Syntheses, crystal structures, and magnetic properties of two p-tert-butylsulfonylcalix[4]arene supported cluster complexes with a totally disordered Ln _4(OH) _4 cubane core

摘要

Two new sandwich calix[4]arene-supported cluster complexes, [Ln _4(OH) _4(TBSOC) _2(H _2O) _4(CH _3OH) _4]?4H _2O (H _4TBSOC = p-tert-butylsulfonylcalix[4]arene; Ln = Dy, 1; Ln = Ho, 2), have been prepared and characterized. An X-ray crystallographic study reveals that both complexes contain a holistically disordered [Ln _4(OH) _4] ~(8+) cubane cluster core, which is sandwiched between two antiparallel calixarene macrocycles. Magnetic investigations indicate that complex 1 displays slow magnetization relaxation typical for single-molecule magnets in the absence of a static applied dc field, with the ΔE/k _B parameter of 22.9 K, the largest value for the calixarene-supported pure 4f single-molecule magnets so far, whereas complex 2 does not show any relaxation of the magnetization above 2 K.