Record Details

A computational insight into a metal mediated pathway for the ring-opening polymerization (ROP) of lactides by an ionic {(NHC)(2)Ag}(+)X(-) (X = halide) type N-heterocyclic carbene (NHC) complex

DSpace at IIT Bombay

View Archive Info
 
 
Field Value
 
Title A computational insight into a metal mediated pathway for the ring-opening polymerization (ROP) of lactides by an ionic {(NHC)(2)Ag}(+)X(-) (X = halide) type N-heterocyclic carbene (NHC) complex
 
Creator STEPHEN, R
SUNOJ, RB
GHOSH, P
 
Subject MOLECULAR-ORBITAL METHODS
AB-INITIO PSEUDOPOTENTIALS
EFFECTIVE CORE POTENTIALS
MIXED AQUEOUS-MEDIUM
SET MODEL CHEMISTRY
EPSILON-CAPROLACTONE
TRIMETHYLENE CARBONATE
TRANSITION-ELEMENTS
GOLD(I) COMPLEXES
TOTAL ENERGIES
 
Description A metal mediated coordination-insertion pathway for the ring-opening polymerization (ROP) of L-lactide by an ionic {(NHC)(2)Ag}(+)X(-) (X = halide) type silver complex of N-heterocyclic carbene (NHC) has been investigated using the density functional theory (DFT) method. A clear insight into the lactide insertion process could be obtained by modeling two consecutive monomer addition steps with the first one mimicking chain initiation with the second representing a propagation step. In particular, in each of the cycles, the reaction initiates with the formation of a lactide coordinated species, [1+LL] and [2+LL] that transforms into a metal bound cyclic lactide intermediate, I([1+LL] -> 2) and I([2+LL] -> 3), which subsequently ring opens to give the lactide inserted products, 2 and 3. The estimated overall activation barrier for the initiation step is 42.0 kcal mol(-1) while the same for the propagation step is 31.5 kcal mol(-1). Studies on higher monomer insertions showed a decrease in the relative product energies as anticipated for an addition polymerization pathway.
 
Publisher ROYAL SOC CHEMISTRY
 
Date 2012-06-26T09:27:48Z
2012-06-26T09:27:48Z
2011
 
Type Article
 
Identifier DALTON TRANSACTIONS,40(39)10156-10161
1477-9226
http://dx.doi.org/10.1039/c1dt10345h
http://dspace.library.iitb.ac.in/jspui/handle/100/14286
 
Language English