Ambient-condition nano-alumina formation through molecular control

Article abstract of DOI:10.1002/zaac.200500131

When toluene solutions of the tetrametallic compound, [Al{μ-OEt) ₂AlMe₂}₃] (1), are stirred in air at room temperature, pure amorphous nanoparticulate Al₂O₃ precipitates. The average particle size is 17.7 ± 7.4 nm. The tetrametallic core of 1, having the correct stoichiometry for alumina (2Al ₂O₃) appears to act as a template or nucleating site for the formation of alumina rather than the expected products of formula, AlOOH. The stability of the Al₄O₆ core of 1 was tested by combining it with six equivalents of Ph₃SiOH. This resulted in [Al{μ-OEt)₂Al(OSiPh₃)₂}₃] (2). Upon exposure to air, compound 2 formed the hydroxide derivative [Al{μ-OH)₂Al(OSiPh₃)₂}₃] (3). This demonstrates that the tetrametallic core of 1 is stable to both peripheral derivatization as well as alcoholysis of the internal bridging groups.

Full text of DOI:10.1002/zaac.200500131

Ambient-Condition nano-Alumina Formation Through Molecular Control
Yuzhong Wanga, Sonali Bhandaria, Amitabha Mitraa, Sean Parkina, Jerry Mooreb, and David A. Atwooda,*
a Lexington, KY/ U.S.A., University of Kentucky, Department of Chemistry
b Argonne, IL / U. S. A., Argonne National Laboratory, Materials Science Division 60439
Received December 27th, 2004.
Dedicated to Professor Herbert W. Roesky on the Occasion of his 70th Birthday
Abstract. When toluene solutions of the tetrametallic compound,
[Al{µ-OEt)2AlMe2}3] (1), are stirred in air at room temperature,
pure amorphous nanoparticulate Al2O3 precipitates. The average
particle size is 17.7 7.4 nm. The tetrametallic core of 1, having
the correct stoichiometry for alumina (2Al2O3) appears to act as a
template or nucleating site for the formation of alumina rather than
the expected products of formula, AlOOH. The stability of the
Al4O6 core of 1 was tested by combining it with six equivalents
of Ph3SiOH. This resulted in [Al{µ-OEt)2Al(OSiPh3)2}3] (2). Upon
exposure to air, compound 2 formed the hydroxide derivative
[Al{µ-OH)2Al(OSiPh3)2}3] (3). This demonstrates that the tetra-
metallic core of 1 is stable to both peripheral derivatization as well
as alcoholysis of the internal bridging groups.
Keywords: Alkoxide; Aluminum; Alumina; Mitsubishi structure;
Tetrametallic
Introduction
variation of starting material, type and amount of solvent
and stirring time have an effect on the surface properties of
the alumina. Kung et al. have recently proven that a con-
trolled synthesis can affect the surface properties of alumina
[12]. The strategy employed in this study is to cap the Lewis
acid sites of alumina with a base during hydrolysis to form
the oxide. The bound amine can then be exchanged with
other bases. Alumina synthesized using piperidine as the
base was found to be a catalyst for the aminolysis of epox-
ide by amine, [13] a class of reactions that have potential in
drug synthesis [14].
Over the past several years, there has been increasing inter-
est in molecular routes to materials [1]. Stoichiometric
single source molecular precursors are appealing because
they favor more intimate mixing of the elements, enable the
reactions to take place at lower temperatures than other
routes, or allow access to more pure or otherwise inaccess-
ible phases. In particular, synthetic routes to nanoparticul-
ate materials would be of great technological value [2]. The
recent discovery of the unusual reactivities and structural
properties of nanostructured materials has led to enhanced
research in the synthesis of such materials by entirely new
approaches or by modifying older methods [3]. The unusual
electronic and catalytic properties of nanostructured mate-
rials render them particularly interesting [3]. Stoichiometric
precursors to Group 13/16 materials requiring a 13/16 ratio
of 2:3, suitable for the formation of Al2O3 for example, are
extremely rare. In general, the known precursors to this ma-
terial have simply used an excess of oxygen, in combination
with an aluminum alkoxide or carboxylate. For example,
Al(acac)3 [4], Al(OOR)3 [5], Al(OR)3 [6], R2Al(OR) [7], and
R2Al(acac) [8] (R ϭ alkyl) have been used to prepare alumi-
num oxide thin films. Bulk quantities of pure alumina are
accessible only through high temperature syntheses [9].
