Metallamacrocyclic complexes of Ni( ii ) with 3,3,3′,3′-tetraalkyl-1,1′-aroylbis(thioureas): crystal and molecular structures of a 2 : 2 metallamacrocycle and a pyridine adduct of the analogous 3 : 3 complex

The crystal and molecular structure of a square planar 2 : 2 metallamacrocyclic Ni(II) complex of 3,3,3′,3′-tetraethyl-1,1′-isophthaloylbis(thiourea) is reported together with that of the octahedral Ni(II) pyridine adduct of the corresponding 3 : 3 metallamacrocycle synthesised from 3,3,3′,3′-tetraethyl-1,1′-terephthaloylbis(thiourea). The former complex is a nearly planar molecule which packs in a manner dictated by strong π–π interactions. The latter is found to possess an unusually large unit cell containing two adduct molecules, with significantly dissimilar conformations, and five pyridine guests. Most of the guest molecules are located in close proximity to the adduct molecules, in contrast with the mode of host–guest interactions observed for pyridine adducts of analogous 2 : 2 metallamacrocycles.