| Abstract | Two guest-free polymorphs and two inclusion compounds of the macrocyclic title complex [NiL] have been isolated and characterized with single-crystal and/or powder XRD, solid-state ¹³C NMR, and other methods. The inclusion compound with methylene chloride, [NiL]*(CH2Cl2), is stable in air and thermally stable up to 128 °C. Its crystal structure is consistent with van der Waals packing of the host [NiL] and guest CH2Cl2 molecules. The host complex has square-planar coordination of the nickel(II) center with four nitrogen atoms of the macrocycle with an average Ni−N distance of 1.86 Å. The molecule has a saddle-shaped conformation with the guest molecule located between one phenylene and two phenyl rings of the host molecule. Isostructural compounds with chloroform and 2-chloropropane form only as mixtures along with a guest-free host polymorph. The inclusion compound with C60 has a composition 3[NiL]*(C60)*2(CS2) and here also the crystal structure is consistent with a van der Waals type of packing. Three crystallographically inequivalent [NiL] molecules have geometries similar to that in the inclusion compound with methylene chloride. The concave surfaces of the complex molecules form a spherical cavity for the C60 molecule. At −100 °C the C60 molecule is disordered over two orientations centered at the same site. 13C NMR studies at room temperature show that the C60 molecule is undergoing rapid pseudo-isotropic rotation. The stability and other properties of the title and related complexes are discussed. |
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