009
Available online 9 March 2009
Keywords:
Indium
Halogenomethyl complexes
Dialkylsulfonium methylide complexes
Crystal structure determination
Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction
duced [21]; further effective halogenomethyl–metal complexes of
samarium [22,23] and aluminium [24] were developed for cyclo-
Oxidation of indium monohalides, InX with alkylhalides, R–X to
produce organoindium(III) compounds of general structure RInX2
is a well-established process [1,2]. Similarly, oxidative insertions
of InX into the carbon–halogen bonds of organyl dihalides, RR1CX2
(R = R1 = H, X = Br, I [3,4]; R = H, R1 = CN, X = Br [5]; R = H, R1 =
PhCO, X = Cl [6,7]) and trihalides, RCX3 (R = H, X = Cl, Br, I [8–10];
R = CN, X = Cl [11]) lead to the corresponding halogenoalkyl, X2InC-
RR1X and the dihalogenoalkyl, X2InCRX2 compounds of indium(III).
While some of these compounds contain nucleophilic alkyl substit-
uents capable of coupling to electrophiles [5–7,10,11], the methy-
lene dihalide derivatives have been used mainly as models for
coordination chemistry studies. Independently, we have deter-
mined that ligands with the hard donor atom oxygen, LH, such as
ethers, dimethylsulfoxide and triphenylphosphine oxide coordi-
nate to the metallic center of the Br2In(LH)nCH2Br complex [12],
while bases with soft donor atoms, LS, displace the bromine atom
of the bromomethyl substituent to form corresponding ylides of
InBr3 of general structure Br3InCH2LS [13–17].
propanations. A ‘‘butterfly-type” transition state structure contain-
ing an electrophilic carbene was proposed during the stereospecific
cyclopropanation of alkenes with IZnCH2I [18,25–27] (Scheme 1).
Despite the structural and electronic similarities between the
X2InCH2X (X = Br, I) compounds with the Simmons–Smith reagent,
IZnCH2I and its analogues, we were disappointed to verify that the
indium complexes were not able to act as methylene carriers in
cyclopropanations. The remarkable stability of the X2InCH2X com-
pounds allied with their ability to coordinate to hard and soft bases
through their two different electrophilic sites suggest that the
halogenomethylic complexes of indium are, on the other hand, po-
tential starting materials to obtain novel metal organic frameworks
(MOFs) which have been extensively studied in the past few years
due to their application in catalysis, fuel storage, ion and molecular
recognition [28]. To acquire a deeper knowledge on the coordina-
tion chemistry of the indium organometallics to design novel
MOF’s, we now set to investigate the conditions to prepare adducts
of X2InCH2X of general structure X3(LH)nInCH2LS using dialkylsul-
fides R2S (R = CH3, CH2Ph) as soft ligands (LS) and dimethylsulfox-
ide and triphenylphosphine oxide acting as hard ones (LH).
The X2InCH2X compounds are structurally related to IZnCH2I,
firstly prepared by Emschwiller from metallic zinc and diiodometh-
ane [18]. The zinc carbenoid is used in the Simmons–Smith reaction
[19,20] for the stereospecific conversion of alkenes into cyclopro-
panes, which is one of the most important methods leading to
three-membered rings. After the pioneer work of Simmons and
Smith, other zinc compounds bearing the Zn–CH2I unit were intro-
2. Results and discussion
2.1. Preparative work
Three new sulfonium methylide complexes X3InCH2SR2 (X = Br,
R = CH3, 1; X = I, R = CH3, 2; X = I, R = CH2Ph, 3) were prepared by
adding the sulfide ligands to solutions of the corresponding
* Corresponding author. Tel.: +55 55 3220 8868; fax: +55 55 3220 8031.
E-mail address: peppe@quimica.ufsm.br (C. Peppe).
0022-328X/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2009.03.001

C. Peppe et al. / Journal of Organometallic Chemistry 694 (2009) 2228–2233
2229
I
ZnI
R
R2
R4
R
R2
R4
R2
R4
- ZnI2
R
IZnCH2I
R1
R1
R1
Scheme 1. Proposed transition state for the Simmons–Smith reaction.
