This is the first review paper focusing on acenaphthylene (AN), an important building block of many organic semiconductors. We summarize the most important literature on -conjugated AN derivatives, both small...
7‐Aminoquinoline (7AQ) and various amino derivatives thereof (‐NHR) have been strategically designed and synthesized to study their excited‐state proton‐transfer (ESPT) properties. Due to the large separation between the proton donor ‐NHR and the acceptor ‐N‐ site, ESPT in 7AQ derivatives, if available, should proceed under protic solvent catalysis. ESPT is found to be influenced by the acidity of ‐NHR and the basicity of the proton‐acceptor ‐N‐ in the quinoline moiety. The latter is varied by the resonance effect at the quinoline ‐N‐ site induced by the ‐NHR substituent. For those 7AQ derivatives undergoing ESPT, increased quinoline basicity results in a faster rate of ESPT, implying that proton donation from methanol to the quinoline moiety may serve as a key step in the process. Our studies also indicate the existence of an equilibrium between cis and trans arrangements of ‐NHR in terms of its hydrogen‐bond (H‐bond) configuration with methanol, whereby only the cis‐H‐bonded form undergoes methanol‐assisted ESPT. With one exception, the interconversion between cis and trans configurations is much faster than the rate of ESPT, yielding amino‐type (normal form) and imine‐type (proton‐transfer tautomer) emissions with distinct relaxation dynamics.
Acrylonitrile–butadiene–styrene (ABS) is a polymer composing of acrylonitrile, butadiene, and styrene. It has been widely used in industry because of its good mechanical and physical properties. The fabrication of ABS fibers, however, has been rarely studied. Here the fabrication of ABS fibers has been reported by an electrospinning technique, in which the sizes and morphologies of the fibers can be controlled by adjusting the electrospinning conditions. The morphologies of the ABS fibers can also be transformed by annealing the fibers on poly (methyl methacrylate) (PMMA) films. After annealing, the ABS fibers gradually transform to ABS particles embedded in the PMMA films by a mechanism similar to the Rayleigh‐instability‐type transformation. To extend the applications of the electrospun ABS fibers, electroless deposition of copper is also conducted, resulting in copper‐coated ABS fibers.
Surface-confined
reactions represent a powerful approach for the
precise synthesis of low-dimensional organic materials. A complete
understanding of the pathways of surface reactions would enable the
rational synthesis of a wide range of molecules and polymers. Here,
we report different reaction pathways of tetrathienylbenzene (T1TB)
and its extended congener tetrakis(dithienyl)benzene (T2TB) on Cu(111),
investigated using scanning tunneling microscopy, X-ray photoelectron
spectroscopy, and density functional theory calculations. Both T1TB
and T2TB undergo desulfurization when deposited on Cu(111) at room
temperature. Deposition of T1TB at 453 K yields pentacene through
desulfurization, hydrogen transfer, and a cascade of intramolecular
cyclization. In contrast, for T2TB the intramolecular cyclization
stops at anthracene and the following intermolecular C–C coupling
produces a conjugated ladder polymer. We show that tandem desulfurization/C–C
coupling provides a versatile approach for growing carbon-based nanostructures
on metal surfaces.
The excited-state solvent-catalysed proton transfer of PyrQs requires a relay of ≧3 methanol molecules, where the N(8) proton-accepting site is the rate-determining step for the intrinsic proton tunnelling kpt.
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