Selective Molecular Recognition, C−H Bond Activation, and Catalysis in Nanoscale Reaction Vessels

Abstract

Supramolecular chemistry represents a way to mimic enzyme reactivity by using specially designed container molecules. We have shown that a chiral self-assembled M4L6 supramolecular tetrahedron can encapsulate a variety of cationic guests with varying degrees of stereoselectivity. Reactive iridium guests can be encapsulated, and the C-H bond activation of aldehydes occurs with the host cavity controlling the ability of substrates to interact with the metal center based upon size and shape. In addition, the host container can act as a catalyst by itself. By restricting reaction space and preorganizing the substrates into reactive conformations, it accelerates the sigmatropic rearrangement of enammonium cations.

Chemoenzymatic elaboration of monosaccharides using engineered cytochrome P450 BM3 demethylases

“…Unlike synthetic supramolecular catalysts (24), the activity and selectivity of BM3 variants can be tuned readily to suit a particular application. Such control enables efficient hydroxylation of C-H bonds lacking any significant stereoelectronic differentiation and augments the means by which synthetic chemists can target otherwise indistinguishable C-H bonds (25).…”

Reversible Guest Exchange Mechanisms in Supramolecular Host—Guest Assemblies

“…31 Collaborative efforts between the Raymond and Bergman groups have explored the ability of the M 4 L 6 assembly to act as a medium for reactions taking place inside of the assembly; stoichiometric as well as catalytic reactivities have been accomplished inside of the assembly, as recently reviewed. 32 The structure of the M 4 L 6 assembly suggests that guest molecules are too large to fit through the apertures of the assembly coincident with the C 3 axis of the T symmetric host, providing two possible mechanisms for guest exchange. 33 The first exchange pathway is a constrictive binding mechanism where expansion of the apertures of the assembly allows for guest ingress and egress.…”

External and Internal Guest Binding of a Highly Charged Supramolecular Host in Water: Deconvoluting the Very Different Thermodynamics

“…[16][17][18] The [Ga 4 L 6 ] 12-assembly (Figure 1, 1) has received the most attention and is used exclusively in the present study. The hydrophobic interior cavity of 1 can encapsulate a variety of hydrophobic monocationic 19 and neutral guest molecules.…”