Template synthetic

In the case of L2" + it was not possible to synthesize [2]catenanes because the cavity of this cyclophane is too large to give stable complexes with aromatic crown ethers in the templated synthetic approach. Starting from Li" +, however, it was possible to prepare the [2]catenane ligands and L4 + which were then used to prepare several mononuclear [2]catenane complexes (Figure 23). These compounds were characterized by NMR spectroscopy, mass spectrometry and, in some cases, X-ray crystallography. 

Figure 3-2 Metal-templated synthetic approaches to the [2]catenate 4. 

Scheme 2.2 The two templated synthetic approaches to azo-macrocycles (a) exo-template...

The template synthetic process allows organization of the DNA helix into an assembly having two antiparallel strands of DNA (Fig. 10). The pendent bases on the strands are paired in such a manner that A is always paired with T and G with C. The strong hydrogen bonding of the complimentary pairs in hydrophobic... 

Template-based synthesis involves the fabrication of the desired material within the pores or channels of a nanoporous template. A template may be defined as a central structure within which a network forms in such a way that removal of the template creates a filled cavity with morphological and/or stereochemical features related to those of the template. Track-etch membranes, porous alumina, and other nanoporous structures have been characterized as templates. Electrochemical and electroless depositions, chemical polymerization, sol-gel deposition, and chemical vapor deposition have been presented as major template synthetic strategies. Template-based synthesis can be used to prepare nanostructures of conductive polymers, metals, metal oxides, semiconductors, carbons, and other solid matter... 

Stoddart et al. developed the donor-acceptor n-n interaction template synthetic strategy. The main interaction holding the components together in a certain supramolec-ular system is the aromatic stacking forces. The most frequently used donor units are 1,5-dioxynaphthalene (DNP), tetrathiafulvalene (TTF), dihydroxyl xenene ether-ate, diamino xenene etherate, and so on. The acceptor units in common use are cyclobis(paraquat-/ -phenylene) (CBPQT" +), viologen, and so on. As shown in Figure 10, ... 

Abraham also reported a [2]rotaxane R12 employing the donor-acceptor n-n interaction template synthetic strategy. The synthesis of R12 used the nature of the interaction between the CBPQT + and molecular threads... 

Figure 12 The snapping synthesis of R12 using the donor-acceptor jt-jt interaction template synthetic strategy.

The template synthetic method is based on the in situ hydrothermal crystallization of clay mineral layers (from a gel) using selected water-soluble polymers as templates [61]. Template synthesis is essentially limited to water-soluble polymers, and the synthetic clay mineral formed under the conditions described by the authors is a poorly ordered fluorohectorite. On the other hand, the method is potentially capable of promoting the dispersion of silicate layers in a one-step process. 

In developing these template synthetic methods, we made an interesting discovery. When these polymers are synthesized (either chemically or electrochemically) within the pores of the track-etched polycarbonate membranes, the polymer preferentially nucleates and grows on the pore walls [11,14,46]. As a result, polymeric tubules are obtained at short polymerization times (Fig. 16.2A). These tubular structures have been quite useful in our fundamental investigations of electronic conductivity in the template-synthesized materials (see below). In addition, tubular structures of this type have a number... 

An optimized non-template synthetic pathway by Scheme 2.95 to the amine caging ligand 144 using reduction of its imine macrobicyclic precursor 145 has been elaborated in [106]. Both these cage molecules have a Ds pseudosymmetry, and the capping tertiary amine nitrogen atoms with the lone pairs located within their cavities are 6.37 and 6.84 A apart, respectively [106]. 

Hurst, S.J., Payne, E.K., Qin, L and Mirldn, CJV. (2006) Multisegmented one-dimensional nanorods prepared by hard-template synthetic methods. Ar ewandte Chemie - International Edition, 45, 2672-92. 

The 15-membered macrocycle 31 was obtained in high yields from cis-[Mo(CO)3(H2PCH2CH2CH=CH2)3] utilizing the same template synthetic approach as that for 12-membered macrocycles 20 (Scheme 12.13) [50]. 

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