Copper(II) oligomeric derivatives for deposition of copper thin films

Article abstract of DOI:10.1002/ejic.200801053

Homobi-, -tri- and -tetranuclear copper(II) oligomeric complexes, [Cu(dmap)(OAc)(H₂O)]₂-H₂O (1), [Cu ₃(dmae)₃(acac)₂- Cl] (2) and [Cu(dmae)(TFA)]₄ (3), have been prepared by reac

Full text of DOI:10.1002/ejic.200801053

FULL PAPER
DOI: 10.1002/ejic.200801053
Copper(II) Oligomeric Derivatives for Deposition of Copper Thin Films
Muhammad Shahid,[a] Asif Ali Tahir,[a] Mazhar Hamid,[a] Muhammad Mazhar,*[a]
Matthias Zeller,[b] Kieran C. Molloy,[c] and Allen D. Hunter[b]
Keywords: Copper / Amino alcohols / Thin films
Homobi-, -tri- and -tetranuclear copper(II) oligomeric com-
plexes, [Cu(dmap)(OAc)(H2O)]2·H2O (1), [Cu3(dmae)3(acac)2-
Cl] (2) and [Cu(dmae)(TFA)]4 (3), have been prepared by re-
acting Cu(OAc)2·H2O with dmapH, [Cu(dmae)Cl]4 with
Na(acac) and Cu(dmae)2 with Cu(TFA)2 [dmae = (N,N-di-
plexes crystallize in the triclinic, while the tetranuclear com-
plex 3 belongs to the monoclinic crystal system. TGA and
AACVD experiments prove that the complexes undergo fac-
ile thermal decomposition in the temperature range 300–
460 °C to deposit thin films of pure copper metal. The SEM
methylamino)ethanolate, dmap = (N,N-dimethylamino)pro- and XRD analyses of the thin films suggest the formation of
panolate, TFA = trifluoroacetate, and acac = 2,4-pentane-
dionate], respectively and characterized by melting point, el-
emental analysis, FT-IR and single-crystal X-ray diffraction.
The crystal analysis shows that bi- (1) and trinuclear (2) com-
Cu crystallites with grain sizes of 100–340 nm (for 1), 75.4–
90.8 nm (for 2 and 3).
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2009)
proved resistance to the formation of stress-induced voids
due to a higher melting point over other conducting metals
such as especially aluminum. In thin-film technology, cop-
per metal has tremendous potential for fabricating of metal
interconnections, filling contacts and vial holes for
designing ultra-large-scale integrated (ULSI) circuits.[14]
Furthermore, copper metal provides enhanced device per-
formance related to reduced cross talk, improved opera-
tional speed and RC delay etc.[15]
Introduction
In the last two decades, evolutionary studies have been
carried out for the synthesis and characterization of poly-
metallic clusters and cages[1,2] as these compounds have
proved to be a solidly built stimulus for developments in
several fields of magnetochemistry,[3,4] solid-state phys-
ics[5–7] and materials science.
Almost all transition metals throughout the periodic
table form compounds utilizing different kinds of bridging
organic and inorganic ligands.[1,8,9] The involvement of car-
boxylato, oxo and alkoxo bridges provide interesting ex-
change coupling in most of the cases. In this sense, alkoxo-
aliphatic ligands or simple amino alcohol ligands can be
expected to improve the coupling between two or more
metal centers, forming homo or heteronuclear com-
plexes.[10,11]
Current interest is in the investigation of stable and solu-
ble homonuclear molecular complexes for their possible ap-
plications in MOCVD and chemical sol-gel processes.[12]
Our particular focus is in those systems involving copper
atoms since this element is the major component in high
temperature super-conductors[13] and metallic copper CVD
components. The copper metal has the advantage of low
resistivity, enhanced electromigration resistance and im-
The successful contribution of precursors towards the re-
quired material and desired device fabrication is mainly de-
pendent upon the precursor properties. They must have sol-
ubility in common organic solvents, volatility and stability
to ambient environment and a large thermal window be-
tween volatilization and decomposition. Previously used
classes of Cu(II) complexes utilized ligands such as fluori-
nated[16] and simple β-diketonates and β-ketoiminates.[17]
These β-diketonate precursors are stable enough to be
cleanly decomposed to metallic copper at low temperature.
