Experimental and Theoretical Studies of the Factors Affecting the Cycloplatination of the Chiral Ferrocenylaldimine

Abstract: The study of the reactivity of the enantiopure ferrocenyl Schiff base ( S C )-[FcCH=N–CH(Me)(C 6 H 5 )] ( 1 ) (Fc = (η 5 -C 5 H 5 )Fe(η 5 -C 5 H 4 )) with cis -[PtCl 2 (dmso) 2 ] under different experimental conditions is reported. Four different types of chiral Pt(II) have been isolated and characterized. One of them is the enantiomerically pure trans -( S C )-[Pt{κ 1 - N [FcCH=N–CH(Me)(C 6 H 5 )]}Cl 2 (dmso)] ( 2a ) in which the imine acts as a neutral N -donor ligand; while the other three are the cycloplatinated complexes: κ 2 -C , N [Pt{ [(C 6 H 4 )–N=CHFc]}Cl(dmso)] ( 7a ) and the two diastereomers { (S p , S C ) and (R p ,S C ) } of [Pt{κ 2 -C , N [(η 5 -C 5 H 3 )–CH=N–{CH(Me)(C 6 H 5 )}]Fe(η 5 -C 5 H 5 )}Cl(dmso)] ( 8a and 9a , respectively). Isomers 7a - 9a , differ in the nature of the metallated carbon atom [C Ph (in 7a ) or C Fc (in 8a and 9a )] or the planar chirality of the 1,2-disubstituted ferrocenyl unit ( 8a and 9a ). Reactions of 7a – 9a with PPh 3 gave [Pt{κ