Non-C2-Symmetric Bis-Benzimidazolium Salt Applied in the Synthesis of Sterically Hindered Biaryls

A novel non-C2-symmetric bis-benzimidazolium salt derived from (±)-valinol has been prepared by a simple and straightforward process in good yield. The structure of bis-benzimidazolium salt provided a bulky steric group on the ethylene bridge; which facilitates the catalytic efficacy in the C(sp2)–C(sp2) formation. Its catalytic activity in Suzuki–Miyaura cross-coupling reaction of unactivated aryl chlorides has been found to have high efficacy in 1 mol% Pd loading. This protocol demonstrated the potential on the synthesis of sterically hindered biaryls.

Impact of donor structure in new D-π-A systems based on indolo[3,2,1-jk]carbazoles on thermal, electrochemical, optoelectronic and luminescence properties

In this work, novel fluorophores with D-π-A architectures (ICz-1 ‒ ICz-6) were synthesized and investigated based on indolo[3,2,1-jk]carbazole (ICz) framework connected by ethylene bridge with extensive donor moieties - fluorene,...

Crystal structure of poly[[aqua(μ-2,3-dihydrothieno[3,4-b][1,4]dioxine-5,7-dicarboxylato-κ2O5:O7)[μ-di(pyridin-4-yl)sulfane-κ2N:N′]zinc] 0.26-hydrate]

The crystal structure of the title polymer, {[Zn(C8H4O6S)(C10H8N2S)(H2O)]·0.26H2O}n, is characterized by a layered arrangement parallel to theabplane. The zinc cation is five-coordinated in a slightly distorted trigonal–bipyramidal coordination environment defined by two pyridine ligands, two carboxylate groups of two thiophene dicarboxylate ligands, and by one water molecule. The ethylene bridge in the dioxine ligand is disordered over two sets of sites [occupancy ratio 0.624 (9):0.376 (9)]. Several hydrogen-bonding interactions of the types O—H...O, C—H...O, C—H...S and C—H...N ensure the cohesion within the crystal structure.

Addition of in situ reduced amidinato-methylaluminium chloride to acetylenes

Addition of in situ reduced amidinato-methylaluminium chloride to acetylenes was observed. Whether the structure of the products contains an ethylene bridge or terminally bonded ethynyl groups, and the further reactivity of the products are closely related to the substituents on the CC group.

Stacking patterns of thieno[3,2-b]thiophenes functionalized by sequential palladium-catalyzed Suzuki and Heck cross-coupling reactions

The crystal structures of three 5-alkenyl-2-arylthieno[3,2-b]thiophenes, namely 3,6-dibromo-5-(4-tert-butylstyryl)-2-(naphthalen-1-yl)thieno[3,2-b]thiophene, C28H22Br2S2, (I), 3,6-dibromo-5-(4-methylstyryl)-2-(naphthalen-1-yl)thieno[3,2-b]thiophene, C25H16Br2S2, (II), and 3,6-dibromo-2-(4-tert-butylphenyl)-5-(4-methylstyryl)thieno[3,2-b]thiophene, C25H22Br2S2, (III), have been determined in order to evaluate the geometry of the molecules. The π-conjugated system containing the thieno[3,2-b]thiophene skeleton, the ethylene bridge and the phenyl rings is almost planar. The aromatic ring directly attached to the thieno[3,2-b]thiophene moiety is not coplanar with the thieno[3,2-b]thiophene moiety itself due to steric hindrance of the bromo substituent. The crystal packings are characterized by π–π stacking [only for (II)] and C—Br...π interactions. The long axes of the molecules in (I) are oriented in two directions; for the two other structures the long axis is oriented in one direction only.

Diethyl 2,2′-(ethane-1,2-diyldioxy)dibenzoate

The molecular title compound, C20H22O6, was obtained by the reaction of ethyl 2-hydroxybenzoate with 1,2-dichloroethane. The molecule lies on a twofold rotation axis which passes through the middle of the central ethylene bridge. This group exhibits agaucheconformation with the corresponding O—C—C—O torsion angle being 73.2 (2)°. The C atoms of the carboxyl group, the aryl and the O—CH2group are coplanar, with an r.m.s. deviation of 0.01 Å. The two aryl rings form a dihedral angle of 67.94 (4)°. The ester ethyl group is disordered over two sets of sites with an occupancy ratio of 0.59 (2):0.41 (2). The crystal packing is dominated by van der Waals forces.

Ethyltrans-12-(pyridin-4-yl)-9,10-ethanoanthracene-11-carboxylate

In the title compound, C24H21NO2, the residues at the central ethylene bridge aretransto each other. The dihedral angles between the pyridine and benzene rings are 67.09 (6) and 61.41 (5)°. In the crystal, centrosymmetrically related molecules are linked into dimers by pairs of C—H...O hydrogen bonds.