Variation in structural features induced by ortho-Substituted Benzoate Ligands in Zinc Cyclam-Based Compounds: Synthesis, Characterization, and Hirshfeld Studies

Abstract

This paper investigates the structural diversity and non-covalent interactions in eight newly synthesized [Zn(II)(cyclam)] sup(2+) compounds (1-8) featuring ortho-substituted benzoate ligands. Compounds (1) and (2) exhibit 1D polymeric structures, wherein aqua ligands bridge the cationic and anionic units, resulting in [Zn sub(2)(Mu-H sub(2)O) sub(2)(cyclam)(L) sub(4)] compounds. Here, L = o-methyl benzoate in 1, L = o-methoxy benzoate in 2, cyclam = 1,4,8,11-tetraazacyclotradecane. Conversely, using hydroxy and nitro substituents at the ortho position results in the formation of zero-dimensional compounds 3 and 4, [Zn(C sub(10)H sub(24)N sub(4))(L) sub(2)] (L = o-hydroxybenzoate in 3, L = o-nitrobenzoate in 4). Interestingly, the application of benzoate, o-chlorobenzoate, o-(methylthio)benzoate, and o-aminobenzoate led to significant variation in the crystal packing, resulting in discrete ionic compounds 5-8. The analysis of geometric descriptors revealed the disruption of isostructurality in related isomorphous compounds upon switching the ortho substituents. To gain a deeper understanding of the non-covalent interactions that govern the supramolecular self-assemblies, we conducted Hirshfeld surface analysis on the compounds.