Synthesis and structures of Ti(III) and Ti(IV) complexes supported by a tridentate aryloxide ligand

Article abstract of DOI:10.1039/b111362c

Titanium complexes of the tridentate aryloxide Me-L^3- [H₃(Me-L) = 2,6-bis(4,6-dimethylsalicyl)-4-tert-butylphenol] have been prepared. Reaction of TiCl₄ with 1 equivalent of H₃(Me-L) gave [Ti(Me-L)Cl]₂

Full text of DOI:10.1039/b111362c

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Synthesis and structures of Ti(III) and Ti(IV) complexes supported
by a tridentate aryloxide ligand
Tsukasa Matsuo,a Hiroyuki Kawaguchi*a and Masahiro Sakaib
a Coordination Chemistry Laboratories, Institute for Molecular Science and CREST,
Japan Science and Technology Corporation (JST), Myodaiji, Okazaki, 444-8585, Japan.
E-mail: hkawa@ims.ac.jp
b Research Center for Molecular Materials, Institute for Molecular Science, Myodaiji, Okazaki,
444-8585, Japan
Received 13th December 2001, Accepted 22nd April 2002
First published as an Advance Article on the web 8th May 2002
Titanium complexes of the tridentate aryloxide Me–L3Ϫ [H3(Me–L) = 2,6-bis(4,6-dimethylsalicyl)-4-tert-butylphenol]
have been prepared. Reaction of TiCl4 with 1 equivalent of H3(Me–L) gave [Ti(Me–L)Cl]2 1. Recrystallization of 1
from THF resulted in formation of the THF adduct Ti(Me–L)Cl(THF)2 2. Treatment of 1 with [NEt4]Cl in THF
quantitatively gave [NEt4][Ti2(Me–L)2Cl3] 3. Complex 1 was reduced with 2 equivalents of potassium to produce the
Ti() complex [Ti(Me–L)(DME)]2 4. Structures of 1, 2, 3 and 4 have been determined by X–ray analyses. For 1, 2
and 4, the Me–L ligand assumes a U-conformation. In the case of 3, it is coordinated in an S-conformation.
Introduction
Results and discussion
Development of ligands that play supporting roles in coord-
ination chemistry has been the subject of intense interest for
many years. In this connection, linked aryloxide ligands have
been very attractive from the viewpoint of determination of the
complex geometry and limited ligand disproportionation. For
example, well characterized transition metal derivatives that
utilized the [4]calixarene ligand were first reported in 1985 by
Power,1 and since then numerous research groups have been
involved in the study of this class of compounds.2 In this con-
text, we are interested in acyclic aryloxide oligomers that are
connected to each other at ortho positions through methylene
linkers,3,4 and our initial focus is on 2,6-bis(4,6-dimethylsalicyl)-
4-tert-butylphenol [H3(Me–L)].5 One of the advantages of this
system is the possible flexible coordination modes, and the
Me–L3Ϫ ligand can adopt either a U- or an S-conformation
(Scheme 1). In addition, there is the opportunity for coordin-
Reaction of TiCl4 with 1 equiv. of H3(Me–L) in refluxing
toluene followed by standard workup afforded [Ti(Me–L)Cl]2 1
as dark red crystals in 85% yield [eqn. (1)]. The 1H NMR spec-
trum in CDCl3 corresponds to a symmetrical conformation,
and the methylene groups appear as one pair of doublets (δ 3.46
and 4.67) along with the singlets of one But (δ 1.17) and two
Me groups (δ 2.24 and 2.38). The crystal structure of 1 was
elucidated by X-ray analysis.
(1)
According to X-ray analysis, an asymmetric unit consists of
two crystallographically independent dimers. In addition, the
lattice contains three toluene molecules per two molecules of
the dimer. Because the two molecules (called molecule A and B)
are structurally very similar, only molecule A is presented in
Fig. 1. Selected bond distances and angles are listed in Table 1.
