Design and supramolecular structure of crystal associates of polyfluoroarylenediamines and 18-crown-6 (2:1)

How does the combination of the nitro group and fluorine atoms affect the (co)crystallization behaviour of arylenediamines?

“…Thus, the results of co-crystallization of diamines A – D containing the NO 2 group, together with data for arylenediamines containing the CF 3 (ref. 12) and CN 14 groups, as well as the heterocyclic N atom, 12 suggest that the presence of an electron-withdrawing group in polyfluorinated arylenediamine increases the range of the co-crystal stoichiometry. Moreover, the NO 2 group, which is a stronger electron-withdrawing substituent, reduces the requirement for the number of F atoms in the ring and allows not only fully fluorinated diaminonitrobenzene A , but also nitrobenzene B containing one less F atom to co-crystallize in various stoichiometries.…”

“…ref. 12) to the estimation of the thermodynamically preferred co-crystallization pattern can be based on a comparison of the crystal packing enthalpies Δ H pack calculated by eqn (1), where H solid (Y x · cr 1− x ) is the enthalpy of a co-crystal normalized per unit Y x · cr 1− x , H isol (Y) and H isol (cr) are the enthalpies of isolated diamine and crown ether molecules. These values were calculated by the DFT method using the structures of co-crystals determined by the X-ray diffraction method as input data for the subsequent optimization (Tables 5 and S3†).…”

“…In the series of diaminopyridines, only 2,6-diamino-4-chloro-3,5-difluoropyridine is capable of forming a strong N–H⋯N py H-bond to give a 2 : 1 co-crystal, while other pyridines co-crystallize with 18-crown-6 in a 1 : 1 ratio exclusively. 12 In the series of diaminobenzonitriles, the key factor is the presence of a fluorine atom in the ortho -position relative to the CN group: the only co-former capable of co-crystallization in stoichiometry different from 1 : 1 is 2,4-diaminotrifluorobenzonitrile. 14 Polyhalogenated phenylene-diamines containing no strong electron withdrawing substituents co-crystallize with 18-crown-6 to give only 1 : 1 co-crystals, irrespective of the component ratio in the growth solution and the solvent.…”

“…14 Polyhalogenated phenylene-diamines containing no strong electron withdrawing substituents co-crystallize with 18-crown-6 to give only 1 : 1 co-crystals, irrespective of the component ratio in the growth solution and the solvent. 12…”

Polyhalogenated aminobenzonitrilesvs.their co-crystals with 18-crown-6: amino group position as a tool to control crystal packing and solid-state fluorescence

“…The arylamine molecules are disposed on both sides of the macrocycle plane and are coordinated by the H-bond N-H⋯O cr typical for the co-crystals of 18-crown-6 with polyhalogenated (hetero) aromatic mono-and diamines. 16,17,56,57 Table S2 † presents the parameters of the H-bonds. π-Electron interactions of the aromatic molecules, i.e.…”