Template Mediation Approaches

Lipofullerenes such as 35-37 self-assemble within lipid bilayers into rod-like structures of nanoscopic dimensions [61, 62]. These anisotropic superstructures may be important for future membrane technology. Significantly, lipofullerenes 35 and 37 have very low melting points, 22 and 67 °C (DSC, heating scan), respectively, with 35 being the first liquid fuUerene derivative at room temperature. 

The Tfj-symmetrical hexaaddition pattern also represents an attractive core tecton for dendrimer chemistry [26, 31, 63-67]. Examples for such dendrimers, involving a core branching multiplicity of 12, are 38 and 39 [63, 64], Addition of six mesotropic cyanobiphenyl malonate addends produced the spherical thermotropic liquid crystal 40 [65], DSC and POM investigations revealed a smectic A phase between 80 and 133 °C. Interestingly, this spherical and highly symmetrical compound gives rise to liquid crystallinity despite the absence of molecular anisotropy. 

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SFB 624 in Bonn proposed a definition for template-assisted reactions [265] which states that a template steers a reaction through spatial pre-organization of the reactants via a suitably defined pattern of non-covalent, covalent, or coordinative-reversible bonds. It acts as an entropic sink such that thermochemical criteria can be used to characterize the template-mediated process. Template-mediated reactions may revolve several times but high turn over numbers are not necessarily required. Also, the template does not necessarily need to be recovered once the reaction took place. In this work, we elaborate on this non-formal description, which aims to embrace as many chemical processes involving templates and host-guest interactions as possible. Our aim is to arrive at a more formal basis utilizing well-established thermochemical concepts. The classical thermochemical approach of physical chemistry to chemical reactions may provide an option to define transferable concepts for the plethora of template-assisted processes. 

Template-mediated ligation, an approach to bring two peptide fragments into close proximity. The N-terminus of one peptide and C-terminus of the other peptide are attached to a template, and consequently close to each other so that they can form a peptide bond. The basic principle was created by Brenner et al. using a salicylamide template based on a base-catalyzed intramolecular rearrangement and has been later exploited in thiol capture ligation [M. Bretmer et al., Helv. Chim. Acta 1957, 40, 1497]. 

Gold nanorods (GNRs) can be produced with reasonable yields through several approaches such as template-based methods [158, 159], electrochemical methods [160, 161], or via seed-mediated wet chemistry methods. Due to their simplicity and the ease of nanorod size and shape control, the latter, seed-mediated growth methods in the presence or absence of Ag+ ions are commonly preferred [162-165],... 

Jana, N. R., Gearheart, L. Murphy, C. J. Seed-mediated growth approach for shape-controlled synthesis of spheroidal and rod-like gold nanoparticles using a surfactant template. Adv. Mater. (Weinheim, Ger.) 13, 1389-1393 (2001). 

Several examples have appeared in the literature in which this linker has been employed in combinatorial chemistry strategies. Thus, it has been used in a Pd-mediated three-component coupling strategy for the solid-phase synthesis of tropane derivatives [46], in the solid-phase synthesis of aspartic acid protease inhibitors [47], in the attachment of cholic acid as a template for a combinatorial approach [48] and, more recently, in the solid-phase synthesis of pyrrolidines via 2-aza allyl anion cycloadditions with alkenes [49]. 

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