However, in the absence of an external reducing agent, these
reagents often undergo unwanted thermal degradation leav-
ing carbon and other contaminants (CuO) on the thin film.
Another group of CuII complexes, aminoalkoxides, have
been successfully employed for the synthesis of high Tc su-
perconductor YBa2Cu3O7–x particles[18] and metallic thin
films.[19–21] Afterwards many investigators proceeded to the
synthesis of simple and fluorinated amino-alcoholic com-
plexes of copper and studied the pyrolysis mechanism in
the presence of N2 to metallic copper.[22] Another regime
relying on the utilization of heteroleptic copper complexes
is based on (hfac)CuL complexes (hfac = hexafluoroacet-
ylacetonate, L = phosphane, alkyne, or olefin) for deposi-
[a] Department of Chemistry, Quaid-I-Azam University,
Islamabad 45320, Pakistan
Fax: +92-51-90642241
E-mail: mazhar42pk@yahoo.com
[b] STaRBURSTT-Cyberdiffraction Consortium at YSU and De-
partment of Chemistry, Youngstown State University,
1 University Plaza, Youngstown, Ohio 44555-3663, USA
[c] Department of Chemistry, University of Bath,
Claverton Down, Bath, BA2 7AY UK
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M. Mazhar et al.
FULL PAPER
tion of metallic copper,[23] the most studied and commer- 1202 and 1135 cm–1 corresponding to TFA ligands. The ab-
cialized compound being (hfac)Cu(VTMS) [where VTMS sorption bands in the range of 513–525 cm–1 in all three
is vinyltrimethylsilane], that drew the attention towards complexes fall in the region reported for Cu–O bond vi-
copper aminoalkoxides.[24] However, (hfac)Cu(VTMS) can brations,[26] while the absorption bands in the frequency
only be used together with a stabilizer and requires low range 432–465 cm–1 are due to the νCu–N vibrations.[27]
temperature storage as it starts to decompose above
Crystal structure data and structure refinement details
for compounds 1, 2, and 3 are given in Table 2. The molecu-
lar structure of complex 1 is shown in Figure 1 and selected
bond lengths and angles are listed in Table 1. Complex 1 is
bimetallic in nature and the molecule is located on a crystal-
lographic inversion center. The two equivalent copper
atoms have a slightly distorted square pyramidal geometry
60 °C.[25]
Results and Discussion
Heterocatenation in copper complexes in which copper with a CuO4N coordination sphere. The dmap ligand is
metal is encapsulated by different chelating ligands to give chelating each one of the copper atoms and its deproton-
homometallic multinuclear molecular blocks with simple ated oxygen atom bridges between the two copper centers.
geometric configurations is common. Such molecular spe- The forth axial position at the copper atom is occupied by
cies can be easily prepared by simple dissolving of CuII alk- an oxygen atom of a monodentate acetate ligand and the
oxides, β-diketonates or carboxylates with suitable ligands apical ligand is a coordinated water molecule. The square
that have atoms which can bridge two or more copper pyramidal geometry of the metal centers is slightly distorted
atoms in an appropriate solvent such as toluene or THF. with angles at the copper ion between 86.92(5) and
Using this general strategy, oligomeric complexes 1, 2 and 93.10(5)°. The metal–metal separation between the two
3 were prepared (Scheme 1) and successively characterized copper centers is 3.033(5) Å. Individual molecules are con-
by melting point, elemental analysis, FT-IR spectroscopy, nected with each other via a series of hydrogen bonds be-
and single-crystal X-ray diffraction.
tween the coordinated water molecule, another interstitial
water molecule and the uncoordinated oxygen atom of the
acetate ligand. Four water molecules form a clinched hydro-
gen bonded square with two acetate O atoms of neigh-
boringmolecules being connected to opposing interstitial
water molecules of the square. Neighboringmolecules are
thus connected to form infinite chains parallel to the a axis
of the unit cell.
Scheme 1. Synthetic methodology adapted for the preparation of
copper cages 1, 2 and 3.