Precedents of powdered nanoalumina formation from
aluminum ethoxide [10], aluminum tri-tert-butoxide [11],
aluminum isopropoxide and aluminum tributoxide precur-
sors exist in the literature. These studies have shown that
Recently, our group reported a series of tetrametallic
i
molecules [Al{µ-OEt)2AlR2}3] (R ϭ Me (1), Et, Bu) with
a tri-diamond or “Mitsubishi” structure [15, 16]. These
molecules were designed for creating corrosion resistant
coatings on metal substrates [17]. The molecules were
thought to diffuse into the corrugated surface of the metals
and, with heating, decompose to Al2O3 in the absence of
additional reagents.
In this publication we report the remarkable discovery
that these tri-diamond molecules hydrolyze in air to form
pure alumina, Al2O3 (rather than boehmite or gibbsite).
The alumina is amorphous based upon XRD (powder X-
ray diffraction) but pure based on EDX (Energy Dispersive
X-ray analysis). Importantly the material was nanoparticul-
ate with an average particle size of 17.7
7.4 nm and a
surface area of 108.82 m2.gϪ1 (BET). Additionally, elemen-
tal analysis demonstrates that there is no significant carbon
or hydrogen contamination (< 0.5 %).
Results and Discussion
* Prof. David A. Atwood
Department of Chemsitry
University of Kentucky
Lexington, KY 40506, USA
E-mail: datwood@uky.edu
Fax: 1-859-323-1069
Preparation of [Al{µ-OEt)2Al(OSiPh3)2}3] (2) and
[Al{µ-OH)2Al(OSiPh3)2}3] (3)
A series of tetrametallic D3-Symmetric alkoxide molecules
containing aluminum of general formula [Al{(µ-OEt2AlR2}3]
Z. Anorg. Allg. Chem. 2005, 631, 2937Ϫ2941
DOI: 10.1002/zaac.200500131
 2005 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
2937

Y. Wang, S. Bhandari, A. Mitra, S. Parkin, J. Moore, D. A. Atwood
where R ϭ Me (1), Et and iBu have been previously synthe-
sized and fully characterized in our laboratory [15, 16]. To
explore the stability of the Al4O6 core, 1 was combined with
6 equivalents of tri(phenyl)silanol (Scheme 1). The result
was a 76 % yield of [Al{µ-OEt)2Al(OSiPh3)2}3] (2), the only
aluminum-containing product that could be isolated from
the reaction. The Al4O6 core of 1 is also present in com-
pound 2. The ethoxide groups do not redistribute in the
presence of tri(phenyl)silanol as observed when an alumi-
num alkoxide and silanol are combined [18]. Compound
2 hydrolyzed upon exposure to air to form the hydroxide
derivative [Al{µ-OH)2Al(OSiPh3)2}3] (3) (Scheme 1). The
fact that water does not displace the tri(phenyl)silanol
ligands as it does the alkyl groups in the formation of
alumina from 1 can be explained by the greater acidity of
HOSiPh3 (pKa, 10.8) compared to water [19].
Figure 1 Molecular structure of [Al{µ-OEt)2Al(OSiPh3)2}3] (2)
˚
Selected bond distances/A and angles/°: Al1-O1A 1.902(4), Al1-O2A
1.896(4), Al1-O1B 1.903(4), Al1-O2B 1.907(4), Al1-O1C 1.917(4), Al1-O2C
1.898(4), Al2A-O1A 1.792(4), Al2A-O2A 1.789(5), Al2BO1B 1.792(4),
Al2B-O2B 1.794(4), Al2C-O1C 1.796(4), Al2CO2C 1.786(4), Si1A-O3A
1.601(5), Si2A-O4A 1.609(5), Si1BO3B 1.610(4), Si2B-O4B 1.612(5), Si1C-
O3C 1.617(4), Si2CO4C 1.608(4), Si1A-O3A-Al2A 173.0(3), Si2A-O4A-
Al2A 170.0(3), Si1B-O3B-Al2B 162.7(3), Si2B-O4B-Al2B 169.3(3); Si1C-
O3C-Al2C 163.7(3), Si2C-O4C-Al2C 164.2(3).
