A neutral 1D coordination polymer constructed from the niii complex of the n-phosphorylated thiourea phnhc(s)nhp(o)(oph)2 and pyrazine: A single-source precursor for nickel nanoparticles

Article abstract of DOI:10.1002/ejic.201402278

The N-phosphorylated thiourea PhNHC(S)NHP(O)(OPh)₂ (HL) was synthesized by the reaction of PhNH₂ and (PhO)₂P(O)NCS. Reaction of the KL salt, generated in situ, with NiCl₂ leads to pale violet [NiL₂] w

Full text of DOI:10.1002/ejic.201402278

FULL PAPER
DOI:10.1002/ejic.201402278
A Neutral 1D Coordination Polymer Constructed from the
II
Ni Complex of the N-Phosphorylated Thiourea
CLUSTER
ISSUE
PhNHC(S)NHP(O)(OPh) and Pyrazine:
A Single-Source Precursor for Nickel Nanoparticles
2
[a]
[a]
[a]
Maria G. Babashkina, Damir A. Safin, Koen Robeyns, and
[
a]
Yann Garcia*
Keywords: Coordination polymers / Organic–inorganic hybrid composites / Nanoparticles / Nickel / N ligands
The N-phosphorylated thiourea PhNHC(S)NHP(O)(OPh)
HL) was synthesized by the reaction of PhNH and (PhO)
P(O)NCS. Reaction of the KL salt, generated in situ, with
NiCl leads to pale violet [NiL ] with a 1,3-N,S- coordination
mode of the ligands. Interaction of [NiL ] with pyrazine (pz)
yields the 1:1 coordination polymer [NiL pz] . An unexpec-
2
taining ligands L from 1,3-N,S- to 1,5-O,S- was found in
(
2
2
-
[NiL
[NiL
2
pz]
pz]
n
upon coordination of additional donor ligands.
dissolved in tri-n-octylphosphine (TOP) was de-
2
n
2
2
composed in hot hexadecylamine to give capped face-cen-
tered cubic Ni nanoparticles with an average particle size of
17(2) nm.
2
2
n
ted change in the coordination mode of the phosphorus-con-
Introduction
nor X and Y atoms. This is, obviously, explained by the
efficient delocalization of the negative charge in the sym-
metrical conjugated chelate backbone upon deprotonation.
Contrariwise, the coordination mode of N-(thio)phosphor-
There is currently an intense activity in the synthesis and
design of coordination polymers (CPs) and metal–organic
frameworks (MOFs).[1] Such compounds belong to an intri-
guing class of hybrid materials, comprising inorganic nodes
and organic ligands linked by coordination interactions,
exhibiting valuable properties, which were used in a wide
range of fields, including MRI contrast agents, adsorp-
tion heat pump processes,[ and so on. In terms of crystal
engineering of CPs, didentate π-electron-containing ligands
are of ever increasing interest. Among them, pyrazine (pz)
and its close analogue 4,4Ј-bipyridine are the most com-
monly used tectons for the formation of CPs.[ Further-
more, pz-containing complexes are used in electron transfer
and magnetic exchange interaction studies,[ thanks to the
capacity of pz to yield complexes with short metal–metal
distances.
ylated thioamides and thioureas RC(S)NHP(X)(ORЈ) (X
2
=
O, S), which are asymmetrical analogues of IDP, AA,
[
2]
II
and ATU, to Ni still remains less studied. This is rather
surprising, as the negative charge is delocalized asymmetri-
cally in these deprotonated ligands, and hence they might
show ambidental coordination properties through the do-
nor atoms of the thiocarbonyl and (thio)phosphoryl groups
and the nitrogen atom of the phosphorylamide group.
Furthermore, the nature of the R and RЈ substituents might
influence considerably the coordination mode by both elec-
tronic and steric factors. Additional donor functions in
these substituents might also affect the complexation prop-
erties crucially.
