Molecular flask

Cyclobutadiene 4 is extremely unstable under normal conditions. However, it was obtained and kept at room temperature for several months inside 5 by Cram and coworkers [5], who called the latter molecule a molecular flask. 

Carcerands, Hemicarcerands and Novel Molecular Flasks Enabling Preparation and Stabilization of Shortlived Species [1]... 

Yoshizawa M, Klosterman JK, Fujita M (2009) Functional molecular flasks new properties and reactions within discrete, self-assembled hosts. Angew Chem Int Ed 48 3418... 

Scheme 17 Molecular flask synthesis and application in size selective catalysis. (See insert for color/color representation of this figure)...

Scheme 17 Molecular flask synthesis and application in size selective catalysis...

Origin of Microvessels as Molecular Flasks 4.3.1 Ternary Complex Formation with y CD... 

Fujita developed the photochemical [2 + 2] and thermal Diels Alder reaction by use of a self-assembled molecular flask (Pd6(l,3,5-tris-(4-pyridyl)triazine)4) 12N03 The photocycloaddition of 1,2,3,4-... 

Cavity-directed chemical transformations represent one of the most important features of three-dimensional hosts. Cavities isolated from the exterior by the frameworks of host complexes offer unusual chemical environment that is different from solution state and serve as unique reaction space as molecular flasks. In 1997, the pioneering work of such reactions was conducted by Rebek et al. They utilized the hydrogen-bonded soft ball ... 

One of the most common types of reactions to be template using CB[ ] nanoreactors is photochemical cycloadditions a few examples were discussed in Section 5.4 [120-124]. A number of other examples will be discussed here [126-137]. Svoboda and Kbning reviewed template photochemical reactions back in 2006, and had a small section on such reactions in molecular flasks [126]. Although most examples at that time involved cyclodextrins as the molecular flask (a nice descriptive name for a nanoreactor), there were a few examples at that time involving CB[7] and CB[8]. Those examples and some more recent ones will be discussed here [127-137]. 

Fujita et al. exploited the coordinalion cage as a molecular flask for perform-... 

The authors proposed a mechanism based on a cage-mediated guest-to-host electron transfer (Fig. 9.30) in which the cage acted as a photosensitizing molecular flask. Excitement of the coordination cage, followed by electron transfer from alkyne to an electron-deficient cage and the reaction of a molecule of water (solvent) with the obtained phenyl alkyne radical cation, results in benzylic radicals and subsequently the anti-Markovnikov product. 

Stoichiometric ally well-defined molecular containers (monodispersed molecular flasks) are suitable for the study of the thermodynamic and kinetic properties of molecular encapsulation processes. On the other hand, the use of polydispersed molecular containers (i.e. vesicles, liposomes [7] and polymeric microcapsules [8] etc.) is not recommended for this purpose. Learning the basic rules and principles governing reversible encapsulation processes is necessary for further development and improvement of the uses and applications of synthetic molecular containers. 

Yoshizawa M, Fujita M (2005) Self-assembled coordination cage as a molecular flask. Pure Appl Chem 77 1107-1112... 

Encaged enzyme-like catalysis of the Nazarov cyclization (i.e., the acid-catalyzed reaction of l,4-dien-3-ol giving cyclopentadiene) by Scheme 5.18 within the tetrahedral coordination capsule 575 as a molecular flask is reported in [18] Cp H product is a competitive guest in this... 

Inokuma Y, Kawano M, Eujita M (2011) Crystalline molecular flasks. Nat Chem 3 349... 

---