Complex 1 is dimeric with two inversion-related Ti(Me–L)Cl
units bridged by the central aryloxides of the Me–L ligands.
Each titanium center has a distorted trigonal bipyramidal
geometry. The equatorial plane is bound by two outer aryl-
oxides of the ligand [O(1), O(3)] and one central aryloxide of
another ligand [O(2A)], while one chlorine atom and one cen-
tral phenoxide [O(2)] are on the axis with a Cl(1)–Ti(1)–O(2)
angle of 159.9(1)Њ. The Ti atom is situated 0.20 Å above the
plane defined by the equatorial donors, and is oriented toward
the axial chloride ligand. The Me–L ligands in 1 assume a
Scheme 1
ative unsaturation as compared to the [4]calixarene system.
However, transition metal complexes with linked aryloxide
trimers are rare.6
Herein we present the coordination chemistry of the ligand
Me–L3Ϫ with tetravalent and trivalent titanium ions. Our study
demonstrates that the coordination geometries of Me–L3Ϫ are
determined by a delicate balance of steric and/or electronic
factors of the incoming ligands.
2536
J. Chem. Soc., Dalton Trans., 2002, 2536–2540
This journal is © The Royal Society of Chemistry 2002
DOI: 10.1039/b111362c

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Table 1 Selected bond lengths (Å) and angles (Њ) for compound 1a
Table 2 Selected bond lengths (Å) and angles (Њ) for compound 2
Molecule A
Ti–O(1)
Ti–O(3)
Ti–O(5)
1.796(2)
1.796(2)
2.217(2)
Ti–O(2)
Ti–O(4)
Ti–Cl(1)
1.889(2)
2.200(2)
2.394(1)
Ti(1)–O(1)
Ti(1)–O(3)
Ti(1)–Cl(1)
1.754(3)
1.751(3)
2.278(1)
Ti(1)–O(2)
Ti(1)–O(2A)
Ti(1)–Ti(1A)
2.046(2)
1.985(2)
3.294(1)
O(1)–Ti–O(3)
O(3)–Ti–O(5)
Ti–O(1)–C(1)
Ti–O(3)–C(15)
100.2(1)
171.8(1)
164.0(2)
166.2(2)
O(1)–Ti–O(4)
O(2)–Ti–Cl(1)
Ti–O(2)–C(8)
171.1(1)
163.6(1)
119.7(2)
O(1)–Ti(1)–O(3)
O(2)–Ti(1)–O(2A)
Ti(1)–O(1)–C(1)
Ti(1)–O(3)–C(15)
114.3(2)
70.4(1)
165.5(3)
164.7(3)
O(2)–Ti(1)–Cl(1)
Ti(1)–O(2)–Ti(1A)
Ti(1)–O(2)–C(8)
Ti(1A)–O(2)–C(8)
159.9(1)
109.6(1)
120.2(2)
130.1(2)
(2)
Molecule B
Ti(2)–O(4)
Ti(2)–O(6)
Ti(2)–Cl(1)
1.762(3)
1.750(3)
2.275(1)
Ti(2)–O(5)
Ti(2)–O(5A)
Ti(2)–Ti(2A)
2.053(2)
1.975(2)
3.300(1)
O(4)–Ti(2)–O(6)
O(5)–Ti(2)–O(5A)
Ti(2)–O(4)–C(29)
Ti(2)–O(6)–C(43)
113.9(1)
70.00(11) Ti(2)–O(5)–Ti(2A)
162.5(3)
173.6(3)
O(5)–Ti(2)–Cl(2)
159.19(8)
110.00(11)
117.9(2)
Ti(2)–O(5)–C(36)
Ti(2A)–O(5)–C(36)
132.1(2)
a Atoms carrying the suffix A are related to their counterpart by the
symmetry operator [1 Ϫ x, 1 Ϫ y, Ϫz] and [Ϫx, 2 Ϫ y, 1 Ϫ z] in molecule
A and B, respectively.
