Fluorometric recognition of both dihydrogen phosphate and iodide by a new flexible anthracene linked benzimidazolium-based receptor

• Kumaresh Ghosh and
• Debasis Kar

Beilstein J. Org. Chem. 2011, 7, 254–264, doi:10.3762/bjoc.7.34

• anthracene and benzimidazolium moieties in 1 is attributed to the formation of hydrogen bonds with I− in the open cavity of 1. The faster decay component (0.28 ns) is assumed to be either due to a very short-lived species or an artifact or for tunneling of extra energy to the bulk by a non-radiative pathway

Anthracene appended pyridinium amide–urea conjugate in selective fluorometric sensing of L-N-acetylvaline salt

• Kumaresh Ghosh,
• Tanmay Sarkar and
• Asoke P. Chattopadhyay

Beilstein J. Org. Chem. 2010, 6, 1211–1218, doi:10.3762/bjoc.6.139

• species or an artifact, or for tunneling of extra energy to the bulk by a non-radiative pathway [29][30]. The emitting species with a life time of 2.59 ns is real. However, in the presence of 1 equiv of L-N-acetylvaline salt, the decay profile followed a tri-exponential fitting that indicated three

Syntheses and properties of thienyl-substituted dithienophenazines

• Annemarie Meyer,
• Eva Sigmund,
• Friedhelm Luppertz,
• Gregor Schnakenburg,
• Immanuel Gadaczek,
• Thomas Bredow,
• Stefan-S. Jester and
• Sigurd Höger

Beilstein J. Org. Chem. 2010, 6, 1180–1187, doi:10.3762/bjoc.6.135

• functional theory at the B3LYP/TZVP level and verify the experimental data. Adsorption of the dithienophenazines on highly ordered pyrolytic graphite (HOPG) was investigated by scanning tunneling microscopy, showing that one of the compounds forms highly organized self-assembled monolayers. Keywords

• : oligothiophenes; phenazines; scanning tunneling microscopy; self-assembled monolayers; TD-DFT calculations; Introduction Thiophene based oligomers and polymers have drawn considerable interest as active materials in various fields of organic electronics such as organic light-emitting diodes (OLEDs), organic thin

• scanning tunneling microscopy (STM). Synthesis The synthesis of 4 is shown in Scheme 1. It is obtained in three steps from commercially available starting materials. The synthesis of 3 has previously been reported by benzoin condensation of the corresponding bithiophene derivative [18]. Alternatively, we

Intramolecular hydroxycarbene C–H-insertion: The curious case of (o-methoxyphenyl)hydroxycarbene

• Dennis Gerbig,
• David Ley,
• Hans Peter Reisenauer and
• Peter R. Schreiner

Beilstein J. Org. Chem. 2010, 6, 1061–1069, doi:10.3762/bjoc.6.121

• trapped in an excess of Ar at 11 K and characterized by infrared spectroscopy. The insertion process kinetically outruns the alternative [1,2]H-tunneling reaction to o-anisaldehyde, a type of reaction observed for other hydroxycarbenes. Traces of the dehydration product, benzo[b]furan, were also detected

• intermediate leading to the tautomeric formyl group. Thermochemical computations at M06-2X/cc-pVDZ in conjunction with a self-consistent solvent reaction field model support this suggested reaction pathway. Keywords: benzofuran; C–H-insertion; hydroxycarbene; singlet carbene; tunneling; Introduction

• surprisingly, several hydroxycarbenes exhibit remarkable [1,2]H-tunneling under cryogenic conditions in solid noble gas matrices, even at temperatures as low as 11 K: Hydroxymethylene (1) [13] and phenylhydroxycarbene (3) [14] yield formaldehyde (2) and benzaldehyde (4), respectively, as a result of facile