[
3]
[4]
5]
6]
7]
In this context, we have studied the coordination proper-
ties of N-(thio)phosphorylated thioureas RRЈNC(S)-
II
A great number of Ni complexes with the imidodiphos-
[
8]
phinates R P(X)NHP(Y)RЈ (IDP) (X, Y = O, S, Se, Te),
2
2
NHP(X)(ORЈЈ) (X = O, S; R, RЈ = H, alkyl, aryl; RЈЈ =
2
acylthioamides RC(S)NHC(X)RЈ (AA), and aroylthioureas
II
OiPr, OPh) (NTTU) towards Ni and demonstrated that
[9]
R NC(S)NHC(X)RЈ (ATU) (X = O, S) have been de-
2
their square-planar complexes exhibit either a 1,3-N,S- or
scribed. The chelate backbones of the IDP, AA, and ATU
ligands are coordinated to the Ni cation through the do-
[10]
1
,5-O,S- and 1,5-S,SЈ- coordination mode. Furthermore,
II
we also examined the interaction of the formed mononu-
II
clear Ni complexes of NTTU with additional chelate do-
[
a] Institute of Condensed Matter and Nanosciences, Molecules, nor ligands, such as 2,2Ј-bipyridine and 1,10-phenanthrol-
Solids and Reactivity (IMCN/MOST), Université Catholique
de Louvain,
ine, and showed that the coordination mode is preserved
[
10e]
Place L. Pasteur 1, 1348 Louvain-la-Neuve, Belgium
E-mail: yann.garcia@uclouvain.be
for the phosphorus-containing ligands.
Thus, inspired
by our recent findings, we have prepared a new CP, using a
mononuclear homoleptic Ni complex of the N-phosphor-
ylated thiourea PhNHC(S)NHP(O)(OPh) (HL) as an inor-
http://www.uclouvain.be/262038.html
II
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.201402278.
2
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The 31P{ H} NMR signal of HL in [D ]DMSO appears
1
ganic node and pz as a bridging organic linker. Further-
more, the resulting CP [Ni{PhNHC(S)NP(O)(OPh) } pz]
n
6
1
as a singlet at δ = –10.2 ppm. The H NMR spectrum of
2
2
(
[NiL pz] ) was used as single-source precursor for the HL in the same solvent contains a multiplet signal for the
2 n
preparation of face-centered cubic nickel nanoparticles by Ph protons at δ = 7.02–7.66 ppm and two singlets at 9.98
using an organic surfactant.
and 10.25 ppm, corresponding to the NHP and PhNH
groups, respectively. The 31P{ H} NMR spectrum of [NiL ]
1
2
in CDCl contains a singlet signal at δ = –7.8 ppm, while in
3
Results and Discussion
[
D ]DMSO this signal is shifted to low field and observed at
6
δ = –5.4 ppm. These findings are very similar to those ob-
served for the close analogue [Ni{iPrNHC(S)NP(O)-
The N-phosphorylated thiourea HL was synthesized by
reacting PhNH with the isothiocyanate (PhO) P(O)NCS
2
2
[
10q]
(
OPh) } ]
and testifies to the formation of [Ni(L-1,3-
(
Scheme 1). Complex [NiL ] was prepared by deprotonating
2 2
2
N,S) ] and [Ni(DMSO-O) (L-1,3-N,S) ] upon dissolving
the ligand in situ with KOH, followed by reaction with
2
2
2
[
NiL ] in CDCl and [D ]DMSO, respectively. It should be
NiCl (Scheme 1). [NiL pz] was synthesized by reacting
2 3 6
2
2
n
noted that anionic ligands L in these structures are coordi-
[
(
NiL ] with an equimolar amount of pz in benzene
2
1
nated in a trans-arrangement. The H NMR spectrum of
Scheme 1).
The IR spectrum of HL contains a band at 1241 cm–1
[NiL ] in CDCl is similar to that of the parent ligand HL.
