Synthesis and crystal structures of a new series of intramolecular bridged alkylcobaloxime complexes.

A new series of intramolecular bridged alkylcobaloxime complexes were prepared by heating a solution of aqua-(3-bromopropyl)cobaloxime (1) through an intramolecular nucleophilic substitution. They are characterized by EA, ESI-MS, and (1)H NMR. Crystal structures of Br(O-C(3)H(6)-(dmgH))(dmgH)Co(III) (2), [H(2)O(O-C(3)H(6)-(dmg))(dmgH(2))Co(III)]ClO(4) (3), [Py(O-C(3)H(6)-(dmg))(dmgH(2))Co(III)]ClO(4) (4), [Bzm(O-C(3)H(6)-(dmg))(dmgH(2))Co(III)]ClO(4) (5), and Im(O-C(3)H(6)-(dmg))(dmgH)Co(III) (6') were determined by X-ray diffraction. It is revealed that an intramolecular tri-methylene bridge exists between cobalt and one of the equatorial oxime oxygens forming a six-membered ring in the complexes. Additionally, the axial bases have some influences in their structure parameters, for example, Co-L bond lengths; folding angles in equatorial ligands; hydrogen atom positions in O-H-O bridge; and the orientations of those L planes with respect to the equatorial planes.