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Organo Palladium(II) Complexes with PdC 4 Coordination: Phenylethinyl‐ and Methylphenylethinylcomplexes
Author(s) -
Walther Dirk,
Lamm Katja,
Görls Helmar
Publication year - 2009
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200801196
Subject(s) - chemistry , palladium , ligand (biochemistry) , catalysis , medicinal chemistry , sonogashira coupling , nuclear magnetic resonance spectroscopy , stereochemistry , organic chemistry , biochemistry , receptor
Tetrakis( p ‐tolyl)oxalamidinato‐bis[acetylacetonatopalladium(II)] ([Pd 2 (acac) 2 (oxam)]) reacted with Li–C≡C–C 6 H 5 in THF with formation of [Pd(C≡C–C 6 H 5 ) 4 Li 2 (thf) 4 ] ( 1a ). Reaction of [Pd 2 (acac) 2 (oxam)] with a mixture of 6 equiv. Li–C≡C–C 6 H 5 and 2 equiv. LiCH 3 resulted in the formation of [Pd(CH 3 )(C≡C–C 6 H 5 ) 3 Li 2 (thf) 4 ] ( 2 ), and the dimeric complex [Pd 2 (CH 3 ) 4 (C≡C–C 6 H 5 ) 4 Li 4 (thf) 6 ] ( 3 ) was isolated upon reaction of [Pd 2 (acac) 2 (oxam)] with a mixture of 4 equiv. Li–C≡C–C 6 H 5 and 4 equiv. LiCH 3 . 1 – 3 are extremely reactive compounds, which were isolated as white needles in good yields (60–90%). They were fully characterized by IR, 1 H‐, 13 C‐, 7 Li‐NMR spectroscopy, and by X‐ray crystallography of single crystals. In these compounds Li ions are bonded to the two carbon atoms of the alkinyl ligand. 1a reacted with Pd(PPh 3 ) 4 in the presence of oxygen to form the already known complexes trans ‐[Pd(C≡C–C 6 H 5 ) 2 (PPh 3 ) 2 ] and [Pd(η 2 ‐O 2 )(PPh 3 ) 2 ]. In addition, 1a is an active catalyst for the Heck coupling reaction, but less active in the catalytic Sonogashira reaction.