[Al{µ-OEt)2AlR2}3] (R ϭ Me (1), Et) which also exhibit a
tetrametallic tri-diamond structural motif [15, 16]. Com-
pound 2 contains one central six-coordinate aluminum and
three four-coordinate aluminum atoms connected to the
central atom through six bridging oxygen atoms. Also, like
the [Al{µ-OEt)2AlR2}3] (R ϭ Me (1), Et) structures, the
AlϪO distances are longer around the central six-coordi-
Scheme 1 Compound 1 reacts with tri(phenyl)silanol to form
compound 2. Compound 2 hydrolyzes to compound 3.
˚
nate aluminum atom (av. 1.9 A) than for the four-coordi-
˚
nate aluminum atoms (av. 1.8 A); this is expected as the
Characterization of [Al{µ-OEt)2Al(OSiPh3)2}3] (2)
and [Al{µ-OH)2Al(OSiPh3)2}3] (3)
atomic radii increase with an increase in coordination num-
ber [15, 16]. The SiϪO bond distances, ranging from
Like 1, compounds 2 and 3 maintain their tetrametallic
structures in solution (based on NMR and reactivity). The
stability of the tetrametallic structure in solution can be at-
tributed to the exceptional strength of the combined
AlϪOϪAl bridges [20]. Compounds 2 and 3 were charac-
terized by 1H NMR, 27Al NMR, elemental analysis, IR
and mass spectrometry (MALDI). The mass spectrum (EI,
positive) of compound 3 contains two important peaks:
78 (100.0 %, [Al(OH)3]ϩ), 1267 (1.0 % [Al{(µ-OH)2Al-
(OSiPh3)2}3 Ϫ Al(OH)(OSiPh3)2]ϩ) that support the pro-
posed structure (Scheme 1).
˚
˚
1.601(5) A to 1.617(4) A, are comparable to those observed
in several related compounds [20, 21]. The AlϪO(SiPh3)
˚
˚
bond distances (1.692(4) AϪ1.701(4) A) are comparable to
those in the previously reported AlϪ(OSiPh3)3(THF)
˚
˚
˚
(1.696(4) A, 1.703(4) A, and 1.709(4) A) [22].
Decomposition of [Al{µ-OEt)2AlMe2}3] (1)
When 2 g of 1 was stirred in 500 mL of dry toluene at room
temperature for one month open to air, a fine white powder
was obtained (Scheme 2). Characterization studies revealed
that the fine white powder was nano-alumina. This nano-
alumina was formed by the hydrolysis of 1 by moisture ab-
sorbed from the air. In the absence of further studies the
complete pathway for the hydrolysis reaction could not be
Description of the crystal structure of
[Al{µ-OEt)2Al(OSiPh3)2}3] (2)
Compound 2 crystallizes as a monomer from CH2Cl2
solution (Fig. 1). The structure is similar to that of
2938
 2005 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
zaac.wiley-vch.de
Z. Anorg. Allg. Chem. 2005, 631, 2937Ϫ2941

Ambient-Condition nano-Alumina Formation Through Molecular Control
ascertained but the initial step was very likely to be the
cleavage of alkyl- aluminum bonds by H2O.
Scheme 2 Compound 1 decomposes to amorphous alumina.
Characterization of the Aluminum Oxide
TGA (thermogravimetric analysis) of the alumina revealed
two weight loss regions. The weight loss of 38.6 % between
0 °C and 250 °C was due to desorption of water and or-
ganic contaminants (Benzene, 1-methyl-2-[(3-methyl-
phenyl)methyl]) as observed by gc/ms. The weight loss of
0.57 % in the 850Ϫ930 °C range can be attributed to the
transformation of amorphous to crystalline alumina. The
absence of weight loss in the 250Ϫ800 °C range rules out
the presence of chemisorbed water [23].
Figure 2 TEM image of Al2O3 formed from the decomposition of
compound 1.
[24, 25], gibbsite [25] and other conventional amorphous
alumina as depicted in Table 2 [26]. Transformation of the
alumina in the current study to crystalline phases at much
higher temperatures than those reported in the literature
suggest the presence of a highly structured core that re-
quires high temperatures for rearrangement.
The TEM image (Fig. 2) of the alumina shows the aver-
age particle size of 17.7 7.4 nm and BET studies give a
surface area of 108.82 m2.gϪ1. These data confirm the nan-
oparticulate nature of the alumina formed.