Infrared absorption frequencies were used to establish
structural similarities and differences between the three
complexes. Complex 1 is characterized by a broad absorp-
tion νOH band at 3428 cm–1 originating from solvate water
molecules present in the crystals of the complex. Similar
features are absent in the spectra of the anhydrous com-
Figure 1. ORTEP drawing showing the molecular structure of
[Cu(dmap)(OAc)(H2O)]2·H2O (1). Thermal ellipsoids are drawn at
the 40% probably level. Interstitial water molecules are omitted for
plexes 2 and 3. Other characteristic bands are asymmetric clarity.
and symmetric CO2 vibrations caused by the monodentate
acetate (for 1) and TFA (for 3) registered at 1668 and
An ORTEP diagram showing the molecular structure of
1414 cm–1 and at 1692 and 1593 cm–1, respectively. A differ- 2 is given in Figure 2 and selected bond lengths and bond
ence of νasyCO2 and νsyCO2 vibrations for 3 suggests the angles are listed in Table 1. In the solid-state structure, three
carboxylate unit of the TFA ligand to be bridging. In com- Cu atoms are bridged by dmae oxygen atoms of coordinat-
plex 2, the bands at 1579 and 1551 cm–1 are assigned to ing ligands. In the core unit of the complex (Figure 2, b),
νC=C and νC=O vibrations. The spectrum of 3 is also charac- two of three Cu atoms are bridged through three oxygen
terized by two strong C–F and C–O absorption bands at atoms each, while one metal center has direct interaction
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Eur. J. Inorg. Chem. 2009, 1043–1050

Production of Copper Thin Films
Table 1. Selected bond lengths [Å] and angles [°] for complex 1, 2
and 3.
1
Cu(1)–O(2)
Cu(1)–N(1)
O(2)–Cu(1)–O(3)
O(2)#1–Cu(1)–O(3)
O(2A)#1–Cu(1)–N(1)
1.9282(11)
2.0582(13)
167.79(5)
92.98(5)
Cu(1)–O(1)
Cu(1)–Cu(1)#1
O(3)–Cu(1)–N(1) 93.59(5)
O(3)–Cu(1)–O(1) 93.10(5)
N(1)–Cu(1)–O(1) 86.92(5)
2.3761(12)
3.0334(5)
172.58(5)
2
Cu(1)–Cl(1)
Cu(1)–Cu(2)
Cu(1)–Cu(3)
Cu(1)–O(6)
O(2)–Cu(1)–O(1)
O(1)–Cu(1)–Cl(1)
O(2)–Cu(1)–Cl(1)
O(3)–Cu(2)–O(4)
2.2245(6)
2.961(16)
2.958(17)
2.695(17)
76.96(6)
174.91(5)
99.32(5)
Cu(2)–O(3)
Cu(2)–Cu(3)
Cu(3)–O(3)
Cu(3)–O(1)
O(1)–Cu(2)–N(2) 153.82(7)
O(2)–Cu(2)–O(1) 70.65(6)
O(2)–Cu(3)–N(3) 165.35(7)
O(2)–Cu(3)–O(1) 65.95(6)
2.0202(16)
2.830(16)
1.9695(16)
2.3446(16)
172.42(7)
3
Cu(1)–O(11)
Cu(2)–O(5)
Cu(3)–O(3)
Cu(3)–O(2)
1.949(3)
1.963(3)
1.935(2)
1.947(2)
Cu(3)–O(1)
Cu(3)–O(7)
Cu(3)–N(3)
Cu(4)–O(9)
2.814(3)
1.955(2)
2.056(3)
1.951(3)
O(1)–Cu(1)–O(11)
O(4)–Cu(1)–N(1)
O(2)–Cu(2)–O(5)
O(3)–Cu(3)–O(7)
169.91(11)
171.77(12)
173.42(12)
167.96(11)
O(2)–Cu(3)–O(7) 96.06(10)
O(3)–Cu(3)–N(3) 85.71(11)
O(2)–Cu(3)–N(3) 174.01(11)
O(3)–Cu(4)–O(9) 94.96(11)
with four oxygen atoms. The triangular plane of the three
copper atoms is capped above and below by triply bridged
oxygen atoms of two dmae ligands. The distances between
these three metal centers span a considerable range: Cu(l)–
Cu(2) 2.961(16), Cu(1)–Cu(3) 2.958(17) and Cu(2)–Cu(3)
2.830(16) Å. The relatively shorter Cu(1)–Cu(3) distance as
compared with the Cu(l)–Cu(2) distance is probably caused
by an asymmetric coordination of the two acac ligands lo-
cated on both sides of the molecule towards the Cu atom
Figure 2. (a) ORTEP drawing showing the molecular structure of
Cu3(dmae)3(acac)2Cl (2); thermal ellipsoids are drawn at the 30%
probability level. (b) Core unit of the complex with the coordina-
tion arrangement around the CuII centers.
