Preparation of substituted triphenylenes via nickel-mediated Yamamoto coupling

Nickel-mediated Yamamoto coupling provides a concise and efficient synthesis of triphenylene derivatives, including electron-deficient discotic mesogens.

Expanded all-Phenylene Molecular Spoked Wheels: Cutouts of Graphenylene-3

All-phenylene molecular spoked wheels, cutouts of graphenylene-3, have been synthesized by intramolecular Yamamoto coupling of the respective dodecabromides. The uneven number of aromatics at the sides of the wheels requires...

Chiral Cyclic [n]Spirobifluorenylenes: Carbon Nanorings Consisting of Helically Arranged Quaterphenyl Rods Illustrating Partial Units of Woven Patterns

Chiral cyclic [n]spirobifluorenylenes consisting of helically arranged quaterphenyl rods, illustrating partial units of woven patterns, were designed and synthesized as a new family of carbon nanorings. The synthesis was accomplished by the Ni(0)-mediated Yamamoto-coupling of chiral spirobifluorene building blocks. The structures of the cyclic 3-, 4-, and 5-mers were determined by X-ray crystallographic analysis. These carbon nanorings exhibited a strong violet colored emission with high quantum yields in solution (95%, 93%, and 94% for 3-, 4-, and 5-mer, respectively). Other spectroscopic properties, including their chiroptical properties, were also investigated. The g-values for circularly polarized luminescence were found to be in the order of 10^-3, where that of the 4-mer showed a relatively higher value 8.5 x 10^-3. Characteristic spiroconjugation induced by multiple<br>3) bifluorenyl units, for example the even-odd effect of the number of units in the matching of the sign of the orbitals, were also indicated by DFT calculations.<br>

Chiral Cyclic [n]Spirobifluorenylenes: Carbon Nanorings Consisting of Helically Arranged Quaterphenyl Rods Illustrating Partial Units of Woven Patterns

Chiral cyclic [n]spirobifluorenylenes consisting of helically arranged quaterphenyl rods, illustrating partial units of woven patterns, were designed and synthesized as a new family of carbon nanorings. The synthesis was accomplished by the Ni(0)-mediated Yamamoto-coupling of chiral spirobifluorene building blocks. The structures of the cyclic 3-, 4-, and 5-mers were determined by X-ray crystallographic analysis. These carbon nanorings exhibited a strong violet colored emission with high quantum yields in solution (95%, 93%, and 94% for 3-, 4-, and 5-mer, respectively). Other spectroscopic properties, including their chiroptical properties, were also investigated. The g-values for circularly polarized luminescence were found to be in the order of 10^-3, where that of the 4-mer showed a relatively higher value 8.5 x 10^-3. Characteristic spiroconjugation induced by multiple<br>3) bifluorenyl units, for example the even-odd effect of the number of units in the matching of the sign of the orbitals, were also indicated by DFT calculations.<br>

Ferrocene-Based Conjugated Microporous Polymers Derived from Yamamoto Coupling for Gas Storage and Dye Removal

Conjugated microporous polymers (CMPs) have conjugated skeleton and permanent porosity, and exhibit huge potential in developing novel functional materials for resolving the challenging energy and environment issues. Metal-containing CMPs often exhibited unique properties. In the present manuscript, ferrocene-based conjugated microporous polymers (FcCMPs) were designed and synthesized with 1,1′-dibromoferrocene and 5,10,15,20-Tetrakis(4- bromophenyl) porphyrin (FcCMP-1) or Tetra (p-bromophenyl) methane (FcCMP-2) as building units via Yamamoto coupling. FcCMPs were amorphous, and exhibited excellent thermal and physicochemical stability. The BET surface area of FcCMP-1 and FcCMP-2 was 638 m2/g and 422 m2/g, respectively. In comparison with FcCMP-2, FcCMP-1 displayed better gas storage capacity due to higher porosity. FcCMPs were also used as an adsorbent for removal of methyl violet from aqueous solution, and exhibited excellent adsorption properties due to the interaction between electron-rich conjugated structure of the polymers and methyl violet with cationic groups. Moreover, FcCMPs could be extracted and regenerated by an eluent and then re-used for high efficient removal of methyl violet.

Chiral Cyclic [n]Spirobifluorenylenes: Carbon Nanorings Consisting of Helically Arranged Quaterphenyl Rods Illustrating Partial Units of Woven Patterns

Chiral cyclic [n]spirobifluorenylenes consisting of helically arranged quaterphenyl rods, illustrating partial units of woven patterns, were designed and synthesized as a new family of carbon nanorings. The synthesis was accomplished by the Ni(0)-mediated Yamamoto-coupling of chiral spirobifluorene building blocks. The structures of the cyclic 3- and 4-mers were determined by X-ray crystallographic analysis. These carbon nanorings exhibited a strong violet colored emission with high quantum yields in solution (95%, 93%, and 94% for 3-, 4-, and 5-mer, respectively). Other spectroscopic properties, including their chiroptical properties, were also investigated. The gvalues for circularly polarized luminescence were found to be in the order of 10-3, where that of the 4-mer showed a relatively higher value 8.5 x 10-3. Characteristic spiroconjugation induced by multiple (≧ 3) bifluorenyl units, for example the even-odd effect of the number of units in the matching of the sign of the orbitals, were also revealed by DFT calculations.<br>

Accessing new microporous polyspirobifluorenes via a C/Si switch

A C/Si switch provides easy access to polybrominated spirosilabifluorenes with tailorable regioselectivities. Yamamoto coupling leads to fluorescent microporous materials that can act as a sensor for nitroaromatics.

Starphenes and Phenes: Structures and Properties

Acenes have been known for a long time but their larger congeners, starphenes and phenes, have only been recently accessible as processable and characterizable derivatives. In this personalized review, we delineate the synthetic approach developed by our group over the last four years. Nickel-mediated Yamamoto coupling of ortho-dibromoacenes generates cyclotrimers. If performed in a shotgun approach, i.e. with substituted 2,3-dibromotetracene or -pentacene in the presence of ortho-dibromobenzene or ortho-dibromoveratrole, trimeric phenes and tetramers would result. Cyclotrimers formed by a pentacenylene and two phenylenes are formally dibenzo[a,c]hexacenes. A direct way to obtain these species is to employ Stille coupling of a dimethylstannafluorene with 2,3-dibromoacenes. If tetrabromoanthracenes or tetrabromopentacenes are fed into this process, tetrabenzopentacene and tetrabenzoheptacenes are easily accessible. Optical and quantum-chemical characterizations provide insight into the electronic situation and aromaticity of these species.