Table 1 X-ray diffraction results of alumina samples after heating
for two hours at different temperatures
Temperature
Phase
600 °C
Amorphous alumina
800 °C
Amorphous alumina ϩ γ-alumina
Amorphous ϩ θ ϩ γ-alumina
α ϩ θ ϩ γ-alumina
1000 °C
1100 °C
1200 °C
Solid-state 27Al NMR reveals peaks at 10.9, 41.0 and
75.5 ppm corresponding to 6-, 5- and 4- coordinate Al en-
vironments, respectively. The appearance of three coordi-
nation environments for Al is consistent with other known
amorphous aluminas [27]. Whereas the solid-state 27Al
NMR for boehmite [28], bayerite [29] and α-alumina [28]
exhibit only six-coordinate Al, Gibbsite [30] and γ-alumina
[28] exhibit six- and four- coordinate Al environments. An
infrared absorption spectrum of the fine white amorphous
material reveals a broad band at 500Ϫ1000 cmϪ1, which is
characteristic of amorphous nano-Al2O3. [26]. In addition,
an unresolved broad band in the range 2900Ϫ3700 cmϪ1 is
also observed, which can be assigned to hydrogen-bonded
hydroxyls, present at the surface of the solid [31]. However,
structural hydroxyls attributable to boehmite (1155(sh)
cmϪ1 and 1065(vs) cmϪ1) [30] and gibbsite (1034(m) cmϪ1
and 980(vs) cmϪ1) [32] were clearly not present. Raman
spectrum reveals peaks at 550 and 1100cmϪ1. This is mark-
edly different from other crystalline or hydrated aluminas
[33].
Mainly α-alumina ϩ traces of θ-alumina
Table 2 Decomposition sequence of aluminum hydroxides [26]
Aluminum
Hydroxide
Decomposition Sequence
Gibbsite
Boehmite
Bayerite
Diaspore
CHI (300-500 °C) Ϫ KAPPA (800-1150 °C) Ϫ
ALPHA (1150 °C Ϫ)
GAMMA (500 Ϫ 850 °C) Ϫ DELTA (850-1050 °C) Ϫ
THETA (1050 Ϫ 1150 °C) Ϫ ALPHA (1150 °C Ϫ)
ETA (300 Ϫ 500 °C) Ϫ THETA (880 Ϫ 1150 °C) Ϫ
ALPHA (1150 °CϪ)
ALPHA (500 °CϪ)
Remarkably, the XRD data (Table 1) indicate that the
alumina remains amorphous up to 800 °C. Crystallization
observable by XRD only occurs between 800 and 1000 °C.
This corresponds to the transformation of amorphous alu-
mina to a crystalline phase and is consistent with the TGA
results. At 1000Ϫ1200 °C, α- and θ-alumina are observed.
These observations are in sharp contrast to the XRD pow-
der patterns obtained from thermal evolution of tran-
sitional aluminas obtained from boehmite [24Ϫ26], bayerite
In contrast with the alumina formation observed for 1,
the hydrolysis of other known alkyl aluminum compounds
produces boehmite (AlOOH) [34]. The tetrametallics used
here clearly undergo some form of hydrolysis but not to the
Z. Anorg. Allg. Chem. 2005, 631, 2937Ϫ2941
zaac.wiley-vch.de
 2005 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
2939

Y. Wang, S. Bhandari, A. Mitra, S. Parkin, J. Moore, D. A. Atwood
(KBr; ν, cmϪ1): 3629(m), 3431(m), 3067(m), 3047(m), 3021(m), 1960(w),
1890(w), 1824(w), 1765(w), 1654(w), 1589(m), 1485(m), 1428(s), 1305(w),
1262(w), 1188(w), 1118(s), 1062(s), 1025(s), 997(m), 878(w), 857(w), 829(w),
741(m), 711(s), 699(s), 661(m). MS (EI, positive): m/z ϭ 78 (100.0 %,
[Al(OH)3]ϩ), 1190 (4.0 %, [Al{(µ-OH)2Al(OSiPh3)2}3-Al(OH)(OSiPh3)2-
Ph]ϩ), 1267 (1.0 %, [Al{(µ-OH)2Al(OSiPh3)2}3-Al(OH)(OSiPh3)2]ϩ).
expected hydrolytic product, AlOOH. This may be attri-
buted to the pre-assembled core of aluminum and oxygen
atoms that apparently pre-ordain the elements involved to
form alumina rather than boehmite. The core, in effect, acts
as a template for the formation of new AlϪO (alumina)
bonds.