2 3
The phenyl and PhNH protons are found at 7.32–8.04 and
for the P=O group. The same band in the IR spectrum of
1
9
.15 ppm, respectively. The H NMR spectrum of [NiL ] in
[
(
NiL ] was observed almost at the same wavenumber
2
2
–
1
[D ]DMSO also contains a single set of signals. Although
1235 cm ) as that for the parent ligand HL, while it is
6
–
1
the signals for the Ph protons are in the characteristic range
at δ = 6.92–7.71 ppm, the singlet for the PhNH protons is
observed at δ = 5.07 ppm, which is an unusual chemical
significantly shifted to lower frequencies (1135 cm ) in the
spectrum of [NiL pz] . The latter observations testify to a
2
n
1
,3-N,S- and 1,5-O,S- coordination mode of the deproton-
[
10]
shift for such a type of protons. This might be explained
by the paramagnetic contribution of the [Ni(DMSO-O) (L-
ated ligand L in the structures of [NiL ] and [NiL pz] ,
2
2
n
[
10]
respectively. In the spectrum of HL, there is a weak band
at 1548 cm , corresponding to the S=C–N fragment, while
2
–
1
1,3-N,S) ] structure formed upon dissolving [NiL ] in [D ]-
2
2
6
DMSO. The NMR spectra of [NiL pz] in CDCl and [D ]-
the spectra of its complexes contain an intense broad band
2
n
3
6
DMSO are very similar. The 31P{ H} NMR spectra contain
a singlet at an extremely low-field region at about 25 ppm.
This might be explained by the change of the coordination
mode of the phosphorus-containing ligands and the forma-
1
–
1
at 1560 and 1673 cm , respectively, due to the conjugated
S–C–N fragment. The spectrum of HL contains bands at
ត ត
155 and 3294 cm , corresponding to the PhNH and NHP
groups. The IR spectra of [NiL ] and [NiL pz] contain the
–
1
3
2
2
n
tion of paramagnetic NiN O S coordination cores in the
characteristic band for the PhNH group at 3257 and
2
1
2 2
–
1
structure of [NiL pz] . The H NMR spectra exhibit signals
3
184 cm , while no bands for the NHP groups are found.
2 n
at 4.18–4.37, 5.27–6.74, and 9.13–10.07, corresponding to
the PhNH, Ph, and pz protons, respectively.
This testifies to a deprotonated form of the phosphorus li-
gands in the structures of the complexes. In addition, in the
IR spectra of HL, [NiL ], and [NiL pz] , there is a broad,
UV/Vis absorption spectra of [NiL ] in CH Cl and
2
2
2
2
2
n
DMSO contain two intense absorption bands in the UV
region, one lying invariantly at 249–260 nm, and the other
intense band arising from the POC group at 956–
–
1 [11]
9
78 cm .
2 2 n
Scheme 1. Preparation of HL, [NiL ], and [NiL pz] (R = OPh).
Eur. J. Inorg. Chem. 2015, 1160–1166
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at 303–321 nm. Notably, these two bands in the spectrum
Lengths of the C=S, C–N, P–N and P=O bonds observed
for the sample in CH Cl exhibit bathochromic shifts com- for HL are in the typical range for NTTU (X = O)
2
2
pared to the spectrum for the sample in DMSO. Further- (Table S1 in the Supporting Information).[
10,13]
The S=C–
more, the latter band is about 7.5 times less intense in the N–P=O backbones in the crystal phase have a cis confor-
spectrum for the sample in DMSO compared to that in the mation (Figure 1). The crystal structure of HL is stabilized
spectrum for the sample in CH Cl . The UV absorptions of by intermolecular bifurcated hydrogen bonds of the PhN–
2
2
[
NiL ] in both solvents can be assigned to the correspond- H···O=P and PN–H···O=P types (Figure 1 and Table S3 in
2
ing intraligand transitions (π–π* or n–π* type). In the vis- the Supporting Information). As a result of these hydrogen
ible region, two absorption bands were essentially observed bonds, 1D polymeric chains are formed.
in the UV/Vis spectrum for the sample in CH Cl , one at
Complex [NiL pz]n comprises [NiL ] building units
2
2
2 2
5
08 nm and another rather invariant one at 630 nm. From linked through bridging 1,4-N,NЈ-coordinated pz molecules
–
1
–1
the rather low intensities (ε = 218 and 185 m cm , respec- with the formation of an infinite 1D neutral CP (Figure 2).
