Synthesis and structures of vinamidine Mn-II, Zn-II, and Cd-II iodine derivatives

We have focused on the synthesis of monomeric, functionalized starting mate rials containing manganese(II), zinc(II), and cadmium(II) by taking advanta ge of the sterically demanding and chelating property of the substituted vi namidine ligand 2-[(2,6-diisopropylphenyl) amino]-4-[ (2,6-diisopropylpheny l) imino]pent-2-ene (NacNacH). Metal iodine derivatives containing vinamidi nes as the bulky ligand can be regarded as interesting precursors for prepa ring complexes with low-valent metal centers by reduction as long as they a re free of coordinated ether. The vinamidine complexes NacNacM(mu -I)(2)Li( OEt2)(2) [M = Mn (3), Zn (4), Cd (5)] are obtained from the corresponding v inamidine lithium complex and MI, (M = Mn, Zn, Cd) in good yields. A crysta l structure analysis of 3, 4, and 5 shows them to be isostructural. All thr ee structures have the vinamidine backbone in a boat conformation with the tetrahedrally coordinated metal center at the prow and the opposing carbon atom at the stern.