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@ARTICLE{Wegner:840176,
author = {Wegner, Susann and Rutz, Christina and Schütte, Kai and
Barthel, Juri and Bushmelev, Alexey and Schmidt, Annette and
Dilchert, Katharina and Fischer, Roland A. and Janiak,
Christoph},
title = {{S}oft, {W}et-{C}hemical {S}ynthesis of {M}etastable
{S}uperparamagnetic {H}exagonal {C}lose-{P}acked {N}ickel
{N}anoparticles in {D}ifferent {I}onic {L}iquids},
journal = {Chemistry - a European journal},
volume = {23},
number = {26},
issn = {0947-6539},
address = {Weinheim},
publisher = {Wiley-VCH},
reportid = {FZJ-2017-07731},
pages = {6330 - 6340},
year = {2017},
abstract = {The microwave-induced decomposition of
bis{N,N′-diisopropylacetamidinate}nickel(II)
[Ni{MeC(NiPr)2}2] or bis(1,5-cyclooctadiene)nickel(0)
[Ni(COD)2] in imidazolium-, pyridinium-, or
thiophenium-based ionic liquids (ILs) with different anions
(tetrafluoroborate, [BF4]−, hexafluorophosphate, [PF6]−,
and bis(trifluoromethylsulfonyl)imide, [NTf2]−) yields
small, uniform nickel nanoparticles (Ni NPs), which are
stable in the absence of capping ligands (surfactants) for
more than eight weeks. The soft, wet-chemical synthesis
yields the metastable Ni hexagonal close-packed (hcp) and
not the stable Ni face-centered cubic (fcc) phase. The size
of the nickel nanoparticles increases with the molecular
volume of the used anions from about 5 nm for [BF4]− to
≈10 nm for [NTf2]− (with 1-alkyl-3-methyl-imidazolium
cations). The n-butyl-pyridinium, [BPy]+, cation ILs
reproducibly yield very small nickel nanoparticles of
2(±1) nm average diameter. The Ni NPs were characterized
by high-resolution transmission electron microscopy (HR-TEM)
and powder X-ray diffraction. An X-ray photoelectron
spectroscopic (XPS) analysis shows an increase of the
binding energy (EB) of the electron from the Ni 2p3/2
orbital of the very small 2(±1) nm diameter Ni particles
by about 0.3 eV to EB=853.2 eV compared with bulk Ni0,
which is traced to the small cluster size. The Ni
nanoparticles show superparamagnetic behavior from 150 K
up to room temperature. The saturation magnetization of a Ni
(2±1 nm) sample from [BPy][NTf2] is
2.08 A m2 kg−1 and of a Ni (10±4 nm) sample from
[LMIm][NTf2] it is 0.99 A m2 kg−1,
([LMIm]=1-lauryl-3-methyl- imidazolium). The Ni NPs were
active catalysts in IL dispersions for 1-hexene or benzene
hydrogenation. Over $90 \%$ conversion was reached under
5 bar H2 in 1 h at 100 °C for 1-hexene and a turnover
frequency (TOF) up to 1330 molhexane (molNi)−1 h−1
or in 60 h at 100 °C for benzene hydrogenation and
TOF=23 molcyclohexane (molNi)−1 h−1.},
cin = {ER-C-2},
ddc = {540},
cid = {I:(DE-Juel1)ER-C-2-20170209},
pnm = {143 - Controlling Configuration-Based Phenomena (POF3-143)},
pid = {G:(DE-HGF)POF3-143},
typ = {PUB:(DE-HGF)16},
pubmed = {pmid:28196305},
UT = {WOS:000400945500017},
doi = {10.1002/chem.201605251},
url = {https://juser.fz-juelich.de/record/840176},
}