Decomposition of 1 to produce Nano-Alumina Particles. To 2 g of 1
in a 1 L Schlenk flask was added 500 mL of dry toluene and the
solution was stirred. After two weeks of stirring open to the air 1
formed a colloidal suspension. The solvent was then removed un-
der vacuum to obtain a white powder. IR (KBr, cmϪ1): 3506(s),
2964(w), 1558(w), 1457(w), 1263(m), 1072(w), 1004(w), 801(s). 27Al
NMR (MAS-NMR, 104.29 MHz): δ 75.54, 41.06, 10.99. Raman
(cmϪ1): 550, 1100. Brunauer-Emmet-Teller (BET): 108.82 m2.gϪ1
Transmission Electron Microscopy (TEM): See Figure 1. Thermo-
gravimetric analysis (TGA): A weight loss of 38.6 % was observed
between 0 °C and 250 °C. No change was observed in the tempera-
ture range of 250Ϫ850 °C. There was a 0.57 % drop in the weight
in the 850Ϫ930 °C.
Experimental Part
The decomposition of 1 and the characterization of the alumina
were carried out in air. All other manipulations were conducted
using Schlenk techniques and an inert atmosphere glove box. All
solvents were rigorously dried prior to use. All glassware was cle-
aned with a base and an acid wash and dried in an oven at 130 °C
overnight prior to use. NMR data were obtained on JEOL-GSX-
400 and Ϫ270 instruments at 270.17 (1H) and 104.5 (27Al) MHz.
Chemical shifts are reported relative to SiMe4 and are in ppm. 27Al
magic angle spinning (MAS) NMR spectra were acquired at
104 MHz (9.4T) on a Varian 400 MHz Inova spectrometer with a
spinning rate of 8 KHz. Pulse width in the range of 1.2 to 3µs was
used together with recycle time ranging from 6-15s. Al(NO3)3 was
used as the reference. Elemental analyses were obtained on a Per-
kin-Elmer 2400 analyzer and were found to be within acceptable
limits for 2 and 3. Infrared data were recorded as KBr pellets on
a Matheson Instruments2020 Galaxy Series spectrometer and are
reported in cmϪ1. Brunauer-Emmet-Teller (BET) surface area was
measured on Micromeritics ASAP 2000 Accelerated Surface Area
and Porosimetry Analyzer. Thermogravimetric analyses were per-
formed on TA Instruments Hi-Res TGA 2950 Analyzer. X-ray
powder diffraction data were collected on Rigaku diffractometer
using CuKα radiation. The working conditions were 40 kV and
20 mA. The presence of different phases was confirmed by compar-
ing the XRD patterns obtained with those in JADE ICDD PDF
database. R3Al, Al(OEt)3 and Ph3SiOH were purchased from Ald-
rich or Strem and used as received. Caution! R3Al is highly pyroph-
oric and must be handled under an inert atmosphere.
X-Ray Experimental Data for 2
X-ray quality crystals of 2 were obtained by recrystallization from
CH2Cl2. X-ray data for 2 was collected on a Nonius Kappa-CCD
unit using Mo-Kα radiation. Crystal data is summarized in
Table 2. All calculations were performed using Siemens software
package SHELXTL-Plus. The structures were solved by direct
methods and successive interpretation of difference Fourier maps,
followed by least-squares refinement. All non-hydrogen atoms were
refined anisotropically. The hydrogen atoms were included in re-
finement in calculated positions using fixed isotropic parameters.
Crystallographic data for 2 have been deposited with the Cam-
bridge Crystallographic Data Center (CCDC reference number
219744 and copies of the data can be obtained free of charge on
application to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK
(Fax: ϩ44-1223-336033, e-mail: deposit@ccdc.cam.ac.uk).
