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Cymene‐Osmium(II) Complexes with Amino‐Phosphane Ligands as Precatalysts for Nitrile Hydration Reactions
Author(s) -
GonzálezFernández Rebeca,
Crochet Pascale,
Cadierno Victorio
Publication year - 2018
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201801023
Subject(s) - chemistry , osmium , medicinal chemistry , ligand (biochemistry) , catalysis , stereochemistry , nitrile , ruthenium , organic chemistry , receptor , biochemistry
Three different series of half‐sandwich Os(II) complexes, namely [OsCl 2 ( η 6 ‐ p ‐cymene){PPh 2 (NR 2 )}] [R=Me ( 5a ), Et ( 5b )], [OsCl 2 ( η 6 ‐ p ‐cymene){PPh(NR 2 ) 2 }] [R=Me ( 6a ), Et ( 6b )] and [OsCl 2 ( η 6 ‐ p ‐cymene){P(NR 2 ) 3 }] [R=Me ( 7a ), Et ( 7b )], have been synthesized. These species proved to be catalytically active for the selective hydration of organonitriles, with compound [OsCl 2 ( η 6 ‐ p ‐cymene){PPh 2 (NMe 2 )}] ( 5a ) being the most effective. In addition, the catalytic activity of 5a was found to be superior to those shown by related Ru(II), Ru(IV), Rh(I) and Pt(II) species containing the amino‐phosphane PPh 2 (NMe 2 ), i. e. compounds [RuCl 2 ( η 6 ‐ p ‐cymene){PPh 2 (NMe 2 )}] ( 10 ), [RuCl 2 ( η 3 : η 3 ‐C 10 H 16 ){PPh 2 (NMe 2 )}] ( 12 ), [RhCl(COD){PPh 2 (NMe 2 )}] ( 13 ) and cis ‐[PtCl 2 {PPh 2 (NMe 2 )} 2 ] ( 15 ). Details on the synthesis and characterization of complexes 10 , 12 and 15 are also included, along with a discussion on the role played by the ligand PPh 2 (NMe 2 ) during the catalytic reactions. In this sense, the amino‐phosphane does not act as H‐bond acceptor for the water molecule, generating instead in the aqueous reaction medium the cooperative phosphinous acid ligand PPh 2 (OH).