Donor guest molecules

Acceptor guest molecules such as quinone, TCNQ, or toluene can be accommodated in the flexible cavity of face-to-face bismacrocyclic Nin complexes (656). The host-guest interactions decrease the energy gap between the LUMO of the organic acceptors and the HOMO of the complex donors.1664... 

Zinc hydroxide and alkoxide species are particularly relevant to catalytic processes, often forming the active species. The cooperative effects of more than one zinc ion and bridged hydroxides are exploited in some enzymatic systems. Zinc alkyl phosphate and carboxylate materials have been important in the formation of framework compounds, often containing large amounts of free space for the inclusion of guest molecules. Aldehyde and ketone compounds are of low stability due to the poor donor capabilities of the ligands however, a number of examples have recently been characterized. 

The latter could be obtained, if particular donor substituents (e.g. specific functional groups) facing corresponding acceptor groups of the guest molecule are added to the host and vice versa, thus using specific host-guest interactions of polar... 

Changing of the flexible scissor-like element, as in 7, to an orthogonal and rigid version of this element, as in 22, reduces the activity of inclusion formation to a certain degree. Nevertheless very different guest molecules are readily accommodated in the crystal lattice of 22, they are proton donors (ethanol, 2-propanol) 47, H-bridge acceptors (dimethylformamide, dioxane), or benzene as an unpolar solvent48 ... 

Abstract Concave molecules with a periphery of complementary hydrogen-bond donors and acceptors dimerize to form non-covalently bound capsules. These host structures feature the ability to bind appropriate guest molecules... 

Two early examples of CTV being incorporated into network structures involves CTV acting as a hydrogen bond acceptor when the hydrogen bond donor is the acidic C-H groups of o-carborane [79]. Carboranes form C-H hydrogen bonds of this type in a number of other instances [80], and may also act as spherical guest molecules for CTV [77]. 

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