Synthesis of Dipotassium 2,2′‐Bis(2‐oxidobenzylideneamino)‐4,4′‐dimethyl‐1,1′‐biphenyl Derivatives and Use as Ligand Transfer Reagent

The condensation of 2,2′‐diamino‐4,4′‐dimethyl‐1,1′‐biphenyl with 2‐hydroxybenzaldehyde (salicylaldehyde) or their 3‐, 4‐ or 5‐methoxy substituted congeners leads to the formation of 2,2′‐bis(salicylideneamino)‐4,4′‐dimethyl‐1,1′‐biphenyl ( 1a ) and their methoxy‐substituted congeners 1b – 1d . Deprotonation of 1a with KH yields octameric and wheel‐shaped dipotassium 2,2′‐bis(2‐oxidobenzylideneamino)‐4,4′‐dimethyl‐1,1′‐biphenyl ( 2a ) that is only very sparingly soluble in common organic solvents. Attached methoxy groups are able to stabilize smaller aggregates and trimeric dipotassium 2,2′‐bis(2‐oxido‐3‐methoxybenzylideneamino)‐4,4′‐dimethyl‐1,1′‐biphenyl ( 2b ) has been isolated. The metathesis reaction of 2a with [(thf) 2 TiCl 4 ] yields 2,2′‐bis(2‐oxidobenzylideneamino)‐4,4′‐dimethyl‐1,1′‐biphenyl titanium(IV) dichloride ( 3 ) with two isomeric forms, one with a cis and another with an uncommon trans arrangement of the halide ions.