Doubly Cavitand‐Capped Porphyrin Capsule by Hydrogen Bonds

Abstract

The components of a 1:2 mixture of meso-tetrakis(4-dodecyl-3,5-dihydroxyphenyl)porphyrin (1) and a bowl-shaped tetrakis(4-pyridylethynyl)cavitand (2) in CDCl3 or C6 D6 self-assemble quantitatively into the doubly cavitand-capped porphyrin capsule 2⋅1⋅2 through eight ArOH⋅⋅⋅Npy hydrogen bonds. Capsule 2⋅1⋅2 possesses two cavities divided by the porphyrin ring and encapsulates two molecules of 1-acetoxy-3,5-dimethoxybenzene (G) as a guest to form G/G@(2⋅1⋅2). Remarkable solvent effect was observed, in which the apparent association constant of 2⋅1⋅2 with G in C6 D6 was much greater than that in CDCl3.

Heterocomponent ternary supramolecular complexes of porphyrins: A review

“…The formation of other supramolecular pockets in benzene was presented by Kobayashi's group [81,82]. One resorcinol-substituted porphyrin and two pyridine-contained cavitands assemble via hydrogen bonding into a single capsule with two symmetric pockets which are divided by the plane of the porphyrin (Fig.…”

“…One resorcinol-substituted porphyrin and two pyridine-contained cavitands assemble via hydrogen bonding into a single capsule with two symmetric pockets which are divided by the plane of the porphyrin (Fig. 12) [81]. Encapsulation of an aromatic guest, the 1-acetoxy-3,5-dimethoxybenzene, into these supramolecular pockets is relatively slow on the NMR scale, while exhibiting a remarkable solvent effect.…”

“…Enthalpically driven strong binding (K a = 10 7 M -2 ) was determined in C 6 D 6 , and significantly weaker binding was found in CDCl 3 (K a = 9.1 × 10 2 M -2 ). Such a difference in the binding strength could be caused by competition between a guest and chloroform molecules [81]. Reducing the number of hydrogen bonds by substituting resorcinol with phenol in the porphyrin unit, in a complex with a similar cavitand, leads to the formation of a capsule with only one pocket [82].…”

Resorcinarene-based cavitands as building blocks for crystal engineering

“…10, guests are not shown for clarity). 80 By mixing 2 molecules of the cavitand and 1 molecule of porphyrin, Kobayashi and co-workers were able to obtain a doubly cavitand-capped porphyrin capsule 2·1·2 assembled via eight ArOH⋯Npy hydrogen bonds, possessing two cavities separated by the porphyrin ring. 80 By mixing 2 molecules of the cavitand and 1 molecule of porphyrin, Kobayashi and co-workers were able to obtain a doubly cavitand-capped porphyrin capsule 2·1·2 assembled via eight ArOH⋯Npy hydrogen bonds, possessing two cavities separated by the porphyrin ring.…”

Allosteric Guest Binding in Chiral Zirconium(IV) Double Decker Porphyrin Cages

“…[1][2][3][4][5] Many of these model compounds have been employed to study electron transfer processes and the binding of O 2 and CO to their metal centers. For the additional binding and catalytic conversion of substrates, more sophisticated porphyrin architectures, in which specific substrate-recognition functionalities [6][7][8][9][10][11][12] or macrocyclic receptor cavities such as cyclocholates, [13] cyclodextrins, [14][15][16] cyclophanes, [17] calixarenes, [18][19][20] cages, [21][22][23] tweezers, [24][25] and boxes [26][27][28][29] have been developed. In our group we have designed cage molecules derived from glycoluril and imparted them with a porphyrin roof, e. g. H 2 1 (Figure 1).…”