tively) the two long-wavelength bands are assigned to ligand Surprisingly, the ligands L now exhibit a 1,5-O,S- coordina-
field (d–d) transitions. The UV/Vis spectrum of [NiL ] in tion mode. Furthermore, the anionic ligands are coordi-
2
DMSO exhibits three bands with maxima at 440, 726, and nated in a cis arrangement. To the best of our knowledge,
II
1
124 nm in the visible range, which are assigned to [NiL pz] is the first example of Ni complexes with NTTU
2
n
3
3
3
3
3
3
B Ǟ Eg(P),
A (P),
2g
B Ǟ E (F),
A (F), and (X = O), exhibiting a cis-1,5-O,S- coordination mode. Re-
1
g
1g
g
2g
3
3
3
B Ǟ E , B , respectively, assuming an octahedral envi- cently, a cis-1,5-S,SЈ- coordination mode was found in the
1
g
g
2g
ronment for the nickel atom in [NiL2][ due to the forma- structure of [Ni{AdNHC(S)NP(S)(OiPr)2}2].
12]
[10c]
Neigh-
tion of [Ni(DMSO-O) (L-1,3-N,S) ] species. Furthermore, boring [NiL ] building units are linked by pz molecules in
2
2
2
–
1
–1
the band intensities (ε = 65, 12, and 15 m cm , respec- a trans arrangement, which might be influenced by the
tively) also unambiguously favor the octahedral coordina- bulky PhO groups at the phosphorus atoms (Figure 1). The
tion core rather than the tetrahedral one.[ The absorption coordination polyhedron around the metal center is best
spectra of [NiL pz] in the two solvents are very similar described as a distorted octahedron. The Ni···Ni separa-
12]
2
n
and testify to the exclusive formation of an octahedrally tions between the neighboring metal centers are about
configured structure. 7.06 Å. The Ni–N bond lengths in the structure of
Crystals of HL were obtained by recrystallization from a [NiL pz] are very similar and about 2.18 Å, while the Ni–
2
n
mixture of CH Cl and n-hexane, while crystals of O and Ni–S bonds, arising from two different ligands L
2
2
[
NiL pz] were obtained by slow concentration of its benz- coordinated to the same metal center, show the opposite
2 n
ene solution. Unfortunately, numerous attempts to obtain trend (Table S2 in the Supporting Information). Thus, the
crystals of [NiL ] suitable for X-ray diffraction analysis Ni1–O6 bond is about 0.17 Å longer than the Ni1–O36
2
failed.
bond, while the Ni1–S2 distance, corresponding to the same
The molecular structures of HL and [NiL pz] are shown ligand L as the former Ni–O bond, is about 0.11 Å shorter
2
n
in Figure 1 and Figure 2, respectively, while the crystal and than that of Ni1–S32. This trend is also reflected in the S–
structure refinement data are given in the Experimental Sec- C and P–O bonds in the structures of L. However, although
tion. Selected bond lengths and angles of the complexes are the S2–C3 bond is about 0.19 Å longer than the S32–C33
given in Tables S1 and S2 in the Supporting Information. bond, which, in turn, has the same value as that in the
According to X-ray diffraction data, HL and [NiL pz] , structure of the parent ligand HL (Table S1 in the Support-
2
n
measured at 150(2) K, crystallize in the monoclinic P2 /c ing Information), the P–O bonds are very similar and are
1
¯
and triclinic P1 space groups, respectively.
about 1.52 Å (Table S2 in the Supporting Information). The
Figure 1. Stick plot of HL along the 0b axis. Hydrogen atoms, not involved in hydrogen bonding, were omitted for clarity.
1162
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Figure 2. Stick plot of 1 along the 0c axis. Hydrogen atoms were omitted for clarity.
latter bond lengths are almost the same as those in HL.