X
X
X
X
X
X
SR2
X
X
SR2
R2S
CH2X2
L
InX
In
X
In
In
L
1, X= Br, R= CH3
2, X= I, R= CH3
3, X= I, R= CH2Ph
4, X= Br, R= CH3, L= Me2SO
5, X=Br, R= CH3, L=Ph3PO
Scheme 2. Preparation of sulfonium methylide complexes of indium(III).
X2InCH2X compounds generated from InX and CH2X2 (Scheme 2).
Analytically pure single crystals of 1–3 were grown from ace-
tone–ethanol solutions in yields varying from 70% to 84%. Addition
of dimethyl sulfoxide and triphenylphosphine oxide to solutions of
1 in cyclic ethers (THF or 1,4-dioxane) gave Br3(L)InCH2S(CH3)2
(L = (CH3)2SO, 4; L = Ph3PO, 5) in 60% and 92% of yield, respectively,
after recrystallization from acetone–chloroform mixtures. The
analogous adducts of 2 and 3 were not formed through similar
procedure.
The molecular formulae of compounds 1–5 were established by
indium and halide analysis. NMR spectroscopy unequivocally re-
vealed the sulfonium methylide ligands attached to the indium(III)
centers according to the singlets corresponding to the methylide
groups observed from 2.60 to 2.86 ppm, which are in the typical
range observed for other indium(III) ylides [13–17].
2.2. Molecular structure determinations
X-ray single crystal studies allowed to determine the struc-
tures of compounds 1–5 depicted in Figs. 1–4, respectively, and
in which the thermal ellipsoids are drawn at 50% probability le-
vel. Only the figure corresponding to compound 1 is showing be-
cause compound 2 is isostructural. In every case, the structures
consist of discrete molecules, with no significant intermolecular
interactions. In compounds 1–3 the indium atoms are coordi-
nated by three halogen atoms and one sulfonium methylide li-
gands. The coordination geometry around the indium atom of
1–3 is distorted tetrahedral.
Fig. 2. Molecular structure of dibenzylsulfoniummethylide-triiodo-indium(III), 3.
Compound 1 reacts with dimethylsulfoxide and triphenylphos-
phine oxide to produce the mono-adducts 4 and 5, respectively. In
Fig. 3. Molecular structure of dimethylsulfoniummethylide-dimethylsulfoxide-
tribromo-indium(III), 4.
Fig. 1. Molecular structure of dimethylsulfoniummethylide-tribromo-indium(III), 1.

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C. Peppe et al. / Journal of Organometallic Chemistry 694 (2009) 2228–2233
The averaged indium–halogen and indium–carbon distances for
compounds 1–5 are close to other ylide complexes of InBr3 of gen-
eral structure Br3InCH2L (L = Et3 N, Ph3P, Ph3As, Ph3Sb, Bn2S)
[13–17]. On the other hand, compounds 4 and 5 show abnormal
longer indium–oxygen bond distances 0 when compared with the
values of 2.20(1), 2.14(1) and 2.281(6) ÅA measured in the fac octa-
hedral InX3(dmso)3 (X = Cl, Br) [29], in the ionic [InCl2(Ph3PO)4]
[InCl4] [29] and in the closely related Br2In(Ph3PO)2CH2Br [16]
compounds, respectively. These tenuous indium–oxygen bonds
observed in 4 and 5 probably explain the failure to prepare stable
dmso or Ph3PO adducts of the iodide derivatives I3InCH2SR2
(R = Me, Bn).