Fig. 1 Structure of molecule A in complex 1.
U-conformation, which is reminiscent of the cone conform-
ation of calix[4]arene. The Ti(1)–O(2)–Ti(1A) bridge is asym-
metric, and the bridging Ti(1)–O(2) and Ti(1)–O(2A) distances
are 2.046(2) and 1.985(2) Å, respectively. The terminal and
bridging Ti–O distances average 1.753 Å and 2.016 Å, respect-
ively, and they are comparable to those found in the known
titanium() aryloxides.4,7 The Ti–Ti separation of 3.294(1) Å is
rather long.
Complex 1 readily adds external ligands due to the Lewis
acidity of the titanium center. For example, dissolution of 1 in
THF resulted in dissociation of the dimer 1 and formation of
Fig. 2 Structure of 2ؒTHF.
Table 2. Complex 2 crystallizes with three THF molecules, from
which one is incorporated in the Me–L ligand cavity. Complex 2
consists of discrete monomeric units where one Me–L ligand
facially coordinates to titanium in the U-conformation. Octa-
hedral coordination is completed by one chlorine atom and two
mutually cis THF molecules. The central aryloxide ring of the
Me–L ligand is arranged in a trans-position to the chlorine
atom. The Ti–O(2) distance of the central aryloxide is 1.889(2)
Å, while the Ti–O distances of the outer aryloxides [O(1) and
1
Ti(Me–L)Cl(THF)2 2 [eqn. (2)]. The H NMR spectrum of 2
shows a pattern similar to that of 1. Although crystals of the
THF adduct 2 are solvated by THF, one set of resonances for
the THF protons is observed. This indicates a rapid exchange
between free THF and THF coordinated to the Ti center in 2
on the NMR time scale.
The structure was determined by X-ray diffraction analysis
(Fig. 2), and selected bond distances and angles are listed in
J. Chem. Soc., Dalton Trans., 2002, 2536–2540
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Table 3 Selected bond lengths (Å) and angles (Њ) for compound 3
Table 4 Selected bond lengths (Å) and angles (Њ) for compound 4a
Ti(1)–O(1)
Ti(1)–O(4)
Ti(1)–Cl(1)
Ti(2)–O(2)
Ti(2)–O(5)
Ti(2)–Cl(2)
Ti(1)–Ti(2)
1.798(3)
1.791(3)
2.332(1)
2.011(3)
2.065(3)
2.678(1)
3.104(1)
Ti(1)–O(2)
Ti(1)–O(5)
Ti(1)–Cl(2)
Ti(2)–O(3)
Ti(2)–O(6)
Ti(2)–Cl(3)
2.064(3)
2.028(3)
2.635(1)
1.802(3)
1.785(3)
2.318(1)
Ti–O(1)
Ti–O(2A)
Ti–O(4)
Ti–Ti(A)
1.912(2)
2.022(2)
2.323(2)
3.113(1)
Ti–O(2)
Ti–O(3)
Ti–O(5)
2.073(2)
1.902(2)
2.187(2)
O(1)–Ti–O(3)
O(4)–Ti–O(2A)
Ti–O(1)–C(1)
Ti–O(3)–C(15)
167.3(1)
171.1(1)
149.1(2)
151.8(2)
O(2)–Ti–O(5)
Ti–O(2)–Ti(A)
Ti–O(2)–C(8)
178.2(1)
99.0(1)
115.5(1)
O(1)–Ti(1)–Cl(2)
O(5)–Ti(1)–Cl(1)
O(2)–Ti(2)–Cl(3)
O(6)–Ti(2)–Cl(2)
Ti(1)–Cl(2)–Ti(2)
Ti(1)–O(5)–Ti(2)
Ti(1)–O(2)–C(8)
Ti(1)–O(5)–C(36)
Ti(2)–O(3)–C(15)
Ti(2)–O(6)–C(43)
165.3(1)
160.8(1)
159.5(1)
165.6(1)
71.51(3)
98.6(1)
139.0(2)
132.8(2)
154.3(3)
162.6(3)
O(2)–Ti(1)–O(4)
Cl(1)–Ti(1)–Cl(2)
O(3)–Ti(2)–O(5)
Cl(2)–Ti(2)–Cl(3)
Ti(1)–O(2)–Ti(2)
Ti(1)–O(1)–C(1)
Ti(1)–O(4)–C(29)
Ti(2)–O(2)–C(8)
Ti(2)–O(5)–C(36)
162.3(1)
88.6(1)
161.7(1)
89.6(1)
a Atoms carrying the suffix A are related to their counterpart by the
symmetry operator [1/2 Ϫ x, 1/2 Ϫ y, Ϫz].