The P35–N34 and N34–C33 bonds are similar to those ob-
served for HL, while they are significantly elongated relative
to the P5–N4 and N4–C3 distances (Table S2 in the Sup-
porting Information). On the contrary, the N7–C3 bond is
very similar, while the N37–C33 bond is about 0.14 Å
longer in comparison to the same bond in the structure of
HL. The six-membered metallacycles Ni–S–C–N–P–O are
almost flattened with the Ni1, O6, and S2 atoms in one
cycle, and Ni1 and O36 atoms in the other one, deviate by
about 0.15 Å from the least-squares planes. The N–Ni–N
angle, 167.7(11)°, deviates slightly from the linear, while the
external interligand angles S–Ni–O are almost linear with
values of about 176 and 180° (Table S2 in the Supporting
Figure 3. Ball and stick plot of π···π stacking interactions between
Information). The remaining O–Ni–N, S–Ni–N, S–Ni–O,
O–Ni–O, and S–Ni–S angles around the metal center are
close to 90°. The torsion angle between the planes formed
by pz rings is about 13.9°, while the planes formed by the
six-membered metallacycles are almost orthogonal to the
1
D polymeric chains of 1 along the 0b axis. Hydrogen atoms were
omitted for clarity.
The reduction of [NiL pz] , dissolved in tri-n-octylphos-
2
n
pz planes (ca. 79.3–84.5°). The structure of [NiL pz] is ad- phine (TOP), at 190 °C in hexadecylamine (HDA) resulted
2
n
ditionally stabilized by close interchain π···π stacking inter- in a fast reaction of the nickel complex and the growth of
actions between the OPh phenylene rings corresponding to nickel nanoparticles. The transmission electron microscopy
neighboring CPs (Figure 3, Table S4 in the Supporting In- (TEM) image (Figure 4A) shows that the TOP-capped
formation).
nickel nanoparticles afford an average particle size of
We have also been interested in the possible formation of 17(2) nm. We conclude that a compact layer of TOP is
Ni-containing nanoparticles from both [NiL2] and formed between the nickel nanoparticles to prevent them
[
NiL pz] . Face-centered cubic (fcc) Ni nanoparticles were from aggregation, confirming TOP to be an effective surfac-
2 n
obtained when [NiL pz] was used as single-source precur- tant for producing well-dispersed metal nanoparticles. The
2
n
[10m]
sor by following our recently reported procedure.
How- lattice fringes with an interplanar distance of 3.53 Å are
ever, using [NiL ] as a precursor for preparing nanoparticles visible in the HRTEM image (Figure 4B). The X-ray dif-
2
resulted in a mixture of different products and requires fraction (XRD) pattern indicates three peaks (111), (200),
more detailed analysis, which will be reported in due course. and (220) above 2θ = 30°, which are characteristic of fcc
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nickel with a lattice constant of a = 3.538 Å (Figure 4). This Experimental Section
[
14]
value is consistent with the corresponding bulk value. To
investigate the composition, X-ray photoelectron spectrom-
etry (XPS) analyses were performed for the Ni nanopar-
ticles (Figure 4). The Ni 2p3/2 and Ni 2p1/2 are centered at
Physical Measurements: Infrared spectra (KBr) were recorded with
a FTIR-8400S SHIMADZU spectrophotometer in the range 400–
–
1
3
3
600 cm . NMR spectra were obtained with a Bruker Avance
1
31
1
00 MHz spectrometer at 25 °C. H and P{ H} NMR spectra
8
53.2 and 869.6 eV, respectively; these peaks coincide with
were recorded at 299.948 and 121.420 MHz, respectively. Chemical
[15]
those of metallic Ni. Therefore, on the basis of XRD and
1
4 3 4
shifts are reported with reference to SiMe ( H) and 85% H PO
3
1
1
XPS results, it can be concluded that the synthesized Ni ( P{ H}). Electronic absorption spectra were recorded with a Per-
nanoparticles have the component of pure metallic Ni kin–Elmer Lambda 35 spectrophotometer. X-ray powder diffrac-
phase.
tion (XRPD) studies were performed with a Bruker AXS D8 dif-
fractometer by using Cu-K radiation. Transmission electron mi-
α
croscopy (TEM) was performed with a Philips CM 20 FEG elec-
tron microscope. X-ray photoelectron spectrometry (XPS) analysis
was performed with a Shimadzu ESCA-3400 instrument. Elemen-
tal analyses were performed with a Thermoquest Flash EA 1112
Analyzer from CE Instruments.
