Binucleating Ligands:  Synthesis of Acyclic Achiral and Chiral Schiff Base−Pyridine and Schiff Base−Phosphine Ligands

5- tert -Butyl-3-(2‘-pyridyl)salicyaldehyde and 5- tert -butyl-3-(diphenylphosphino)salicyaldehyde were synthesized from 4- tert -butylphenol in good overall yields. Condensation of the salicyaldehydes with 2,3-diamino-2,3-dimethylbutane afforded the desired dinucleating Schiff base−pyridine and Schiff base−phosphine ligands, respectively. 5- tert -Butyl-3-(2‘-pyridyl)salicyaldehyde reacted with optically active 1,2-diaminocyclohexanes to give chiral dinucleating Schiff base−pyridine ligands.