Cu(1) of the Cu–Cl unit. Both acac ligands coordinate in a irregular open face Cu4O4 cubane (Figure 3, b). In the cub-
chelating fashion with each one copper atom [Cu(3) and ane, the copper and triply bridging oxygen atoms of dmae
Cu(2), respectively]. However, only one of the acac ligands are arranged at alternate vertices of the cube. Cu–O bond
form an additional bond towards Cu(1) via oxygen atom lengths within the Cu4O4 cubane do vary, and Cu(3) and
O(6). Towards the other side of the Cu–Cl unit the equiva- O(1) are separated by a distance larger than a usual Cu–O
lent oxygen atom O(4) of the other acac ligand does not bond (2.814 Å), thus leaving the cubane motif incomplete.
bind to the copper atom. Cu(1) is thus dragged significantly
Ignoring this extended Cu(3)–O(1) bond, all cooper
away from the median plane of the molecule towards O(6). atoms have a distorted octahedral geometry and each is six-
This asymmetry is also evident by the dihedral angles be- coordinate and bonded to three alkoxy groups of the cub-
tween the O(1)–Cu–O(2) planes which are 47.17° between ane, an amine and two carboxylate oxygen donors from two
O(1)–Cu(1)–O(2) and O(1)–Cu(2)–O(2), but 57.95° between different trifluoroacetate ions. The trifluoroacetates bridge
O(1)–Cu(1)–O(2) and O(1)–Cu(3)–O(2).
between two copper atoms diagonally cross a face of the
As expected, all the three dmae ligands are bonded to cubane, while each aminoethanol unit lies along an edge of
Cu atoms in a chelating/bridging fashion. As mentioned the Cu4O4 structure. All the copper centers show the ex-
above, the deprotonated oxygen atoms of two of the dmae pected distortion typical for CuII complexes that are forced
ligands are coordinated to three copper atoms each in a into an octahedral or pseudooctahedral environment. The
similar fashion as found in [Cu(dmae)Cl]4.[26] The O atom direction of the distortion lies along one of the carboxylate–
of the third dmae molecule is bonded to two Cu centers: Cu–alkoxy axes; each alkoxy group therefore has one Cu–
Cu(2)–O(3) 2.0202(16), Cu(3)–O(3) 1.9695(16) Å which is O bond which is significantly longer than the other two.
in good agreement with similar compounds.[28]
This is most pronounced for Cu(3) for which, as mentioned
Selected bond lengths and angles for 3 are listed in above, the Cu(3)–O(1) is reduced to a weak interaction and
Table 1, its molecular structure is delineated in Figure 3. In Cu(3) thus has actually a five-coordinate CuO4N coordina-
case of complex 3, the core of the neutral molecule is an tion sphere with a square pyramidal geometry.
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M. Mazhar et al.
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Pyrolysis Studies, Thin Film Deposition and
Characterization
The TG curve of complex 1 (Figure 4, a) performed un-
der an inert atmosphere of flowing nitrogen shows four
major stages of weight loss upon heating. The first, occur-
ring at 50–121 °C, is associated with a 14.99% weight loss
which agrees well with both the coordinated and interstitial
water molecules being expelled (13.82%). Immediately after
the complex itself starts breaking down and in the second
step between 121–167 °C a weight loss of 7.41% is ob-
served. The third step, which starts at 167 °C and is com-
pleted at 264 °C, is associated with the largest weight loss
of 47.53%, which is directly followed by the last stage rang-
ing from 264 °C to about 450 °C, resulting in a residue
amounting to 24.73% of the initial weight. This residual
weight (24.73%) is very close to the expected amount
(24.37%) for Cu metal.
Figure 4. Thermogravimetric plot showing loss in weight with in-
crease in temperature for complexes 1 (a), 2 (b) and 3 (c).