99.3(1)
147.3(3)
167.3(3)
121.8(2)
128.3(2)
bridging Ti–O distances of 1.794 and 2.042 Å are slightly
longer than the corresponding values of 1, reflecting an increase
in coordination number of the metal center. As expected, the
Ti–Ti distance of 3.104(1) Å is shortened relative to that of 1.
The solid-state structure of 3 is reflected in solution at room
1
temperature by H NMR spectroscopy. The methyl and tert-
butyl protons of Me–L3Ϫ appear as four singlets (δ 2.38, 2.27,
2.19, 2.15) and one singlet (δ 1.11), respectively. The methylene
protons of Me–L3Ϫ are observed as four doublets (δ 6.08, 5.43,
3.24, 2.99), in which one overlaps at δ 2.99 with the resonances
ϩ
due to the CH2 protons of the NEt4 cation. Isolation of 3
from the THF solution implies that this dimeric form is stable
compared to 1.
To examine the robustness of the Ti(Me–L) moiety towards
reduction chemistry, 1 was treated with 2 equivalents of potas-
sium in THF. The reaction proceeded smoothly to give a dark
green solution. After removal of an insoluble material and
replacement of the solvent with DME, [Ti(Me–L)(DME)]2 4
was isolated as apple-green crystals in 76% [eqn. (3)]. The
1H NMR spectrum of 4 in THF-d8 was not informative due to
the paramagnetic nature of the Ti() compound. The solid
state magnetic moment is 0.90 µB (per Ti atom) at room temp-
erature, which is comparable to those of aryloxide-bridged
Ti() dimers.9–11 Upon adding CH2Cl2 to the solution of 4
in THF-d8, we noticed the formation of the Ti() complex 2
1
according to the H NMR spectra. The formulation of 4 was
eventually confirmed by X-ray analysis.
(3)
Fig. 3 Structure of the anion in 3.
O(2)] are 1.796(2) Å. They are similar to terminal aryloxide
ligands of known Ti() complexes4,7–9 but clearly distinct from
each other. The shorter Ti–O bonds involving the outer aryl-
oxides [O(1), O(3)] are coupled with the wider Ti–O–C
bond angles at O(1) [164.0(2)Њ] and O(3) [166.2(2)Њ], indicative
of a greater Ti–O π bonding interaction as compared to the
central aryloxide [O(2), 119.7(2)Њ]. The O(1)–Ti–O(3) angle of
100.2(1)Њ is smaller than that in the parent dimer 1 (av. 114Њ). It
is quite obvious that the Me–L ligand has to undergo significant
distortion in order to accommodate two THF ligands, showing
the flexibility of this ligand.
On the other hand, 1 was found to react cleanly with
[NEt4]Cl in THF generating [NEt4][Ti2(Me–L)2Cl3] 3. The
X-ray structure of 3 shows a dimer with two distorted octa-
hedral metal centers connected through facial bridging (Fig. 3).
The two Me–L ligands span both metals in an S-conformation.
