A Palladium(II)‐Clipped Aromatic Sandwich

Abstract

Enclathration of large p-conjugated molecules by a synthetic receptor is an interesting task because the properties of these molecules, such as stability, reactivity, solubility, and photoand electroresponse, can be controlled.[1] To enclathrate large p-conjugated molecules, however, a synthetic receptor with a cavity is required, whose dimensions should be larger than that of the p-conjugated guests. While there are many examples of three-dimensional receptors, [2] large two-dimensional receptors have been less explored.[3] Herein we describe the self-assembly of a p-stacked host-guest system in which large aromatic guests are sandwiched by metalclipped p-conjugated ligands. The ligand 1 is a roughly 2-nmsized hexagonal planar molecule that consists of ten aromatic rings with six pyridyl donor sites at the periphery. Upon complexation with [(en)Pd(NO 3 ) 2 ] (en = 1,2-ethanediamine) this ligand is assembled to give large two-dimensional receptors. In the presence of D 3h -symmetric guests (2), sandwich complexes [2&3] 12+ , where 3 12+ has a composition of [{(en)Pd} 6 (1) 2 ] 12+ , are quantitatively assembled. The guest molecule is wrapped by two ligands whose pyridyl donor sites

Recognition Properties and Self‐assembly of Planar [M(2‐pyridyl‐1,2,3‐triazole)2]2+ Metallo‐ligands

“…There was no evidence of the formation of larger assemblies upon introduction of Ag I ions to solutions of the metallo-li- Figure 6. Depictionoft he X-raycrystal structure of n2&[Ag n Pt 1n ] 3n + .Interplaned istance between cationic panel and guest:3 .37 (9) .C olors: Carbon greyf or the cationic linear chain, blackf or the guest, nitrogen blue, oxygen red,p latinump urple, silvers ilver.H ydrogen atoms and counterions are omitted for clarity. Figure 5.…”

“…Figure 5. Depictionoft he X-raycrystal structures of a) 1&Pd 1 .Distance between 1 and Pd 1 :3.416 (9) .b )2&Pd 1 .Distance between 2 and Pd 1 :3.35(2) .c)2(3)&Pd 1 .Distance between 3 and Pd 1 : % 3.4 .D istance between adjacent 3 molecules:3.1 .P d II ÀPt II distance:3.358(2). Colors:Carbon greyf or Pd 1 ,black for guests, nitrogen blue, oxygen red, palladiumm agenta, platinump urple, sulphur yellow.H ydrogena toms, counterions and solvent where applicable are omittedf or clarity.…”

Palladium(II)‐Based Self‐Assembled Heteroleptic Coordination Architectures: A Growing Family

“…However,t here are many homoleptic hexanuclear complexes of [(PdL') 6 (L) n ]c omposition. [24][25][26][27][28] Althoughc omplexes of [(PdL') 6 (L) 4 ]a re widely known, [24] other complexes,s uch as [(PdL') 6 (L)]-typet ubes, [25] [(PdL') 6 (L) 2 ]-type discs, [26] [(PdL') 6 (L) 3 ]-type tubes [27] and [(PdL') 6 (L) 6 ]-type hexagons, [28] are also known.H owever,h eteroligated hexanuclear assemblies with similar designs to those mentioned above are 6 (L a )(L b )] 2 -type [2]catenanes [29] and [(PdL') 6 (L a ) 2 (L b ) 4 ]-type [3]catenanes. [30] The complexation of cis-[Pd(en)(NO 3 ) 2 ]w ith am ixture of tripodal tridentate ligand L24 andf lat tridentate ligand L25 in a3 :1:1 stoichiometry under aqueous conditions resulted in catenane [Pd 3 (en) 3 (L26)(L27)] 2 (NO 3 ) 12 (30;F igure 12).…”

Carbon-rich supramolecular metallacycles and metallacages

“…Fujita and coworkers have demonstrated the ability of a carbon-rich supramolecular tetrahedron cage to selectively recognize and bind sequence-specific peptides50 and, in the case of a supramolecular trigonal prism, capable of folding an Ala-Ala-Ala tripeptide in to a β-turn on account of hydrophobic encapsulation 51. The use of largely aromatic moieties in various precursors enables many supramolecular cages to act as hosts for other aromatic guests through a combination of π-π and hydrophobic interactions 39,52. Both Hupp53 and Mirkin54 have recently used porphyrin-based supramolecular rectangles as catalysts for epoxidation and acyl transfer reactions, respectively.…”