Solvothermal synthesis of enneanuclear [Cu₇(II)Ln₂(III)] clusters

Employment of H3L (= 2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol) in mixed-metal copper-lanthanide cluster chemistry has led to the isolation of four new enneanuclear heteronuclear isostructural [Cu₇(II)Ln₂(III)] complexes. More specifically, the solvothermal reaction of Cu2(OAc)4·2H2O with H3L and the corresponding lanthanide nitrate salt in MeCN in the presence of a base, NEt3, yielded three complexes with the general formula [Cu₇(II)Ln₂(III)(L)4(HL)2(OAc)4]·2MeCN (Ln: Gd, 1·2MeCN; Tb, 2·2MeCN; Dy, 3·2MeCN), while in addition the Y(III) analogue, [Cu₇(II)Y₂(III)(L)4(HL)2(OAc)4]·2MeCN (4·2MeCN), was also synthesized in the same manner. The structure of the cluster describes two corner-sharing [Cu3Ln] cubane metallic units, each one further connected to one Cu(II) ion. Dc magnetic susceptibility studies in the 5-300 K range for complexes 1-4 reveal the presence of both ferromagnetic and antiferromagnetic exchange interactions within the metallic clusters.