Département de chimie moléculaire

The synthesis of the new potentially hexadentate ligands N,N'-bis(2,2'-bipyridin-6-ylmethyl)butane-1,4-diamine (bmbu), N,N'-bis(2,2'-bipyridin-6-ylmethyl)pentane-1,5-diamine (bmpt) and N,N'-bis(2,2'-bipyridin-6-ylmethyl)octane-1,8-diamine (bmot) from the condensation of 2,2'-bipyridine-6-carbaldehyde with the appropriate diamine (butane-1,4-diamine, pentane-1,5-diamine and octane-1,8-diamine, resp.) and subsequent redn., is reported. Bmet, bmpp and bmbu all form mononuclear complexes with first-row transition metal ions (Co3+, Fe2+, Ni2+, Mn2+), and x-ray structures of [Mn(bmet)](ClO4)2, [Ni(bmet)](ClO4)2, [Fe(bmet)](ClO4)2, [Mn(bmpp)](ClO4)2·2MeCN and [Co(bmpp)](ClO4)3·H2O are reported. As the aliph. methylene chain increases in length, formation of dinuclear, and in some cases trinuclear, complexes becomes more pronounced, as evidenced by mass spectral anal. of solns. contg. Ni2+ and bmpt, and Ni2+, Fe2+ and Mn2+ with bmot. The increasing preference for multinuclear complexes with increasing chain length is ascribed to the difficulty of incorporating a medium-sized (8 to 13-membered) chelate ring in a mononuclear complex. [on SciFinder(R)]