2.3. The chemical properties of X3InCH2SR2 compounds
Sulfonium ylides are reactive species containing nucleophilic
carbon atoms directed bonded to leaving groups. Their most typi-
cal reactions include coupling with carbonyl compounds (Darzens-
type) and alkenes bearing electron withdrawing groups (Michael
Induced Ring Closure – MIRC) and consecutive ring closures lead-
ing to epoxides and cyclopropanes, respectively. None of the new
indium compounds 1–5 promote these processes. To acquire a
better knowledge about the chemical properties of these com-
pounds, we have examined the thermal decomposition of com-
pound 3 by TGA analysis. The temperature dependence-weight
loss curve shows lost weight in two different range of tempera-
tures: ca. 190–200 °C (ca. 15%) and 205–600 °C (ca. 70%). We were
unable to derive any simple decomposition pathway from the
experiment. We therefore induced the decomposition (Scheme 3
– part a) of compound 3 in boiling 1,4-dimethylbenzene (138 °C).
We were pleased to verify that, after standard work up (see Section
3), two products were isolated: 2,5-dimethylphenyl-phenylmeth-
ane and bis(2,4-dimethylphenyl)methane in 80% of yield. 2,5-
Dimethylphenyl-phenylmethane was produced in similar yield
(84%) refluxing equimolar amounts of dibenzylsulfide and indium
triiodide in p-xylene (Scheme 3 – part b). Bis(2,4-dimethylphenyl)
methane was produced from reactions involving I3InCH2I, InI3 and
CH2I2 in yields varying from 25% to 98% (Scheme 2 – part b) in
refluxing p-xylene. An interesting observation related to this last
reaction is that in some cases we have detected simultaneous
production of trace amounts of 2,5-dimethylphenyl-4-meth-
ylphenylmethane. Friedel–Crafts alkylations for the synthesis of
diarylmethanes using alkyl halides as alkylating agents and tradi-
tional Lewis acid catalysts are known for long time [30]. Recent lit-
erature introduced indium trihalides as efficient catalysts for
Friedel–Crafts reactions using both alkyl halides [31] and benzyl
alcohols [32] as alkylating agents, but to the best of our knowledge
there is no report on Friedel–Crafts alkylation catalyzed by indium
salts using thioethers as the alkyl group source. Despite the nov-
elty, the reaction has little practical value because thioethers are
normally prepared from alkyl halides or alcohols [33]. The rele-
vance of this reaction in the present context is that it allows one
to understand the lack of reactivity of the X3InCH2SR2 compounds
as methylene carriers. Upon heating, it is reasonable to postulate
that the sulfononium methylide complexes of InX3 decompose to
their precursors (see Scheme 1), R2S and X2InCH2X [16], and that
the halogenomethyl compound of indium(III) also decomposes to
InX3 (and/or InX plus CH2X2) [12] which catalyzed the Friedel–
Crafts alkylations of p-xylene.
Fig. 4. Molecular structure of dimethylsulfoniummethylide-tribromo-triphenyl-
phosphineoxide-indium(III), 5.
both cases, the coordination geometry around the indium is dis-
torted trigonal bipyramidal. The equatorial positions are occupied
by two bromine atoms and one sulfonium methylide ligand, while
the apical ligands are one bromine atom and the hard sulfoxide or
phosphine oxide ligands. Perhaps the most interesting difference
between structures 4 and 5 is the orientation relating the sulfo-
nium methylide and the hard sulphoxide and phosphine oxide
ligands. In compound 4 the dimethylsulfonium moiety of the sul-
fonium methylide and the dmso ligands are in the same side of
the equatorial plane, while in compound 5 the dimethylsulfonium
moiety and the Ph3PO are in opposite planes. The torsion angles
S1–C1–In1–O1 are 14.1(3) and 173.1(2)° in 4 and 5, respectively;
no doubt the bulky Ph3PO ligand imposes such stereochemistry.
Table 1 compares the relevant bond distances in compounds
1–5. There are no significant differences in the In–C1 bond lengths
for tetra (in 1) or penta-coordinated (4 and 5) sulfonium methylide
complexes of InBr3. One significant feature is the difference
between the equatorial and axial indium–bromine bonds in com-
0
0
pounds 4 and 5, with the axial bonds 0.125 ÅA and 0.150 ÅA longer
in 4 and 5, respectively.