Figure 3. (a) ORTEP drawing showing the molecular structure of
[Cu(TFA)(dmae)]4 (3); thermal ellipsoids are at the 40% probability
level. All hydrogen atoms are omitted for clarity. (b) Core unit of
the complex with the coordination arrangement around the CuII
centers; atoms are drawn at 30% probability level.
The TGA curve of complex 2 (Figure 4, b) shows five
stages of weight loss. The decomposition starts at 71 °C and
is completed at 350 °C. In the first three consecutive steps
All three complexes show the tendency of CuII to avoid between 71 °C to 255 °C, a weight loss of 21.55% occurs.
a symmetrical octahedral or pseudooctahedral environment The forth one starts at 255 °C and is completed at 276 °C
wherever possible, even if the coordination environment of with a weight loss of 39.52%, which is directly followed by
the ligands dictates such an arrangement. In the case of the last stage ranging from 276 °C to about 350 °C, re-
dimeric 1 all the ligands could be arranged in an essentially sulting in a residue amounting to 25.99% of the initial
2D planar way around the Cu atoms and the CuII centers weight. The residual mass of 25.99% is slightly less than
can assume their preferred square pyramidal geometry with expected for Cu metal (27.68%). The TGA pattern of 3
the apical positions being occupied by the water molecules. (Figure 4, c) shows a one step weight loss starting at about
No significant distortion of Cu–O bond lengths is thus ob- 175 °C and decomposition ends at about 300 °C to leave a
served for the dimeric complex. In complexes 2 and 3, how- residue of 27.76% of the initial mass. This is slightly higher
ever, with a larger number of coordinating ligand donor than 26.31%, calculated for a complete conversion to Cu
atoms vs. copper centers, this is not possible any more and metal. The residual weight remains the same from 300 °C
the metal centers are forced into a pseudooctahedral envi- to 500 °C, which indicates the conversion to copper metal
ronment, followed by distortion of the Cu–O bonds as de- for all three compounds. The thermogravimetric analysis of
scribed above. For both compounds 2 and 3 one can, how- precursors 1, 2 and 3 performed under an inert atmosphere
ever, assume that the distortions observed are fluxional indicates that all three precursors have a low enough de-
once packing effects in the solid state are removed, and composition temperatures to be suitable for the deposition
both in solution and in the gas phase the complexes can be of copper metal thin films. Best suited, however, is complex
assumed to easily flip back and forth between a series of 3 as it lacks the multi-step decomposition patterns of pre-
energetically very similar metal ligand arrangements.
cursors 1 and 2.
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Production of Copper Thin Films
Thin films of the copper metal were prepared as de- as calculated by the Scherrer equation are 200, 75.4 and
scribed in the experimental section and were studied and 90.8 nm for 1, 2 and 3, respectively and are comparable to
characterized by SEM, EDX and powder XRD. The films the values determined by SEM.
prepared from all three precursors exhibit a good adhesion
to the substrate as verified by the “scotch tape test” and are
stable toward air and moisture. They reflect light in
multishaded colors depending upon the thickness of the de-
posited films and the denser parts of the films shine in the
red metallic luster characteristic for copper. Energy disper-
sive X-ray analysis proves the presence of metallic copper
in the case of films deposited using argon. EDX analysis
also proves the clean decomposition of the complexes with-
out incorporation of impurities either from the organic
parts of the complexes or the carrier gas, and ensures the
formation of pure copper metal thin films.
SEM images of copper metal thin films deposited from
complexes 1, 2 and 3 (Figure 5) show compact and smooth
film morphologies with homogenously dispersed particles.
Individual grains are well defined with clear boundaries.
The packing density of the microstructure and the grain
sizes apparently seem to be affected by variation of the de-
position temperature. In the case of 1, where a temperature
of 450 °C was employed, a compact dense morphology was
obtained. At the lower temperatures of 350 and 300 °C used
for 2 and 3 the roughness of film is more pronounced. The
deposition was done at the minimum temperature for each
complex at which Cu metal could be deposited as found by
the TGA analysis. The SEM also shows the growth of few
particles in somewhat elongated shape, (Figure 5, b) which
are more clearly indicated by the SEM micrograph of thin
film deposited from precursor 3 (Figure 5, c).
Figure 6. The XRD patterns of thin films deposited on glass sub-
strate; (a) for complex 1, (b) for 2 and (c) for 3 using argon as
carrier gas.
