Zinc Complexes of Tripodal N3O Ligands

The tripodal N,O ligands bis(2-pyridylmethyl)(o-hydroxybenzyl)amine (L1) and bis(2-pyridylmethyl)(2-carboxyethyl)amine (L2) were tested for their ligating properties towards zinc. Zinc halides yielded L1·Zn−Hal (1a−c, Hal = Cl, Br, I) and L2·Zn−Hal (2a−c, Hal = Cl, Br, I). Subsequent treatment of L1 with ZnEt2 or Zn[N(SiMe3)2]2 and phenol, thiophenols or diphenylphosphate led to L1·Zn−OPh (3), L1·Zn−SAr (4) and L1·Zn−OPO(OPh)2 (5). Zinc salts of noncoordinating anions yielded oligonuclear ligand-bridged complexes [L1·Zn]ClO4 (6), [L2·Zn]ClO4 (7) and [L2·Zn]NO3 (8), of which 6 was identified as a phenolate bridged dimer and 8 as a η1-η2-carboxylate bridged polymer.