Table 1
0
Important bond distances (ÅA) and angles (°) for 1–5.
0
Length (AÅ)
1
2
3
4
5
In–Xa
In–Breq
In–Brax
In–C1
S–C1
S–Ca
2.504(1)
–
–
2.17(1)
1.75(1)
1.78(1)
–
2.7107(9)
–
–
2.210(9)
1.73 (1)
1.76(1)
–
2.7097(6)
–
–
2.209(5)
1.737(5)
1.803(6)
–
_
_
a,b
2.5228(6)
2.6482(7)
2.1695(5)
1.750(4)
1.771(5)
2.302(3)
2.5178(6)
2.6677(9)
2.180(4)
1.764(4)
1.791(6)
2.372(3)
c
In–O
Angle (°)
X1–In1–X2
X1–In1–X3
X2–In1–X3
X1–In1–C1
X2–In1–C1
X3–In1–C1
In1–C1–S1
O1–In1–C1
107.29(6)
106.17(8)
104.84(7)
112.6 (3)
108.7(3)
116.7(3)
114.4(5)
–
109.67(3)
111.02(3)
108.36(3)
108.8(2)
110.0 (3)
109.0(3)
114.7(4)
–
109.46(2)
109.78(2)
109.13(2)
107.3(1)
110.9(2)
110.3(2)
118.1(3)
–
97.11(2)
92.85(2)
111.24(3)
90.5 1)
116.9(1)
130.9(1)
118.2(2)
86.3(1)
93.69(2)
96.03(2)
113.86(3)
99.9(1)
120.0(1)
122.1(1)
117.6(2)
77.9 (1)
To conclude, we have synthesized three new dialkylsulfonium
methylide complexes of indium trihalides, X3InCH2SR2 from halog-
enomethyl complexes, X2InCH2X and determined the characteris-
tics of the ligands capable to coordinate to the metallic site of
the ylide complexes to produce compounds of general structure
X3In(L)CH2SR2. We expect to use the full coordinating ability of
the X2InCH2X, in reactions with bidentate ligands, to synthesize
a
Mean value.
Equatorial bromine.
Axial bromine.
b
c

C. Peppe et al. / Journal of Organometallic Chemistry 694 (2009) 2228–2233
2231
(a)
(b)
(PhCH2)2S
2
InI3
84%
I3InCH2S(CH2Ph)2
80%
+
i, ii, iii, iv, v
i: I2InCH2I, p-xylene(exc.), 25%; ii: I3InCH2SMe2, p-xylene(exc.),54%;
iii: InI3, CH2I2, p-xylene(exc.), 60-80% plus traces of 1,4-dimetilphenyl-
tolil-methane, iv: InI3, CH2I2, Me2S, p-xylene(exc.), 73%; v:
I3InCH2SMe2, CH2I2, p-xylene(exc.),98%.
Scheme 3. Friedel–Crafts alkylation of 1,4-dimethylbenzene with 3 (a) and with (PhCH2)2S or CH2I2 catalyzed by indium(III) compounds.
some new one and two-dimensional metal organic frameworks
(MOF’s) of indium, which we shall report briefly. Further, we have
determined that the most important reactivity trend of the
X3InCH2SR2 compounds is their decomposition into their precur-
sors instead of acting as ylide carriers.
under stirring for 24 h. After this time, all the volatiles were re-
moved under vacuo and the residue obtained recrystallized in ace-
tone:ethanol (95%) (1:1, v/v) under the laboratory atmosphere.
This treatment leads to deposition of 1.57 g (3.65 mmol, 73%,
m.p. dec. 105 °C) of Br3InCH2S(CH3)2 as colourless single crystals.
Anal. Calc. for C3H8Br3InS: In, 26.6; Br, 55.7. Found: In, 26.5; Br,
55.8%. 1H NMR (acetone-d6), d 2.72 s, 2H, InCH2S ; 3,14 s, 6H,
S(CH3)2. 13C NMR (acetone-d6), d 31.55, S(CH3)2; InCH2S not de-
tected (due to the high quadrupolar moment of indium, I = 9/2).