Conclusions
Three oligomeric copper complexes 1, 2 and 3 have been
successfully designed, synthesized and characterized by
melting point, elemental analysis, FT-IR, TG and single
crystal analysis. These precursors have sufficient solubility
in non-polar solvents such as toluene and THF, and the
required stability and volatility for the deposition of good
quality copper thin films on a non-crystalline substrate by
aerosol-assisted chemical vapor deposition. The deposited
thin films are characterized by SEM, EDX and XRD for
their morphology and crystallinity for applications in high
performance miniaturized devices.
Experimental Section
General: All manipulations were carried out under an inert atmo-
sphere (dry argon) using Schlenk tube and glovebox techniques.
Solvents were rigorously dried with sodium benzophenoate. N,N-
dimethylaminoethanol (dmaeH) and N,N-dimethylaminopropanol
(dmapH) were purchased from Aldrich and dried by refluxing over
K2CO3 for 10 h and distilled immediately before use. All other rea-
gents were purchased from Fluka. [Cu(dmae)Cl]4 was synthesized
using a literature procedure.[26] Melting points were determined in
a capillary tube using an electrothermal melting point apparatus,
Figure 5. SEM micrographs of thin films deposited on a glass sub-
strate (a) for complex 1, (b) for 2 and (c) for 3 using argon as the
carrier gas.
Powder X-ray diffraction patterns of the thin films de- model MP.D Mitamura Riken Kogyo (Japan) and are uncorrected.
Elemental analyses were performed using a CHN analyzer LECO
model CHNS-932. FT-IR spectra were recorded from KBr discs
with a Spectrum-1000 spectrometer of Perkin–Elmer. TGA mea-
surements were carried out using a Seiko SSC/S200 thermal ana-
lyzer at a heating rate of 10 °C/min under N2 flow. Powder XRD
studies were carried out by means of a Bruker AXS D8 dif-
fractometer using monochromatic Cu-Kα radiation. The mor-
phology of films was determined by scanning electron microscopy
using a FEG-SEM Philips XL30. Samples were carbon-coated be-
fore observation and EDAX-DX4 was used to calculate the compo-
posited under argon from precursors 1, 2 and 3 are shown
in Figure 6. The hkl values (111), (200) and (220), 2θ values
43.43°, 50.60°, 74.19° and the corresponding d-spacings,
2.087, 1.806 and 1.273 Å, respectively, were used to deter-
mine the lattice parameter which refined to 3.616 Å as-
suming a cubic cell. The position and the integral width of
the X-ray diffraction peaks indicate a face centred cubic
lattice and the relative peak intensities and the positions of
the diffraction peaks of the pattern match closely those of
the ICDD data for Cu [03-065-9026].[29] The particle sizes sition of films.
Eur. J. Inorg. Chem. 2009, 1043–1050
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M. Mazhar et al.
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Single Crystal X-ray Crystallography: Single crystal diffraction data
of complexes 1 and 3 were collected on a Bruker AXS SMART
tav.[33] The structure of 2 was solved by direct method using
SIR97[34] and refined by full-matrix least-squares on F2 using
APEX CCD diffractometer at 100(2) K using monochromatic Mo- SHELXL97.[35] All non-hydrogen atoms were refined anisotropi-
Kα radiation with omega scan technique. The unit cells were deter-
mined using SAINT+ and the data were corrected for absorption
using SADABS in SAINT+.[30] The structures were solved by direct
methods and refined by full-matrix least-squares against F2 with
all reflections using SHELXTL.[31] Refinement of extinction coeffi-
cients was found to be insignificant. All non-hydrogen atoms were
refined anisotropically. Water hydrogen atoms in 1 were located in
the difference density Fourier map and have been refined with an
isotropic displacement parameter 1.5 times that of the adjacent
oxygen atom. The O–H distances were restrained to be 0.84(2) Å.
All other hydrogen atoms were placed in calculated positions and
were refined with an isotropic displacement parameter 1.5 (methyl)
or 1.2 times (all others) that of the adjacent carbon atom.
cally. Table 2 summarizes the crystal data and refinement details
for all the three complexes.
