A Series of Octanuclear-Nickel(II) Complexes Supported by Thiacalix[4]arenes

A series of discrete complexes, [Ni8(BTC4A)2(μ6-CO3)2(μ-CH3COO)4(dma)4]·H2O (1), [Ni8(BTC4A)2(μ6-CO3)2(μ-Cl)2(μ-HCOO)2(dma)4]·2DMF·2CH3CN (2), [Ni8(PTC4A)2 (μ6-CO3)2(μ-CH3COO)4(dma)4]·DMF (3), and [Ni8(PTC4A)2(μ6-CO3)2(μ-OH)­(μ-HCOO)3 (dma)4] (4) (p-tert-butylthiacalix­[4]­arene
= H4BTC4A, p-phenylthiacalix­[4]­arene =
H4PTC4A, dma = dimethylamine,
and DMF = N,N′-dimethylformamide),
have been prepared under solvothermal conditions and structurally
characterized by single-crystal X-ray diffraction analyses, powder
XRD, and IR spectroscopy. These four complexes are stacked by dumbbell-like
building blocks with one chairlike octanuclear-nickel­(II) core, which
is capped by two thiacalix[4]­arene molecules and connected by two
in situ generated carbonato anions and different auxiliary anions.
This work implied that not only the solvent molecules but also the
upper-rim groups of thiacalix[4]­arenes have significant effects on
the self-assembly of the dumbbell-like building blocks. The magnetic
properties of complexes 1–4 were
examined, indicating strong antiferromagnetic interactions between
the nickel­(II) ions in the temperature range of 50–300 K.