Palladium(ii) driven self-assembly of a saturated quadruple-stranded metallo helicate

Abstract

Complexation of the bridging bidentate ligand N,N'-(pyridine-2,6-diyl)dinicotinamide, L with palladium(II) resulted in a single discrete M(2)L(4) self-assembly, 1, in a quantitative manner. The entropically-controlled assembly of 1 resulted in a rare saturated, quadruple-stranded metallo-helicate, in which both the left-handed (M) and right-handed (P) helicates exist in the crystal structure.

Self-assembled conjoined-cages

“…The bidentate ligand L3 possesses a central aromatic spacer and two terminal 3-pyridyl moieties connected by ester linkages. A few ligands of comparable designs with amide linkages are known, which form [Pd 2 L 4 ] complexes [45][46][47] . The amide linkages are somewhat rigid and are capable of interacting with counteranions inside the corresponding cavity, when suitably oriented thereby influencing the formation of smaller [Pd 2 L 4 ] complexes.…”

Supramolecular coordination chemistry

“…23 However, rather than a single product, a mixture of hetero-ligand rhomboid and homo-ligand triangles and other higher order polygons was observed. It was found that this could be overcome by using the tris(terpy) ligand L 35 ; reaction with L 33 and Zn 2+ in a ratio of 1 : 1 : 1.5 gave selectively [Zn 6 (m-Z 3…”

Structural and Dynamic Aspects of Palladium(II)‐Based Self‐Assembled Binuclear Coordination Complexes

“…Inspired by our previous progress on synthesis of self‐assembled binuclear complexes,–,,,,, we envisioned that the introduction of the 4,4′‐diphenylmethane moiety as spacer into a ligand back‐bone would end up self‐assembled complexes with large cavities. For this purpose, we considered a “C‐shaped” lengthy bidentate pyridine appended ligand, L containing two urea functionalities and a central 4,4′‐diphenylmethane spacer, (Scheme ).…”