Synthesis and structure of polynuclear indoxanes and thalloxanes containing bulky m-terphenyl substituents

Article abstract of DOI:10.1021/om9007967

Depending on the reaction conditions, the base hydrolysis of (2,6-MeS ₂C₆H₃In)₂(μ-Cl) ₂Cl₂ (1) in a two-layer system of aqueous NaOH/diethyl ether or toluene afforded 2,6-MeS₂C

Full text of DOI:10.1021/om9007967

Organometallics 2009, 28, 6893–6901 6893
DOI: 10.1021/om9007967
Synthesis and Structure of Polynuclear Indoxanes and Thalloxanes
Containing Bulky m-Terphenyl Substituents
S. Usman Ahmad and Jens Beckmann*
€
Institut fu€r Chemie und Biochemie, Freie Universitat Berlin, Fabeckstrasse 34-36, 14195 Berlin, Germany
Received September 11, 2009
Depending on the reaction conditions, the base hydrolysis of (2,6-Mes2C6H3In)2(μ-Cl)2Cl2 (1) in a
two-layer system of aqueous NaOH/diethyl ether or toluene afforded 2,6-Mes2C6H3InCl2 H2O (2),
3
(2,6-Mes2C6H3In)2(μ-OH)2Cl2 (3), (2,6-Mes2C6H3In)3(μ-OH)4Cl2 (4), and (2,6-Mes2C6H3In)4(μ-
OH)8 (5), respectively, in high yields. The indoxane 5 can be regarded as a heavier and aggregated
congener of arylboronic acids. An attempt at preparing (2,6-Mes2C6H3Tl)2(μ-Cl)2Cl2 (6) by the
chlorination of 2,6-Mes2C6H3Tl (prepared in situ from 2,6-Mes2C6H3Li and TlCl) using SO2Cl2
provided the isomeric diarylthallium cation [(2,6-Mes2C6H3)2Tl]TlCl4 (7). The exposure of crude
reaction mixture consisting of 2,6-Mes2C6H3Tl and LiCl to moist air surprisingly produced (2,6-
Mes2C6H3Tl)2(μ-OH)2Cl2 (8), which reacted with hydrochloric acid to give 6. Base hydrolysis of 8 in
a two-layer system of aqueous NaOH/CHCl3 proceeded with partial cleavage of the m-terphenyl
substituents and yielded the thalloxane cluster (2,6-Mes2C6H3Tl)4Tl2(μ3-O)4(μ-OH)6 (9) in moderate
yield. Compounds 1-9 were characterized by X-ray crystallography.
Introduction
and [(Me3Si)3CGa]4(μ-O)2(μ-OH)4, respectively.5 The de-
gree of condensation and aggregation within these clusters
depends on the method of preparation and most importantly
the nature of the organic substituents, which provide the
kinetic stabilization. In the same review it was pointed out
that there are surprisingly few studies dealing with the heavier
group 13 congeners, which was attributed to the reduced
oxophilicity and lower Lewis acidity of In and Tl.4 We are
aware of only two well-defined indoxane clusters,
The importance of boronic acids, RB(OH)2, and the related
boroxine rings, [RB(μ-O)]3, for many branches of chemistry
cannot be overstated. Arguably, the most prominent applica-
tion involves the use as reagents for transition metal catalyzed
cross-coupling reactions,1 but boronic acids are also of current
interest as building blocks in supramolecular chemistry2 and
for applications in carbohydrate sensing.3 The chemistry of
the heavier aluminoxanes and galloxanes also progresses
at a rapid pace, as highlighted by a recent review.4 This research
is stimulated by the industrial use of polymeric methylalumi-
noxane (MAO) as cocatalyst for the polymerization of ethylene.
While the exact structure of MAO is unknown, a number
of discrete molecular aluminoxane and galloxane clusters
were obtained by the controlled hydrolysis of sterically encum-
bered triorganoallanes and -gallanes. Well-defined examples
include the aluminoxane clusters (t-BuAl)6(μ3-O)4(μ-OH)4,
[t-BuAl(μ3-O)]n (n = 6, 7, 9, 12), [(2,4,6-t-Bu3C6H2Al)4(μ-
O)]4, and [(Me3Si)3CAl]4(μ-O)2(μ-OH)4 and the gallox-
ane clusters (t-BuGa)12(μ3-O)8(μ-O)2(μ-OH)4, (t-BuGa)9(μ3-
6
[(Me3Si)3CIn]4(μ4-O)(μ-OH)6 and [(Me3Si)3CIn(μ3-O)]4,7
which adopt an oxygen-centered adamantane structure and
a cubane-like structure, respectively. During the course of
this work two asymmetric four-membered galloxane and
indoxane rings, [2,6-(20,60-i-Pr2C6H3)C6H3E(μ-O)]2 (E =
Ga, In), were also reported in which further aggregation is
prevented by a bulky m-terphenyl substituent.8 Herein, we
report a number of complementary polynuclear indoxanes
(5) (a) Atwood, D. A.; Cowley, A. H.; Harris, P. R.; Jones, R. A.;
Koschmieder, S. U.; Nunn, C. M.; Atwood, J. L.; Bott, S. G. Organo-
metallics 1993, 12, 24. (b) Mason, M. R.; Smith, J. M.; Bott, S. G.; Barron,
A. R. J. Am. Chem. Soc. 1993, 115, 4971. (c) Landry, C. C.; Harlan, C. J.;
Bott, S. G.; Barron, A. R. Angew. Chem., Int. Ed. Engl. 1995, 34, 1201. (d)
Harlan, C. J.; Gillan, E. G.; Bott, S. G.; Barron, A. R. Organometallics 1996,
15, 5479. (e) Storre, S.; Klemp, A.; Roesky, H. W.; Schmidt, H.-G.;
Noltemeyer, M.; Fleischer, R.; Stalke, D. J. Am. Chem. Soc. 1996, 118,
1380. (f) Storre, S.; Schnitter, C.; Roesky, H. W.; Schmidt, H.-G.;
Noltemeyer, M.; Fleischer, R.; Stalke, D. J. Am. Chem. Soc. 1997, 119,
7505. (g) Storre, J.; Klemp, A.; Roesky, H. W.; Fleischer, R.; Stalke, D.
Organometallics 1997, 16, 3074. (h) Schnitter, C.; Roesky, H. W.; Albers, T.;
Schmidt, H.-G.; Riipken, C.; Parisini, E.; Sheldrick, G. M. Chem.;Eur. J.
1997, 3, 1783. (i) Wehmschulte, R. J.; Power, P. P. J. Am. Chem. Soc. 1997,
119, 8387.
O)9, [(MesGa)6(μ3-O4)(μ-OH)4 THF], (MesGa)9(μ3-O)6(μ-O)3,
3
*Corresponding author. E-mail: beckmann@chemie.fu-berlin.de.
(1) Hall, D. G., Ed. Boronic Acids; Wiley-VCH: Weinheim, 2005; and
references therein.
