Competition between hydrogen and halogen bonding in the structures of 5,10-dihydroxy-5,10-dihydroboranthrenes

Abstract

X-ray crystallographic and computational studies are reported for a series of boranthrenes, substituted with halogen atoms. The role of competitive hydrogen (O-H...O, O-H...F, C-H...O) and halogen (Cl...Cl, O...Br, F...F) bonding interactions on the molecular arrangement in the crystal structures is discussed. The structural analysis and calculations reveal that the O-H...O hydrogen bond in the unsubstituted derivative 5,10-dihydroxy-5,10-dihydroboranthrene, C12H10B2O2, is of moderate strength (ca -20 kJ mol(-1)), but weaker than that in the related thiophene derivative 4,8-dihydro-4,8-dihydroxy-p-diborino[2,3-b:5,6-b]dithiophene, C8H6B2O2S2 (ca -40 kJ mol(-1)). This is due to shielding of the OH group by the H atoms in the β-position of the boranthrene unit. Structural diversity derived from the flexibility of the O-H...O hydrogen bond facilitates the occurrence of other competitive interactions. For instance, in the 1,6-difluoro derivative, C12H8B2F2O2, the crystal packing results from O-H...F and F...F interactions. In turn, the 1,6-dibromo derivative, C12H8B2Br2O2, is dominated by Br...O halogen-bond interactions. In the most interesting case, the 1,6-dichloro derivative, C12H8B2Cl2O2, molecular disorder leads to the formation of two different supramolecular arrangements co-existing in the crystal lattice, one based on the Cl...Cl and C-H...O bonds, and the other stabilized by O-H...O hydrogen bonds. Calculations performed with density-functional theory (DFT; CRYSTAL09) and PIXEL methodologies show that both lattices are characterized by similar energy values (ca -100 kJ mol(-1)). A mixed arrangement with random or short-range-ordered molecular orientations can also be expected.

Influence of the halogen substituent on the formation of halogen and hydrogen bonding in co-crystals formed from acridine and benzoic acids

“…Crystal structure of acridine•3-iodobenzoic acid co-crystal (9) Single-crystal X-ray diffraction measurements show that compound 9 crystallized in the triclinic P1 ¯space group with one acridine and one 3-iodobenzoic acid molecule in the asymmetric unit (Fig. 1i and Table 1).…”

“…8 Finally, Woźniak and co-workers described the influence of a halogen substituent on the packing of halogen-and hydrogen-bonded crystals of boranthrenes. 9 In the context of investigations into the competition between halogen and hydrogen bonding in crystals, orthoand metahalobenzoic acids represent an interesting object of study. This follows directly from the fact that a search of the Cambridge Structural Database (CSD version 5.36, update November 2014) 10 shows that there are relatively few structures of organic cocrystals, salts or solvates formed from them (10,21,7 and 4 structures of compounds containing 2-fluorobenzoic acid, 10a 2-chlorobenzoic acid, 10b 2-bromobenzoic acid, 10c and 2-iodobenzoic acid 10d moieties respectively, and 11, 32, 8 and 14 structures of compounds containing 3-fluorobenzoic acid, 10e 3-chlorobenzoic acid, 10f 3-bromobenzoic acid, 10g and 3-iodobenzoic acid 10h moieties respectivelyincluding the structures of the acids themselves).…”

“…Acridine•3-iodobenzoic acid co-crystal (9) Acridine (0.050 g, 0.279 mmol) and 3-iodobenzoic acid (0.069 g, 0.278 mmol) were dissolved in 50 cm 3 of an ethanol/water mixture (10 : 1, v/v) and boiled for ca. 15 minutes.…”

Theoretical study of the interaction of fluorinated dimethyl ethers and the ClF and HF molecules. Comparison between halogen and hydrogen bonds

“…They are both characterized by a charge transfer from B to YX (YH) along with a polarization of the YX (YH) bond. In this context, halogen and hydrogen bonds have been compared in several recent studies . Theoretical studies have shown that the electrostatic interaction is larger in hydrogen‐bonded systems than in the halogen‐bonded structures in contrast to the dispersive and inductive terms which seem to predominate in halogen bonds .…”

Electronic features and hydrogen bonding capacity of the sulfur acceptor in thioureido-based compounds. Part 2. Further insight by theoretical charge density study

“…Alongside the energy information that can be extracted from electron density distribution and topological analysis we also employed CRYSTAL09 for the study of cohesive energy between the molecules. Latter theoretical approach has recently been successfully applied for study of different systems [27][28][29][30][31][32][33][34] including the sulfur containing systems [35][36][37].…”