The crystal structures of {LnCu5}3+ (Ln = Gd Dy and Ho) 15-metallacrown-5 complexes and a reevaluation of the isotypic EuIII analogue

摘要

Three new isotypic heteropolynuclear complexes, namely penta­aqua­carbonato­penta­kis­(glycinehydroxamato)nitrato­penta­copper(II)lanthanide(III) x-hydrate, [LnCu5(GlyHA)5(CO3)(NO3)(H2O)5]·xH2O (GlyHA²⁻ is glycine­hydrox­amate, N-hy­droxy­glycinamidate or amino­aceto­hydroxamate, C2H4N2O2 ²⁻), with lanthanide(III) (Ln ^III) = gadolinium (Gd, >1, x = 3.5), dysprosium (Dy, >2, x = 3.28) and holmium (Ho, >3, x = 3.445), within a 15-metallacrown-5 class were obtained on reaction of lanthanide(III) nitrate, copper(II) acetate and sodium glycinehydroxamate. Complexes >1–>3 contain five copper(II) ions and five bridging GlyHA²⁻ anions, forming a [CuGlyHA]5 metallamacrocyclic core. The Ln ^III ions are coordinated to the metallamacrocycle through five O-donor hydroxamates. The electroneutrality of complexes >1–>3 is achieved by a bidentate carbonate anion coordinated to the Ln ^III ion and a monodentate nitrate anion coordinated apically to one of the copper(II) ions of the metallamacrocycle. The lattice parameters of complexes >1–>3 are similar to those previously reported for an Eu^III–Cu^II 15-metallacrown-5 complex with glycine­hydroxamate of proposed composition [EuCu5(GlyHA)5(OH)(NO3)2(H₂O)₄]·3.5H₂O [Stemmler et al. (1999). Inorg. Chem. >38, 2807–2817]. High-quality X-ray data obtained for >1–>3 have allowed a re-evaluation of the X-ray data solution proposed earlier for the EuCu₅ complex and suggest that the formula is actually [EuCu₅(GlyHA)₅(CO₃)(NO₃)(H₂O)₅]·3.5H₂O.