Syntheses and Characterization of Complexes 1–3
Synthesis of [Cu(dmap)(OAc)(H2O)]2·H2O (1): 0.24 g (2.33 mmol)
of dmapH was added dropwise from a syringe under inert atmo-
sphere of argon gas to a suspension of 0.50 g (2.50 mmol) of cop-
per(II) acetate monohydrate [Cu(OAc)2·H2O] in toluene (20 mL).
The mixture was stirred for 2 h at room temperature and further
heated to 40 °C in an oil bath for another 2 h. The excess of
Cu(OAc)2·H2O was removed by filtration through a cannula. The
filtrate was evaporated to dryness under vacuum and the solid was
redissolved in 5 mL of toluene to give blue crystals after 5 d by
slow evaporation at room temperature; yield 85%, m.p. 55 °C. The
analysis of the resulting product resembled that for [Cu(dmap)-
(OAc)(H2O)]2·H2O, as determined by X-ray crystallography.
C14H38Cu2N2O10 (521.54): calcd. C 32.24, H 7.34, N 5.37; found
In case of 3, the carbon atoms of two of the dmae ligands are
disordered over each two positions with occupancy ratios of
0.587(5) to 0.413(5) and 0.685(6) to 0.315(6). Equivalent bonds
within the disordered moieties were set to be the same within a
standard deviation of 0.02 Å and equivalent atoms were set to have
identical anisotropic displacement parameters. All other hydrogen
atoms were placed in calculated positions and were refined with an
isotropic displacement parameter 1.5 (methyl) or 1.2 times (all
others) that of the adjacent carbon atom.
C 32.01, H 7.25, N 5.31. FT-IR (KBr): ν = 3428 (br), 2963 (w),
˜
2923 (w), 1568 (s), 1414 (m), 1261 (m), 1095 (w), 1025 (w), 803 (m),
678 (w), 560 (w), 516 (m), 465 (m) cm–1. TGA: 50–121 °C (14.99%
weight loss), 121–167 °C (7.41% weight loss), 167–264 °C (47.53%
weight loss), 264–456 °C (residue 24.73%).
Diffraction data of complex 2 were collected at 150(2) K using a
Nonius Kappa image plate diffractometer using monochromatic
Mo-Kα radiation. The unit cell was determined, the reflections were
integrated and scaled with the HKL Denzo-Scale pack suite of pro-
grams[32] and the data were corrected for absorption using Sor-
Synthesis of Cu3(dmae)3(acac)2Cl (2): 1.25 g (1.67 mmol) of [Cu-
(dmae)Cl]4 in 20 mL of toluene were transferred to 0.50 g
(4.44 mmol) of Na(acac) which was prepared by reaction of an ap-
propriate amount of Na metal with acetylacetonate in toluene at
room temperature. The mixture was stirred for 3 h and filtered
Table 2. Crystal data and structure refinement for compounds 1, 2 and 3.
Empirical formula
C14H38Cu2N2O10
C22H44ClCu3N3O7
C24H40Cu4F12N4O12
Formula weight
Solvent
Crystal habit, color
Temperature [K]
521.54
688.67
toluene
block, pale turquoise
150(2)
1058.80
toluene
plate, blue
100(2)
toluene/THF
block, blue
100(2)
Crystal system
Space group
triclinic
P1
triclinic
P1
monoclinic
P21/c
¯
¯
a [Å]
b [Å]
c [Å]
α [°]
6.3586(9)
8.2571(12)
10.9032(15)
79.903(2)
8.4980(1)
13.8517(17)
20.726(3)
14.0355(17)
90
12.6650(2)
14.7460(2)
80.413(1)
β [°]
81.783(2)
77.114(2)
546.17(13)
1
1.586
1.997
274
83.638(1)
75.514(1)
1511.18(4)
2
1.513
2.221
714
104.249(2)
90
3905 (8)
γ [°]
Volume [Å3]
Z
4
Density (calculated) [Mg/m3]
Absorption coefficient [mm–1]
F(000)
1.801
2.264
2128
Crystal size [mm]
θ range for data collection [°]
Index ranges
0.37ϫ0.34ϫ0.09
1.91 to 28.28
–8 Յ h Յ 8
–10 Յ k Յ 11
–14 Յ l Յ 14
5717
0.30ϫ0.20ϫ0.20
3.54 to 27.57
–11 Յ h Յ 11
–16 Յ k Յ 16
–19 Յ l Յ 19
31164
0.60ϫ0.50ϫ0.30
1.52 to 28.28
–18 Յ h Յ 18
–27 Յ k Յ 27
–18 Յ l Յ 18
39593
Reflections collected
