(6,17-dimethyl-8,15-diphenyldibenzo[b,i][1,4,8,11]-tetra-aza[14]annulenato)nickel(II) in solids: Two guest-free polymorphs and inclusion compounds with methylene chloride and fullerene (C-60)-carbon disulfide

Two guest-free polymorphs and two inclusion compounds of the macrocyclic ti tle complex [NiL] have been isolated and characterized with single-crystal and/or powder XRD, solid-state C-13 NMR, and other methods. The inclusion c ompound with methylene chloride, [NiL]*(CH2Cl2), is stable in air and therm ally stable up to similar to 128 degreesC. Its crystal structure is consist ent with van der Waals packing of the host [NiL] and guest CH2Cl2 molecules . The host complex has square-planar coordination of the nickel(H) center w ith four nitrogen atoms of the macrocycle with an average Ni-N distance of 1.86 Angstrom. The molecule has a saddle-shaped conformation with the guest molecule located between one phenylene and two phenyl rings of the host mo lecule. Isostructural compounds with chloroform and 2-chloropropane form on ly as mixtures along with a guest-free host polymorph. The inclusion compou nd with C-60 has a composition 3[NiL]*(C-60)*2(CS2) and here also the cryst al structure is consistent with a van der Waals type of packing. Three crys tallographically inequivalent [NiL] molecules have geometries similar to th at in the inclusion compound with methylene chloride. The concave surfaces of the complex molecules form a spherical cavity for the C-60 molecule. At -100 degreesC the C-60 molecule is disordered over two orientations centere d at the same site, C-13 NMR studies at room temperature show that the C-60 molecule is undergoing rapid pseudo-isotropic rotation. The stability and other properties of the title and related complexes are discussed.