Synthesis of [Al{(µ-OEt)2Al(OSiPh3)2}3] (2). To a suspension of
Ph3SiOH (3.540 g, 12.8 mmol) in toluene (25 mL) at room
Table 3 Crystal data and structure refinement for 2
temperature was added
a
toluene solution (15 mL) of
Empirical formula
M/ g molϪ1
Color
C120 H120 Al4 O12 Si6
2030.67
colorless
0.34 x 0.22 x 0.20
monoclinic
P 21/n
15.091(3)
38.495(8)
23.174(5)
92.94(3)
13445(5)
1.230
[Al{(µ-OEt)2AlMe2}3] (1.000 g, 2.13 mmol) (prepared according to
the literature) [15]. After the solution was stirred for 3 days, a white
precipitate formed which was isolated by filtration. It was sub-
sequently recrystallized from CH2Cl2 at room temperature. Yield:
3.28 g (75.7 %) Mp: 174Ϫ176 °C. Anal. Calcd: C, 70.98; H, 5.96.
Found: C, 70.73; H, 5.85 %.
1H NMR (CDCl3, 200 MHz): δ 0.49 (t, 18H, OCH2CH3), 3.24 (m, 6H,
OCHaHb), 3.52(m, 6H, OCHaHb), 6.99Ϫ7.53 (m, 90H, PhH). 27Al NMR
(CDCl3, 52.1 MHz): δ 58.3(ω1/2ϭ2288 Hz), 5.3(ω1/2ϭ312 Hz). IR(KBr; ν,
cmϪ1): 3067(m), 3048(m), 2998(w), 2977(w), 2904(w), 1960(w), 1890(w),
1825(w), 1765(w), 1654(w), 1589(w), 1485(w), 1428(s), 1305(w), 1260(w),
1187(w), 1115(s), 1060(s), 1026(m), 998(m), 900(m), 744(m), 707(s), 660(m),
Crystal size/ mm
Crystal system
Space group
˚
a/ A
˚
b/ A
˚
c/ A
β/ °
3
˚
V/ A
ρcalc/ g cmϪ3
Z
4
F(000)
5193
0.343
173(1)
µ (Mo-Kα) /mmϪ1
T/ K
620(w), 516(s). MS (MALDI, positive): m/z
ϭ
1363 (68.0 %,
[Al{(µ-OEt)2Al(OSiPh3)2}2]ϩ), 1755 (2.0 %, [Al{(µ-OEt)2Al(OSiPh3)2}3-
OSiPh3]ϩ).
hkl range
Ϫ16ՅhՅ16, Ϫ41ՅkՅ41, Ϫ24ՅlՅ24
1.73-22.46
34495
Θ range/ °
Reflections measured
Unique reflections (Rint
Obsd reflections, n [FՆ 4σ (F)]
Refinement method
Refined parameters/restraints
R1 [I > 2σ]
Synthesis of [Al{(µ-OH)2Al(OSiPh3)2}3] (3). Al{(µ-OEt)2Al-
(OSiPh3)2}3 (2) (1.000 g, 0.49 mmol) was dissolved in CH2Cl2
(100 mL) and permitted to stir exposed to air until the solvent was
evaporated totally. A white residue was obtained. Yield: (0.889 g,
96.9 %). Mp: 64Ϫ68 °C.
1H NMR (CDCl3, 200 MHz): δ 2.73 (br S, 6H, AlϪOHϪAl), 6.94Ϫ7.65 (m,
90H, PhH); 27Al NMR (CDCl3, 52.1 MHz, ϩ70 °C): δ 66.1 (ω1/2ϭ2340 Hz),
7.8 (ω1/2ϭ780 Hz); 27Al NMR (MAS-NMR, 104.29 MHz): δ 59.0, 11.0. IR
)
17464 (0.0441)
12256
Full-matrix least-squares on F2
1767/6250
0.1028, wR2 ϭ 0.2652
0.1391, wR2 ϭ 0.2888
1.061
R1 (all data)
Goodness-of-fit on F2
Ϫ3
˚
Largest diff. peak and hole/ e. A
0.884 and 0.704
2940
 2005 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
zaac.wiley-vch.de
Z. Anorg. Allg. Chem. 2005, 631, 2937Ϫ2941

Ambient-Condition nano-Alumina Formation Through Molecular Control
[9] I. Bennett, R. Stevens, British Ceramic Trans. 1998, 97, 117;
K. Wolf, DE-OS 2358663 1975; W. C. Ziegenhain, R. L. Poe,
L. L. Bendig, J. F. Scamehorn, US Pat. 4133871 1979.
[10] G. W. Wagner, L. R. Procell, R. J. O’Connor, S. Munavalli, C.
