Diazadienkomplexe elektronenarmer übergangsmetalle: Synthese, Eigenschaften und Struktur von CpTi(diazadien)Cl

Diazadiene Complexes of Electron‐Deficient Transition Metals: Synthesis, Properties, and Structure of CpTi(diazadiene)Cl The electron‐deficient 1,4‐diazadiene (DAD) complex CpTi‐(DAD)Cl ( 3 ), [DAD=1],4‐bis(4‐methoxyphenyl)‐2,3‐dimethyl‐1,4‐diazabutadiene] is prepared either by reduction of CpTiCl 3 ( 1 ) with magnesium in the presence of free DAD ( 2 ) or by the reaction of 1 with Na 2 DAD. NMR spectroscopic and X‐ray diffraction analysis of 3 indicate that the bonding of the DAD ligand has σ 2 ,π‐metallacyclopentene rather than η 4 ;‐π character. As a result of steric repulsion between the Cp ring and methyl groups of the DAD ligand 3 exhibits a supine ( exo ) geometry for DAD coordination is solid state. Substitution reaction of 3 affords the novel complex CpTi(DAD)R (RCH 2 Ph).