Structures from MnX ₂ and proline: isomorphous racemic compounds and a series of chiral non-isomorphous chain polymers

Abstract

Reactions of manganese(II) chloride, bromide and iodide with proline as an enantiopure and racemic ligand result in six crystalline solids for which diffraction experiments have been performed at 100 K. For two of these compounds, crystal structures at ambient temperature had been reported previously. The most surprising outcome of our systematic comparison lies in the role of chirality: with enantiopure proline three different coordination polymers have been obtained, whereas racemic proline yields isomorphous mononuclear complexes under the same reaction conditions.

Coordination Polymers and Cage-Containing Frameworks in Uranyl Ion Complexes with rac- and (1R,2R)-trans-1,2-Cyclohexanedicarboxylates: Consequences of Chirality

“…Complexes 7 and 8 , with overall formulas close to one another, crystallize as species of different dimensionalities, as will be described below (the different cosolvents used during the syntheses of these two compounds, although not retained in the final species, may however play a role here; unfortunately, we could not grow crystals from both ligands with the same cosolvent or without an organic solvent in the UO 2 /Cu/bipy case). Overall, these observations point to a genuine effect of enantiopurity on the nature of the isolated solids, as previously encountered, for example, in complexes formed by manganese­(II) halides with l - and dl -proline or in salts of [Tb­(dipic) 3 ] 3– (dipic = pyridine-2,6-dicarboxylate) with Δ,Λ- and Δ-[Co­(en) 3 ] 3+ . A significant aspect of the present observations is that R -chdc 2– appears to be stable to inversion under the reaction conditions employed, unlike related species with higher degrees of substitution on the cyclohexane ring.…”

An unusual linker and an unexpected node: CaCl2dumbbells linked by proline to form square lattice networks

“…With respect to the dimensionality of these coordination compounds, 1b has a molecular structure highly resembling that of a previously reported manganese analogue, 31 although the packing and weak interactions between the molecules differ. 2b on the other hand forms a one-dimensional coordination polymer extending along the shortest unit cell axis (a = 6.9732(6) Å).…”

One- and two-dimensional polymers from proline and calcium bromide

“…The role of chirality, halide anions and metal cations on the reaction products of metal halides with racemic and enantiopure amino acids as ligands has been highlighted in previous contributions from our group (MnX 2 and proline: Lamberts & Englert, 2012; MnX 2 /CaX 2 and alanine: Lamberts, Mö ller & Englert, 2014; CaX 2 and proline: Lamberts, Porsche et al, 2014; CuCl 2 and proline: Lamberts et al, 2015).…”