3. Experimental
3.1. General
3.2.2. Preparation of I3InCH2S(CH3)2 (2)
InI (0.73 g, 3.0 mmol) and CH2I2 (224 lL, 0.80 g, 3.0 mmol) were
stirred together in acetonitrile (5 mL) until the indium(I) iodide
had completely dissolved (ca. 0.5 h). After dissolution of indium(I)
iodide, (CH3)2S (198 lL, 0.22 g, 3.5 mmol) was added to the
solution, and the mixture was stirred for 3 h. All the volatiles were
removed under vacuo, and the white solid obtained was recrystal-
lized in acetone/ethanol (1:3), giving a colourless crystalline solid
identified as I3InCH2S(CH3)2 (yield 1.30 g, 2.1 mmol, 70% based
on InI, m.p. dec. 114–118 °C). Anal. Calc. for I3InCH2S(CH3)2: In,
20.1; Br, 66.9. Found: In, 20.5; Br, 66.6%. 1H NMR (acetone-d6), d:
2.86 s, 1H, CH2; 3.15 s, 3H, CH3. 13C NMR (acetone-d6), d: 30.90,
InCH2 not detected.
Indium monobromide and monoiodide were prepared by heat-
ing indium metal and the corresponding indium trihalide in a vac-
uum sealed tube at 450 °C. Methylene bromide and iodide (Aldrich)
were dried over Linde 4°Å molecular sieves. X2In(diox)2CH2X
(X = Br, I) wes prepared from InX and CH2X2 as described earlier
[12]. 1,4-Dioxane (diox) was dried over sodium and benzophenone,
and distilled just before use from the blue ketyl form. Chloroform
(ACS grade) was used as supplied. All preparative work was carried
out under dry nitrogen atmosphere, up to the isolation of final prod-
ucts. Proton, carbon and NMR spectra were recorded on the Bruker
DPX-200 and DPX-400 instruments. Thermogravimetric analysis
was carried out on a Shimadzu DTG-60 instrument (nitrogen flow
rate 50 mL minꢀ1); the sample (ca. 10 mg) contained in a platinum
cell was heated from 25 to 600 °C at heating rate of 10 °C minꢀ1
.
Indium and halogen analysis were as described previously [15].
3.2.3. Preparation of I3InCH2S(CH2C6H5)2 (3)
InI (484 mg, 2 mmol) and CH2I2 (536 mg, 0.16 mL, 2 mmol) in
2 mL of dried acetonitrile (CaH2) were stirred in a Schlenk flask
round bottomed flask at room temperature (25 °C), under a dry
nitrogen atmosphere until all the violet solid monoiodide dissolved
(around 30 min) and a clear colourless solution obtained. At this
point, solid dibenzyl sulfide (428 mg, 2 mmol) was added and the
reaction kept under magnetic stirring for 4 h until all the white so-
lid adduct precipitated. The solid is redissolved upon addition of
acetone and slow removal of solvents coupled with freezing gave
I3InCH2S(CH2C6H5)2 as colourless single crystals (1.22 g, 84%, m.p.
dec. 179–180 °C). Anal. Calc. for C15H16I3InS: In, 15.8; I, 52.6.
Found: In, 16.3; I, 53.0%. 1H NMR (acetone-d6), d 2.61 s, 2H, InCH2S;
4.73, d, J = 12.9 Hz, 2H, SCH2Ph; 4.82, d, J = 12.9 Hz, 2H, SCH2Ph;
3.2. Preparative chemistry
3.2.1. Preparation of Br3InCH2S(CH3)2 (1)
InBr (978 mg, 5 mmol) and CH2Br2 (4350 mg, 1.75 mL,
25 mmol) in 25 mL of dried (sodium) 1,4-dioxane were stirred in
a Schlenk round bottomed flask at room temperature (25 °C) under
a dry nitrogen atmosphere until all the red solid monobromide dis-
solved (about 2 h) and a clear colourless solution obtained. At this
point, all the solvents were removed under high vacuo to remove
the dihalide excess. The white solid obtained was redissolved in
25 mL of 1,4-dioxane and to this solution (CH3)2S (253 mg,
0.43 mL, 5.7 mmol) was added via syringe. The solution was kept

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C. Peppe et al. / Journal of Organometallic Chemistry 694 (2009) 2228–2233
7.50, m, 10H. 13C NMR (acetone-d6), d 49.26, SCH2Ph, 129.77,
131.31, 131.68, 132.65; InCH2S not detected.