L. Carnes, P. N. Kapoor, K. J. Klabunde, J. Am. Chem. Soc.
2001, 123, 1636.
[11] C. L. Carnes, P. N. Kapoor, K. J. Klabunde, J. Bonevich,
Chem. Mater 2002, 14, 2922.
[12] A. I. Kozlov, M. C. Kung, W. M. Xue, H. H. Kung, Angew.
Chem. 2003, 115, 2517; Angew. Chem. Int. Ed. Engl. 2003,
42, 2415.
[13] G. H. Posner, D. Z. Rogers, J. Am. Chem. Soc. 1977, 99, 8208;
G. H. Posner, D. Z. Rogers, J. Am. Chem. Soc. 1977, 99, 8214;
Y. Harrak, M. D. Pujol, Tetrahedron Lett. 2002, 43, 819.
[14] M. Karpf, R. Trussardi, J. Org. Chem. 2001, 66, 2044.
[15] D. A. Atwood, J. A. Jegier, S. Liu, D. Rutherford, P. Wei, R.
C. Tucker, Organometallics. 1999, 18, 976.
[16] M.-A. Munoz-Hernandez, P. Wei, S. Liu, D. A. Atwood,
Coord. Chem. Rev. 2000, 210, 1.
[17] D. A. Atwood, Eur. Pat. 869103 1998.
Conclusions
We have introduced a group of stoichiometric molecular
precursors that possess a pre-existing framework related to
the desired Al2O3 solid-state material. The low-temperature
atmospheric decomposition to form alumina rather than a
hydrated alumina, such as boehmite, is a phenomenon that
warrants further study. We are currently exploring similar
precursors for mixed-metal chalcogenides, as well as other
transition metal containing derivatives of compound 1 for
use as precursors to new composite materials.
Acknowledgements. We thank the Office of Naval Research for fin-
ancial support of this research. NMR instruments used in this
research were obtained from the CRIF program of the National
Science Foundation (CHE 997841) and from the Research Chal-
lenge Trust Fund of the University of Kentucky. Thanks are ex-
pressed to the MRI program of the NSF(DMR-9977388). The au-
thors would also like to thank Professor Dibakar Bhattacharya for
the BET surface area measurements, the University of Kentucky
Mass Spectrometry Facility and Environmental Research and
Training Laboratory (ERTL) for mass spectra.
[18] J. H. Wengrovius, M. F. Garbauskas, E. A. Williams, R. C.
Goint, P. E. Donahue, J. F. Smith, J. Am. Chem. Soc. 1986,
108, 982.
[19] Measured in DMSO: R. Duchateau, U. Cremer, R. J.
Harmsen, S. I. Mohamud, H. C. L. Abbenhuis, R. A. Van
Santen, A. Meetsma, S. K.-H. Thiele, M. F. H. Van Tol, M.
Kranenburg, Organometallics. 1999, 18, 5447.
[20] The AlϪOϪAl bond energy is typically in the range of
80Ϫ150 kJ molϪ1: J. P. Oliver, R. Kumar, Polyhedron 1990,
9, 409.
[21] D. A. Atwood, M. S. Hill, J. A. Jegier, D. Rutherford,
Organometallics. 1997, 16, 2659; P. Wei, D. A. Atwood, J.
Organomet. Chem. 1998, 563, 87.
[22] A. W. Apblett, A. C. Warren, A. R. Barron, Can. J. Chem.
1992, 70, 771.
References
[1] Some recent examples: J. Kim, B. Chen, T. M. Reineke, H. Li,
M. Eddaoudi, D. B. Moler, M. O’Keeffe, O. M. Yaghi, J. Am.
Chem. Soc. 2001, 123, 8239; E. G. Tulsky, J. R. Long, Chem.
Mater. 2001, 13, 1149; P. A. Berseth, J. J. Sokol, M. P. Shores,
J. L. Heinrich, J. R. Long, J. Am. Chem. Soc. 2000, 122, 9655;
M. Lazell, P. O’Brien, D. J. Otway, J.-H. Park, J. Chem. Soc.
Dalton Trans. 2000, 4479; M. M. Banaszak Holl, P. T. Wol-
czanski, D. Proserpio, A. Bielecki, D. B. Zax, Chem. Mater.
1996, 8, 2468; J. A. Jegier, W. L. Gladfelter, Coord. Chem. Rev.