(2) (a) Braga, D.; Polito, M.; Bracaccini, M.; D’Addario, D.; Tagliavini,
E.; Sturba, L.; Grepioni, F. Organometallics 2003, 22, 2142. (b) Fournier,
J.-H.; Maris, T.; Wuest, J. D.; Guo, W.; Galoppini, E. J. Am. Chem. Soc. 2003,
125, 1002. (c)Pedireddi, V. R.;Lekshmi, N. S.Tetrahedron Lett. 2004, 45, 1903.
(d) Fujita, N.; Shinkai, S.; James, T. D. Chem. Asian J. 2008, 3, 1076. (e)
Mastalerz, M. Angew. Chem., Int. Ed. 2008, 47, 445. (f) Severin, K. Dalton
Trans. 2009, 5254, and references therein.
(3) James, T. D.; Sandanayake, K. R. A. S.; Shinkai, S. Angew.
Chem., Int. Ed. Engl. 1996, 35, 1910. (b) James, T. D.; Shinkai, S. Top.
Curr. Chem. 2002, 218, 159, and references therein.
(4) Roesky, H. W.; Walawalkar, M. G.; Murugavel, R. Acc. Chem.
Res. 2001, 34, 201, and references therein.
(6) Al-Juaid, S. S.; Buttrus, N. H.; Eaborn, C.; Hitchcock, P. B.;
Roberts, A. T. L.; Smith, J. D.; Sullivan, A. C. J. Chem. Soc., Chem.
Commun. 1986, 908.
(7) Uhl, W.; Pohlmann, M. Chem. Commun. 1998, 451.
(8) Zhu, Z.; Wright, R. J.; Brown, Z. D.; Fox, A. R.; Phillips, A. D.;
Richards, A. F.; Olstead, M. M.; Power, P. P. Organometallics 2009, 28,
2512.
r
2009 American Chemical Society
Published on Web 10/29/2009
pubs.acs.org/Organometallics

6894 Organometallics, Vol. 28, No. 24, 2009
Ahmad and Beckmann
Scheme 1
and thalloxanes containing hydroxy groups and chlorine
atoms, which were obtained by the controlled hydrolysis of
arylindium and arylthallium dichlorides containing a similar
m-terphenyl substituent.
easily by their melting points. The molecular structures of
2-5 are shown in Figures 2-5, and selected bond parameters
are collected in the captions of the figures. The structure of
2,6-Mes2C6H3InCl2 H2O (2) comprises a simple Lewis acid
3
-base pair (Figure 2). The spatial arrangement of the In
atom is distorted tetrahedral and defined by a CCl2O donor
Discussion
˚
set. The In-Cl bond lengths of 2 (2.374(2) and 2.408(2) A)
The arylindium dichloride (2,6-Mes2C6H3In)2(μ-Cl)2Cl2
(1)9 was obtained by the reaction of 2,6-Mes2C6H3Li10 with
InCl3 similar to a procedure already published by Robinson
et al. (Scheme 1). While these authors used a benzene/toluene
are somewhat longer than the exocyclic In-Cl bond lengths
˚
of 1, and the In-O bond length of 2 (2.207(5) A) falls within
the range of In-μ-OH groups being observed for 3-5 (see
below). In the crystal lattice, the water molecule is involved in
weak hydrogen bonding with chlorine atoms of adjacent
mixture for the extraction and isolated the solvate 1 C6H6,
3
˚
we avoided the use of aromatic solvents and obtained a
solvent-free crystalline product 1.
molecules (O Cl 3.173(6) and 3.256(6) A). The IR spec-
3 3 3
trum of 2 shows two absorptions at ν~ (OH) = 3611 and
3587 cm-1 that were assigned to OH stretching vibrations.
The molecular structure of (2,6-Mes2C6H3In)2(μ-OH)2Cl2
(3) consists of a four-membered In2(μ-OH)2 ring featuring
tetrahedral In atoms defined by CO2Cl donor sets. It is
noteworthy that similar four-membered In2(μ-OR)2 ring
structures were also observed in methylindium(III) alkoxides
(R = alkyl, aryl).12
The molecular structure of 1 is shown in Figure 1, and
selected bond parameters are collected in the caption of the
figure. The solvent-free orthorhombic modification of 1
measured at 150 K adopts a four-membered In2(μ-Cl)2 ring
structure very similar to that of the monoclinic pseudo
polymorph 1 C6H6 measured at room temperature.9 While
3
the exocylic In-Cl bond lengths are identical within the
experimental error (2.346(4) and 2.344(3) A), the endocylic
˚
The molecular structure of (2,6-Mes2C6H3In)3(μ-OH)4Cl2
(4) contains two of these In2(μ-OH)2 rings that are linked by
a central spirocylic In atom that adopts a square-pyramidal
arrangement defined by a CO4 donor set. The spatial ar-
rangement of the two terminal In atoms resembles those of 3.
The structure of (2,6-Mes2C6H3In)4(μ-OH)8 (5) possesses C2
symmetry and contains four of these spirocylic In atoms that
are involved in four In2(μ-OH)2 rings, two of which are
crystallographically independent. Compound 5 can be re-
garded as a heavier and aggregated analogue of arylboronic
acids. It is worth mentioning that the central (LnM)4(μ-O)8
structural motif of 5 is unprecedented in metalloxane chem-
istry, whereas similar motifs, such as (LnM)3(μ-O)6 and
(LnM)6(μ-O)12, are already known.13 The In-O bond
In-Cl bond lengths are slightly shorter in 1 (2.482(4) and
9
2.491 A) than in 1 C6H6 (2.519(2) and 2.514(2) A). The
˚
˚
3
slightly shorter bond lengths can be attributed to the lower
temperature during the X-ray data collection and is not due
to the “contamination of the μ-Cl sites by μ-OH groups”, as
it was discussed for the related [2,6-(20,60-i-Pr2C6H3)-
C6H3In]2(μ-Cl)2Cl2 (see below).11
The base hydrolysis of (2,6-Mes2C6H3In)2(μ-Cl)2Cl2 (1)
in a two-layer system of aqueous NaOH/diethyl ether or
toluene afforded 2,6-Mes2C6H3InCl2 H2O (2), (2,6-Mes2-
3
C6H3In)2(μ-OH)2Cl2 (3), (2,6-Mes2C6H3In)3(μ-OH)4Cl2 (4),
and (2,6-Mes2C6H3In)4(μ-OH)8 (5), depending on the reac-
tion conditions (NaOH concentration and reaction time)
applied (Scheme 1). Compounds 2-5 were isolated in high
yields as single crystalline materials and can be distinguished
˚
lengths of 3-5 vary within the range 2.093(6) to 2.224(3) A
(12) (a) Veith, M.; Hill, S.; Huch, V. Eur. J. Inorg. Chem. 1999, 1343.
(b) Hecht, E.; Gelbrich, T.; Thiele, K.-H.; Sieler, J. Main Group. Chem.
2000, 3, 109. (c) Chitsaz, S.; Neum€uller, B. Z. Anorg. Allg. Chem. 2001,
627, 2451. (d) Chamazi, N. N.; Heravi, M. M.; Neum€uller, B. Z. Anorg. Allg.
Chem. 2006, 632, 2043.
(13) Roesky, H. W.; Haiduc, I.; Hosmane, N. S. Organometallics
2003, 103, 2579, and references therein.
(9) Robinson, G. H.; Li, X.-W.; Pennington, W. T. J. Organomet.
