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Monodentate and Bridging Coordination of 3,3′‐Annelated 2,2′‐Bipyridines in Zerovalent Palladium‐ and Platinum‐ p ‐quinone Complexes
Author(s) -
Klein René A.,
Witte Peter,
van Belzen Ruud,
Fraanje Jan,
Goubitz Kees,
Numan Milco,
Schenk Henk,
Ernsting Jan M.,
Elsevier Cornelis J.
Publication year - 1998
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/(sici)1099-0682(199803)1998:3<319::aid-ejic319>3.0.co;2-h
Subject(s) - chemistry , denticity , diimine , palladium , ligand (biochemistry) , crystallography , platinum , bridging ligand , stereochemistry , crystal structure , quinone , medicinal chemistry , catalysis , receptor , organic chemistry , biochemistry
Compounds of the type M(N∩N‐κ N )(nq) 2 and M 2 (μ 2 ‐N∩N)(μ 2 ‐pbq) 2 , in which nq = 1,4‐naphthoquinone, pbq = 1,4‐benzoquinone, and N∩N is a monodentate or bridging ligand of the α‐diimine type, were obtained from reactions of Pd(dba) 2 in toluene with the 3,3′‐annelated‐2,2′‐bipyridines: 4,5‐diazafluoren‐9‐one (dafo) and 4,5‐diazafluorene (dafe) in the presence of the appropriate p ‐quinone. In the corresponding reactions with 2,2′‐bipyridine (bpy), 1,10‐phenanthroline (phen), 2,2′‐bipyrimidine (bpym), N,N′ ‐dicyclohexyl‐1,4‐diaza‐1,3‐butadiene (chex‐dab), bis[ N ‐( o,o′ ‐diisopropyl)phenylimino]acenaphthene ( o,o′ ‐ i Pr 2 ‐bian) and 5,6‐dihydro‐1,10‐phenanthroline (dh‐phen) only complexes of the type M(N∩N‐κ 2 N )(Q) were formed (Q = nq, pbq). The structures of the complexes have been established by NMR in solution and by X‐ray diffraction in the solid state; crystal structures of Pd(bpy‐κ 2 N )(η 2 ‐pbq) ( 1 ) Pd(dafo‐κ N )(η 2 ‐nq) 2 ( 14 ) and Pd 2 (μ 2 ‐dafo)(μ 2 ,η 2 :η 2 ‐pbq) 2 ( 16 ) have been determined. Of the ligands, dafo and dafe are the only ones apt to form complexes containing a monodentate or bridging N∩N ligand. This behaviour is ascribed to the geometrical constraints of dafo and dafe; the annelation by one carbon atom at the 3,3′‐positions in these ligands causes an increase in bite angle from approximately 77° to 82°.