863099-47-2Relevant academic research and scientific papers
Alternative coordination modes in palladium(II)-diimino-bispyridine complexes with an axially chiral biphenyl backbone
Kettunen, Mika,Vedder, Christoph,Brintzinger, Hans-Herbert,Mutikainen, Ilpo,Leskelae, Markku,Repo, Timo
, p. 1081 - 1089 (2005)
The chiral biphenyl-bridged diimino-bispyridine ligands N,N′-(6,6′-dimethylbiphenyl-2,2′-diyl)bis(2-pyridylmethyl) -diimine(1)and N,N′-(6,6′-dimethylbiphenyl-2,2′-diyl)bis[(6- methyl-2-pyridyl)methyl]diimine (2) react with Pd(COD)Cl2 to give, depending on the reaction conditions, either mono- or binuclear PdCl2 complexes. In the binuclear complex 1-(PdCl2)2, the Pd nuclei are held at a distance of 3.37 A by the ligand backbone. N,N′-(6,6′-dimethylbiphenyl-2,2′-diyl) bis[(5-methyl-2-furyl) methyl]diimine (3), with furyl instead of pyridyl rings, gives mononuclear, C2-symmetric complexes only. Reactions of [Pd(NCCH3) 4]2+(BF4-)2 with ligand 1 or 3 give the C2-symmetric cations [1-Pd]2+or [3-Pd(NCCH3)2]2+, respectively, as their BF4- salts, Solid-state structures of the chloride complexes 1-PdCl2, 1-(PdCl2)2 and 3-PdCl 2, and of the complex cations [1-Pd]2+ and [3-Pd(NCCCH3)2]2+ with tetradentate and bidentate ligand coordination, respectively, all show square-planar coordination, with some distortion toward tedrahedral geometry due to the twisted biaryl-backbone. Preliminary observations on norbornene polymerization with the catalysts 1-PdCl2/MAO, 2-PdCl2/MAO and [(3-Pd(NCCH3)2]2+ suggest that a certain degree of stereoregularity of the polymers is induced by these chiral catalysts. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.