Independent reflections
Absorption correction
max. / min. transmission
Data / restraints / parameters
Goodness-of-fit on F2
Final R indices [IϾ2σ(I)]
R indices (all data)
2709 [R(int) = 0.0165]
multiscan
0.835 / 0.635
2709 / 4 / 149
1.081
6875 [R(int) = 0.0406]
semiempirical from equivalents multiscan
0.28 / 0.24
6875 / 0 / 336
9695 [R(int) = 0.0383]
0.507 / 0.356
9695 / 46 / 543
1.080
R1 = 0.0446, wR2 = 0.1193
R1 = 0.0520, wR2 = 0.1234
1.278 and –0.779
1.051
R1 = 0.0251, wR2 = 0.0659
R1 = 0.0264, wR2 = 0.0670
R1 = 0.0250, wR2 = 0.0632
R1 = 0.0277, wR2 = 0.0645
0.922 and –0.442
Largest diff. peak and hole[eÅ–3] 0.574 and –0.659
1048
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Eur. J. Inorg. Chem. 2009, 1043–1050

Production of Copper Thin Films
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through cannula to remove the NaCl produced. The filtrate was
evaporated to dryness under vacuum and the solid was redissolved
in 5 mL of toluene and stored at –10 °C for one week to give blue
crystals suitable for X-ray diffraction; yield 79%, m.p. 138 °C.
C22H44ClCu3N3O7 (688.67): calcd. C 38.37, H 6.44, N 6.10; found
C 37.98, H 6.29, N 5.63. FT-IR (KBr): ν = 2964 (m), 2896 (w),
˜
1579 (s), 1551 (m), 1528 (s), 1461 (s), 1413 (w), 1389 (w), 1277 (m),
1261 (m), 1184 (w), 1071 (s), 1021 (s), 952 (s), 900 (m), 785 (s), 650
(m), 614 (m), 513 (m), 455 (s) cm–1. TGA: 71–255 °C (21.55%
weight loss); 255–276 °C (39.52% weight loss); 276–350 °C (residue
25.99%).
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Synthesis of [Cu(dmae)(TFA)]4 (3): 0.71 g (7.96 mmol) of dmaeH
and 1.07 g (7.96 mmol) of trifluoroacetic acid (TFAH) were added
to a suspension of 1.0 g (7.96 mmol) of Cu(OCH3)2 [which was
synthesized by the reaction of an appropriate amount of CuCl2
(anhydrous) with CH3OLi in dry methanol] in 20 mL of THF. The
reaction mixture was stirred for 2 h at room temperature, evapo-
rated to dryness under vacuum and then the solid was redissolved
in 10 mL of THF to give blue crystals suitable for X-ray diffraction;
yield 80%, m.p. 210 °C. C24H40Cu4F12N4O12 (1058.80): calcd. C
27.23, H 3.80, N 5.29; found C 27.93, H 3.88, N 5.62. FT-IR (KBr):
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ν = 2982 (m), 2923 (w), 2884 (m), 1692 (s), 1593 (m), 1466 (w),
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[11]
[12]
Deposition of Thin Films: Copper thin films were deposited on a
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Parameters
Values
Precursor concentration
0.3 g/25 mL (toluene)
Carrier gas (Ar) flow rate [cm3/min] 25
Sample solution injection [mL/min]
Substrate
Deposition time
0.2
soda glass
125 min
Deposition temperature
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350 °C for 2
300 °C for 3
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M. S., A. A. T., M. H., and M. M. would like to thank the Higher
Education Commission Islamabad, Pakistan for financial support
through the “Indigenous 5000 and open merit 200 Ph. D. Scholar-
ship Scheme” and Pakistan Science foundation [PSF/RES/C-QU/
CHEM(408)]. The X-ray diffractometer at Youngstown State Uni-
versity was funded by NSF Grant 0087210, Ohio Board of Regents
Grant CAP-491, and by Youngstown State University.
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Received: October 27, 2008
Published Online: February 5, 2009
1050
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Eur. J. Inorg. Chem. 2009, 1043–1050