“Pyrene Box” Cages for the Confinement of Biogenic Amines

Abstract

The complete structure of non-crystalline compounds can be determined by confining them in crystalline structures. The reduced motional degrees of freedom of encapsulated guests can be obtained through their anchoring to the host cages, which results in the reduction of a significant amount of disorder. The "pyrene box" cages that easily crystallize from aqueous solutions are recommended to achieve complete structure elucidation of compounds of biological interest. In this study, the "pyrene box" cages have been used for the in situ encapsulation of biogenic amines: histamine, dopamine, and serotonin. NMR spectroscopy illustrates that these systems are stable in aqueous solution. The X-ray single-crystal structure analysis reveals that the pyrene box/biogenic amine systems are stabilized through combined interactions, strongly contributing to in situ fixation and accurate determination of their crystal structures.

Combining a Titanium–Organic Cage and a Hydrogen‐Bonded Organic Cage for Highly Effective Third‐Order Nonlinear Optics

“…It is worth mentioning that the four axial‐chiral NH 3 centers have the same configuration (ΔΔΔΔ) in the tetrahedron. Furthermore, compared to serial tetrahedral anionic [(PO 4 ) 4 L 4 ] 12− cage reported by Wu's group, [18–20] the [(NH 3 ) 4 (TIPA) 4 ] cage is neutral, as each vertex of tetrahedron is a NH 3 molecule. Interestingly, the NH 4 + cation (the hydrolysis of NH 3 ⋅H 2 O generates NH 4 + cation) further connects four adjacent [(NH 3 ) 4 (TIPA) 4 ] cages through strong N−H⋅⋅⋅N interactions (Supporting Information, Figure S4b; the N⋅⋅⋅N distance is 2.79 Å and the N−H⋅⋅⋅N angle is 152.73°).…”

“…Among them, M 4 L 6 ‐ and M 4 L 4 ‐type tetrahedral cages have been intensely investigated because they are relatively easy to prepare and display interesting host–guest properties [10–17] . As another new type of supramolecular ensemble, hydrogen‐bonded organic cages (HOCs) have only emerged very recently [18–22] . So far only several tetrahedral HOCs have been reported by Wu et al [20–22] .…”

“…It is worth mentioning that the four axial-chiral NH 3 centers have the same configuration (DDDD) in the tetrahedron. Furthermore, compared to serial tetrahedral anionic [(PO 4 ) 4 L 4 ] 12À cage reported by Wus group, [18][19][20] Figure S8). From the viewpoint of topology, it can be described as a 4 Figure S6).…”

“…[10][11][12][13][14][15][16][17] As another new type of supramolecular ensemble, hydrogenbonded organic cages (HOCs) have only emerged very recently. [18][19][20][21][22] So far only several tetrahedral HOCs have been reported by Wu et al [20][21][22] What is more, the cooperative self-assembly of MOCs and HOCs into mixed co-crystal system has never been explored.…”

Combining a Titanium–Organic Cage and a Hydrogen‐Bonded Organic Cage for Highly Effective Third‐Order Nonlinear Optics

“…It is worth mentioning that the four axial-chiral NH 3 centers have the same configuration (DDDD) in the tetrahedron. Furthermore, compared to serial tetrahedral anionic [(PO 4 ) 4 L 4 ] 12À cage reported by Wus group, [18][19][20] S6). However, the bulk sample is a conglomerate with an equal mixture of crystals with opposite handedness.…”