Recently, we discovered that the delocalization of nitrogen lone-pair electrons (NLPEs) in five-membered heterocycles created a second σ-aromaticity addition to prototypical π-aromaticity. Such dual-aromatic compounds, such as pentazole anion, were proved have distinct chemistry comparison traditional π-aromatics, benzene, and surprisingly unstable, susceptible electrophilic attack, relatively ...

Emanuelsson, R. 2014. Conjugation in Organic Group 14 Element Compounds. Design, Synthesis and Experimental Evaluation. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1140. 70 pp. Uppsala: Acta Universitatis Upsaliensis. ISBN 978-91-554-8929-8. This thesis focuses on the chemical concept of conjugation, i.e., electron delocalization, and the ...

There are significant twists in the title compound, C(16)H(15)N(3)O(2), as seen in the dihedral angle between the benzene and adjacent but-2-enal group [29.26 (4)°] and between the pyridine ring and amide group [24.79 (6)°]. A twist is also evident around the hydrazine bond [the C-N-N-C torsion angle is -138.25 (13)°]. The conformation about the ethene bond is Z. An intra-molecular N-H⋯O hydrog...

Through-space isotropic NMR shielding values of a perpendicular diatomic hydrogen probe moved in a 0.5 Å grid 2.5 Å above several polycyclic aromatic/antiaromatic ring and aromatic/aromatic hydrocarbons were computed with Gaussian 03 at the GIAO HF/6-31G(d,p) level. Combinations of benzene fused with cyclobutadiene, with the tropylium ion, and with the cyclopentadienyl anion were investigated. ...

7-Dimethyl-amino-2-phenyl-1,2,4-triazolo[1,5-a][1,3,5]triazin-5-amine crystallized with one mol-ecule of methanol to give the title compound, C(12)H(13)N(7)·CH(3)OH. The triazolo[1,5-a][1,3,5]triazine heterocyclic core is essentially planar as are both amino groups that are involved in π-electron delocalization with the triazolo[1,5-a][1,3,5]triazine nucleus. The methyl groups of the dimethyl-a...

The potential use of amphiphilic fullerene derivatives as a bionanomaterial was investigated by cyclic voltammetry (CV), scanning electron microscopy (SEM), and the ferrous ion oxidation-xylenol orange (FOX) method. Despite the disrupted delocalization of the π-electronic system over the C60 sphere, its antioxidant capacity remained high for all twelve derivatives. The compounds expressed up to...

The title mol-ecule, C(12)H(6)Cl(2)N(2), is almost planar (the r.m.s. deviation of C atoms is 0.04 Å). The C-N and C-C distances indicate delocalization of the π-electrons in the aromatic fused-ring system.

The crystal structure of the title compound, 4-hydr-oxy-2-pyridone, C(5)H(5)NO(2), which has been the subject of several determinations using X-rays and neutron diffraction, was first reported by Low & Wilson [Acta Cryst. (1983). C39, 1688-1690]. It has been redetermined, providing a significant increase in the precision of the derived geometric parameters. The asymmetric unit comprises a plana...

We present semi-empirical tight binding calculations on thienylenevinylene oligomers up to the hexadecamer stage (n = 16) and ab initio calculations based on the local density approximation up to n = 8. The results correctly describe the experimental variations of the gap versus size, the optical spectra and the electrochemical redox potentials. We propose a simple model to deduce from the band...