Mimicking biological structures such as fruits and seeds using molecules and molecular assemblies is a great synthetic challenge. Here we report peanut-shaped nanostructures comprising two fullerene molecules fully surrounded by a dumbbell-like polyaromatic shell. The shell derives from a molecular double capsule composed of four W-shaped polyaromatic ligands and three metal ions. Mixing the double capsule with various fullerenes (that is, C60, C70 and Sc3N@C80) gives rise to the artificial peanuts with lengths of ∼3 nm in quantitative yields through the release of the single metal ion. The rational use of both metal–ligand coordination bonds and aromatic–aromatic π-stacking interactions as orthogonal chemical glue is essential for the facile preparation of the multicomponent, biomimetic nanoarchitectures.

Complexation of 1,4-phenylenebis(methylene) diisonicotinate, L1, with cis-protected Pd(II) components, [Pd(L')(NO3 )2 ], in an equimolar ratio yielded binuclear complexes, 1 a-d of [Pd2 (L')2 (L1)2 ](NO3 )4 formulation where L' stands for ethylenediamine (en), tetramethylethylenediamine (tmeda), 2,2'-bipyridine (bpy), and phenanthroline (phen). The combination of 4,4'-bipyridine, L2, with the cis-protected Pd(II) units is known to yield molecular squares, 2 a-d. However, 2 b-d coexist with the corresponding molecular triangles, 3 b-d. Combination of an equivalent each of the ligands L1 and L2 with two equivalents of cis-protected Pd(II) components in DMSO resulted in the D-shaped heteroligated complexes [Pd2 (L')2 (L1)(L2)](NO3 )4 , 4 a-d. Two units of the D-shaped complexes interlock, in a concentration dependent fashion, to form the corresponding [2]catenanes [Pd2 (L')2 (L1)(L2)]2 (NO3 )8 , 5 a-d under aqueous conditions. Crystal structures of the macrocycle [Pd2 (tmeda)2 (L1)(L2)](PF6 )4 , 4 b'', and the catenane [Pd2 (bpy)2 (L1)(L2)]2 (NO3 )8 , 5 c, provide unequivocal support for the proposed molecular architectures.

A pentanuclear coordination complex assembled from any palladium(II) component and non-chelating ligands is hitherto unreported. The pentanuclear complex [Pd (L1) (L2) ](BF ) , 1 reported here was prepared by the spontaneous complexation of [Pd(DMSO) ](BF ) with the non-chelating bidentate ligands 1,4-phenylenebis(methylene) diisonicotinate, L1 and 4,4'-bipyridine, L2 in a one-pot method at room temperature. The planar polycyclic complex 1 with outer diameters of ≈3 nm is termed as a "molecular star" owing to its resemblance with a pentagram shape. Interim paths leading to the star were also probed to decipher related dynamics of the system.

Concentration-dependent equilibria of molecular squares [Pd 4 (L′) 4 (L) 4 ](NO 3 ) 8 and triangles [Pd 3 (L′) 3 (L) 3 ](NO 3 ) 6 were obtained when cis-protected Pd(II) units [PdL′(NO 3 ) 2 ] (L′ = tmeda, 2,2′-bpy, and phen) were combined independently with 4,4′-bipyridine (L) in water. However, complexation of [PdL′(OTs) 2 ] with L resulted in exclusive formation of the corresponding molecular squares. The addition of AgOTs to each mixture of square and triangle led to a shift in the equilibrium, resulting in the disappearance of the triangles and exclusive formation of the corresponding squares. The crystal structures of the molecular squares [Pd 4 (L′) 4 (L) 4 ](OTs) 8 revealed a pair of tosylate anions encapsulated in the hydrophobic cavity of the square. Further, [Pd 4 (2,2′-bpy) 4 (L) 4 ](OTs) 8 and [Pd 4 (phen) 4 (L) 4 ](OTs) 8 exhibited solvatomorphism, yielding two crystalline forms each, respectively. The cationic units in these crystals associate through intermolecular π•••π stacking interactions wherein the cis-protecting units (i.e., 2,2′-bpy and phen) of adjacent molecules overlap via side-on or end-on modes. Thus, the cations may be considered as "tectons", each of which contains four peripheral 2,2′-bpy/ phen units, which behave as "supramolecular synthons" in the self-assembly of the squares. The tosylates interact with the cations through C−H•••O and C−H•••π interactions and play a role in the packing of the molecular squares.

A series of stellated metallosupramolecular architectures have been assembled through threecomponent integrative self-sorting. Building on the complementary ligand pairing, the initial attempts to synthesize the hexagram complex from a combination of X-shaped tetrakis-and V-shaped bis-terpyridine ligands, and Cd II ions, resulted in an unprecedented mixture of stellated octanuclear and dodecanuclear metallocages, which were further isolated by column chromatography. To overcome the unexpected obstacle, the multivalent ligand design along with spontaneous heteroleptic complexation was applied to realization of the one-pot synthesis of the intricate topology. A centrally situated triangle served as a prop for quantitative formation of the six-pointed stellated complex. Notably, in the absence of the triangular prop, a four-pointed star was produced.