Polytopic interactions

Quadrupolar interactions (termed complementary polytopic interactions by the authors) are also responsible for mesophase induction and modification in a series of disc-like materials (e.g. 2 and 3) as described by, for example, Bushby and co-workers [11-13]. 

Di- and Polytopic Interactions Change of Binding Mechanism with Different Fit... 

Bushby et al. were able to access similar AB stacks with derivatives of 25 using aromatic units, which are not electron-poor [86-88]. They showed that hexakis(4-nonylphenyl)triphenylene (28, n = 8) forms alternating stacks with 25 (Fig. 13). Unlike the electron-deficient derivatives mentioned previously, which exhibit single liquid crystal phases over a wide composition range of the two components, phase separation between the 25 28 and the 25 or 28 mesogenic phases occurs [89]. The driving force for the AB stack formation is a combination of a number of different non-covalent interactions which the authors termed complimentary polytopic interactions (CPIs). 

Fig. 13 Self-assembly of alternating stacks can be achieved with an electron-rich 25 and electron-poor 26 or mellitic triimde 27. Alternatively, complimentary polytopic interactions (CPI) can be used to organize 25 and 28 as shown, yielding the desired assemblies...

Fig. 8.5 Chemical structures of two types of triphenylene derivatives for Complimentary Polytopic Interaction (CPI) studies toward highly efBcient charge transptnt...

A well-studied binary system of discotic liquid crystal toward high carrier mobility systems is a blend of two types of triphenylene-based compounds (Fig. 8.5). These two compounds were mixed in expectation to give a new semiconducting system that exhibits enhancement of charge transport efficiency. The concept is based on Complimentary Polytopic Interaction (CPI) [16-18]. 

The other classic example of the use of quadrupolar interactions was from the Leeds group, " " who coined the term complementary polytopic interaction to describe the phenomenon and to distinguish it subtly from other examples... 

The first liquid crystalline derivatives of HAT were reported by Bushby and coworkers [90-92]. They prepared several hexaphenyl-substituted HAT derivatives 48 with different peripheral chains as shown in Scheme 4.13. It is worth noting that some non-mesomorphic HAT derivatives when mixed with other discotic liquid crystals, exhibit stable columnar phases due to complimentary polytopic interactions [90, 91],... 

Lozman, O.R., Bushby, R.J., Vinter, J.G. Complementary polytopic interactions (CPI) as revealed by molecular modelling using the XED force field. J. Chem. Soc. Perkin Trans. 2 2, 1446-1452(2001)... 

Polytopic macrocyclic receptors 1, 2 (Figure 10.1) are able to complex the zwitterionic form of the amino acids by a double non-covalent charge interaction [28,29]. The unsymmetrical benzocrown sulfonamide derivative, 2 which contains benzo-18-crown-6 and benzo-15-crown-5 moieties was used as a ditopic receptor for multiple molecular recognition of the amino acids, by combining two non-covalent interactions ammonium-crown hydrogen bonding and carboxylate- complexed Na+-benzo-15-crown-5 charge interactions [28,33]. 

Synaptobrevins (VAMPs) Synaptogyrin Synaptophysins PKA but diverge C-terminally. Synapsins Ia/b contain C-terminal phosphorylation sites for CaMKII and CDK 5. Interact with microfilaments, neurofilaments, microtubules, SH3 domains, calmodulin and annexin VI in vitro. Small-membrane proteins that are cleaved by tetanus toxin and by botulinum toxins B, D, F and G. Polytopic membrane protein that is tyrosine-phosphorylated. Function unknown. Polytopic membrane proteins, including synaptoporin, that are tyrosine-phosphorylated and bind to synaptobrevins. May regulate SNARE function... 

Since the structure of DNA was first revealed by Watson and Crick in 1953, the formation of the double helix of nucleic acids by a self-directing, co-operative process has fascinated several generations of scientists. In general terms, DNA may be seen to self-assemble by a process in which two long chain polytopic receptors interact with the base pairs in such a way that each association step sets the stage for the one that follows. 

The difficulties somehmes encountered in the synthesis of polytopic hgands might be overcome by the development of efficient synthehc protocols (such as click chemistry) or the use of noncovalent bonding interactions (H bond or coordinahon). tn addihon, the development of conhnuous-flow reachon systems might prove advantageous for the practical apphcations of MOCP catalysts. 

In conclusion, an illuminating insight of the reaction path is obtained by means of a rather naive, but inexpensive method of computation. Other reactions studied along these lines, include the addition of methylene to ethylene 76>, addition and insertion of sulfur to ethylene 77>, dimerization of methylenes and nitroso compounds 78> fragmentation of cyclo-butane to ethylenes 79>, the Cope rearrangement 80>, the interaction of tricycloalkanes with acids and bases 81>, and the polytopal rearrangements in (CH)s, (CH)i, and (CH CO systems 82). 

Popov, M., and Reithmeier, R. A. F. (1999). Calnexin interaction with ALglycosylation mutants of a polytopic membrane glycoprotein, the human erythrocyte anion exchanger 1 (band 3)./. Biol. Chem. 274, 17635-17642. 

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