HL: A solution of aniline (0.465 g, 5 mmol) in anhydrous CH
2
Cl
15 mL) was treated under vigorous stirring with a solution of
PhO) P(O)NCS (1.746 g, 6 mmol) in the same solvent. The mix-
2
(
(
2
ture was stirred for 1 h. The solvent was removed in a vacuum, and
the product was purified by recrystallization from a 1:5 (v/v) mix-
ture of CH
2
Cl
2
and n-hexane. Yield: 1.653 g (86%). IR: ν˜ = 978
–
1
1
(
POC), 1241 (P=O), 1548 (S=C–N), 3155, 3294 (NH) cm .
H
6
NMR ([D ]DMSO): δ = 7.02–7.66 (m, 15 H, Ph), 9.98 (br. s, 1 H,
3
1
1
NHP), 10.25 (s, 1 H, PhNH) ppm. P{ H} NMR ([D
–10.2 ppm. C19 PS (384.39): calcd. C 59.37, H 4.46, N
.29; found C 59.42, H 4.49, N 7.17.
6
]DMSO): δ
=
7
17 2 3
H N O
[
NL ]: A suspension of HL (3 mmol, 1.153 g) in MeOH (10 mL)
2
was mixed with a MeOH (10 mL) solution of KOH (3.3 mmol,
0.185 g). An aqueous (10 mL) solution of NiCl
2
(1.9 mmol,
0
.247 g) was added dropwise under vigorous stirring to the re-
Figure 4. TEM (A), HRTEM (B) images, XRD pattern (bottom
left), and XPS spectrum (bottom right) of TOP-capped Ni nano-
particles synthesized from 0.2 mmol [NiL pz] .
2 n
sulting potassium salt. The mixture was stirred at room tempera-
ture for a further 3 h and left overnight. The resulting complex was
extracted with CH
hydrous MgSO . The solvent was removed under vacuum, and the
product was purified by recrystallization from a 1:3 (v/v) mixture
of CH Cl and n-hexane. Yield: 1.072 g (87%). IR: ν˜ = 956 (POC),
560 (SCN), 1235 (P=O), 3257 (NH) cm . H NMR (CDCl
2 2
Cl , washed with water, and dried with an-
4
2
2
–
1 1
1
7
3
): δ =
.32–8.04 (m, 30 H, Ph), 9.15 (s, 2 H, PhNH) ppm. P{ H} NMR
Conclusions
31
1
1
(
CDCl
3 6
): δ = –7.8 ppm. H NMR ([D ]DMSO): δ = 5.07 (br. s, 2
II
In summary, we have synthesized a homoleptic Ni com-
31
1
H, PhNH), 6.92–7.71 (m, 30 H, Ph) ppm. P{ H} NMR ([D ]-
DMSO): δ = –5.4 ppm. UV/Vis (CH Cl ): λmax (ε, m cm ) = 260
2 2
6
plex with N-thiophosphorylated thiourea PhNHC(S)-
–1
–1
NHP(O)(OPh) , [NiL ]. In both the solid state and in (26135), 321 (18120), 508 (218), 630 (185) nm. UV/Vis (DMSO):
2
2
–
1
–1
CDCl3 and CH Cl solutions, the complex exhibits a
λ
max (ε, m cm ) = 249 (25053), 303 (2425), 440 (65), 726 (12),
square-planar 1,3-N,S- coordination mode of the ligands, 1124 (15) nm. C38 NiO (825.45): calcd. C 55.29, H 3.91,
N 7.11; found C 55.42, H 4.02, N 7.16.
2
2
H
32
N
4
6 2 2
P S
while an octahedral coordination environment, formed by
two 1,3-N,S-coordinated phosphorus ligands and two mo-
lecules of the solvent, was established in DMSO.
