PERSONAL DE APOYO
CALDERON SEGOVIA Matias Francisco
artículos
Título:
New Findings for the Composition and Structure of Ni Nanoparticles Protected with Organomercaptan Molecules
Autor/es:
MATIAS F. CALDERÓN; EUGENIA ZELAYA; GUILLERMO A. BENITEZ; PATRICIA L. SCHILARDI; ALBERTO HERNÁNDEZ CREUS; ALEJANDRO GONZÁLEZ ORIVE ; ROBERTO C. SALVAREZZA; FRANCISCO J. IBAÑEZ
Revista:
LANGMUIR
Editorial:
AMER CHEMICAL SOC
Referencias:
Lugar: Washington; Año: 2013 p. 4670 - 4678
ISSN:
0743-7463
Resumen:
Here we explore the synthesis of alkanethiol-coated Ni NPs following the one-phase reaction method by Brust et al.(1) The reduction of NiCl2 with NaBH4 in the presence of dodecanethiol (C12SH)
yields a complex product that is difficult to identify as illustrated
in the figure of merit. We synthesized Ni(II) dodecanethiolate (C12S) (without the addition of NaBH4)
for comparison and performed an exhaustive characterization with TEM,
HR-TEM, AFM, MFM, XPS, XRD, UVvis, magnetism, and FT-IR. It is found
that the organic coating is not quite a well-organized self-assembled
monolayer (SAM) surrounding the Ni cluster as previously reported.(2, 3)
XPS and XRD data show slight differences between both syntheses;
however, Ni(II) thiolate appears to be more stable than reduced Ni when
exposed to ambient air, indicating the propensity of metallic Ni to
oxidize. It has been shown that irradiating with TEM electrons over
various metal thiolates leads to nanoparticle formation.(4)
We irradiated over Ni(II) thiolate and observed no evidence of NP
formation whereas irradiating a reduced Ni sample exhibited an 3.0
nm nanoparticle diameter. Magnetism studies showed a difference between
both samples, indicating ferromagnetic character for the reduced Ni
sample. According to our results, the product of the synthesis is
comprised of ultrasmall metallic clusters embedded in some form of
Ni(II) C12S. In this work, we open a discussion of the
chemical nature of the core and the shell in the synthesis of Ni NPs
protected with organomercaptan molecules.