A Self‐Assembled Palladium(II) Barrel for Binding of Fullerenes and Photosensitization Ability of the Fullerene‐Encapsulated Barrel

Abstract

Fullerene extracts obtained from fullerene soot lack their real application due to their poor solubility in common solvents and difficulty in purification. Encapsulation of these extracts in asuitable host is an important approach to address these issues.W ep resent an ew Pd 6 barrel (1), whichi s composed of three 1,4-dihydropyrrolo[3,2-b]pyrrole panels, clipped through six cis-Pd II acceptors.L arge open windows and cavity make it an efficient host for alarge guest. Favorable interactions between the ligand and fullerene (C 60 and C 70 ) allows the barrel to encapsulate fullerene efficiently.Thorough investigation reveals that barrel 1 has as tronger binding affinity towards C 70 over C 60 ,r esulting in the predominant extraction of C 70 from am ixture of the two.F inally,t he fullerene encapsulated barrels C 60 &1 and C 70 &1 were found to be efficient for visible-light-induced singlet oxygen generation. Such preferential binding of C 70 and photosensitizing ability of C 60 &1 and C 70 &1 are noteworthy.

Porphyrin-Based Multicomponent Metallacage: Host–Guest Complexation toward Photooxidation-Triggered Reversible Encapsulation and Release

“…Compared with two-dimensional metallacycles, metallacages possess three-dimensional structures and cavities, making them encapsulate guest molecules from multiple directions and thus offering host–guest complexes with high binding affinities. 45 , 46 Therefore, during the past three decades, various metallacages have been extensively investigated and applied for guest encapsulation, 47 − 49 catalysis, 50 − 53 stabilizing reactive intermediates, 54 , 55 etc. Among them, porphyrin-based metallacages 56 , 57 have received much attention because they integrate the interesting optical and redox abilities of porphyrins and the host–guest properties of metallacages, offering extra functionalization such as light-harvesting and biological catalysis.…”

Solvent and Counteranion Assisted Dynamic Self-Assembly of Molecular Triangles and Tetrahedral Cages

“…Various synthetic advantages associated with this synthetic protocol include one-step synthesis, inherent self-correction due to the dynamic nature of the coordination bond between the metal and ligand that governs the formation of thermodynamically stable products in high yield. Judicial selection of donors in combination with suitable acceptors by self-assembly generates highly ordered structures like cubes, spheres, tetrahedra, octahedra, and higher-order structures. − These molecular architectures have attracted increasing curiosity not only for their structural and topological aspects but also for their applications in host–guest chemistry, drug-delivery systems, molecular capsules, and catalysis. − In most cases exclusive formation of a single discrete structure was observed due to thermodynamic constraints. However, equilibrium or nonequilibrium mixtures of more than one structure are also noticed in several cases .…”

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

“…In search of supramolecular cavity-induced catalysis, chemists have become fascinated toward the design of large and sophisticated molecular vessels. In this context, Stang [ 54 ], Nitschke [ 55 ], Fujita [ 56 ], and others [ 57 ] have reported several template-free assemblies giving access to novel structures. The primary objective of these nanovessels as supramolecular catalysts is to encapsulate organic reactant/s to lower the activation barrier, thereby mimicking the functions of enzymes (without replicating their structures).…”