Chem. 1995, 501, 399.
(10) Ruhlandt-Senge, K.; Ellison, J. J.; Wehmschulte, R. J.; Pauer,
F.; Power, P. P. J. Am. Chem. Soc. 1993, 115, 11353.
(11) (a) Su, J.; Li, X.-W.; Robinson, G. H. Chem. Commun. 1998,
2015. (b) Twamley, B.; Power, P. P. Chem. Commun. 1999, 1805.

Article
Organometallics, Vol. 28, No. 24, 2009 6895
Figure 3. Molecular structure of (2,6-Mes2C6H3In)2(μ-OH)2Cl2
(3) showing 30% probability ellipsoids and the crystallographic
numbering scheme (symmetry code used to generate equivalent
˚
atoms: a = -x, -y, -z). Selected bond parameters [A, deg]:
Figure 1. Molecular structure of (2,6-Mes2C6H3In)2(μ-Cl)2Cl2
(1) showing 30% probability ellipsoids and the crystallographic
numbering scheme. Selected bond parameters [A, deg]: In1-Cl1
2.346(4), In1-Cl2 2.482(4), In1-Cl3 2.491(4), In1-C10 2.118(8),
Cl1-In1-Cl2 103.7(2), Cl1-In1-Cl3 100.0(2), Cl2-In1-Cl3
85.0(1), Cl1-In1-C10 121.7(3), Cl2-In1-C10 120.9(4), Cl3-
In1-C10 118.2(4).
In1-O1 2.130(3), In1-O1a 2.131(3), In1-Cl1 2.368(2), In1-C10
2.138(4), O1-In1-O1a 76.6(1), O1-In1-Cl1 101.72(9), O1a-
In1-Cl1 103.53(9), O1-In1-C10 122.5(2), O1a-In1-C10
120.3(1), C10-In1-Cl1 122.3(1).
˚
Figure 2. Molecular structure of 2,6-Mes2C6H3InCl2 H2O (2)
3
showing 30% probability ellipsoids and the crystallographic
˚
numbering scheme. Selected bond parameters [A, deg]: In1-O1
2.207(5), In1-Cl1 2.374(2), In1-Cl2 2.408(2), In1-C10 2.130(8),
O1-In1-Cl1 91.4(2), O1-In1-Cl2 91.5(2), O1-In1-C10
117.4(3), Cl1-In1-Cl2 109.70(9), Cl1-In1-C10 117.3(2), Cl2-
In1-C10 122.5(2).
Figure 4. Molecular structure of (2,6-Mes2C6H3In)3(μ-OH)4Cl2
(4) showing 30% probability ellipsoids and the crystallographic
numbering scheme. Selected bond parameters [A, deg]: In1-O1
˚
(average 2.159(6) A). None of the hydroxy groups of 3-5 are
˚
involved in hydrogen bonding. This is confirmed by the IR
spectra, which show absorptions at ν~(OH) = 3617 and 3534
cm-1 (3), 3633, 3598, 3568, 3529, and 3484 cm-1 (4), and
3646, 3632, and 3599 cm-1 (5), respectively, which were
assigned to OH stretching vibrations. The endocylic In-Cl
2.211(5), In1-O2 2.142(6), In1-O3 2.138(4), In1-O4 2.200(5),
In1-C10 2.164(6), In2-O1 2.093(6), In2-O2 2.107(5), In2-Cl1
2.455(3), In2-C40 2.122(7), In3-O3 2.1152(5), In3-O4
2.0999(5), In3-Cl2 2.5207(3), In3-C70 2.1420(7), O1-In1-O2
72.5(2), O1-In1-O3 87.0(2), O1-In1-O4 140.2(2), O2-
In1-O3 118.7(2), O2-In1-O4 87.3(2), O3-In1-O4 72.9(2),
O1-In1-C10 111.1(2), O2-In1-C10 121.9(2), O3-In1-C10
119.5(2), O4-In1-C10 108.7(2), O1-In2-O2 75.6(2),
O1-In2-Cl1 104.0(2), O1-In2-C40 124.4(2), O2-In2-Cl1
108.9(2), O2-In2-C40 120.6(3), Cl1-In2-C40 116.3(2),
O3-In3-O4 75.4(2), O3-In3-Cl2 105.7(2), O3-In3-C70
121.4(2), O4-In3-Cl2 108.5(2), O4-In3-C70 121.3(2), Cl2-
In3-C70 117.1(2), In1-O1-In2 104.6(2), In1-O2-In2 106.5(2),
In1-O3-In3 106.0(2), In1-O4-In3 104.4(2).
˚
bond lengths of 4 (2.455(3) and 2.5207(3) A) are somewhat
longer than the related values of 1 and 3. In light of
established molecular structures and bond parameters, we
support the hypothesis of Twamley and Power that the
crystal of [2,6-(20,60-i-Pr2C6H3)C6H3In]2(μ-Cl)2Cl2 origin-
ally investigated by Robinson et al. was in fact a mixture of
the related hydrolysis products [2,6-(20,60-i-Pr2C6H3)C6H3-
In]2(μ-OH)2Cl2 and [2,6-(20,60-i-Pr2C6H3)C6H3In]2(μ-OH)2-
(OH)2.11 It is interesting to compare the (average) In In
3 3 3
separation, which is significantly larger in the chlorine-
˚
11
˚
bridged compounds
1
(3.896(9) A) and [2,6-(20,60-i-
[2,6-(20,60-i-Pr2C6H3)C6H3In]2(μ-OH)2(OH)2 (3.38(2) A)
and the four-membered asymmetric indoxane ring
11
˚
Pr2C6H3)C6H3In]2(μ-Cl)2Cl (3.7765(4) A) than in the hy-
˚
droxy-bridged compounds 3 (3.345(1) A), 4 (3.401(2) A), and
˚
5 (3.350(2) A). Notably, the latter values are also in good
agreement with the In In separation observed in the
mixture of [2,6-(20,60-i-Pr2C6H3)C6H3In]2(μ-OH)2Cl2 and
8
0
0
˚
˚
[2,6-(2 ,6 -i-Pr2C6H3)C6H3In(μ-O)]2 (3.598 A). Compounds
1-5 are readily soluble in most organic solvents. The 1H and
13C NMR spectra show one (1, 2, 3, 5) and two sets (4) of
signals for the m-terphenyl substituents.
3 3 3

6896 Organometallics, Vol. 28, No. 24, 2009
Ahmad and Beckmann
Figure 6. Molecular structure of [2,6-Mes2C6H3)2Tl]TlCl4 (7)
showing 30% probability ellipsoids and the crystallographic
numbering scheme. Selected bond parameters [A, deg]: Tl1-
C10 2.126(9), Tl1-C40 2.127(9), Tl2-Cl1 2.412(4), Tl2-Cl2
2.394(4), Tl2-Cl3 2.413(6), Tl2-Cl4 2.398(5), C10-Tl1-C40
177.4(3), Cl1-Tl2-Cl2 108.2(2), Cl1-Tl2-Cl3 111.0(2), Cl1-
Tl2-Cl4 107.1(2), Cl2-Tl2-Cl3 106.9(2), Cl2-Tl2-Cl4 112.7-
(2), Cl3-Tl2-Cl4 110.9(2).
