Synthesis and spectroscopy of unsymmetric mononuclear lanthanide cryptates. Structure of two europium(III) cryptates co-existing in the same crystal [EuL(OH2)]·[Eu(HL)(NCS)]·9H2O·2MeCN·EtCN·EtOH (H3L = a phenol-bridged N8O3 Schiff-base cryptand)

Abstract

Lanthanide cryptates of a phenol-bridged N₈O₃ Schiff-base cryptand (H₃L) have been synthesized by transmetallation with the sodium cryptate [Na(H₂L)], where the cryptand was obtained by a basic template condensation of tris(2-aminoethyl)amine and 2,6-diformyl-4-methoxyphenol. The structure of [EuL(OH₂)]·[Eu(HL)(NCS)]·9H₂O·2MeCN·EtCN·EtOH showed the coexistence in the same crystal of two kinds of unsymmetric eight-co-ordinate europium(III) cryptates with different second ligands. The Eu–NCS linkage in [Eu(HL)(NCS)] is linear [Eu–NC–S 175(2), NC–S 179(2)° and Eu–N 2.42(1)Å].