[
NiL pz] : An equimolar mixture of [NiL
pyrazine (0.5 mmol, 0.040 g) in benzene (10 mL) was stirred at
2
n
2
] (0.5 mmol, 0.413 g) and
[
NiL ] was involved in the reaction with pyrazine to form room temperature for 10 min and left for slow evaporation of the
2
of a 1D coordination polymer [NiL pz] . An unexpected solvent. Green rod-like crystals were formed during the next days.
2
n
change in the coordination mode of L from 1,3-N,S- to 1,5- Yield (calculated for [NiL
2
pz]): 0.326 g (72%). IR: ν˜ = 968 (POC),
–
1 1
1
573 (SCN), 1135 (P=O), 3184 (NH) cm . H NMR (CDCl
3
): δ =
O,S- was observed in the latter complex upon coordination
of additional donor ligands.
4
.18 (s, 2 H, PhNH), 5.27–6.11 (m, 30 H, Ph), 9.13–9.84 (m, 4 H,
3
1
1
1
pyrazine) ppm. P{ H} NMR (CDCl
[D ]DMSO): δ = 4.37 (s, 2 H, PhNH), 5.47–6.74 (m, 30 H, Ph),
.42–10.07 (m, 4 H, pyrazine) ppm. P{ H} NMR ([D
3
): δ = 24.2 ppm. H NMR
We have also demonstrated that the coordination poly-
mer [NiL pz] dissolved in tri-n-octylphosphine decom-
(
9
6
2
n
31
1
6
]DMSO):
): λmax (ε, m cm ) = 252 (26775),
06 (2570), 452 (68), 722 (14), 1125 (17) nm. UV/Vis (DMSO): λmax
poses in hot hexadecylamine to give capped face-centered
cubic Ni nanoparticles with an average particle size of
–1
–1
2 2
δ = 26.1 ppm. UV/Vis (CH Cl
3
17(2) nm. These nanoparticles retain their shape over long
–1
–1
(
ε, m cm ) = 250 (26830), 310 (2545), 448 (64), 729 (13), 1119
periods and also their monodispersity, a finding which (15) nm. C H N NiO P S (905.54): calcd. C 55.71, H 4.01, N
4
2
36
6
6 2 2
could be of interest in catalysis.[
16]
9.28; found C 55.87, H 4.09, N 9.36.
Eur. J. Inorg. Chem. 2015, 1160–1166
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Synthesis of TOP-Capped Nickel Nanoparticles: Complex
NiL pz] (0.2 mmol, 0.181 g) was dissolved in tri-n-octylphosphine
TOP) (6 mL) and injected into hot hexadecylamine (HDA)
6.025 g, 25 mmol) at 190 °C. An initial decrease in temperature
from 190 to about 175 °C was observed. The solution was then
allowed to stabilize, and the reaction was continued for 45 min at
[7] W. Kaim, Angew. Chem. Int. Ed. Engl. 1983, 22, 171; Angew.
Chem. 1983, 95, 201.
[
(
(
2
n
[
8] For examples: a) R. Rösler, C. Silvestru, G. Espinosa-Perez, I.
Haiduc, R. Cea-Olivares, Inorg. Chim. Acta 1996, 241, 47; b)
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Hoz, H. Nöth, I. Haiduc, C. Silvestru, Inorg. Chem. Commun.
1
7
90 °C. After completion, the reaction mixture was cooled to
0 °C, and methanol was added to precipitate the nanoparticles.
2000, 3, 173; d) S. D. Robertson, T. Chivers, J. Akhtar, M.
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The solid was separated by centrifugation and washed five times
with methanol. The resulting solid precipitates of TOP-capped
nickel nanoparticles were dispersed in toluene for further analysis.
