An Organic Zeolite With 10 Å Diameter Pores Assembles From a Soluble and Flexible Building Block by Non-Covalent Interactions

Sequential Nucleophilic Aromatic Substitution Reactions of Activated Halogens

Building blocks have been identified that can be functionalised by sequential nucleophilic aromatic substitution. Some examples are reported that involve the formation of cyclic benzodioxin and phenoxathiine derivatives from 4,5-difluoro-1,2-dinitrobenzene, racemic quinoxaline thioethers, and sulfones from 2,3-dichloroquinoxaline and (2-aminophenylethane)-2,5-dithiophenyl-4-nitrobenzene from 1-(2-aminophenylethane)-2-fluoro-4,5-dinitrobenzene. Four X-ray single-crystal structure determinations are reported, two of which show short intermolecular N-O…N "π hole" contacts.

Reactions of 4,5-difluoro-1,2-dinitrobenzene with amines in dimethylformamide or EtOH

Substitution reactions of 1,2-difluoro-4,5-dinitrobenzene were explored in dimethylformamide alone and with KOH/H2O, Hünig’s base or Et3N and with Me2NHCl/Et3N in EtOH. The fluorine atoms were always displaced in preference to the nitro groups. Three compounds were prepared from these studies and were characterised by X-ray single crystal structure determinations.

Bis(3-butylamino-4-nitro)piperazine

2,4-Difluoronitrobenzene is treated sequentially with butylamine and then piperazine to prepare a building block for forming a crystalline lattice by non-covalent interactions. A single crystal X-ray structure determination was performed.

An Organic Zeolite With 10 Å Diameter Pores Assembles From a Soluble and Flexible Building Block by Non-Covalent Interactions

Two similar molecular building blocks, which both contain a hydrogen-bonded nitro group, have been prepared and crystallised. One structure has more flexibility with a butyl side chain which allows an open framework organic zeolite to form with large 10 Å diameter pores, whereas the other structure has less flexibility with an aryl side chain and is close packed. The pore size is comparable with those of the aluminophosphate VPI-5 (12 Å). It is concluded that some flexibility in the design of the building block for porous organic molecular materials was beneficial.