ChemComm
Communication
the oxidation sensitivity of the reaction mixtures due to the
presence of its reducing triphenylphosphine ligands and allows
the use of standard Schlenk techniques rather than that of dry
boxes. Nanoparticles of different sizes, 10 nm and 30 nm, were
obtained in narrow size distributions by changing the precur-
sor concentration from 0.1 mM to 1.0 mM. We are confident
that 3, the respective tris(triphenylphosphine) copper(I) complex 2,
as well as the copper(II) carboxylate 1 can be applied successfully in
further applications such as the preparation of metal–organic inks
for inkjet printing, spray pyrolysis or spin-coating of conductive
copper patterns and layers as successfully shown for the respective
silver and gold carboxylates.12
We thank Prof. Dr Michael Mehring and Dr Maik Schlesinger
for performing the XRPD measurements and we gratefully
acknowledge generous financial support from the Deutsche
Forschungsgemeinschaft (FOR1713 SMINT) and the Fonds der
Chemischen Industrie (FCI). M. Korb thanks the FCI for a
doctoral fellowship.
Fig. 4 TEM images and size distribution of copper nanoparticles obtained
at different precursor concentrations. (A) c = 0.5 mM, d = 9.8 nm, s = 1.7 nm;
(B) c = 1.0 mM, d = 28.2 nm, s = 2.6 nm, inset: multiply twinned particles.
Notes and references
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31 Æ 2 nm, which fits well to the size distributions obtained using
electron microscopy (vide infra).
The copper nanoparticle size and size distribution were
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For the 0.5 mM sample spherical particles with a mean
diameter of d = 9.8 nm and a standard derivation of s = 1.7 nm
(size variation cv = 17%) were found (Fig. 4A). The 1.0 mM sample
yielded larger particles with d = 28.2 nm in a narrower size
distribution (s = 2.6 nm, cv = 9%, Fig. 4B). Rounding these results
to a reasonable accuracy we regard the particles to have sizes of
10 and 30 nm. The particles in both probes tend to form two- and
three-dimensional close-packed arrangements with short inter-
particle distances of about 2 nm which are likely due to the
presence of the long-chained amine (vide supra).3b In the 1 mM
sample, simple and multiple twinning can be observed in about
5% of the particles (see the inset in Fig. 4B), which is a known
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diffraction studies did not show any mark of the formation of
either copper(I) or copper(II) oxides, even though the probe pre-
paration was performed under non-inert conditions (see ESI†).
In terms of their microscopic images the particles prepared in
this work are similar to the particles obtained in other precursor
approach studies.3b,c The size variations are slightly larger than in
comparable systems. However, the accessibility of a range of particle
sizes by changing the copper precursor concentration seems to be
unique to our system and will be part of future investigations.
In conclusion, the synthesis of the new copper(I) precursor
[Cu(PPh3)2(O2CCH2OC2H4OC2H4OCH3)] (3) is discussed.
This metal–organic complex allows the easy and straightfor-
ward solution synthesis of oxide-free copper nanoparticles by
mere thermal decomposition, i.e. without the addition of any
reducing agents. Compared with other copper precursors such
as copper(II) carboxylates,3d,e,h complex 3 significantly reduces
7 Crystal data for [Cu(PPh3)2(OOCCH2OC2H4OC2H4OCH3)] (3):
C43H43CuO5P2, Mr = 765.25 g molÀ1, crystal dimensions 0.20 Â 0.10 Â
%
0.05 mm, T = 110 K, l = 154.184 pm, triclinic, P1, a = 10.7844(5) Å, b =
13.4639(6) Å, c = 14.1917(6) Å, a = 71.163(4)1, b = 77.783(4)1, g = 84.067(4)1,
V = 1904.74(15) Å3, Z = 2, rcalcd = 1.344 g cmÀ3, m = 1.958 mmÀ1
,
y range = 3.35–65.481, reflections collected: 12 298, independent: 6090
(Rint = 0.0380), R1 = 0.0390, wR2 = 0.0805 [I > 2s(I)]. CDCC 932859†.
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`
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¨
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12 S. F. Jahn, T. Blaudeck, R. R. Baumann, A. Jakob, P. Ecorchard,
T. Ru¨ffer, H. Lang and P. Schmidt, Chem. Mater., 2010, 22, 3067;
C. Schoner, A. Tuchscherer, T. Blaudeck, S. F. Jahn, R. R. Baumann
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c
This journal is The Royal Society of Chemistry 2013
Chem. Commun., 2013, 49, 6855--6857 6857