The central aryloxides of the two Me–L ligands and one chlor-
ine atom serve as the bridges. Each metal coordination sphere is
completed by one terminal chlorine atom. Selected bond dis-
tances and angles are listed in Table 3. The average terminal and
The structure of 4 is illustrated in Fig. 4, and selected bond
distances and angles are listed in Table 4. The molecule adopts a
dimeric structure in the solid, the dimer possessing a center of
inversion about a central Ti2O2 square core. The geometry
about titanium is best described as distorted octahedral, with a
chelate DME ligand, a tridentate Me–L ligand, and a central
aryloxide of another Me–L ligand. The central aryloxides of
the Me–L ligand asymmetrically bridge two Ti metals [Ti–O(2),
2.073(2) Å; Ti–O(2A), 2.022(2) Å]. The average Ti–O distances
of 1.907 Å (terminal) and 2.048 Å (bridging) are in the expected
range for the corresponding distances of Ti() aryloxide.9,10,12
The Me–L ligand is coordinated in a meridional manner and
assumes a U-conformation. The Ti–O distances involving the
chelate DME ligand [Ti–O(4), 2.323(2) Å; Ti–O(5), 2.187(2) Å]
are noticeably different, because the methyl group attached
to the O(4) atom experiences some steric repulsion within
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J. Chem. Soc., Dalton Trans., 2002, 2536–2540

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tilled from calcium hydride prior to use. Deuterated tetrahydro-
furan (THF-d8) was dried and degassed over a potassium
mirror in vacuo prior to use.
Elemental analyses (C, H and N) were carried out on a
YANACO CHN Corder MT-6 element analyser. 1H NMR
(500 MHz) spectra were recorded at room temperature using a
JEOL LA-500 spectrometer. Chemical shifts (in ppm) for
1H NMR spectra were referenced to residual protic solvents
peaks. Magnetic susceptibility was measured on a Quantum
Design MPMS-7 SQUID susceptometer. Corrections were
applied for diamagnetism calculated from Pascal constants.
Preparations
2,6-Bis(4,6-dimethylsalicyl)-4-tert-butylphenol [H3(Me–L)].
The ligand [H3(Me–L)] was prepared according to the reported
method.5,6
A mixture of 2,6-dihydroxymethyl-4-tert-butyl-
phenol (20.0 g, 0.095 mol), 2,4-dimethylphenol (70.0 g,
0.57 mol), and conc. HCl (ca. 2 mL) in hexane (100 mL)
was refluxed for 2 h. After the solvent was evaporated, excess
2,4-dimethylphenol was removed by distillation under reduced
pressure. The residual solid was dissolved into dichloro-
methane–hexane (200 mL/100 mL), and then the solution was
reduced to half its original volume. Colorless crystals of
2,6-bis(4,6-dimethylsalicyl)-4-tert-butylphenol [H3(Me–L)] was
obtained from this concentrated solution at Ϫ20 ЊC. More
crystalline material could be obtained from the mother liquor.
Yield 21.9 g, 55%. 1H NMR (CDCl3, 500 MHz): δ 7.14 (s, 2H,
Ph), 6.92 (s, 2H, Ph), 6.76 (s, 2H, Ph), 3.84 (s, 4H, CH2), 2.20
(s, 6H, Me), 2.17 (s, 6H, Me), 1.27 (s, 9H, But).
[Ti(Me–L)Cl]2 1. Addition of TiCl4 (0.99 g, 5.22 mmol) to a
toluene (50 mL) solution of H3(L–Me) (2.09 g, 5.00 mmol)
immediately gave a red solution. The reaction mixture was
stirred for 1 h in refluxing toluene. The solvent was removed in
vacuo, and then the residue was washed with Et2O to afford 1 as
dark red crystals (85% yield). Elemental analysis (%) found
C, 67.69; H, 6.25. C56H62O6Cl2Ti2 requires C, 67.41; H 6.26.
