Supramolecular Polymers with [Co(en)₃]³⁺Cores (en = ethylenediamine)

Abstract

From aqueous solutions containing Λ-[Co(en) 3 ]I 3 (1, 2), Δ-[Co-(en) 3 ]I 3 (5), or racemic [Co(en) 3 ]I 3 (3, 4) AgI and PbI 2 respectively were precipitated by addition of Ag 2 EDC, [Ag(en)][Ag(BDC)], PbADC or (NH 4 )[Ag 5 (BTC) 2 (NH 3 )-(H 2 O) 2 ] and filtered off (en = ethylenediamine, H 2 EDC = fumaric acid, H 2 BDC = terephthalic acid, H 2 ADC = acetylenedicarboxylic acid, H 3 BTC = trimesic acid). After slow evaporation of the remaining solutions single crystals of ∞ 1and ∞ 2 {Δ-[Co(en) 3 ]EDC(NO 3 )}•2H 2 O (C2, Z = 4, 5) were obtained. In all compounds the [Co(en) 3 ] 3+ cores are connected in a T-shaped mode via N−H•••O hydrogen bonds to the carboxylates to form complex networks. Water molecules are bound via O−H•••O hydrogen bonds to the networks, further increasing their complexity. It is noteworthy that the chirality of the starting material (Λ-or Δ-[Co(en) 3 ]I 3 ) is maintained during the reaction thus leading to non-centrosymmetric polymers, whereas with racemic [Co(en) 3 ]I 3 centrosymmetric polymers are obtained.

A Missing Structural Link in the Werner Series of Cobalt(III) Complexes: The Crystal Structure of Δ‐(–)589‐Tris(ethylenediamine)cobalt(III) Iodide Monohydrate

“…Several structural reports of diastereomeric coordination compounds such as Δ‐[Co(en) 3 ] Y 3 , where Y is a chiral anion have appeared as well as a coordination compound adduct. Examples of diastereomeric Δ‐[Co(en) 3 ] Y 3 coordination compounds: Δ‐[Co(en) 3 ](fumarate)(NO 3 ) · 2H 2 O, Δ‐[Co(en) 3 ][MoO 3 (C 2 O 4 )OH 2 ]I · 2H 2 O, Δ‐[Co(en) 3 ]Δ‐[Co(en)(ox) 2 ]I 2 · H 2 O, and Δ‐[Co(en) 3 ]Δ‐[Cr(ox) 3 ], and an adduct: Δ‐[Co(en) 3 ](ClO 4 ) 3 · 2[Pd 3 ( d ‐pen) 3 ], where d ‐pen = d ‐penicillamine . In contrast to these examples, to the best of our knowledge, we report the first example of the enantiomeric Δ‐[Co(en) 3 ] X 3 coordination compound.…”

3-D Topo Surface Visualization of Metal Ion Anti-buffering: An Unexpected Behavior in Metal–Ligand Complexation Systems

“…Thus, they are important for students in several fields to understand. For chemistry students, most metal complexation reactions include systems with higher stoichiometries. − The copper­(II)–ammonia system is routinely used in many introductory laboratories as a model system for metal–ligand reactions and a confirmation step in qualitative analysis schemes . In biochemistry, metal complexation helps explain how amino acids and carboxylic acids in the Krebs cycle interact with metal ions .…”