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Hexaarylbenzene (HAB) derivatives are versatile aromatic systems playing a significant role as chromophores, liquid crystalline materials, molecular receptors, molecular‐scale devices, organic light‐emitting diodes and candidates for organic electronics. Statistical synthesis of simple symmetrical HABs is known via cyclotrimerization or Diels–Alder reactions. By contrast, the synthesis of more complex, asymmetrical systems, and without involvement of statistical steps, remains an unsolved problem. Here we present a generally applicable synthetic strategy to access asymmetrical HAB via an atom‐economical and high‐yielding metal‐free four‐step domino reaction using nitrostyrenes and α,α‐dicyanoolefins as easily available starting materials. Resulting domino product—functionalized triarylbenzene (TAB)—can be used as a key starting compound to furnish asymmetrically substituted hexaarylbenzenes in high overall yield and without involvement of statistical steps. This straightforward domino process represents a distinct approach to create diverse and still unexplored HAB scaffolds, containing six different aromatic rings around central benzene core., A high yielding and scalable metal‐free four‐step linear domino reaction results in functionalized triarylbenzene (TAB) and opens the door for making a broad variety of synthetically challenging hexaarylbenzene (HAB) molecules with six different aryl groups.

The synthesis of hydrogenated carbon nanothreads at tens of GPa from aromatic systems is one of the most brilliant recent findings in high-pressure science. C-nanothreads combine the high tensile strength of diamond with the high flexibility of polymers, and many efforts are currently being undertaken to taylor some useful physicochemical properties by smartly modifying their local structure. We present the synthesis of double core diamond-like nanothreads with the two cores being bound by a conjugated C, polyacetylene-like backbone. The two cores also form a protecting sheath for the backbone. This material exhibits an optical bandgap of 1.74 eV, similar to polyacetyelene; it is then very attractive as a potential organic semiconductor with simultaneous outstanding mechanical properties. The synthesis was achieved by reacting diphenylacetylene in diamond anvil cells, at 25-30 GPa and room temperature, and the materials were characterized by optical spectroscopy, synchrotron X-ray diffraction, and ab initio computer simulations.

We have studied the ion pair structure of [NHC-Au(eta(2)-3-hezyne)] [BF4] (NHC = nitrogen-heterocyclic carbene) by solution NOE NMR spectroscopy and relativistic DFT calculation. The neutral complexes [NHC-AuCl] have been synthesized through an improved, silver-free one-pot synthesis, by reaction (in air and using solvents and substrates without any previous purification) of the appropriate [NHC(H)]Cl, gold precursor, and KHCO3. Ion pairs were generated in situ in NMR tubes. In our previous work, two main ion pair orientations were observed for unsaturated NHC ligands: one with the anion close to the carbene backbone (A, most populated) and another with the anion close to the alkyne (B). Here we focus on the effect of the carbene backbone on the ion pair structure, comparing the unsaturated NHC (1BF(4)) with two different variants: a saturated NHC (2BF(4)) and a polycyclic ligand with an extended aromatic system (3BF(4)). For 2BF(4), the A:B ratio remains almost the same as for 1BF(4), while the ion pair structure of 3BF(4) becomes mainly nonspecific, with a slight preference for the orientation B. Both cases can be explained analyzing the DFT Coulomb potential map, which shows an attractive region on the backbone of 2BF(4) and a flat weak potential around the whole 3BF(4).

Bose Research Institute, Calcutta 700 009 Manuscript received 21 May 1977, accepted 3 October 1977 Mahanimbine and Murrayazoline from Murraya exotica Linn.* (Syn. Murraya paniculata) &nbsp

The resonance enhanced two-photon ionization time-of-flight (R2PI-TOF) excitation spectra of supersonically expanded complexes of isomeric 2,3- butanediols with a suitable chromophore, i.e. R-(+)-1-phenyl-1-propanol, represent powerful means for structurally discriminating the diol moiety and for investigating the nature of the intra- and intermolecular interactions involved in the complexes.