1H NMR (CDCl3, 500 MHz): δ 6.98 (s, 4H, Ph), 6.88 (s, 4H,
Ph), 6.76 (s, 4H, Ph), 4.67 (d, J 13.2, 4H, CH2), 3.46 (d, J 13.2,
4H, CH2), 2.38 (s, 12H, Me), 2.24 (s, 12H, Me), 1.17 (s, 18H,
But).
Fig. 4 Structure of 4.
the cavity of the Me–L ligand. This may also be explained by
electronic factors, and the long Ti–O(4) bond is trans to the
short bridging Ti–O(2A) bond. Owing to steric congestion
between the Me–L ligand and DME, the O(1)–Ti–O(3) angle
of 167.3(1)Њ is opened up relative to those of 1 (av. 114.1Њ) and
2 (100.2(1)Њ). This again indicates the flexibility of this ligand.
The long Ti–Ti distance of 3.113(1) Å rules out any possible
metal–metal bonding interaction, which is consistent with the
paramagnetic nature of 4.
Ti(Me–L)Cl(THF)2 2. Complex 1 was dissolved into THF
and then removal of the solvent in vacuo quantitatively gave
2 as red microcrystals. This compound crystallized with THF
molecules contained in the unit cell. Hence accurate micro-
analytical data was difficult to obtain due to partial loss of
solvate during analysis. 1H NMR (CDCl3, 500 MHz): δ 6.97 (s,
2H, Ph), 6.87 (s, 2H, Ph), 6.75 (s, 2H, Ph), 4.67 (d, J 13.6, 2 H,
CH2), 3.76 (br s, THF), 3.46 (d, J 13.6 Hz, 2H, CH2), 2.37 (s,
6H, Me), 2.24 (s, 6H, CH3), 1.84 (br s, THF), 1.17 (s, 9H, But)
Conclusions
In this study, the coordination chemistry of the tridentate
aryloxide Me–L3Ϫ has been examined with titanium. The use of
linked aryloxide ligands for synthesis of transition metal com-
plexes is not a new approach to ligand design. Indeed, there are
many examples of those in the literature.1–4,8,9,13–15 What is sig-
nificant about this work is that the examples of tetravalent and
trivalent titanium complexes having a Ti(OR)3 unit have been
prepared in high yields. Other complexes with linked aryloxide
dimers and calixarenes are known. However, our approach of
using the acyclic aryloxide trimer Me–L3Ϫ is unique to our
knowledge. It can also be emphasized that coordination of Me–
L3Ϫ is flexible. Depending on the nature of incoming ligands,
the Me–L3Ϫ ligand can adopt either a U- or an S-conformation.
Further studies into Me–L3Ϫ and related linked aryloxides are
in progress.
[NEt4][Ti2(Me–L)2Cl3] 3. A mixture of 1 (1.13 g, 1.14 mmol)
and NEt4Cl (96 mg, 0.58 mmol) in THF (20 mL) was stirred at
room temperature for 22 h. After the solvent was removed in
vacuo, 3 was quantitatively obtained as red crystals. Elemental
analysis (%) found C, 64.29; H, 6.99; N, 1.20. C64H82-
1
N1O6Cl3Ti2ؒ0.5CH2Cl2 requires C, 64.24; H 6.94; N, 1.16. H
NMR (CDCl3, 500 MHz): δ 6.62–6.81 (m, 12H, Ph), 6.08 (d,
J 13.5, 2H, CH2), 5.43 (d, J 13.5, 2H, CH2), 3.24 (d, J 13.5, 2H,
CH2), 2.99 (d ϩ q, 10H, linker CH2 overlapping with CH2 of
ϩ
Experimental
the NEt4 cation), 2.38 (s, 6H, Me), 2.27 (s, 6H, Me), 2.19 (s,
6H, Me), 2.15 (s, 6H, Me), 1.11 (s, 18H, But), 1.06 (t, J 7.2 Hz,
General
12H, NEt4).