i. I2InCH2I (0.5 mmol) produced 28 mg (0.125 mmol, 25%) of
bis(2,5-dimethylphenyl)methane,
ii. I3InCH2SMe2 (0.5 mmol) produced 60.5 mg (0.27 mmol, 54%)
of bis(2,5-dimethylphenyl)methane,
iii. InI3 (0.5 mmol), CH2I2 (0.5 mmol) produced 78.4 mg (0.35
mmol, 70%) of bis(2,5-dimethylphenyl)methane together with
trace amounts of 2,5-dimethylphenyl-4-methylphenylme-
thane,
iv. InI3 (0.5 mmol) and CH2I2 (0.5 mmol) and Me2S (0.5 mmol)
produced 78.4 mg (0.36 mmol, 73%) of bis(2,5-dimethyl-
phenyl)methane,
v. I3InCH2SMe2 (0.5 mmol) and CH2I2 (0.5 mmol) produced
78.4 mg (0.49 mmol, 98%) of bis(2,5-dimethylphenyl)meth-
ane.
3.2.4. Preparation of Br3[OS(CH3)2]InCH2S(CH3)2 (4)
Br3InCH2S(CH3)2 (1) (431 mg, 1 mmol) was dissolved in 1,4-
dioxane (7 mL), under a nitrogen atmosphere, and to this solution
was added dimethyl sulfoxide (234 mg, 0.21 mL, 3 mmol) via
syringe. After 2 h of continuous stirring the white solid formed
was filtered, dried under vacuo and recrystallized in acetone:chlo-
roform (1:1, v/v) to produce Br3[OS(CH3)2]InCH2S(CH3)2 (305 mg,
0.6 mmol, 60%, m.p. 109–111 °C). Anal. Calc. for C5H14Br3InOS: In,
22.6; Br, 47.1. Found: In, 22.2; Br, 47.1%. 1H NMR (acetone-d6), d
2.60 s, 6H, OS(CH3)2; d 2.66 s, 2H, InCH2S ; 3.11 s, 6H, S(CH3)2.
13C NMR poor solubility prevented reliable spectrum.
4. Supplementary material
3.2.5. Preparation of Br3[OP(C6H5)3]InCH2S(CH3)2 (5)
The compound was prepared as Br3[OS(CH3)2]InCH2S(CH3)2, ex-
cept that THF was used as the solvent. Br3[OP(C6H5)3]InCH2S(CH3)2
was obtained in 92% of yield (m.p. dec. 180 °C). Colourless single
crystals were grown from acetone:chloroform (1:1, v/v) solution.
Anal. Calc. for C21H23Br3InOPS: In, 16.2; Br, 33.8. Found: In, 15.9;
Br, 33.5%. 1H NMR (acetone-d6); d 2.71 s, 2H, InCH2S ; 3.13 s, 6H,
S(CH3)2; d 7.68 m, 15H, OP(C6H5)3. 13C NMR poor solubility pre-
vented reliable spectrum.
CCDC 711962, 711963, 711964, 711965 and 711966 contain the
supplementary crystallographic data for 1, 2, 3, 4 and 5. These data
can be obtained free of charge from The Cambridge Crystallo-
graphic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Acknowledgment
C.P. thanks CNPq for financial support. Scholarship from CNPq
(to F.M.D., J.P.V., M.D.M, R.A.B.) and from CAPES (to R.M.S.D.) are
acknowledged.
