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Covalently Bonded Bis(phosphane)gold(I) Cations in a Cross‐Linked Phosphazene Polymeric Matrix as Recyclable Supported Catalysts for Thermal and Microwave‐Assisted Hydration of Alkynes
Author(s) -
Carriedo Gabino A.,
López Salomé,
SuárezSuárez Silvia,
PresaSoto David,
PresaSoto Alejandro
Publication year - 2011
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.201001317
Subject(s) - phenylacetylene , chemistry , phosphazene , cationic polymerization , catalysis , acetylene , alkyne , medicinal chemistry , molecule , covalent bond , polymer chemistry , organic chemistry , polymer
The unexpected finding that the complex [Au(PPh 3 ) 2 ]PF 6 ( C1 ) catalyses the specific hydration of 1‐octyne, ( p ‐phenoxyphenyl)acetylene, phenylacetylene, ( p ‐chlorophenyl)acetylene and benzylacetylene at 100 °C in the presence of H 2 SO 4 and THF or methanol as solvents, specially using microwave radiation, led to the first gold(I) recyclable catalysts for this reaction. The phosphazene polymeric framework of idealised formula {[NP(O 2 C 12 H 8 )] 0.85 [NP(OC 6 H 4 PPh 2 ) 2 (AuPF 6 ) 0.5 ] 0.15 } n ( C2 ), and the newly synthesised cyclomatrix material of idealised formula {[N 3 P 3 (OC 6 H 4 PPh 2 ) 6 ](AuPF 6 ) 3.5 } n ( C3 ), both having cationic [–Ph 2 P–Au + –PPh 2 –] cross‐linking sites, catalysed the complete hydration of terminal alkynes at 100 °C and 150 °C and could be used six and four times respectively without significant loss of activity. The mechanism of the catalytic system is based on the initial reversible displacement of one anchoring O–C 6 H 5 –PPh 2 group from the [–Ph 2 P–Au + –PPh 2 –] cross‐linking sites by an alkyne molecule. Using microwave radiation, the hydration of ( p ‐phenoxyphenyl)acetylene, phenylacetylene, ( p ‐chlorophenyl)acetylene and benzylacetylene can be completed in 5 min to 2 h in the absence of any gold(I) catalyst.