http://www.cnr.it/ontology/cnr/individuo/prodotto/ID47768
Can the clusters Zr6O4(OH)4(OOCR)12 and [Zr6O4(OH)4(OOCR)12]2 be converted into each other? (Articolo in rivista)
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- Can the clusters Zr6O4(OH)4(OOCR)12 and [Zr6O4(OH)4(OOCR)12]2 be converted into each other? (Articolo in rivista) (literal)
- Anno
- 2006-01-01T00:00:00+01:00 (literal)
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
- 10.1002/ejic.200600348 (literal)
- Alternative label
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
- Puchberger M.; Kogler F.R.; Jupa M.; Gross S.; Fric H.; Kickelbick G.; Schubert U. (literal)
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- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#url
- http://onlinelibrary.wiley.com/doi/10.1002/ejic.200600348/abstract (literal)
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
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- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#pagineTotali
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- ISI Web of Science (WOS) (literal)
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
- 1-7 : Institute of Materials Chemistry, Vienna University of Technology, Getreidemarkt 9/165, 1060 Wien, Austria
4 : Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy (literal)
- Titolo
- Can the clusters Zr6O4(OH)4(OOCR)12 and [Zr6O4(OH)4(OOCR)12]2 be converted into each other? (literal)
- Abstract
- Upon reaction of zirconium alkoxides, Zr(OR)4, with carboxylic
acids, the clusters Zr6O4(OH)4(OOCR)12 (Zr6) or
[Zr6O4(OH)4(OOCR)12]2 (Zr12) were obtained, depending on
the employed carboxylic acid. The structures of Zr12 clusters
with acetate, propionate, vinyl acetate or 3,3?-dimethylacrylate
ligands were determined by single-crystal X-ray diffraction,
as well as that of methacrylate/acetate and methacrylate/
propionate mixed-ligand clusters. The structure of the
hafnium cluster [Hf6O4(OH)4(acetate)12]2 is also reported for
comparison. The Zr12 clusters are structurally related to the
Zr6 clusters since they are composed of two Zr6 sub-units
which are bridged by four carboxylate ligands. In each compound,
carboxylic acid molecules interact with the cluster by
hydrogen bonding to part of the ?3-OH ligands. The clusters
are highly dynamic in solution, due to site exchange of the
Introduction
We have previously prepared a variety of carboxylatesubstituted
titanium and zirconium oxo clusters, mainly to
use the (meth)acrylate derivatives for the preparation of
cluster-crosslinked polymers.[1] During this work, we obtained
several types of zirconium oxo clusters, among them
Zr6O4(OH)4(OOCR)12 (Zr6) and the dimer [Zr6O4(OH)4-
(OOCR)12]2 (Zr12), having the same overall stoichiometry.
Previous to this work, we obtained crystalline Zr6 clusters
for RCOO = methacrylate (1)[2] and 5-norbornene-2-carboxylate,[
3] and the Zr12 type for RCOO = acrylate.[4] The
crystal structures of both cluster types additionally contain
carboxylic acid molecules interacting with the ligand shell
of the clusters by hydrogen bonding (see below).
The Zr6 clusters consist of a Zr6O4(OH)4 cluster core in
which the triangular faces of a Zr6 octahedron are alternatively
capped by ?3-O and ?3-OH groups. The structure of
the Zr12 cluster consists of two Zr6 sub-units which are
connected by four carboxylate bridges. This will be discussed
below in more detail. In a formal manner, the Zr12
[a] Institute of Materials Chemistry, Vienna University of Technology,
Getreidemarkt 9/165, 1060 Wien, Austria
[?] Current address: Department of Chemical Sciences, University
of Padova,
Via Marzolo 1, 35131 Padova, Italy
Eur. J. Inorg. Chem. 2006, 3283-3293 © 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 3283
carboxylate ligands; low-temperature NMR spectra of the
clusters correspond to the solid-state structures. The Zr6 and
Zr12 clusters can be clearly distinguished by their solution
NMR spectra. Reactions between selected Zr12 clusters and
carboxylic acids led to the conclusion, that only part of the
ligands is accessible for ligand exchange reactions. In contrast,
all ligands were exchanged when the Zr6 cluster
Zr6O4(OH)4(methacrylate)12 was treated with an excess of
propionic acid, and Zr6O4(OH)4(propionate)12 was formed.
However, the Zr12 cluster [Zr6O4(OH)4(propionate)12]2 was
obtained from the reaction of Zr(OBu)4 with propionic acid.
The Zr6 and Zr12 clusters thus do not interconvert at the
given reaction conditions. (literal)
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