3.2.6. Reactions of I3InCH2SR2 (R = Me, Bn) with (CH3)2SO and
(C6H5)3PO
Solutions of I3InCH2SR2 and dimethylsulfoxide or I3InCH2SR2
and triphenylphosphine oxide in acetone always deposited unre-
acted I3InCH2SR2 upon addition of ethanol 95%, and no sign of ad-
duct formation was observed.
References
[1] C. Peppe, D.G. Tuck, L. Victoriano, J. Chem. Soc., Dalton Trans. (1982) 2165–
2168.
[2] M.A. Khan, C. Peppe, D.G. Tuck, J. Organomet. Chem. 280 (1985) 17–25.
[3] M.A. Khan, C. Peppe, D.G. Tuck, Organometallics 5 (1986) 525–530.
[4] T.A. Annan, M.A. Khan, D.G. Tuck, C. Peppe, Organometallics 10 (1991) 2159–
2166.
3.3. The chemical properties of X3InCH2SR2 compounds
[5] J.A. Nobrega, S.M.C. Gonçalves, C. Peppe, Tetrahedron Lett. 41 (2000) 5779–
5782.
[6] C. Peppe, R.P. das Chagas, Synlett (2004) 1187–1190.
[7] C. Peppe, R.P. das Chagas, Synlett (2006) 605–609.
[8] J.E. dos Santos, C. Peppe, M.A. Brown, D.G. Tuck, Organometallics 15 (1996)
2201–2204.
[9] J.A. Nobrega, C. Peppe, M.A. Brown, D.G. Tuck, Chem. Commun. (1998) 381–
382.
[10] C. Peppe, D.G. Tuck, F.M. de Andrade, J.A. Nobrega, M.A. Brown, R.A. Burrow, J.
Organomet. Chem. 690 (2005) 925–931.
[11] J.A. Nobrega, S.M.C. Gonçalves, C. Peppe, Tetrahedron Lett. 42 (2001) 4745–
4746.
[12] A.B. de Carvalho, M.A.M.A. de Maurera, J.A. Nobrega, C. Peppe, M.A. Brown, D.G.
Tuck, M.Z. Hernandes, E. Longo, F.R. Sensato, Organometallics 18 (1999) 99–
105.
[13] T.A. Annan, D.G. Tuck, M.A. Khan, C. Peppe, Organometallics 10 (1991) 2159–
2166.
[14] L.D. Felix, C.A.F. de Oliveira, R.K. Kross, C. Peppe, M.A. Brown, D.G. Tuck, M.Z.
Hernandes, E. Longo, F.R. Sensato, J. Organomet. Chem. 603 (2000) 203–212.
[15] A.C. de Souza, C. Peppe, Z.G. Rian, D.G. Tuck, Organometallics 8 (1993) 3354–
3357.
3.3.1. The thermal decomposition of I3InCH2SBn2 in 1,4-
dimethylbenzene
I3InCH2SBn2 (179.4 mg, 0.25 mmol) and freshly distilled 1,4-
dimethylbenzene (1.5 mL) were heated under reflux in a Schlenk
tube, under dry N2, for 20 h. At the end of this period, the reaction
was quenched with a saturated NaCl solution and the organic com-
ponents extracted with CH2Cl2 (3 ꢁ 10 mL); this solution was dried
(Na2SO4), filtered and pumped to dryness under vacuum. The oil
obtained was purified by column chromatography (gradient ethyl
acetate:hexanes, 2:98% up to 5:95%). This procedure gave (2,5-
dimethylphenyl)phenylmethane (77 mg, 0.39 mmol, 80%) and
bis(2,5-dimethylphenyl)methane (44.6 mg, 0.20 mmol, 80%).
(2,5-Dimethylphenyl)phenylmethane [32]: colourless oil. 1H
NMR (CDCl3), d 2.19, s, 3H; 2.29, s, 3H; 3.95, s, 2H; 6.93–7.30. m,
8H. 13C NMR (CDCl3), d 19.13; 20.93; 39.39; 125.81; 127.07;
128.31; 128.66; 130.16; 130.74; 133.38; 135.30; 138.62; 140.51.