Figure 5. Molecular structure of (2,6-Mes2C6H3In)4(μ-OH)8 (5)
showing 30% probability ellipsoids and the crystallographic
numbering scheme. Selected bond parameters [A, deg]: In1-O1
˚
˚
2.189(3), In1-O2 2.137(3), In1-O3 2.163(3), In1-O4 2.190(3),
In2-O1a 2.198(3), In1-C10 2.198(5), In2-O2a 2.141(3),
In2-O3 2.136(3), In2-O4 2.224(3), In2a-O1 2.198(3), In2a-O2
2.141(3), In2-C40 2.192(4), O1-In1-O2 71.5(1), O1-In1-O3
84.0(1), O1-In1-O4 142.6(1), O2-In1-O3 106.9(1),
O2-In1-O4 87.8(1), O3-In1-O4 72.3(1), O1-In1-C10
108.7(2), O2-In1-C10 127.0(2), O3-In1-C10 126.1(2), O4-
In1-C10 108.6(2), O1-In2a-O2 71.3(1), O1a-In2-O3 86.1(1),
O1a-In2-O4 142.1(1), O2a-In2-O3 107.4(1), O2a-In2-O4
85.8(1), O3-In2-O4 72.2(1), O1a-In2-C40 110.4(2), O2a-
In2-C40 125.2(2), O3-In2-C40 127.4(2), O4-In2-C40 107.4-
(2), In1-O1-In2a 102.1(1), In1-O2-In2a 105.8(1), In1-O3-
In2 108.5(1), In1-O4-In2 104.4(1).
Scheme 2
The m-terphenyllithium 2,6-Mes2C6H3Li10 was reacted
with TlCl to produce 2,6-Mes2C6H3Tl in analogy with a
procedure published for similar m-terphenylthallium(I)
compounds.14 It is noted that the structure of these com-
pounds is very sensitive to the steric demand of the organic
substituent; for example, 2,6-(20,40,60-i-Pr3C6H2)2C6H3Tl is a
monomer, 2,6-(20,60-i-Pr2C6H3)2C6H3Tl is a dimer, and
2,6-(20,60-Me2C6H3)2C6H3Tl is a trimer, respectively. De-
spite several attempts, we failed to separate 2,6-Mes2C6H3Tl
from the byproduct LiCl by recrystallization from inert
solvents, such as toluene and diethyl ether. Consequently,
the crude mixture of 2,6-Mes2C6H3Tl and LiCl was chlori-
nated using SO2Cl2, upon which the color changed from
purple to yellow. To our surprise, the extraction of the crude
reaction mixture with CHCl3 did not afford the expected
(2,6-Mes2C6H3Tl)2(μ-Cl)2Cl2 (6), but the isomeric dia-
rylthallium cation [(2,6-Mes2C6H3)2Tl]TlCl4 (7) as a color-
less crystalline solid in good yield (Scheme 2), which implies
that a migration of m-terphenyl groups occurred. The mole-
cular structure of 7 is shown in Figure 6, and selected bond
parameters are collected in the caption of the figure. Crystals
of 7 contain essentially separated [(2,6-Mes2C6H3)2Tl]þ ca-
organothallium cations that are involved in significant second-
˚
ary Tl Cl (3.046(3) and (3.119(3) A) and Tl F (2.796-
3 3 3
3 3 3
˚
(8) A) interactions, which can be attributed to the smaller size
of the mesityl groups. Like the isoelectronic [(2,6-Mes2C6-
H3)2Hg]17 and the cation of [(2,6-Mes2C6H3)2Ga]Li{Al[OCH-
(CF3)2]4}2,18 the [(2,6-Mes2C6H3)2Tl]þ cation of 7 possesses an
almost linear C-M-C linkage (178.6(3)°, M = Hg; 175.69-
(7)°, M = Ga; 177.4(3)°, M = Tl). By contrast, the more Lewis
acidic cation of [(2,6-Mes2C6H3)2Al][B(C6F5)4]19 reveals an
-
tions and TlCl4 anions. By contrast, the closely related
compounds [Mes2Tl][MesTlCl3]15 and [Mes2Tl]BF416 comprise
(14) (a) Niemeyer, M.; Power, P. P. Angew. Chem., Int. Ed. 1998, 37,
1277. (b) Wright, R. J.; Phillips, A. D.; Hino, S.; Power, P. P. J. Am. Chem.
Soc. 2005, 127, 4794.
(17) Niemeyer, M.; Power, P. P. Organometallics 1997, 16, 3258.
(18) Wehmschulte, R. J.; Steele, J. M.; Young, J. D.; Khan, M. A.
J. Am. Chem. Soc. 2003, 125, 1470.
(15) Laguna, A.; Fernandez, E. J.; Mendia, A.; Ruiz-Romero, M. E.;
Jones, P. G. J. Organomet. Chem. 1989, 365, 201.
(16) Kuzu, I.; Neumuller, B. Z. Anorg. Allg. Chem. 2007, 633, 941.
(19) Young, J. D.; Khan, M. A.; Wehmschulte, R. J. Organometallics
2004, 23, 1965.
€

Article
Organometallics, Vol. 28, No. 24, 2009 6897
Figure 8. Molecular structure of (2,6-Mes2C6H3Tl)2(μ-OH)2Cl2
(8) showing 30% probability ellipsoids and the crystallographic
numbering scheme (symmetry code used to generate equivalent
Figure 7. Molecular structure of (2,6-Mes2C6H3Tl)2(μ-Cl)2Cl2
(6) showing 30% probability ellipsoids and the crystallographic
numbering scheme (symmetry code used to generate equivalent
˚
atoms: a = -x, -y, -z). Selected bond parameters [A, deg]: Tl1-
˚
atoms: a = -x, -y, -z). Selected bond parameters [A, deg]:
O1 2.202(9), Tl1-O1a 2.25(1), Tl1-Cl1 2.546(4), Tl1-C10 2.10-
(1), O1-Tl1-O1a 76.1(3), O1-Tl1-Cl1 96.6(3), O1a-Tl1-Cl1
97.2(3), O1-Tl1-C10 125.4(4), O1a-Tl1-C10 121.4(4), Cl1-
Tl1-C10 126.8(3).
Tl1-Cl1 2.427(3), Tl1-Cl2 2.633(2), Tl1-Cl2a 2.681(2), Tl1-
C10 2.159(7), Cl1-Tl1-Cl2 93.08(7), Cl1-Tl1-Cl2a 99.05(8),
Cl2-Tl1-Cl2a 84.37(7), Cl1-Tl1-C10 130.7(2), Cl2-Tl1-
C10 124.6(2), Cl2a-Tl1-C10 113.8(2).
vibrations of hydroxy groups that are not involved in
hydrogen bonding. Similarly to the In In separation of 1
C-Al-C angle (159.17(5)°) that is distorted from linearity,
due to significant Al π interaction with the ipso-C atoms of
3 3 3
3 3 3
˚
˚
(3.896(9) A) and 3 (3.345(1) A), the Tl Tl separation of 6
the o-mesityl groups. Similar M π interactions appear to be
3 3 3
3 3 3
˚
˚
(3.937(2) A) and 8 (3.502(4) A) is distinctively different.
