Ales Ruzicka

Synthesis and structural characterization of heteroboroxines with MB2O3 core (M = Sb, Bi, Sn).

Reaction of organoantimony and organobismuth oxides (LSbO)(2) and (LBiO)(2) (where L is [2,6-bis(dimethylamino)methyl]phenyl) with four equivalents of the organoboronic acids gave new heteroboroxines LM[(OBR)(2)O] 1a-2c (for M = Sb: R = Ph (1a), 4-CF(3)C(6)H(4) (1b), ferrocenyl (1c); for M = Bi: R = Ph (2a), 4-CF(3)C(6)H(4) (2b), and ferrocenyl (2c)). Analogously, reaction between organotin carbonate L(Ph)Sn(CO(3)) and two equivalents of organoboronic acids yielded compounds L(Ph)Sn[(OBR)(2)O] (where R = Ph (3a), 4-CF(3)C(6)H(4) (3b), and ferrocenyl (3c)). All compounds were characterized by elemental analysis and NMR spectroscopy. Their structure was described both in solution (NMR studies) and in the solid state (X-ray diffraction analyses 1a, 1c, 2b, 3b, and 3c). All compounds contain a central MB(2)O(3) core (M = Sb, Bi, Sn), and the bonding situation within these rings and their potential aromaticity was investigated by the help of computational methods.

1-(3-Chloro­benz­yl)-5-iodo­indoline-2,3-dione

In the title compound, C15H9ClINO2, which possesses anticonvulsant activity, the iodoindoline ring system is essentially planar (maximum deviation 1.245 Å) and is oriented with respect to the 3-chlorobenzyl ring at a dihedral angle of 76.59 (3)°. In the crystal, there is a π–π contact between iodoindoline ring systems [centroid–centroid distance = 3.8188 (4) Å].

Methyl 2,5-dichloro-benzoate.

In the molecule of the title compound, C8H6Cl2O2, the benzene ring is oriented with respect to the planar ester group at a dihedral angle of 39.22 (3)°.

3-(4-Methoxybenzoyl)propionic acid

In the crystal of the title compound, C11H12O4, inversion dimers arise from pairs of intermolecular O—H⋯O hydrogen bonds and C—H⋯O bonds further consolidate the packing. There is also a C—H⋯π contact between the benzene ring and the methylene group.

2-[(4-Chloro-benz-yl)carbonyl-meth-yl]benzoic acid.

The title compound, C16H13ClO3, is an important intermediate in the conversion of isocoumarin to 3,4-dihydroisocoumarin. The two aromatic rings are oriented at a dihedral angle of 67.18 (3)°. In the crystal structure, intermolecular O—H⋯O hydrogen bonds link the molecules into centrosymmetric dimers. There is also a C—H⋯π contact between the benzoic acid and 4-chlorobenzyl rings.

3-(3-Fluoro­benz­yl)-1H-isochromen-1-one

The asymmetric unit of the title compound, C16H11FO2, contains two independent molecules. The isochromene ring systems are planar and are oriented with respect to the fluorobenzene rings at dihedral angles of 87.15 (3) and 87.85 (3)° in the two molecules.

3-(3-Methoxy­benz­yl)-4-(2-methoxy­phen­yl)-1H-1,2,4-triazole-5(4H)-thione

In the title compound, C17H17N3O2S, the five-membered ring forms dihedral angles of 53.02 (3) and 78.57 (3)° with the 3-methoxy-substituted and 2-methoxy-substituted benzene rings, respectively. In the crystal structure, molecules are linked into centrosymmetric dimers via intermolecular N—H⋯S hydrogen bonds.

2-(2-Fluoro­benzoyl­meth­yl)benzoic acid

In the title compound, C15H11FO3, the aromatic rings are oriented at a dihedral angle of 69.26 (3)°. In the crystal structure, inversion dimers arise from pairs of intermolecular O—H⋯O hydrogen bonds, and C—H⋯O hydrogen bonds further consolidate the packing. There are also C—H⋯π contacts between the benzoic acid and 2-fluorobenzene rings.

(E)-3-(3,5-Dimethoxy­phen­yl)acrylo­hydrazide

In the title compound, C11H14N2O3, the planar hydrazide group is oriented with respect to the benzene ring at a dihedral angle of 48.00 (3)°. In the crystal structure, intermolecular N—H⋯O hydrogen bonds link the molecules.