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Rhodium Nanoparticles from Dirhodium(II) Ethylene Glycol Tetracarboxylates
Author(s) -
Tuchscherer André,
Packheiser Rico,
Rüffer Tobias,
Schletter Herbert,
Hietschold Michael,
Lang Heinrich
Publication year - 2012
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201101424
Subject(s) - rhodium , chemistry , ethylene glycol , thermal decomposition , nanoparticle , powder diffraction , decarboxylation , decomposition , thermogravimetry , reagent , catalysis , crystallography , nuclear chemistry , stereochemistry , polymer chemistry , organic chemistry , inorganic chemistry , nanotechnology , materials science
A straightforward synthesis methodology for the preparation of rhodium(II) carboxylates [Rh 2 {O 2 CCH 2 (OCH 2 CH 2 ) 2 OCH 3 } 4 ] n ( 1 ) and [Rh{μ‐O 2 CCH 2 (OCH 2 CH 2 ) 2 OCH 3 } 2 (PPh 3 )] 2 ( 2 ) is reported. The ethanol‐mediated reduction of RhCl 3 · 3H 2 O with [K{O 2 CCH 2 (OCH 2 CH 2 ) 2 OCH 3 }] produced 1 , which on further addition of PPh 3 afforded 2 . Single‐crystal X‐ray diffraction studies of 2 were carried out showing a paddlewheel arrangement of the dirhodium(II) tetracarboxylate unit with a Rh–Rh distance of 2.4599(5) Å. Compounds 1 and 2 were applied in the formation of rhodium nanoparticles (NPs) using 1,2‐ethanediol as reducing reagent and poly(vinylpyrrolidone) (PVP) as capping component. Rhodium NPs with a narrow size distribution (<4 nm) were obtained from 1 . The dependency of the concentration and temperature on the NP size and size distribution is discussed. Characterization of the Rh colloids was performed by TEM, X‐ray powder diffraction (XRPD), and electron‐diffraction studies, which revealed that Rh NPs with diameters between (3.0±0.4) and (3.9±0.4) nm were formed. Additionally, the decomposition of 1 and 2 was studied by thermogravimetry (TG)–MS coupling experiments, which showed their differing thermal behavior. Complex 1 follows a two‐step decomposition, whereas degradation of 2 occurs in three steps. The main difference in degradation is that decarboxylation of 1 starts at 230 °C, whereas for 2 the main CO 2 formation is observed above 600 °C.