All manipulations of air and/or moisture sensitive materials
were performed under an inert atmosphere of argon using
standard Schlenk line techniques. All dried solvents and
chemicals commercially available were used as received without
further purification. Deuterated chloroform (CDCl3) was dis-
[Ti(Me–L)(DME)]2 4. A 100 mL flask was charged with 1
(0.95 g, 0.95 mmol), potassium metal (85 mg, 2.17 mmol),
and THF (50 mL). Upon stirring at room temperature for
20 h, the solution changed from red to dark green. After being
J. Chem. Soc., Dalton Trans., 2002, 2536–2540
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Table 5 Crystallographic data
Compound
Formula
M
1ؒ1.5C7H8
C66.5H74O6Cl2Ti2
1136.02
2ؒ3THF
C48H71O8ClTi
859.44
3ؒ3CH2Cl2
C67H88NO6Cl9Ti2
1418.31
4
C64H82O10Ti2
1107.15
T /K
Crystal system
Space group
a/Å
b/Å
c/Å
α/Њ
β/Њ
193
193
173
173
Triclinic
Monoclinic
P21/c (no. 14)
12.901(1)
20.966(1)
17.2189(3)
Triclinic
Monoclinic
C2/c (no. 15)
23.319(9)
15.250(6)
16.708(7)
¯
¯
P1 (no. 2)
P1 (no. 2)
11.8839(5)
16.0695(6)
17.2465(9)
88.638(3)
71.058(1)
76.614(1)
3025.8(2)
2
1.247
4.019
28599
13466
13.448(4)
15.768(5)
19.078(5)
65.464(7)
76.20(1)
88.95(1)
3559.0(2)
2
1.323
6.099
27952
15559
90.9616(5)
95.167(6)
γ/Њ
V/Å
Z
4656.7(4)
4
5917.3(4)
4
1.228
3.267
23265
6744
1.031
0.051
0.138
Dc/g cmϪ3
µ(Mo-Kα)/cmϪ1
Measured reflections
Unique
1.226
2.915
43651
10635
1.029
0.071
0.191
GOF
R1 [I > 2σ(I )]
wR2 (all data)
1.011
0.067
0.178
1.014
0.083
0.253
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centrifuged to remove an insoluble solid, the solvent was evap-
orated to dryness. The residue was recrystallized from DME (50
mL) to afford 4 as apple-green crystals in 76% yield. Elemental
analysis (%) found C, 67.96; H, 7.26. C64H82O10Ti2ؒC4H10O2
requires C, 68.22; H 7.75. µeff = 0.90 µB.
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933; S. W. Schweiger, D. L. Tillison, M. G. Thorn, P. E. Fanwick and
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Chisholm, J.-H. Huang, J. C. Huffman and I. P. Parkin, Inorg.
Chem., 1997, 36, 1642; M. H. Chisholm, J.-H. Huang and J. C.
Huffman, J. Organomet. Chem., 1997, 528, 221.
4 C. Floriani, F. Corazza, W. Lesureur, A. Chiesi-Villa and C.
Guastini, Angew. Chem., Int. Ed. Engl., 1989, 28, 66; M. H.
Chisholm, J.-H. Huang, J. C. Huffman, W. E. Streib and D. Tiedtke,
Polyhedron, 1997, 16, 2941; J. Okuda, S. Fokken, H.-C. Kang and
W. Massa, Chem. Ber., 1995, 128, 221; D. R. Mulford, P. E.
Fanwick and I. P. Rothwell, Polyhedron, 2000, 19, 35; P. V. Rao, C. P.
Rao, E. K. Wegelius, E. Kolemainen and K. Rissanen, J. Chem. Soc.,
Dalton Trans., 1999, 4469.
