Abstract:The relationship between electronic and geometrical structures in acceptor-substituted cyclopropanes has been investigated by B3LYP DFT calculations and photoelectron (PE) spectroscopy. The spectra of cyclopropanecarbaldehyde (2), cyclopropanecarboxylic acid (3), cyclopropanecarboxylic acid methyl ester (4), nitrocyclopropane (5), isothiocyanatocyclopropane (6), cyanocyclopropane (7), and 1,1-dicyanocyclopropane (8) have been analyzed. The first ionization potential (IP 1 ) of compounds 2 ± 5 was found to be 0.1 ± 0.4 eV higher than that of the analogous isopropyl derivatives indicating-contrary to expectation-that in these compounds the cyclopropyl group acts as a weaker electron donor than an isopropyl group. In the other compounds, IP 1 values are 0.4 ± 1.1 eV lower than in the open-chain congeners. The Walsh orbitals w S and w A of the three-membered ring are substantially stabilized to different extents by interactions with substituent orbitals, and this is reflected in shortened distal and elongated vicinal CÀC bonds. Although the nitro group in compound 5 causes large stabilizations of both w S and w A , their energy difference Dw remains rather small; this is in agreement with a relatively small difference Dr of the CÀC bond lengths. For the investigated monosubstituted cyclopropanes 2 ± 7, the largest effects with respect to Dw and Dr are caused by the formyl group in carboxaldehyde 2. Comparison of the results for nitriles 7 and 8 indicates that the effects of the cyano groups are additive. A linear relationship between Dw and Dr was established by B3LYP DFT calculations on geometrically distorted cyclopropane (1) and from the PE data of 2 ± 8.

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Glycerol is converted to a mixture of butyric and iso-butyric acid via the rhodium or iridium catalysed carbonylation using HI as the co-catalyst. The initial reaction of glycerol with HI results in several intermediates that lead to isopropyl iodide, which upon carbonylation forms butyric and isobutyric acid. At low HI concentration, the intermediate allyl iodide undergoes carbonylation to give vinyl acetic acid and crotonic acid. Higher poly-ols C n H n+2 (OH) n are carbonylated to the corresponding C n+1 mono-carboxylic acids.2

Organic chemistry Z 0200 Axial Coordination to Metalloporphyrins Leading to Multinuclear Assemblies -[127 refs.]. -(BOUAMAIED, I.; COSKUN, T.; STULZ, E.; Struct. Bonding (Berlin, Ger.) 121 (2006) 1-47; Dep. Chem., Univ. Basel, CH-4056 Basel, Switz.; Eng.) -Lindner 28-263