A Zn₄L₆ Capsule with Enhanced Catalytic C−C Bond Formation Activity upon C₆₀ Binding

Abstract

A redox-switchable self-assembled Zn II 4L6 cage was synthesized that contains naphthalenediimide (NDI) motifs. Its reduction lent these NDI panels persistent radical anion character. The redox activity of this cage allows it to act as a catalyst for the oxidative coupling of different tetraarylborates to give biphenyls. The catalytic activity of the cage was enhanced following its binding of C60, which implies a mechanism that does not involve encapsulation of the substrate.

Reversible reduction drives anion ejection and C60 binding within an FeII4L6 cage

“…The electrochemical properties of cage 1 and subcomponent A were investigated by cyclic voltammetry, carried out in 0.1 M n Bu 4 N + Tf 2 N À in MeCN at a scan rate of 500 mV s À1 . Similar to other NDI derivatives, 14,16 cage 1 exhibited a quasi-reversible process upon reduction (Fig. 2), in which the rst reduction wave appeared at À0.81 V vs. Fc/Fc* and the second occurred at À1.19 V. The related oxidation waves were found at À1.29 and À0.78 V. Reduction was reversible over several cycles.…”

“…Following reduction, the cage signals became NMR silent due to the formation of radical species, as was observed previously in the case of related systems. 14,17 When AgNTf 2 (12 equiv.) was added to the mixture, the cage signals reappeared cleanly (Fig.…”

“…S26 †) to accommodate C 60 , and analogous cages have been shown to bind fullerenes well. 14,18 C 60 thus appeared to be an ideal guest molecule to test the catch-and-release cycle shown in Fig. 5.…”

A Regulable Internal Cavity inside a Resorcinarene‐Based Hemicarcerand

“…Molecular recognition is ak ey function of supramolecular chemistry.The internal space provided by hosts enables encapsulationo fs mall to medium-sized molecules,p ermitting their application for the encapsulation of two or more spherical molecules, [1][2][3] as nanoreactors, [4,5] and as catalysts. [6][7][8][9] Carcerands and hemicarcerands, [10,11] which are composed of covalently linked cavitands, are interesting types of single-molecular capsules. In contrast to self-assembled capsules, in which the components are held together by noncovalent interactions such as hydrogen, [12][13][14][15][16][17][18][19][20][21] chalcogen, [22] halogen, [23] and coordination bonds, for example, palladium-nitrogen coordination bonds, [24][25][26][27] covalently linked molecular containers are thermally and chemically stable,t hought heir production is synthetically more difficult.…”

Reaction Rate Inside the Cavity of [Ga4L6]12− Supramolecular Metallocage is Regulated by the Encapsulated Solvent

“…[13,14] Examples include Raymond's Ga 4 L 6 (L = (L = N,N'bis(2,3-dihydroxybenzoyl)-1,5-diaminonaphthalene), [15] Fujita's Pd 6 L 4 (L = 1,3,5-tris(4-pyridyl)triazine), [16] Nitschke'st erphenyl edged Fe 4 L 6 , [17] Lusby's Pd 2 L 4 (L = 2,6-bis(3-pyridinylethynyl)pyridine), [18] among others. [19,20] The tetrahedron supramolecular metallocage, K 12 [Ga 4 L 6 ]d evelopedb yR aymonda nd co-workers,h as been applied to many reactions as the CÀCr eductive elimination from Au III and Pt IV complexes, [21] the orthoformate hydrolysis, [22] Nazarov cyclization, [23] the hydroalkylation, [24] etc. [25][26][27] The great catalytic power of the metallocage, [Ga 4 L 6 ] 12À ,f or the CÀCr eductive elimination has been studied in detail by Bergman,R aymond and To ste.…”