Crystal structure determination
Crystallographic data for 1, 2, 3 and 4 are summarized in Table
5. Crystals of these complexes were mounted by nylon loops,
which were set on a Rigaku Mercury CCD system with graphite
monochromated Mo-Kα radiation (λ = 0.71070 Å) under a cold
nitrogen stream. All structures were solved by direct methods
and refined on F 2 by the full-matrix least-squares method using
the Crystal Structure software package.16,17 Anisotropic refine-
ment was applied to all non-hydrogen atoms except for the dis-
torted atoms, and all the hydrogen atoms were put at calculated
positions.
Single crystals of 1 were obtained by crystallization from
toluene. Two crystallographically independent dimers are pre-
sent. The tert-butyl group belonging to one half of the mole-
cule is disordered over two positions with occupancy factors of
50 : 50. The unit cell contains three toluene molecules as crystal
solvents, and one of them was located on the inversion center.
Single crystals of 2 were obtained by crystallization from THF,
and the tert-butyl group is disordered over two positions with
occupancy factors of 50 : 50. Single crystals of 3 and 4 were
obtained by crystallization from CH2Cl2 and DME, respect-
ively. Crystals of 3 were solvated by CH2Cl2.
5 T. Sone, Y. Ohba and H. Yamazaki, Bull. Chem. Soc. Jpn., 1989, 62,
1111; B. Dhawan and C. D. Gutsche, J. Org. Chem., 1983, 48, 1536;
V. Boehmer, D. Rathay and H. Kaemmerer, Org. Prep. Proced. Int.,
1978, 10, 113.
6 Alkali metal clusters with linked aryloxide ligands, see: B. W. F.
Gordon and M. J. Scott, Inorg. Chim. Acta, 2000, 297, 206.
7 L. R. Chamberlain, L. D. Durfee, P. E. Fanwick, L. M. Kobriger,
L. M. Latesky, A. K. Mcmullen, B. D. Steffey, I. P. Rothwell,
K. Folting and J. C. Huffman, J. Am. Chem. Soc., 1987, 109, 6068;
T. J. Boyle, N. W. Eilerts, J. A. Heppert and F. Takusagawa,
Organometallics, 1994, 13, 2118; H. Yasuda, Y. Nakayama, K.
Takei, A. Nakamura, Y. Kai and N. Kasai, J. Organomet. Chem.,
1994, 473, 105; P. E. Collier, A. J. Blake and P. Mountford, J. Chem.
Soc., Dalton. Trans., 1997, 2911; W. Clegg, M. R. J. Elsegood,
S. J. Teat, C. Redshaw and V. C. Gibson, J. Chem. Soc., Dalton
Trans., 1998, 3037; J. M. Tanski, T. P. Valid, E. B. Lobkovsky and
P. T. Wolczanski, Inorg. Chem., 2000, 39, 4756.
8 A. Kayal, A. F. Ducruet and S. C. Lee, Inorg. Chem., 2000, 39, 3696.
9 A. Zanotti-Gerosa, E. Solari, L. Giannini, C. Floriani, N. Re,
A. Chiesi-Villa and C. Rizzoli, Inorg. Chim. Acta, 1998, 270, 298.
10 R. Minhas, R. Duchateau, S. Gambarotta and C. Bensimon, Inorg.
Chem., 1992, 31, 4933.
11 M. F. Lappert and A. R. Sanger, J. Chem. Soc. A, 1971, 1314.
12 M. Mazzanti, C. Floriani, C. Guastini and A. Chiesi-Villa, J. Chem.
Soc., Dalton. Trans., 1989, 1793; B. Cetinkaya, P. B. Hitchcock,
M. F. Lappert, S. Torroni, J. L. Atwood, W. E. Hunter and M. J.
Zaworotko, J. Organomet. Chem., 1980, 188, C31.
CCDC reference numbers 172983–172985 and 176066.
See http://www.rsc.org/suppdata/dt/b1/b111362c/ for crystal-
lographic data in CIF or other electronic format.
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