Ab initio calculations of the current density induced by an external magnetic field in altan-[10,5]coronene 3 (or altan(2)-[10]annulene) indicate the onset of a diatropic current on the outer loop (the "perimeter"), thus in contrast to the intentional design of altan-molecules. Spectral decomposition of the current shows that the failure of the altanisation design can be expected whenever the p...

Enhanced thermodynamic stability is a fundamental characteristic of aromatic molecules, yet most previous studies stabilization energy (ASE) have been limited to small rings with up 18 ?-electrons. Here we demonstrate that ASE can be detected experimentally in ?-conjugated porphyrin nanorings Hückel circuits 76–108 This conclusion supported by analyzing redox potentials calculate the change for...

Atomic clusters often show unique, size-dependent properties and have become a fertile ground for the discovery of novel molecular structures and chemical bonding. Here we report an investigation of the B19 2 cluster, which shows chemical bonding reminiscent of that in [10]annulene (C10H10) and [6]circulene (C24H12). Photoelectron spectroscopy reveals a relatively simple spectrum for B19 , with...

Electron correlation at the Møller‚Plesset second-order level was incorporated into the „-system portion of MM3 calculations for several … † … † … † conformers of 10 annulene, 18 annulene, bicyclo 5.3.1 undecapentaene, and … † bicyclo 4.4.1 undecapentaene. The conformers with ‘‘localized’’ C—C „ bonds Ž . strongly alternating bond lengths were found to be of lower energy than their Ž . counterp...

Dibenzopyracylene (indeno[l ,2,3-cdjfluoranthene) (4) is of theoretical interest due to its electron system, which is regarded as a perturbed [12]annulene [4]. 4 wras only accessible by a multistep synthesis starting from fluoranthene [5]. It was also isolated in traces from the tar formed by pyrolysis of several low molecular compounds [6]. According to the results [3, 7, 8] of the CO eliminat...

Synthesis and electronic properties of a dinuclear (bpy)(2)Ru(II) polypyridyl complex are described in which the bridging ligand consists of two dipyridophenazines fused to a formally antiaromatic dehydro[12]annulene and where the electronic and electrochemical properties of the complex are markedly influenced by the cyclic all-carbon core.

Magnetically induced current densities have been calculated for a series of hydrocarbons consisting of hexadehydro[12]annulene rings alternatingly fused with benzenes. The calculations show that all molecular rings of the studied molecules sustain paramagnetic ring currents. The new class of molecules is therefore coined polycyclic antiaromatic hydrocarbons (PAAH).

A Pt microelectrode modified with nickel(II) polytetramethyldibenzo[b,i]tetraaza[14]annulene was prepared by electropolymerization of nickel(II) tetramethyldibenzo[b,i]tetraaza[14]annulene monomers and applied to determine sulfur dioxide in vitriol plant wastewater. For determination of SO2 with this electrochemically modified Pt microelectrode, the linear range was from 9.6 x 10(-6) to 2.4 x 1...