Host-guest molecular systems

The electronic processes in the host-guest molecular system are best illustrated by a classical Jablonski diagram [20], which was first proposed in 1933 to describe absorption and emission of light (Figure 4.1). 

Dietrich, B., Sauvage, J-P (1988). In 1987, The Nobel Award Goes to Crown Ethers, Cryptands and Other Host-Guest Molecular Systems. NewJ. Chem. 12 8/9. 

Host-guest binding systems (supramolecular compounds) e.g., molecular cavities [271], clathrate systems [272]... 

Another example of a side-chain supra-raolecular polymer is prepared from poly(4-vinylpyridine) and H-bonding side chains [32-35]. In this case, mesogenic side-chain groups are directly attached to the polymer backbone and liquid-crystalline polymers such as 19 are formed by the noncovalent interaction [33]. This molecular design has been used to incorporate functional molecules into liquid-crystalline, host-guest polymeric systems [32]. 

In recent decades, designing molecular devices containing host-guest recognition systems or supramolecular assembly to achieve a specific biological or physical function is one of the most important challenges for chemists. This chapter has covered some developments of the spectrophotometric studies on... 

Strkcttire inflkence. The specificity of interphase transfer in the micellar-extraction systems is the independent and cooperative influence of the substrate molecular structure - the first-order molecular connectivity indexes) and hydrophobicity (log P - the distribution coefficient value in the water-octanole system) on its distribution between the water and the surfactant-rich phases. The possibility of substrates distribution and their D-values prediction in the cloud point extraction systems using regressions, which consider the log P and values was shown. Here the specificity of the micellar extraction is determined by the appearance of the host-guest phenomenon at molecular level and the high level of stmctural organization of the micellar phase itself. 

On the basis of data obtained the possibility of substrates distribution and their D-values prediction using the regressions which consider the hydrophobicity and stmcture of amines was investigated. The hydrophobicity of amines was estimated by the distribution coefficient value in the water-octanole system (Ig P). The molecular structure of aromatic amines was characterized by the first-order molecular connectivity indexes ( x)- H was shown the independent and cooperative influence of the Ig P and parameters of amines on their distribution. Evidently, this fact demonstrates the host-guest phenomenon which is inherent to the organized media. The obtained in the research data were used for optimization of the conditions of micellar-extraction preconcentrating of metal ions with amines into the NS-rich phase with the following determination by atomic-absorption method. 

Other low-molecular systems that have been investigated in waveguiding films are the guest-host system Alq3 DCM (see below for the emission in tme resonators), arylamines, and oligothiophenes. TPD (6) shows an emission peak in thin films at 418 nm when pumped with 35-ps pulses at 347 nm [185]. The... 

Thus, the Platonic and Archimedean solids not only provide a means for host design, but a way in which to maximize chemical information, allowing the chemist to simplify the structures of complex molecular frameworks and, in effect, engineer host-guest systems. 

Noncovalent interactions play a special role in synthetic procedures used to assemble various types of supramolecular species. These syntheses rely on the stabilization provided by non-covalent interactions between recognition sites incorporated within precursors. Various types of non-covalent interactions can be used as a recognition motif utilized to guide the synthesis.Targeted synthesis of macro- and supramolecular structures of various sizes, shapes, and functionality has now become possible. Supramolecular chemistry offers incredible applications in various fields such as medicinal chemistry (drug delivery systems),host-guest chemistry,catalysis,and molecular electronics. ... 

---