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Proximity Effect using a Nanocage Structure: Polyhedral Oligomeric Silsesquioxane‐Imidazolium Tetrachloro‐ palladate Salt as a Precatalyst for the Suzuki–Miyaura Reaction in Water
Author(s) -
Bivona Lucia Anna,
Giacalone Francesco,
Carbonell Esther,
Gruttadauria Michelangelo,
Aprile Carmela
Publication year - 2016
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201600155
Subject(s) - silsesquioxane , nanocages , catalysis , salt (chemistry) , chemistry , polymer chemistry , biphenyl , x ray photoelectron spectroscopy , organic chemistry , materials science , chemical engineering , polymer , engineering
A polyhedral oligomeric silsesquioxane‐imidazolium tetrachloropalladate salt (POSS‐Imi‐PdCl 4 ) was prepared by the reaction of a polyhedral oligomeric silsesquioxane‐imidazolium chloride salt (POSS‐Imi‐Cl) with PdCl 2 and used as a pre‐catalyst for the Suzuki–Miyaura reaction in water at 100 °C at a low loading (0.08–0.16 mol %). Biphenyl compounds were isolated in high to excellent yields. A comparison of the POSS‐based catalyst with the corresponding catalyst without the nanocage structure (i.e., 1‐butyl‐3‐methylimidazolium tetrachloropalladate) highlighted the role of the POSS structure to reach higher yields in the Suzuki–Miyaura reaction. This result is ascribed to a proximity effect of the imidazolium moieties linked to the nanocage structure. Fresh and used catalytic materials were characterised by using X‐ray photoelectron spectroscopy and TEM.