The base hydrolysis of (2,6-Mes2C6H3Tl)2(μ-OH)2Cl2 (8)
in a two-layer system of aqueous NaOH/CHCl3 afforded
absent in the heavier compounds with M = Hg, Ga, Tl.
˚
The Tl-Cl bond lengths (average 2.404(4) A) of the
-
tetrahedral TlCl4 anion of 7 resemble those with other
counterions (e.g., Bu4Nþ).20 The electrospray ionization
time-of-flight mass (ESI-TOF-MS) spectrum of 7 (MeOH,
positive mode) shows only one mass cluster at m/z = 831.4 g
mol-1, which was assigned to the [(2,6-Mes2C6H3)2Tl]þ
cation.
only
a single product, the thalloxane cluster (2,6-
Mes2C6H3Tl)4Tl2(μ3-O)4(μ-OH)6 (9), which was isolated as
colorless crystals in moderate yield (Scheme 2). The forma-
tion of 9 can be rationalized by the partial hydrolytic
cleavage of Tl-C bonds. All attempts to prepare a chlorine-
free thalloxane without the concomitant cleavage of Tl-C
bonds failed. The molecular structure of 9 is shown in
Figure 9, and selected bond parameters are collected in the
caption of the figure. We critically note that with the excep-
tion of Tl1 and Tl2 all atoms of the inorganic core are
disordered over two positions (see Supporting Information),
which can be attributed to the shielding of the m-terphenyl
substituents dominating the crystal packing. We already
made a similar observation for the molecular structure of
the mixed-valent antimony oxo cluster (2,6-Mes2C6H3Sb)2-
(ClSb)4(μ3-O)8, which contains the same m-terphenyl sub-
stituent.21 The spatial arrangement of the organometallic Tl
atoms of 9 is distorted tetradedral, whereas the inorganic Tl
atoms are best described as distorted square pyramidal. The
When a crude reaction mixture consisting of 2,6-
Mes2C6H3Tl and LiCl was exposed to moist air, the color
faded immediately. Extraction with chloroform surprisingly
afforded (2,6-Mes2C6H3Tl)2Cl2(μ-OH)2 (8), the Tl analogue
of 3, in reasonable yields (Scheme 2). Treatment of 8 with
hydrochloric acid provided (2,6-Mes2C6H3Tl)2(μ-Cl)2Cl2
(6), the elusive analogue of 1. The molecular structures of 6
and 8 are shown in Figures 7 and 8, and selected bond
parameters are collected in the captions of the figures. Not
surprising, the structures of 6 and 8 closely resemble those of
the lighter homologues 1 and 3. The spatial arrangement of
the Tl atoms is tetrahedral and defined by CCl3 and CO2Cl
donor sets, respectively. Again, the endocyclic Tl-Cl bond
˚
˚
lengths (2.681(2) and 2.633(2) A for 6 and 2.546(4) A for 8)
˚
Tl-O bond lengths of 9 vary between 2.00(2) and 2.69(2) A
are slightly longer than the related exocyclic value (2.427(3)
˚
and are not discussed in more detail due to the disorder (see
Supporting Information). The hydroxy groups were tenta-
tively assigned on the basis of the coordination numbers of
the O atoms. The presence of hydroxy groups is confirmed by
IR spectroscopy. The IR spectrum of 9 shows only one
absorption at ν~(OH) = 3596 cm-1 that arose from OH
stretching vibrations. Attempts to independently confirm the
A for 6). Interestingly, the Tl-O bond lengths of 8 (2.202(9)
˚
and 2.25(1) A) are only marginally longer than the In-O
˚
bond lengths of 3-5 (average 2.159(6) A), which is presum-
ably due to the fact that Tl is only marginally larger than In
(as the result of the lanthanide contraction). The IR spec-
trum of 8 shows two absorptions at ν~(OH) = 3574 and 3551
cm-1, which were unambiguously assigned to OH stretching
(20) Rudawska-Frackiewicz, K.; Siekierski, S. J. Coord. Chem. 2004,
57, 777.
(21) Beckmann, J.; Heek, T.; Takahashi, M. Organometallics 2007,
26, 3633.

6898 Organometallics, Vol. 28, No. 24, 2009
Ahmad and Beckmann
Experimental Section
General Procedures. The m-terphenyl lithium 2,6-Mes2-
C6H3Li was prepared according to a literature procedure.10
The starting materials InCl3, TlCl, and SO2Cl2 were obtained
from commercial sources and used as received. The 1H and 13
C
NMR spectra were recorded using Jeol GX 270 and Varian 300
Unity Plus spectrometers and are referenced to SiMe4. Micro-
analyses were obtained from a Vario EL elemental analyzer.
Infrared spectra were recorded using a Nexus FT-IR spectro-
meter with a Smart DuraSamplIR. Electron impact mass (EI-
MS) spectra were measured using a Varian MAT 711 mass
spectrometer. The electron energy was set to 80 eV. The
electrospray ionization time-of-flight mass (ESI-TOF-MS)
spectrum was obtained using an Agilent 6210 ESI-TOF mass
spectrometer. The solvent flow rate was adjusted to 4 μL min-1
and the spray voltage set to 4 kV.
Synthesis of (2,6-Mes2C6H3In)2(μ-Cl)2Cl2 (1).9 To a suspen-
sion of InCl3 (1.50 g, 6.77 mmol) in Et2O (20 mL) cooled to
-78 °C was slowly added a solution of 2,6-Mes2C6H3Li (2.16 g,
6.77 mmol) in Et2O (40 mL). The reaction mixture was allowed
to warm to room temperature and stirred overnight. The solvent
was removed under reduced pressure, and the product was
extracted with warm hexane (100 mL) and filtered. The solvent
was reduced in vacuum to almost one-third, and the precipitates
were redissolved by heating. Crystallization afforded 1 as color-
less crystals (2.57 g, 2.57 mmol, 76%; mp dec at 270 °C).
1H NMR (CDCl3): δ 7.51 (t, 1H; p-C6H3), 7.14 (d, 2H;
m-C6H3), 6.94 (s, 4H; m-Mes), 2.34 (s, 6H; p-CH3), 2.03 (s, 12H;
o-CH3). 13C NMR (CDCl3): δ 148.7, 146.5, 140.2, 137.6, 136.6,
130.4, 128.7, 127.3, (Ar-C) 21.2, 20.9 (Me-C). Anal. Calcd
for C48H50Cl4In2 (998.30): C, 57.75; H, 5.05. Found: C, 57.77;
H, 5.21.
Synthesis of 2,6-Mes2C6H3InCl2 H2O (2). A solution of 1
3
(300 mg, 0.3 mmol) in diethyl ether (30 mL) was hydrolyzed with
a solution of NaOH (48 mg, 1.20 mmol) in water (30 mL). The
mixture was vigorously stirred for 30 min at room temperature
before the layers were separated. The solvent was dried over
Na2SO4 and removed under vacuum. Recrystallization of the
solid residue from CH2Cl2/hexane (1:3) provided 2 as colorless
crystals (280 mg, 0.275 mmol, 92%; mp dec at 300 °C).