2000, 206Ϫ207, 631; O. Kahn, Acc. Chem. Res. 2000, 33, 647;
J. S. Matthews, W. S. Rees, Jr., Adv. Inorg. Chem. 2000; R. J.
P. Corriu, Angew. Chem. 2000, 112, Angew. Chem. Int. Ed.
Engl. 2000, 39, 1376; W. R. Entley, G. S. Girolami, Science
1995, 268, 397.
[2] K. J. Klabunde (ed.), Nanoscale Materials in Chemistry, John
Wiley Sons, Inc., New York, 2001.
[3] J. Y. Ying (ed.), Nanostructured Materials, Academic Press,
New York, 2001.
[4] M. Pulver, W. Nemetz, G. Wahl, Surf. Coat. Technol. 2000,
125, 400; D. Temple, A. Reisman, J. Electron. Mater. 1990, 19,
995; J. S. Kim, H. A. Marzouk, P. J. Reucroft, J. D. Robertson,
C. E. Hamrin, Jr., Appl. Phys. Lett. 1993, 62, 681.
[5] T. Maruyama, T. Nakai, Appl. Phys. Lett. 1991, 58, 2079.
[6] V. A. C. Haanappel, J. B. Rem, H. D. van Corbach, T.
Fransen, P. J. Gellings, Surf. Coat. Technol. 1995, 72, 1; H. D.
van Corbach, V. A. C. Haanappel, T. G. Fransen, P. J. Gel-
lings, Thin Solid Films 1994, 239, 31; J. Saraie, K. Ono, S.
Takeuchi, J. Electrochem. Soc. 1989, 136, 3139; G. Pauer, H.
Altena, B. Lux, Int. J. Refract. Hard Met. 1986, 5, 165.
[7] D. Barreca, G. A. Battiston, R. Gerbasi, E. Tondello, J. Mater.
Chem. 2000, 10, 2127; W. Koh, S.-J. Ku, Y. Kim, Thin Solid
Films 1997, 304, 222.
´
[23] J. A. Wang, X. Bokhimi, A. Morales, O. Novaro, T. Lopez, R.
`
Gomez, J. Phys. Chem. B 1999, 103, 299.
´
`
[24] C. Pecharroman, I. Sobrados, J. E. Iglesias, T. Gonzalez-
Carren˜o, J. Sanz, J. Phys. Chem. B 1999, 103, 6160.
[25] T. Tsuchida, N. Ichikawa, Reactivity of Solids 1989, 7, 207.
[26] C. H. Shek, J. K. L. Lai, T. S. Gu, G. M. Lin, Nanostruct.
Mater. 1997, 8, 605.
[27] H.-M. Kao, R.-R. Wu, T.-Y. Chen, Y.-H. Chen, C.-S. Yeh, J.
Mater. Chem. 2000, 10, 2802; G. Kunath-Fandrei, T. J. Bastow,
J. S. Hall, C. Jaeger, M. E. Smith, J. Phys. Chem. 1995, 99,
15138.
[28] J. J. Fitzgerald, ACS Symp. Ser. 1999, 717.
[29] S. E. Ashbrook, K. J. D. MacKenzie, S. Wimperis, Solid State
Nucl. Magn. Reson. 2001, 20, 87.
[30] R. C. T. Slade, J. C. Southern, I. M. Thompson, J. Mater.
Chem. 1991, 1, 563.
[31] C. Morterra, C. Emanuel, G. Cerrato, G. Magnacca, J. Chem.
Soc., Faraday Trans. 1992, 88, 339; K. A. Wickersheim, G. K.
Korpi, J. Chem. Phys. 1965, 42, 579.
[32] L. D. Frederickson, Jr., Anal. Chem. 1954, 26, 1883.
[33] H. D. Ruan, R. L. Frost, J. T. Kloprogge, J. Raman Spectros.
2001, 32, 745.
[8] G. A. Battiston, G. Carta, G. Cavinato, R. Gerbasi, M.
Porchia, G. Rossetto, Chem. Vap. Dep. 2001, 7, 69.
[34] C. J. Harlan, M. R. Mason, A. R. Barron, Organometallics.
1994, 13, 2957.
Z. Anorg. Allg. Chem. 2005, 631, 2937Ϫ2941
zaac.wiley-vch.de
 2005 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
2941