A new sterically loaded pentadentate N 3S 2 ligand and its zinc complexes

Abstract

In quest of complexes having [MN 3S 2] cores in the monomeric form and trans-thiolate donor atoms, the new pentadentate thiolate amine py t BuN 2H 2S 2–H 2 [ = py t Bu N 2 H 2 S 2 2 - = 2 , 6 -bis ( 2 -mercapto- 3 , 5 -di- tert -butylphenylaminomethyl ) pyridine ( 2 - ) ] has been synthesized.The template condensation reaction of bis(2-mercapto-3,5-di- tert-butylaniline)zinc (II)[Zn( t Bu 2ma) 2] and pyridine-2,6-dicarbaldehyde in methanol at 40 °C leads to the formation of imine zinc complex [Zn(py t BuN 2S 2)] ( 7), which is very unstable and decomposes to give thiazole 5. However, if the template condensation is followed by in situ reduction with an excess of NaBH 4, the stable saturated amine complex [Zn(py t BuN 2H 2S 2)] ( 8) is formed. Demetallation of zinc complex 8 under acidic conditions leads to the formation of the desired dithiolate py t BuN 2H 2S 2–H 2 ligand ( 9).