Enantiospecific Syntheses of Copper Cubanes, Double‐Stranded Copper/Palladium Helicates, and a (Dilithium)–Dinickel Coronate from Enantiomerically Pure Bis‐1,3‐diketones—Solid‐State Self‐Organization Towards Wirelike Copper/Palladium Strands

Abstract

Enantiomerically pure, vicinal diols 1 afforded in a two-step synthesis (etherification and subsequent Claisen condensation) chiral bis-1,3-diketones H(2)L((S,S)) (3 a-c) with different substitution patterns. Reaction of these C(2)-symmetric ligands with various transition-metal acetates in the presence of alkali ions generated distinct polynuclear aggregates 4-8 by diastereoselective self-assembly. Starting from copper(II) acetate monohydrate and depending on the ratio of transition-metal ion to alkali ion to ligand, chiral tetranuclear copper(II) cubanes (C,C,C,C)-[Cu(4)(L((S,S)))(2)(OMe)(4)] (4 a-c) or dinuclear copper(II) helicates (P)-[Cu(2)(L((S,S)))(2)] (5) could be synthesized with square-pyramidal and square-planar coordination geometry at the metal center. In analogy to the last case, with palladium(II) acetate double-stranded helical systems (P)-[Pd(2)(L((S,S)))(2)] (6,7) were accessible exhibiting a linear self-organization of ligand-isolated palladium filaments in the solid state with short inter- and intramolecular metal distances. Finally, the introduction of hexacoordinate nickel(II) in combination with lithium hydroxide monohydrate and chiral ligand H(2)L((S,S)) (3 a) allowed the isolation of enantiomerically pure dinuclear nickel(II) coronate [(LiMeOH)(2) subset{(Delta,Lambda)-Ni(2)(L((S,S)))(2)(OMe)(2)}] (8) with two lithium ions in the voids, defined by the oxygen donors in the ligand backbone. The high diastereoselectivity, induced by the chiral ligands, during the self-assembly process in the systems 4-8 could be exemplarily proven by circular dichroism spectroscopy for the synthesized enantiomers of the chiral copper(II) cubane 4 a and palladium(II) helicate 6.

Supramolecular Coordination Chemistry: The Synergistic Effect of Serendipity and Rational Design

“…The CD spectrum of 28 exhibits two negative and one positive Cotton effect, while ent-28 shows Cotton effects of the opposite sign at the same wavelengths ( Figure 17). [21] 3.6. Threading of Copper(II) and Palladium(II) Ions…”

“…Analogously, (P)-[Pd 2 (L (S,S) ) 2 ] (30) could be obtained from palladium(II) acetate in the presence of one equivalent of pyridine (Scheme 12). [21] Interestingly, the molecules 29 and 30 are packed in the crystal in parallel, leading to copper and palladium metal strings with short intra-and intermolecular metal-metal separations ( Figure 18). [21] Scheme 10.…”

“…[21] Interestingly, the molecules 29 and 30 are packed in the crystal in parallel, leading to copper and palladium metal strings with short intra-and intermolecular metal-metal separations ( Figure 18). [21] Scheme 10. Synthesis and schematic presentation of 27.…”

Neutral discrete metal–organic cyclic architectures: Opportunities for structural features and properties in confined spaces

“…Both hydrophilic and hydrophobic regions, respectively, were present in the interior and exterior part of 190 and the disordered water or ethanol solvent of crystallization were located inside the cluster (Fig. 85) Bis(␤-diketone) derivatives can be utilized as chelates for the construction of discrete and extended metal-organic architectures [291][292][293][294][295]. Two hexanuclear metallacycles [Cu 6 L150 3 Py 8 ]·6.25Py (191a) and [Cu 3 Ni 3 L150 3 Py 9 ]·3.25Py (191b) (L150 = 1,4-aryl linked bis(␤,␦-triketone)) were self-assembled by the reaction of L150 with Cu II salt or a combination of Ni II and Cu II salts followed by recrystallization of the product from pyridine (Scheme 71) [296].…”

Hierarchical assembly of discrete copper(ii) metallo-structures from pre-assembled dinuclear (bis-β-diketonato)metallocycles and flexible difunctional co-ligands

“…3 We, and others, have found that ligands incorporating more than one β-diketone motif react with selected metal ions to yield an array of metallo-supramolecular architectures with the products in many instances exhibiting a significant degree of predictability. 1,3,10 Structures generated with these ligands include helicates, [11][12][13][14] tetrahedra, 15,16 boxes, 17 capsules 18 and an unprecedented universal 3-ravel; 14 for example, the well defined coordination vectors of ligands L 1-3 produce neutral planar metallocyclic species of type [M 2 (L 1 ) 2 ] (1) 11,13,[19][20][21] [M 3 (L 2 ) 3 ] (2) 16,22 and the larger [M 3 (L 3 ) 3 ] (3) 23,24 upon reaction with selected divalent transition metals.…”