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Molecular Structure of a Hydridoniobocene Complex [Nb(η 5 ‐C 5 H 4 SiMe 3 ) 2 (H) 3 ] and Its Use as Catalyst for the Ring‐Opening Polymerization of Cyclic Esters
Author(s) -
AlonsoMoreno Carlos,
Antiñolo Antonio,
GarcíaMartínez Joaquín C.,
GarcíaYuste Santiago,
LópezSolera Isabel,
Otero Antonio,
PérezFlores Juan C.,
TerceroMorales Maria T.
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.201101263
Subject(s) - chemistry , polymerization , polymer , hydride , crystallography , oxygen atom , ring opening polymerization , yield (engineering) , monomer , polymer chemistry , stereochemistry , molecule , hydrogen , organic chemistry , materials science , metallurgy
The second polyhydridoniobocene complex that was characterized by X‐ray diffraction is reported. On the basis of H–H distances and H–Nb–H angles, [Nb(η 5 ‐C 5 H 4 SiMe 3 ) 2 (H) 3 ] ( 1 ) is classified as a “compressed hydride”. Compound 1 acts as an efficient single‐component initiator for the ring‐opening polymerization of ϵ‐caprolactone and δ‐valerolactone. ϵ‐Caprolactone and δ‐valerolactone are both polymerized within a few hours to yield high‐to‐medium‐molecular‐weight polymers with medium to broad polydispersities. Polymer end‐group analysis showed that the polymerization proceeds through a coordination–insertion mechanism based on the cleavage of the ring between the oxygen atom and the acyl carbon atom.