Abstract

The preparations and crystal structures of (Ph₄P)[Cr(phen)(ox)₂](H₂O) 1, [Co(phen)₂(ox)](BF₄) 2 and [Co(phen)₂(ox)]I(H₂O)₂(EtOH)_0.53 are described (phen⊕=⊕1,10-phenanthroline, ox⊕=⊕oxalate), and their crystal packing analysed in terms of the crystal supramolecular motifs and multiple aryl embraces. The crystal packing of 1 is determined by embrace motifs involving both the Ph₄P⁺ cation and the anion [Cr(phen)(ox)₂]⁻, principally an eight component concerted embrace (Ph₄P⁺)·{[Cr(phen)(ox)₂]⁻}₂·(Ph₄P⁺) comprised of three offset face-to-face (OFF) and six edge-to-face (EF) primary motifs. Complex 2 is dominated by well developed OFF-chain motifs for the phen ligands, reinforced by multiple C–H⋯O hydrogen bonds, to form a strongly hydrophobic lattice crystallising from water. Structure 3 crystallises with an efficient three-dimensional net using all three ligands of [Co(phen)₂(ox)]⁺ in primary embrace motifs, with separate domains for the hydrogen bonded solvent molecules. The analyses identify crystal packing principles, especially the favourability of OFF phen embraces, the segregation of hydrophobic M(phen)_n domains, and the prevalence of C–H⋯O hydrogen bonds involving oxalate or water. Predictions about crystal packing are made.