GCMS (% rel. intens.) 196 (M, 72), 181 (100), 165 (50), 118 (35),
91 (33).
Bis(2,5-dimethylphenyl)methane [34]: m.p. 53.5–54.5 °C. 1H
NMR (CDCl3), d 2.22, s, 6H; 2.23 s, 6H; 3.83, s, 2H; 6.71, s, 2H;
6.94, d, J = 7.6 Hz, 2H; 7.06, d, J = 7.6 Hz, 2H. 13C NMR (CDCl3), d
19.11, 21.01, 36.57, 126.92, 130.03, 133.52, 135.52, 138.26,
138.45. GCMS (% rel. intens.) 224 (M, 86), 209 (57), 194 (24), 179
(30) 118 (100), 91 (31).
(2,5-Dimethylphenyl)phenylmethane was also prepared
(164 mg; 0,84 mmol; 84%) by refluxing InI3 (0.5 mmol) and diben-
zylsulfide (0.5 mmol) in 1,4-dimethyl benzene (1 mL), under dry
N2.
[16] C. Peppe, J.A. Nobrega, M.Z. Hernandes, R.L. Longo, D.G. Tuck, J. Organomet.
Chem. 626 (2001) 68–75.
[17] F.M. de Andrade, W. Massa, C. Peppe, W. Uhl, J. Organometl. Chem. 690 (2005)
1294–1299.
[18] G. Emschwiller, Compt. Rend. 188 (1929) 1555–1557.
[19] H.E. Simmons, R.D. Smith, J. Am. Chem. Soc. 80 (1958) 5323–5324.
[20] H.E. Simmons, R.D. Smith, J. Am. Chem. Soc. 81 (1959) 4256–4264.
[21] H. Lebel, J.-F. Marcoux, C. Molinaro, A.B. Charette, Chem. Rev. 103 (2003) 977–
1050.
[22] G.A. Molander, L.S. Harring, J. Org. Chem. 54 (1989) 3525–3532.
[23] G.A. Molander, J.B. Etter, J. Org. Chem. 52 (1987) 3942–3944.
[24] K. Maruoka, Y. Fukutani, H. Yamamoto, J. Org. Chem. 50 (1985) 4412–4414.
[25] W.-H. Fang, D.L. Phillips, D.-Q. Wang, Y.-L. Li, J. Org. Chem. 67 (2002) 154–160.
[26] H. Hermann, J.C.W. Lohrenz, A. Kühn, G. Boche, Tetrahedron 56 (2000) 4109–
4115.
[27] J. Mareda, N.G. Rondan, K.N. Houk, T. Clark, P.V. Schleyer, J. Am. Chem. Soc. 105
(1983) 6997–6999.
[28] C.R. Samanamú, A.F. Richards, Polyhedron 26 (2007) 923–928.
Bis(2,5-dimethylphenyl)methane was prepared by heating the
following mixtures under refluxing 1,4-dimethyl benzene (1 mL):

C. Peppe et al. / Journal of Organometallic Chemistry 694 (2009) 2228–2233
2233
[29] W.T. Robinson, C.J. Wilkins, Z. Zeying, J. Chem. Soc., Dalton Trans. (1990) 219–
227.
[30] G.A. Olah, Friedel-Crafts and Related Reactions, Wiley Interscience, New York,
NY, 1964. vol. II, Part I.
[32] H.-B. Sun, B. Li, S. Chen, J. Li, R. Hua, Tetrahedron 63 (2007) 10185–10188.
[33] J. March, Advanced Organic Organic Chemistry. Reactions, mechanisms and
structure, Wiley Interscience, New York, NY, 1991.
[34] N. Yonezawa, T. Hino, Y. Tokita, K. Matsuda, T. Ikeda, Tetrahedron 53 (1997)
14287–14296.
[31] M. Kaneko, R. Hayashi, G.R. Cook, Tetrahedron Lett. 48 (2007) 7085–7087.