ORTHOMETALLATED PRIMARY AMINES .1. FACILE PREPARATION OF THE 1ST OPTICALLY-ACTIVE CYCLOPALLADATED PRIMARY AMINES

Reaction of [PdCl2{NH2CH(Me)Ph}2] 1 with AgClO4 (1:2) gave a solution containing an orthopalladated complex 2. Addition to this solution of neutral ligands or NaBr led to isolation of the complexes [Pd{C6H4[CH(Me)NH2-2]}(L2)]ClO4 [L = pyridine 3a, L2 = cycloocta-1,5-diene(cod) 3b or 2,2'-bipyridine 3c] or [{Pd{C6H4[CH(Me)NH2-2]}(mu-Br)}2] 4, respectively. Reaction of 4 with PPh3 or TI(acac) (Hacac = acetylacetone) gave [Pd{C6H4[CH(Me)NH2-2]}Br(PPh3)] 5 or [Pd{C6H4[CH(Me)NH2-2]}(acac)] 6, respectively. Complexes 1, 4 and 5 can be obtained optically pure by using (R)-(+)- or (S)-(-)-alpha-methylbenzylamine as starting material. The solid-state crystal structures of 3b and R-5 were determined at low temperatures. In both complexes the palladium atom adopts the usual square-planar co-ordination. The major angular distortion is associated with the small bite of the chelating ligand (80.8 and 81.2-degrees, respectively). The weaker trans influence of the cod ligand in 3b accounts for ca. 0.02 angstrom longer Pd-N and Pd-C bonds in R-5 than in 3b. Short contacts between the perchlorate anion or bromo ligand in 3b or R-5 with the amino group (N ... 0 3.06 or N ... Br 3.41 A, respectively) probably represent hydrogen bonds.