The Crystal and Molecular-Structure of Two Complexes of Cobalt(III) With Pentaaza Macrocyclic Ligands Chloro (1,4,7,10,14-pentaazacycloheptadecane)cobalt(III) Bromide Chloride Hydrate [Co(C12H29N5)Cl] (Br0.33Cl1.67)H2O and Bromo(1,4,7,11,15-pentaazacyclooctadecane)cobalt(III) Bromide [Co(C13H31N5)Br]Br2
Australian Journal of Chemistry
40(5) 829 - 839
The structures of the compounds chloro (1,4,7,10,14-pentaazacycloheptadecane) cobalt(III) bromide chloride hydrate, [Co( chad )Cl] ( Br0.33Cl1.67)H2O(1) and bromo (1,4,7,11,15-pentaazacyclooctadecane) cobalt(III) bromide, [Co( coad )Br]Br2(2),have been determined by X-ray diffractometry. [Compound (1) orthorhombic, space group P bac, a 1208.5, b 2305.5, c 1318.9 pm, Z 8, R 0.056, Rw 0.071 for 1943 reflections. Compound (2), triclinic, space group P1, a 930.8, b 953.5, c 1120.3pm, α 84.60,β 398.82, γ 105.26º, Z 2, R 0.045, RW0.054 for 4821 reflections.] The compounds have structures with two ( chad ) or three ( coad ) six-membered chelate rings in the equatorial (N4) plane, but with different configurations of the chiral nitrogen centres ; chad : 1SR , 4SR, 7RS, 10RS, that is, with only the NH group at the junction of the two six-membered chelate rings on the same side of the N4 plane as the axial nitrogen; coad : 1 RS, 7SR, 11 SR, 15RS, that is, with NH groups of the central six-membered chelate ring on the same side of the N4 plane as the axial nitrogen, and the others on the opposite side. The chad compound has regular octahedral geometry, with one chair and one boat conformation six-membered chelate ring. The coad compound has distorted octahedral geometry, with long Co-N distances in the N4 plane, attributed to intra-ligand interactions.
© CSIRO 1987