Competitive self-assembly

Pranger, L., Goldstein, A. and Tannenbaum, R. (2005) Competitive self-assembly of symmetrical, difunctional molecules on ambient copper surfaces. Langmuir, 21, 5396-404. 

Other experiments involved competitive self-assembly in which the precursors... 

The remarkable strength of some XBs allows them to prevail over HBs in identifying the modules to be involved in self-assembly. For instance, in experiments of competitive co-crystal formation, a dipyridyl derivative prefers to co-crystallize with XB donors rather than HB donors and the same occurs for NjNjN jN -lclramclhylclhylcncdiaminc (TMEDA) [36]. In solution, solute-solute intermolecular HBs are considerably diminished if a strong XB donor co-solute is added. If haloperfluorocarbons (halo-PFCs) are used, the HB breaking potency increases moving from perfluorocarbons to chloro-, bromo-, and iodoperfluorocarbons [37-43], perfectly consistent with the order of the increasing XB donor ability of the halo-PFCs co-solutes, hi aque-... 

Gassensmith JJ, Arunkumar E, Barr L, Baumes JM, DiVittorio KM, Johnson JR, Noll BC, Smith BD (2007) Self-assembly of fluorescent inclusion complexes in competitive media including the interior of living cells. J Am Chem Soc 129 15054-15059... 

Cgo single molecules between electrodes fabricated by electromigration [103] to create single Cgo molecule transistors were measured at a temperature of 40 mK. The results showed the coexistence and competition of the effects of Coulomb repulsion, Kondo correlations and superconductivity [104]. The Kondo effect had been previously observed in similar devices [105]. Recently a SAM of a tricarboxylic acid fullerene derivative was used to fabricate a transistor. The SAM was created by allowing the fullerene compound to self assemble on top of an AI2O3 layer just above the aluminum drain electrode the source lead was created by... 

Upon the first reduction, the voltammetric wave shifts by 20-30 mV, presumably due to donor-acceptor interactions resulting from the naphthalene and cyclophane moieties.39 The second reduction remains relatively unaffected, indicating that the complex disassembles prior to the second reduction of the cyclophane. Alternatively, the complex can disassemble through competitive binding interactions with a tetrathiafulvalene derivative. Thus, Cooke and coworkers demonstrate that self-assembly at exo-active surfaces can be reversibly controlled via an external electrochemical stimulus or competitive binding interactions. 

Scheme 10.4 Self-assembly of molecular square 10.10 from Pd (en)2+ and 4,4 bipyridine in competition with protonation reactions.

Water was preferred to acetonitrile as the solvent, allowing moderately hindered and anionic amines to self-assemble. Acetonitrile is a much better ligand for copper(I) than water, making it more difficult for hindered ligands (such as the one formed from serinol, third entry in Table 1.1) to form complexes in competition with the solvent. More hindered amines as well as cationic amines were not incorporated in either solvent, which we attribute to steric and Coulombic repulsion, respectively. 

The selective self-assembly of a receptor molecule with its complementary recognition unit in the presence of a competitive recognition unit has been described as self-sorting in the literature. DNA and RNA are the prime examples of this concept. Using the above-described copolymers containing two hydrogenbonding units, Burd and Week [95] were able to prove this concept of self-sorting also in synthetic polymer systems (Fig. 7.22). 

The kind of attachment of the metal coordinating groups to the cavitand is an important structure-defining parameter. Hong et al. studied the self-assembly of a cavitand 15 functionalized with pyridyl groups via flexible ether linkages (Fig. 5) [48, 49]. Due to the conformational freedom of the connection, intramolecular coordination of the metal (Pt2+ and Pd2+) centers is observed in competition with intermolecular complexation leading to the supramolecular capsules 16a-b. While the capsules 16a b and the half-capsules 17a-b are in dynamic equilibrium in nitromethane, the dimeric capsule is formed exclusively in chloroform/methanol mixtures. 

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