Two mixed-ligand lanthanide-hydrazone complexes: [Pr(NCS)(3)(pbh)(2)] center dot H2O and [Nd(NCS)(NO3)(pbh)(2)(H2O)]NO3 center dot 2.33H(2)O [pbh is N0-(pyridin-2-ylmethylidene) benzohydrazide, C13H11N3O]

The gel-mediated syntheses and crystal structures of [N'-(pyridin-2-ylmethylidene-kappa N) benzohydrazide-kappa(2) N', O] tris(thiocyanato-kappa N) praseodymium(III) monohydrate, [Pr(NCS)(3)(C13H11N3O)(2)] center dot H2O, (I), and aqua(nitrato-kappa(2) O, O ')[N'-(pyridin-2-ylmethylidene-kappa N) benzohydrazide-kappa(2) N', O](thiocyanato-kappa N) neodymium(III) nitrate 2.33-hydrate, [Nd(NCS)(NO3)(C13H11N3O) 2(H2O)] NO3 center dot 2.33H(2)O, (II), are reported. The Pr3+ ion in (I) is coordinated by two N, N, O-tridentate N'-(pyridin-2-yl-methylidene) benzohydrazide (pbh) ligands and three N-bonded thiocyanate ions to generate an irregular PrN7O2 coordination polyhedron. The Nd3+ ion in (II) is coordinated by two N, N, O-tridentate pbh ligands, an N-bonded thiocyanate ion, a bidentate nitrate ion and a water molecule to generate a distorted NdN5O5 bicapped square antiprism. The crystal structures of (I) and (II) feature numerous hydrogen bonds, which lead to the formation of three-dimensional networks in each case.