The role of 2-hydroxypyridine in the formation of pivalate Zn–Gd complexes

The reactions of [Zn(Piv)2]n and [Gd(Piv)3]n or Gd(NO3)3 ∙ 6H2O with 2-hydroxypyridine (Hhp) or its 6-methyl derivative (Hmhp) afford heterometallic complexes [ZnGd(Рiv)5(Hhp)2] · 0.5H2O (I), [Zn2Gd (Рiv)6(Hhp)2NO3] ∙ 2C6H6 (II), [Zn3GdO(Рiv)7(Hmhp)2] ∙ MeCN (III) и [Zn2Gd(Рiv)6(Hmhp)2NO3] ∙ ∙ 0.5MeCN (IV) respectively. In the carboxylate metal cage of the synthesized complexes, the Hhp and Hmhp molecules in the form of 2-pyridone are coordinated by the metal atoms via the monodentate mode through the oxygen atoms. The introduction of Et3N into the reaction with [Zn(Рiv)2]n, Gd(NO3)3 ∙ 6H2O, and Hhp is found to result in the formation of compound [Zn4Gd2(OH)2(Рiv)6(hp)6(Hhp)2] (V) in which the 2-hydroxypyridine anions perform the bridging function. The molecular structures of complexes I‒V are determined by XRD (CIF files CCDC nos. 2365419–2365423).