1H NMR (CDCl3): δ 7.49 (t, 1H; p-C6H3), 7.12 (d, 2H; m-
C6H3), 6.93 (s, 4H; m-Mes), 2.33 (s, 6H; p-CH3), 2.02 (s, 12H; o-
CH3). 13C NMR (CDCl3): δ 148.3, 140.5, 138.0, 136.6, 130.3,
128.7, 128.0, 127.1 (Ar-C), 21.2, 20.8 (Me-C). IR ν~(OH): 3611,
3587 cm-1. Anal. Calcd for C24H27Cl2InO (517.19): C, 55.73; H,
5.26. Found: C, 55.30; H, 5.43.
Figure 9. (a) Molecular structure of (2,6-Mes2C6H3Tl)4Tl2(μ3-
O)4(μ-OH)6 (9) showing 30% probability ellipsoids and the
crystallographic numbering scheme (symmetry code used to
generate equivalent atoms: a = -x, -y, -z). (b) Inorganic core
˚
of 9. Selected bond parameters [A, deg]: Tl1-O2 2.24(2),
Tl1a-O4 2.19(2), Tl1a-O7 2.14(2), Tl1-O8 2.11(2), Tl1-O9
2.25(2), Tl1a-O10 2.29(2), Tl1-C40 2.14(1), Tl2-O1 2.27(2),
Tl2a-O3 2.21(2), Tl2a-O7 2.08(2), Tl2-O8 2.18(2), Tl2-O9
2.29(2), Tl2a-O10 2.24(1), Tl2-C10 2.14(1), Tl3-O1 2.66(2),
Tl3-O2 2.59(2), Tl3-O3 2.69(2), Tl3-O4 2.59(2), Tl4-O1
2.00(2), Tl4-O2 2.12(2), Tl4-O7 2.40(2), Tl-O8 2.45(2).
Synthesis of (2,6-Mes2C6H3In)2(μ-OH)2Cl2 (3). A solution
of 1 (300 mg, 0.3 mmol) in diethyl ether (30 mL) was hydro-
lyzed with a solution of NaOH (48 mg, 1.2 mmol) in water (30
mL). The mixture was vigorously stirred for 12 h at room
temperature before the layers were separated. The solvent
was dried over Na2SO4 and removed under vacuum. Recrys-
tallization of the solid residue from CH2Cl2/hexane (1:3)
provided 3 as colorless crystals (230 mg, 0.25 mmol, 83%;
mp 300-302 °C).
molecular mass of 9 using electron impact mass (EI-MS)
spectroscopy at ambient conditions failed, as no reason-
able spectrum could be obtained. At 200 °C, the only mass
cluster observed was at m/z = 831.4 g mol-1 and unambigu-
ously assigned to the [(2,6-Mes2C6H3)2Tl]þ cation, which
apparently formed by migration of the m-terphenyl substi-
tuent under MS conditions. Compounds 6-9 are readily
1
soluble in most organic solvents. The H and 13C NMR
1H NMR (CDCl3): δ 7.30 (t, 1H; p-C6H3), 7.02 (d, 2H; m-
C6H3), 6.86 (s, 4H; m-Mes), 2.43 (s, 6H; p-CH3), 1.91 (s, 12H; o-
CH3). 13C NMR (CDCl3): δ 149.2, 142.5, 136.3, 136.2, 135.5,
128.2, 127.8, 126.8 (Ar-C), 21.5, 21.4 (Me-C). IR ν~(OH): 3617,
3534 cm-1. Anal. Calcd for C48H52Cl2In2O2 (961.46): C, 59.96;
H, 5.45. Found: C, 60.13; H, 5.32.
spectra show one set of signals for the m-terphenyl substit-
uents.
Conclusion
Synthesis of (2,6-Mes2C6H3In)3(μ-OH)4Cl2 (4). A solution of
1 (500 mg, 0.5 mmol) in toluene (35 mL) was hydrolyzed with a
solution of NaOH (7.0 g, 175 mmol) in water (35 mL). The
mixture was vigorously stirred overnight at room temperature
before the layers were separated. The solvent was dried over
Na2SO4 and removed under vacuum. Recrystallization of the
solid residue from CHCl3/hexane (1:3) provided 5 as colorless
crystals (380 mg, 0.27 mmol; 80%; mp 342-348 °C).
The family of group 13 element oxide hydroxides has
been extended to a new series of well-defined indoxanes
and thalloxanes that are kinetically stabilized by a bulky
m-terphenyl substituent. These air-stable compounds are
easy accessible on a multigram scale via a simple hydrolysis
route. Studies are underway to investigate the reactivity of
these compounds.

Article
Organometallics, Vol. 28, No. 24, 2009 6899
Table 1. Crystal Data and Structure Refinement for 1-9
1
2
3 2CH2Cl2
3
formula
fw, g mol-1
cryst syst
C48H50Cl4In2
998.32
orthorhombic
0.18 ꢀ 0.17 ꢀ 0.15
Fdd2
27.593(6)
14.179(3)
23.793(5)
90
90
90
9309(3)
8
1.425
150
1.251
4032
C24H25Cl2InO
515.16
C49H50Cl4In2O2
1042.33
monoclinic
0.17 ꢀ 0.16 ꢀ 0.13
P21/n
10.874(5)
16.852(7)
13.180(4)
90
91.89(3)
90
2413(2)
2
1.434
orthorhombic
0.25 ꢀ 0.25 ꢀ 0.11
P212121
8.292(4)
15.249(8)
19.409(9)
90
90
90
2454(2)
4
1.394
cryst size, mm
space group
˚
a, A
˚
b, A
˚
c, A
R, deg
β, deg
γ, deg
3
˚
V, A
Z
Dcalcd, Mg m-3
T, K
150
1.191
1040
150
1.212
1052
μ, mm-1
F(000)
θ range, deg
index ranges
0.99 to 25.25
-32 e h e 31
-19 e k e 17
-37 e l e 36
16 640
99.8
2162
1767
250
1.033
0.0543
0.1389
<0.001
0.970/-0.743
0.99 to 25.25
-9 e h e 9
-17 e k e 18
-23 e l e 19
9466
99.3%
4280
3519
253
0.956
0.0528
0.1304
<0.001
0.533/-1.017
1.96 to 25.25
-13 e h e 12
-20 e k e 18
-15 e l e 15
11 285
99.2%
4321
3045
262
0.938
0.0343
0.0910
<0.001
1.015/-0.922
no. of reflns collcd
completeness to θ max
no. of indep reflns/Rint
no. of reflns obsd with (I > 2σ(I))
no. refined params
GooF (F2)
R1(F) (I > 2σ(I))
wR2(F2) (all data)
(Δ/σ)max
-3
˚
largest diff peak/hole, e A
4
5 H2O 2CHCl3
3
6 1/2CH2Cl2
3
3
formula
fw, g mol-1
cryst syst
C72H75Cl2In3O4
1419.68
triclinic
0.50 ꢀ 0.50 ꢀ 0.14
P1
