Attractive fluorine···fluorine interactions between perfluorinated alkyl chains: a case of perfluorinated Cu(II) diiminate Cu[C₂F₅–C(NH)–CF=C(NH)–CF₃]₂

Abstract

A synthesis of the perfluorinated copper diiminate complex Cu[C2F5–C(NH)–CF=C(NH)–CF3]2 (3) and its self-assembly into infinite 1D chains in the crystal via Type II C(sp3)–F···F–C(sp3) contacts between perfluoroethyl substituents is reported. Rare Type II F···F interactions were studied by DFT calculations and topological analysis of the electron density distribution within the formalism of Bader’s theory (QTAIM method). This is the first report which discusses Type II contacts between perfuoroalkyl chains.

Unsymmetrical Trifluoromethyl Methoxyphenyl β-Diketones: Effect of the Position of Methoxy Group and Coordination at Cu(II) on Biological Activity

“…There was a typical very strong enolic intramolecular hydrogen bond in the structure, with the O2•••O1 distance being 2.4955(12) Å; and the O2-H2-O1 angle as 154.3(16) • . The CF 3 group is fully ordered, similarly to what we observed earlier [44]. The torsion angle O1-C1-C5-C6 was equal to 7.03(13) • , the major contribution to the deviation from the planarity of the whole molecule came from the rotation around the C1-C5 bond.…”

Exploring Supramolecular Assembly Space of Cationic 1,2,4-Selenodiazoles: Effect of the Substituent at the Carbon Atom and Anions

“…), zero or very close to zero energy density (0.000–0.002 a.u.) in these bond critical points (3, –1), and estimated strength for appropriate short contacts (0.9–5.0 kcal/mol) are typical for weak hydrogen bonds [ 3 , 4 , 36 ] and non-covalent interactions involving halogen [ 8 , 9 , 10 , 11 , 12 , 32 , 37 , 38 ] and chalcogen [ 22 , 23 , 39 , 40 , 41 , 42 ] atoms in similar chemical systems. The strongest non-covalent interactions in the studied model supramolecular associates 3 – 10 were chalcogen bonds: Se1···Cl24 in 3 (4.7 kcal/mol), Se1···Cl30 in 4 (4.4 kcal/mol), Se1···Cl38 in 5 (5.0 kcal/mol), Se1···Cl24 in 6 (3.5 kcal/mol), Se29···Cl56 in 7 (5.0 kcal/mol), Se1···Br15 in 8 (3.5 kcal/mol), Se2···C31 in 9 (1.3 kcal/mol), and Se1···F29 (4.7 kcal/mol) in 10 .…”

“…Although the construction of larger and more complex structures is an important task within this field, the other major challenges include the utilization of other weak interactions (apart of HB and metal coordination) for obtaining more complex aggregates, determining recognition units, as well as designing and synthesizing novel recognition units. The attractive non-covalent interactions between polarizable main group elements and Lewis basic species, which include chalcogen bonding (ChB) and halogen bonding (XB), have recently attracted considerable attention and emerged as powerful alternatives to complexation and HB in supramolecular chemistry [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ].…”

2-Pyridylselenenyl versus 2-Pyridyltellurenyl Halides: Symmetrical Chalcogen Bonding in the Solid State and Reactivity towards Nitriles

“…), and very close to zero energy density (0.000-0.001 a.u.) in appropriate bond critical points (3, −1) and energies for these short contacts (0.9-1.9 kcal/mol) are typical for weak noncovalent interactions involving halogen and chalcogen atoms in similar chemical systems [6,7,9,[49][50][51][52]. The ratio -G(r)/V(r) > 1 at the bond critical points (3, −1) reveals that the nature of appropriate interaction is purely noncovalent [53].…”