Chiral metal complexes 47.‡ the solid state and solution structure of Λ;-α-[(N,N′-dimethyl-N,N′-di(2-picolyl)-1S, 2S-diaminocyclohexane) (S-phenylalaninato(1-)]cobalt(III) perchlorate

The structure of the complex Λ-α-[Co(S,S-picchxnMe₂)(S-phe)](ClO₄) ₂ where 5,5′-picchxnMe₂ is N,N′-dimethyl-N,N′-di(2-picolyl)-1S,2S-diaminocyclohexane and S-phe is the S-phenylalaninate anion, has been determined by X-ray diffraction techniques. The perchlorate salt is monoclinic, space group P2₁, with a = 11.833(1), b = 11.029(2), c = 14.020(2) Å, β = 115.63(2)° and Z = 2. The structure was refined to R = 0.050 for 4280 independent reflections with I > 2σ(I). In the solid state, the phenyl ring of the phe ligand is hydrophobically bonded to one of the picolyl rings of the tetradentate ligand in intramolecular fashion; the two rings are virtually parallel (φ = 13.6°) and the distance between the rings averages about 3.8 Å. Considerable ring overlap is evident. Remarkably, this structure persists in solution as revealed by nmr experiments. These show that the conformer of the cation, with respect to the three possible staggered rotamers, observed in the crystal structure, predominates in dmso-d₆ solution (population parameter = 0.528).