Crystal Structure Determination: X-ray data collections for HL and
[
NiL
2
pz]
n
were performed with a Mar345 image plate detector by
radiation (Zr-filter) at 150(2) K. The data were inte-
using Mo-K
α
[17]
grated with the crysAlisPro software. The implemented empirical
absorption correction was applied. The structures were solved by
direct methods with the SHELXS-97 program
[18]
and refined by
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full-matrix least-squares on |F | with SHELXL-97.[18] Non-
hydrogen atoms were anisotropically refined, and the hydrogen
atoms were placed on calculated positions in riding mode with tem-
perature factors fixed at 1.2 times the Ueq value of the parent
atoms. Figures were generated with the program Mercury.[
2
1
416; d) O. Hallale, S. A. Bourne, K. R. Koch, CrystEngComm
2005, 7, 161.
19]
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10] a) F. D. Sokolov, S. V. Baranov, D. A. Safin, F. E. Hahn, M.
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M. Bolte, F. E. Hahn, Dalton Trans. 2011, 40, 4806; k) M. G.
Babashkina, D. A. Safin, M. Srebro, P. Kubisiak, M. P. Mito-
raj, M. Bolte, Y. Garcia, CrystEngComm 2011, 13, 5321; l)
M. G. Babashkina, D. A. Safin, K. Robeyns, Y. Garcia, Dalton
Trans. 2012, 41, 1451; m) M. G. Babashkina, D. A. Safin, Y.
Garcia, Dalton Trans. 2012, 41, 2234; n) M. G. Babashkina,
D. A. Safin, M. Srebro, P. Kubisiak, M. P. Mitoraj, M. Bolte,
Y. Garcia, CrystEngComm 2012, 14, 370; o) M. G. Babashkina,
D. A. Safin, M. Srebro, P. Kubisiak, M. P. Mitoraj, M. Bolte,
Y. Garcia, Eur. J. Inorg. Chem. 2013, 545; p) D. A. Safin, M. G.
Babashkina, P. Kubisiak, M. P. Mitoraj, K. Robeyns, E.
Goovaerts, Y. Garcia, Dalton Trans. 2013, 42, 5252; q) D. A.
Safin, M. G. Babashkina, K. Robeyns, M. P. Mitoraj, P. Kubis-
iak, M. Brela, Y. Garcia, CrystEngComm 2013, 15, 7845; r)
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–1
Crystal Data for HL: C19
clinic, space group P2 /c, a = 16.2222(7) Å, b = 11.2641(4) Å, c
10.2615(5) Å, β = 91.410(5)°, V = 1874.50(14) Å , Z = 4, ρ =
17 2 3 r
H N O PS, M = 384.38 gmol , mono-
1
3
=
–3
–1
1.623 gcm , μ(Mo-K
α
) = 0.279 mm , reflections: 14376 collected,
(all) = 0.0579, wR (all) = 0.1544.
3436 unique, Rint = 0.045, R
1
2
Crystal Data for [NiL
2
pz] NiO
n
:
C
42
H
36
¯
N
6
6
P
2
S
2
,
M
r
=
–1
9
1
7
0
05.54 gmol , triclinic, space group P1, a = 13.238(7) Å, b =
3.993(4) Å, c = 15.354(9) Å, α = 77.87(4), β = 70.08(5), γ =
3
–3
4.89(4)°, V = 2558(2) Å , Z = 2, ρ = 1.176 gcm , μ(Mo-K
α
) =
.568 mm , reflections: 3741 collected, 1868 unique, Rint = 0.149,
(all) = 0.1208, wR (all) = 0.3220.
–1
R
1
2
2 n
CCDC-983543 (for HL) and -983544 (for [NiL pz] ) contain the
supplementary crystallographic data for this paper. These data can
be obtained free of charge from The Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Supporting Information (see footnote on the first page of this arti-
cle): Selected bond lengths and bond angles for HL, selected bond
lengths and bond angles for [NiL
lengths and bond angles of HL, and π···π bond lengths (Å) and
angles (°) for [NiL pz]
2 n
pz] , selected hydrogen bond
2
n
.
Acknowledgments
We thank Wallonie-Bruxelles International (WBI, Belgium) for
postdoctoral positions allocated to M. G. B. and D. A. S. This
work was supported by COST (MP1202).
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Received: April 6, 2014
Published Online: June 3, 2014
150, 55.
Eur. J. Inorg. Chem. 2015, 1160–1166
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© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim