Synthesis and Structural Characterization of Lithium and Titanium Complexes Bearing a Bulky Aryloxide Ligand Based on a Rigid Fused-Ring s‑Hydrindacene Skeleton

The bulky aryl alcohols, (Rind)­OH (1) [Rind = EMind (a) and Eind (b)], based on the rigid fused-ring 1,1,3,3,5,5,7,7-octa-R-substituted s-hydrindacene skeleton were prepared by the reaction of (Rind)Li with nitrobenzene followed by protonation. The treatment of 1 with nBuLi affords the lithium aryloxide dimers [(Rind)­O­Li­(THF)]2 (2) or trimers [(Rind)­OLi]3 (3), depending on the employed solvents (THF = tetrahydrofuran). The salt metathesis reaction of [(EMind)­O­Li­(THF)]2 (2a) with TiCl4(THF)2 leads to the formation of the mononuclear diamagnetic mono- and bis­(aryloxide) Ti­(IV) complexes, [(EMind)­O]­TiCl3(THF) (4a) and [(EMind)­O]2TiCl2 (5a). We also isolated a trace amount of the tris­(aryloxide) Ti­(IV) complex, [(EMind)­O]3TiCl (6a). The reaction between 2a and TiCl3(THF)3 resulted in the isolation of the mononuclear paramagnetic mono- and bis­(aryloxide) Ti­(III) complexes, [(EMind)­O]­TiCl2(THF)2 (7a) and [(EMind)­O]2­TiCl­(THF)2 (8a). The discrete monomeric structures of the titanium complexes 4a, 5a, 6a, 7a, and 8a were determined by X-ray crystallography.