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Alkali Metallosilicates: Synthesis, Structure and Evaluation in the ROP of ϵ‐Caprolactone
Author(s) -
PérezPérez Jovana,
HernándezBalderas Uvaldo,
MartínezOtero Diego,
MoyaCabrera Mónica,
Jancik Vojtech
Publication year - 2021
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.202100427
Subject(s) - chemistry , alkali metal , steric effects , monomer , caprolactone , yield (engineering) , crystallography , metal , solid state , polymer chemistry , stereochemistry , polymerization , organic chemistry , polymer , materials science , metallurgy
A series of metallosilicate complexes ( t BuO) 2 (RO)SiOM (R= t Bu, i Pr, Et, Me; M=Li, Na, K) were prepared from tailor‐made silanols. The complexes show different degree of association and feature heterocubane, double‐heterocubane or hexagonal prism framework in solid state while ESI‐MS shows fragmentation of the oligomers. The steric hindrance around the silicon atom has a direct influence over the association of the alkali derivatives, and the size of the alkali metal influences the shape of the M x O x core. These compounds were studied as initiators in the ROP of ϵ‐caprolactone, varying temperature, reaction‐time, monomer/initiator ratio, metal center variation and association degree. The best results were achieved with [{( t BuO) 3 SiO} 4 Li 4 ] ( 1 ) producing an almost quantitive yield of polycaprolactone (97 %, M n =35 kg mol −1 , M w / M n =1.72).