Procedure Template

Jurewicz K., Vix C., Frackowiak E., Saadallach S., Reda M., Parmentier J., Patarin J., Beguin F. Capacitance properties of ordered porous carbon materials prepared by a templating procedure. J Phys Chem Solids (2004) in press. 

A normal priority in both direct and template procedures is to maximize yields of the required product by choosing strategies which inhibit competing linear polymerization and other reactions. Unless special circumstances obtain, polymeric materials are often the major product when macrocyclic syntheses are attempted in the absence of appropriate conditions. 

Apart from this one-reaction type, the routine use of metal template procedures for obtaining a wide range of macrocyclic systems stems from 1960 when Curtis discovered a template reaction for obtaining an isomeric pair of Ni(n) macrocyclic complexes (Curtis, 1960). Details of this reaction are discussed later in this chapter. The template synthesis of these complexes marked the beginning of renewed interest in macrocyclic ligand chemistry which continues to the present day. 

Examples of template procedures in which the ring-closing condensation involves reaction at a centre other than a donor atom have been documented. In an early synthesis of this type, the reaction of bis-(dimethylglyoximato)nickel(n) (62) with boron trifluoride was demonstrated to yield the corresponding complex of the N4-donor macrocycle (63) (Schrauzer, 1962 Umland Thierig, 1962). In this reaction the proton of each bridging oxime linkage is replaced by a BF2+ moiety. X-ray... 

Other aza-donor macrocyclic ligand complexes of manganese(II) have been synthesized using metal template procedures." ... 

The complex [MnL](PF6)2, where L is the pendant arm ligand (184), also based on a N5 diimine macrocycle, was obtained directly by a template procedure." . The coordination geometry is pentagonal bipyramidal with the pendant amino groups occupying the axial sites. The aqueous HNMR relaxation rate enhancement in the presence of this complex is small in comparison to... 

The Schiff base complex [SrL](BPh4)2 (L = (188)) was obtained by an in situ metal template procedure." This species undergoes a transmetallation reaction in dry ethanol to yield [Mn2NCS4] (L = (188)). No evidence for a magnetic exchange interaction was observed in this case. 

The purpose is to describe the template procedure for an example of lyophilizer performance qualihcation. 

The second volume provides 139 template procedures, protocols, and reports that can be downloaded and, after minor changes, adopted. The ready-to-use protocols allow end users to record all raw hard data, further enabling them to prepare final reports. The additional chapters included in this edition provide details on how to ensure sterility and prepare sterility assurance reports. 

Preparation of the first rotaxanes was also accomplished by means of statistical threading of a chain through a cycle with following attaching of bulky substituents to the loose ends of the threaded chain [5], Statistical means of molecular threading were pushed out by much more efficient covalent templation procedures developed by Schill etal. [6,7],... 

Another advantage of this template procedure is that it allows access to optically active cryptophanes of known absolute configuration, from suitable optically active C3-cyclotriveratrylene templates. The cyclization step, however, requires high dilution conditions, which certainly represents a limitation, if the preparation of large quantities of these substances is contemplated. 

Table 3. Yields (%) of anti and syn isomers by using the template procedure or the direct method [20]...

The fact that the direct method does not exhibit the same odd/even dependence as does the template procedure obviously means the reaction does not proceed via the intermediate of Fig. 7 but suggests that the two cyclotriveratrylene caps are formed simultaneously. Possible intermediates leading to anti and syn cryptophanes are shown in Fig. 8. 

Descriptions of the synthesis of the tetraaza macrocycle (197) by a non-template procedure from o-phthalonitrile and 2,6-diaminopyridine as well as the synthesis of its Mn" compound have been published.539 The manganese species is very insoluble it is high spin with a magnetic moment of 5.80 BM and obeys the Curie law between 85 and 300 K. 

As mentioned already, a further group of catenanes have been synthesised via metal-ion template procedures discussion of these species is presented in the next chapter as part of a wider treatment of the use of metals in self-assembly processes. 

In another study,a chiral templating procedure was employed to direct the helicity of an oligo-bipyridine, double-stranded copper(I) helicate. The strategy employed is illustrated in Figure 6.29 in which spiro-bisindanol 71 and dimethyl-biphenic acid 72 were employed as the chiral template starters for the twisting process inherent in helicate formation. The above approach serves as a model for a general route towards the synthesis of enantio-pure helicates and is also of considerable intrinsic interest since it illustrates the manner by which stereochemical information may be transmitted over nanometer distances. 

The use of the metal ion template procedure for producing topologically sophisticated structures is well illustrated by the synthesis of composite molecular knots such as 105 and 106 (Figure 6.41) in this case two topological diasteromers are... 

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