Gürtelförmige Moleküle mittels repetitiver Synthesestrategie

Abstract

Belt-Shaped Molecules by a Repetitive Synthetic StrategyBelt-shaped molecules of the general type 2 containing up to five benzene ring units (cf. 37

Linear and Macrocyclic Molecular Thread, Ribbon and Belt Assemblies of Nanometric Scale

“…Furthermore, the preparation of the belt precursors is then carried out more easily and in good yields. According to space filling models the mixed thread-belt macrocycles still look very similar to molecular belts and like those we described earlier 9 (cf. Figure 3).…”

“…Pseudobeltane 29 containing four benzene units can be prepared under high-dilution conditions in 28% yield from the cyclophane dibromide 16 and the cyclophane dithiol 17 . A comparison to 3% macrocyclization yield using tetrafunctionalized cyclophane units 13 to generate beltane 30 9,10,13 demonstrates the advantage of this new approach (Scheme 6).…”

“…6 ). By double in-termolecular cyclization of dibromide 11 and 1,2,4,5tetrakis [ N -(4-tolylsulfonyl)aminomethyl]benzene 9 18 we obtained the meta/meta -cyclophane 19b in 10% yield and meta/para -cyclophane 20 in 21Ð24% yield (Scheme 3). Separation of the isomeric mixture is possible by extraction of 20 in ethyl acetate (residue: 19 ).…”

“…Following this we prepared structure-perfect molecular ribbons like 6 with up to nine benzene units 8 and molecular belts like 7 containing five benzene units 9 (Figure 2). Mass spectrometry revealed molecular belts with up to 30 benzene units 9 , but their separation met with difficulties. As a consequence it seems that avoiding oligomeric macrocycles by structure directed synthesis of every single belt is the better choice presently.…”

“…A problem on the way to longer molecular belts was the final macrocyclization step with low yields due to the high number of covalent bonds which have to be formed 9,10 . The new strategy described here bases on the following consideration: The substitution of one or more [3.3]metacyclophane 11 bridges by single bridges of the same character should result in higher flexibility and solubility of the macrocycle.…”