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Synthesis of End‐Functionalized Polyacetylenes that Contain Polar Groups by Employing Well‐Defined Palladium Catalysts
Author(s) -
Rodriguez Casta Jesus,
Kuwata Keiko,
Shiotsuki Masashi,
Sanda Fumio
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201202256
Subject(s) - monomer , chemistry , trifluoromethanesulfonate , ferrocene , polymer chemistry , acetylene , polymer , palladium , catalysis , polymerization , stereochemistry , organic chemistry , electrode , electrochemistry
A series of [(dppf)PdBr(R)]‐type complexes (dppf=1,1′‐bis(diphenylphosphino)ferrocene; R= p ‐cyanophenyl ( 1 a ), o ‐hydroxymethylphenyl ( 1 b ), and triphenylvinyl ( 1 c )), in combination with silver trifluoromethanesulfonate (AgOTf), were demonstrated to be active for the polymerization of monosubstituted polar acetylene monomers HCCCONHC 4 H 9 ( 2 ), HCCCO 2 C 8 H 17 ( 3 ), HCCCH 2 OCONHC 6 H 13 ( 4 ), HCCCH 2 OCO 2 C 6 H 13 ( 5 ), and HCCCH(CH 3 )OH ( 6 ). The yields and molecular weights of the polymers depended on the combination of the Pd catalyst and monomer that was employed. Matrix‐assisted laser‐desorption/ionization–time of flight (MALDI‐TOF) mass spectrometric analysis indicated the formation of polymers that contained the “R” and “H” groups at the chain ends. IR spectroscopic analysis supported the R‐end‐functionalization of the polymers. NMR spectroscopy and MS identified the presence of species that were formed by single, double, and triple insertion of the monomers into the Pd‐C 6 H 4 ‐ p ‐CN bond, thereby giving solid evidence for an insertion mechanism for the present system. Density functional theory (DFT) calculations suggested the preference for 1,2‐insertion of the monomer compared to 2,1‐insertion.