13.300(8)
16.108(9)
18.934(7)
89.87(4)
105.87(4)
90.73(5)
3901(3)
2
C98H100Cl6In4O9
2093.76
monoclinic
0.48 ꢀ 0.20 ꢀ 0.06
C2/c
24.77(1)
15.353(5)
27.74(1)
90
115.91(3)
90
9488(6)
4
1.466
C49H50Cl6Tl2
1260.33
monoclinic
0.21 ꢀ 0.10 ꢀ 0.09
P21/n
10.615(6)
16.90(1)
13.685(9)
90.00
94.10(5)
90.00
2448(3)
2
1.710
cryst size, mm
space group
˚
a, A
˚
b, A
˚
c, A
R, deg
β, deg
γ, deg
3
˚
V, A
Z
Dcalcd, Mg m-3
T, K
1.208
150
0.987
1440
150
1.183
4232
150
6.933
1216
μ, mm-1
F(000)
θ range, deg
index ranges
1.69 to 25.25
-13 e h e 15
-19 e k e 19
-22 e l e 22
28823
99.3%
14 021
9660
730
1.040
0.0581
0.1943
<0.001
1.916/-1.025
0.99 to 25.25
-29 e h e 29
-18 e k e 17
-23 e l e 33
21866
99.1%
8538
5172
532
0.890
0.0397
0.0836
<0.001
0.894/-0.751
1.92 to 25.25
-12 e h e 12
-20 e k e 20
-16 e l e 16
13128
99.5%
4413
3298
262
0.995
0.0375
0.0973
<0.001
1.569/-1.579
no. of reflns collcd
completeness to θ max
no. of indep reflns/Rint
no. of reflns obsd with (I > 2σ(I))
no. refined params
GooF (F2)
R1(F) (I > 2σ(I))
wR2(F2) (all data)
(Δ/σ)max
-3
˚
largest diff peak/hole, e A

6900 Organometallics, Vol. 28, No. 24, 2009
Ahmad and Beckmann
Table 1. Continued
7 2CHCl3
3
8 2H2O
3
9
formula
fw, g mol-1
cryst syst
C
50H52Cl10Tl2
C48H54Cl2O4Tl2
1174.55
Monoclinic
0.50 ꢀ 0.28 ꢀ 0.27
P21/n
10.84(2)
17.12(2)
13.36(2)
90.00
92.52(10)
90.00
2477(5)
1
1.575
C96H100O10Tl6
2639.98
Monoclinic
0.50 ꢀ 0.17 ꢀ 0.16
P21/n
14.30(1)
20.80(2)
18.082(2)
90.00
108.26(6)
90.00
5108(8)
2
1.716
1416.16
triclinic
0.50 ꢀ 0.50 ꢀ 0.43
P1
10.46(1)
15.55(3)
18.04(2)
87.7(1)
75.30(9)
74.5(1)
2733(7)
2
1.721
cryst size, mm
space group
˚
a, A
˚
b, A
˚
c, A
R, deg
β, deg
γ, deg
3
˚
V, A
Z
Dcalcd, Mg m-3
T, K
150
6.411
1368
150
6.642
1140
150
9.478
2484
μ, mm-1
F(000)
θ range, deg
index ranges
1.77 to 25.25
-12 e h e 11
-18 e k e 18
-21 e l e 21
21358
99.3%
9827
7923
554
1.029
0.0567
0.1687
<0.001
1.590/-2.341
2.37 to 25.25
-13 e h e 13
-20 e k e 18
-13 e l e 16
11063
99.4%
4450
3342
261
1.072
0.0649
0.2045
<0.001
3.258/-1.789
2.37 to 25.25
-17 e h e 14
-24 e k e 24
-21 e l e 21
25482
99.1%
9159
5464
568
1.006
0.0723
0.1782
<0.001
3.542/-1.723
no. of reflns collcd
completeness to θ max
no. of indep reflns/Rint
no. of reflns obsd with (I > 2σ(I))
no. refined params
GooF (F2)
R1(F) (I > 2σ(I))
wR2(F2) (all data)
(Δ/σ)max
-3
˚
largest diff peak/hole, e A
1H NMR (CDCl3): δ 7.46, 7.40 (t, 1H; p-C6H3) 7.10, 7.00 (d,
2H; m-C6H3) 6.93, 6.88 (s, 4H; m-Mes) 2.45, 2.41 (s, 6H; p-
CH3)1.94, 1.92 (s, 12H; o-CH3). 13C NMR (CDCl3): δ 148.6,
148.5, 141.3, 141.0, 137.3, 137.2, 136.8, 136.7, 136.6, 136.5,
128.5, 128.4, 128.2, 128.1, 126.6 126.5 (Ar-C) 21.5, 21.0, 20.9,
Synthesis of [(2,6-Mes2C6H3)2Tl]TlCl4 (7). In the absence of
light, a stirred suspension of TlCl (1.55 g, 6.46 mmol) in Et2O (75
mL) was cooled to -18 °C, and a solution of 2,6-Mes2C6H3Li
(2.07 g, 6.46 mmol) in Et2O (30 mL) was added dropwise. The
reaction mixture was then allowed to warm to room tempera-
ture and stirred for 4 h. Then, the solution was cooled to 0 °C,
and SO2Cl2 (2.11 g, 15.65 mmol) was slowly added via syringe.
The reaction mixture was stirred at room temperature for 2 h
before the precipitate of LiCl was filtered off. The solvent was
removed under reduced pressure and the crude solid recrystal-
20.7 (Me-C). IR ν~(OH): 3633, 3598, 3568, 3529, 3484 cm-1
.
Anal. Calcd for C72H79Cl2In3O4 (1423.75): C, 60.74; H, 5.59.
Found: C, 60.79; H, 5.41.
Synthesis of (2,6-Mes2C6H3In)4(μ-OH)8 (5). A solution of 1
(500 mg, 0.5 mmol) in toluene (35 mL) was hydrolyzed with a
solution of NaOH (7.0 g, 175 mmol) in water (35 mL). The
mixture was vigorously stirred for 12 h at room temperature
before the layers were separated. A fresh solution of NaOH
(7.0 g, 175 mmol) in water (35 mL) was added, and the mix-
ture stirred again for 12 h. The solvent was dried over Na2SO4
and removed under vacuum. Recrystallization of the solid
residue from CHCl3/hexane (1:3) provided 4 as colorless crystals
(340 mg, 0.18 mmol, 74%; mp 354-360 °C).
lized from CHCl3/hexane to give colorless crystals of 7 2
3
CHCl3. The crystals were dried at 50 °C under high vacuum to
give an analytical sample of 7 (yield 2.58 g, 2.20 mmol, 68%; mp
120-124 °C).
1H NMR (CDCl3): δ 7.46 (t, 3H; p-C6H3), 7.09 (d, 2H, m-
C6H3), 6.94 (s, 8H; Ar), 2.33 (s, 12H; Me), 2.05 (s, 24H; Me). 13
C
NMR (CDCl3): δ 141.0, 138.9, 136.4, 135.8, 130.2, 128.3, 127.9,
127.4 (Ar), 21.0, 20.7 (Me). Anal. Calcd for C48H50Cl4Tl2
(1177.48): C, 48.96; H, 4.28. Found: C, 48.73; H, 4.15. ESI-
TOF-MS (MeOH, positive mode): m/z 831.4 ([C48H50Tl]þ).
