Supramolecular Yield

Aside from these fundamental limitations, it is difficult to establish any general guidelines because negative co-crystallisation results are reported less consistently in the academic literature and they are very much harder to collate in a systematic way. Statistics based on known crystal structures (and possibly robust theoretical predictions of hypothetical crystal structures) therefore provide the best practical guideline that is available frequent observation of a particular heterosynthon in the CSD establishes it to be viable within co-crystals and shows that co-crystallisation of molecules containing the constituent functional groups frequently can compete with separate 

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Isonicotinamide has been identified as a reliable supramolecular reagent (SR) that, in combination with carboxylic acids,is capable of producing cocrystals in a high supramolecular yield,where the primary intermolecular interaction is an 0-H- N hydrogen bond between the acid and the N-heterocyclic nitrogen atom (Scheme 3). 

Table 1 Supramolecular yields for each type of oxime.

Relating Supramolecular Yield to the Charge on the Hydrogen-Bond Donor. .. 131... 

Especially notable is also the synthesis and structural characterization of an unusual antimony(III) guanidinate. 1,2,3-Tiiisopropylguanidine, Pr N = C(NHPr )2,was found to react with 1 molar equivalent of Sb(NMe2)3 in toluene under formation of a yellow solution, from which the novel compound Sb[Pr NC(NPr )2][Pr NHC(NPr )2] could be isolated in 10% yield as highly air-sensitive crystals. In the solid state, the complex adopts a heavily distorted trigonal-bipyramidal molecular structure in which the Sb is chelated by a [CfNPr ls] dianion and a [Pr NHC(NPr )2] monoanion (Figure 16). Supramolecular... 

Successive H-bond urea self-assembly of 4 and sol-gel transcription steps yield preferential conduction pathways within the hybrid membrane materials. Crystallographic, microscopic and transport data confirm the formation of self-organized molecular channels transcribed in solid dense thin-layer membranes. The ionic transport across the organized domains illustrates the power of the supramolecular approach for the design of continual hydrophilic transport devices in hybrid membrane materials by self-organization (Figure 10.8) [42-44]. 

Polyfunctional organomercurials have emerged as useful building blocks for the construction of supramolecular species. Compound 137, for instance, was shown to complex benzene, yielding extended binary stacks where the two components alternate (Figure 25).235 These stacks are rather compact (centroid distance of 3.24 A), so that secondary 7t-interactions occur between the benzene molecule and the mercury centers. Each of the six C-C bonds of the benzene molecule interacts with one of the six mercury centers of the two juxtaposed molecules of 137. As a result, the benzene is hexacoordinated in a fashion. The strength of the Hg-C interactions must... 

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