Synthesis of (2,6-Mes2C6H3Tl)2(μ-OH)2Cl2 (8). In the ab-
sence of light, a stirred suspension of TlCl (1.55 g, 6.46 mmol)
in 75 mL of Et2O was cooled to -18 °C, and a solution of 2,6-
Mes2C6H3Li (2.07 g, 6.46 mmol) in 25 mL of Et2O was added
dropwise to the suspension. The reaction mixture was then
allowed to warm to room temperature and stirred for over
4 h. The solvent was removed under vacuum. The solid residue
was extracted with CHCl3 in the air. After filtration the solvent
was again removed under vacuum. Recrystallization of the
colorless residue from CHCl3/hexane (1:3) yielded 8 as colorless
crystals (2.57 g, 2.25 mmol, 69.8%; mp dec at 270 °C).
1H NMR (CDCl3): δ 7.30 (t, 1H; p-C6H3), 6.87 (d, 2H; m-
C6H3), 6.85 (s, 4H; m-Mes), 2.43(s, 6H; p-CH3), 1.90 (s, 12H; o-
CH3). 13C NMR (CDCl3): δ 149.1, 142.5, 136.3, 135.8, 135.4,
128.2, 127.8, 126.8 (Ar-C) 21.5, 21.4 (Me-C). IR ν~(OH): 3646,
3632, 3599 cm-1. Anal. Calcd for C96H108In4O8 (1849.2): C,
62.35; H, 5.89. Found: C, 62.29; H, 5.87.
Synthesis of (2,6-Mes2C6H3Tl)2(μ-Cl)2Cl2 (6). A solution of 8
(500 mg, 0.43 mmol) in diethyl ether was treated with 1 M HCl
(10 mL). The mixture was stirred for 2 h before the layers were
separated. The organic layer was dried over Na2SO4 and the
solvent removed under vacuum. Recrystallization from CHCl3/
hexane (1:3) furnished 6 as colorless crystals (470 mg, 0.37
mmol, 92%; mp 132-134 °C).
1H NMR (CDCl3): δ 7.45 (t, 1H, p-C6H3), 7.11 (d, 2H, m-
C6H3), 6.94 (s, 4H, m-Mes), 2.32 (s, 6H, p-CH3), 2.05 (s, 12H; o-
CH3). 13C NMR (CDCl3): δ 141.1, 139.0, 136.4, 135.8, 130.2,
128.4, 128.0, 127.5 (Ar-C) 21.0, 20.7 (Me-C). Anal. Calcd for
C48H50Cl4Tl2 (1177.48): C, 48.96; H, 4.28. Found: C, 48.92; H,
4.59.
1H NMR (CDCl3): δ 7.46 (t, 1H; p-C6H3), 7.11 (d, 2H;
m-C6H3), 6.95 (s, 4H; m-Mes), 2.33 (s, 6H; p-CH3), 2.05 (s,
12H; o-CH3). 13C NMR (CDCl3): δ 141.2, 139.1, 136.6, 136.0,
130.3, 128.5, 128.2, 127.6 (Ar-C) 21.2, 21.0 (Me-C). IR ν~(OH):
3574, 3551 cm-1. Anal. Calcd for C48H52Cl2O2Tl2 (1140.59): C,
50.54; H, 4.60. Found: C, 50.50; H, 4.48.

Article
Synthesis of (2,6-Mes2C6H3Tl)4Tl2(μ3-O)4(μ-OH)6 (9). A so-
Organometallics, Vol. 28, No. 24, 2009 6901
model and were refined isotropically. Disorder was resolved
for the In atom of 1 and refined with split occupancies of 0.9
(In1) and 0.1 (In0). Disorder was also resolved for one Tl atom
and five O atoms of 9 and refined with split occupancies of 0.45
(Tl3), 0.05 (Tl30), and 0.5 (Tl4) as well as 0.5 (O1-O10),
respectively. Crystal and refinement data are collected in
Table 1. The absolute structures of 1 and 2 were determined
by refinement of the Flack parameters 0.0(4) and 0.0(3) and
comparison of the R-values of the enantiomeric space groups.
Figures were created using the program DIAMOND.24 Crystallo-
graphic data (excluding structure factors) for the structural
analyses have been deposited with the Cambridge Crystallo-
graphic Data Centre, CCDC numbers 751065 (1), 751066 (2),
751067 (3), 751068 (4), 751069 (5), 751070 (6), 751071 (7),
751072 (8), and 751073 (9). Copies of this information may
be obtained free of charge from The Director, CCDC, 12
Union Road, Cambridge CB2 1EZ, UK (fax: þ44-1223-336033;
e-mail: deposit@ccdc.cam.ac.uk; or http://www.ccdc.cam.
ac.uk).
lution of 8 (500 mg, 0.43 mmol) in CHCl3 (30 mL) was hydro-
lyzed with a solution of NaOH (1.2 g, 30 mmol) in water (30
mL). The mixture was vigorously stirred for 2 h at room
temperature before the layers were separated. The solvent was
dried over Na2SO4 and removed under vacuum. Recrystalliza-
tion of the solid residue from CHCl3/hexane (1:3) provided 9 as
colorless crystals (300 mg, 0.11 mmol, 79%; mp 120-124 °C).
1H NMR (CDCl3): δ 7.45 (t, 1H; p-C6H3), 7.11 (d, 2H;
m-C6H3), 6.94 (s, 4H; m-Mes), 2.33 (s, 6H; p-CH3), 2.05 (s,
12H; o-CH3). 13C NMR (CDCl3): δ 141.1, 139.0, 136.4, 135.8,
130.2, 128.4, 128.0, 127.5 (Ar-C), 21.0, 20.7 (Me-C). IR ν~(OH):
3596 cm-1. Anal. Calcd for C96H106Tl6O10 (2644.2): C, 43.56; H,
4.00. Found: C, 43.49; H, 4.06.
X-ray Crystallography. Intensity data were collected on a
STOE IPDS 2T area detector with graphite-monochromated
˚
Mo KR (0.7107 A) radiation. Data were reduced and corrected
for absorption using the program Stoe X-Area.22 The structures
were solved by direct methods and difference Fourier synthesis
using SHELXS-97 implemented in the program WinGX 2002.23
Full-matrix least-squares refinements on F2, using all data. All
non-hydrogen atoms were refined using anisotropic displace-
ment parameters. Carbon-bonded hydrogen atoms were in-
cluded in geometrically calculated positions using a riding
€
Acknowledgment. Dr. Malte Hesse (Freie Universitat
Berlin) is thanked for the X-ray data collection. The
Deutsche Forschungsgemeinschaft (DFG) is gratefully
acknowledged for financial support.
(22) STOE X-Area and X-Red; Stoe & Cie GmbH: Darmstadt,
Germany, 2004.
(23) Farrugia, L. J. J. Appl. Crystallogr. 1999, 32, 837.
(24) Brandenburg, K.; Putz, H. DIAMOND V3.1d; Crystal Impact
GbR, 2006.
Supporting Information Available: Cif files of 1-9 and figures
of the disordered structure of 9. This material is available free of
charge via the Internet at http://pubs.acs.org.