20334-52-5Relevant academic research and scientific papers
Photochemistry of the Matrix-isolated α,β-Unsaturated Aldehydes Acrolein, Methacrolein and Crotonaldehyde at 4.2 K
Johnstone, Duncan E.,Sodeau, John R.
, p. 409 - 415 (2007/10/02)
The UV photolysis of the α,β-unsaturated aldehydes acrolein, methacrolein and crotonaldehyde in argon matrices at λ > 300 nm has shown a major photochemical deactivation pathway to be conformational isomerism to the thermodynamically less stable s-cis form.This type of isomerization may account for the rapid internal conversion observed in the gas phase.Matrix-isolated crotonaldehyde undergoes further isomerization to ethylketene and enol-crotonaldehyde, as observed in the analogous gas-phase photolysis.In addition, another H-abstraction product was detected (νOH = 3674 cm-1) which is probably derived from the photolysis of s-cis-crotonaldehyde.At shorter excitation wavelenths (λ > 230 nm) acrolein and methacrolein isomerize to methylketene and dimethylketene, respectively.
A Semiempirical (AM1, MNDO, and MINDO/3) Study on the Thermolysis of 1-Alkynyl Ethers. Reaction Analysis by Correlation of Localized Molecular Orbitals
Moyano, Albert,Pericas, Miquel A.,Serratosa, Felix,Valenti, Eduard
, p. 5532 - 5538 (2007/10/02)
The thermolyses of ethoxyethyne (2a), isopropoxyethyne (2b), tert-butoxyethyne (2c), 1-ethoxy-1-propyne (3a), 1-isopropoxy-1-propyne (3b), 1-tert-butoxy-1-propyne (3c), and 1-ethoxy-1-butyne (4) leading to ketenes and olefins have been studied by means of the semiempirical SCF MO methods AM1, MNDO, and MINDO/3 at the RHF level.The reactions have been found in all cases to be concerted and to exhibit a highly synchronous character.The predicted order of reactivity, -CCO-t-Bu > -CCO-i-Pr > -CCOEt, fully coincides with the experimental one, the AM1 calculated activation entha lpies being the closest to the experimentally determined Arrhenius activation energies.Observed deuterium primary and secondary kinetic isotope effects are well reproduced by the calculation.A reaction analysis by correlation of localized molecular orbitals identifies the direction of flow of electron density along the reaction coordinate and suggests that the lack of adaptation of the ?-component of the initial triple bond to the geometrical changes taking place along the reaction path makes an important contribution to the activation energy of the reaction.
Copper(I) Chemical Ionization-Mass Spectroscopic Analysis of Esters and Ketones
Burnier, R. C.,Byrd, G. D.,Freiser, B. S.
, p. 1641 - 1650 (2007/10/02)
The present work lays the foundation for the understanding and evaluation of atomic metal ions as a new class of chemical ionization reagent ions.In particular, a thorough study of the gas phase ion chemistry of Cu(1+), generated by laser ionization from the pure metal, with a series of oxygenated compounds is reported.Definite patterns of reactivity for different classes of oxygenated compounds are observed which, together with an understanding of the reaction mechanisms, provide the basis for predicting the Cu(1+) chemical ionization mass spectra of new compounds with analogous functional groups.The chemistry of Cu(1+) is found to be dramatically different from that of Ti(1+) and Li(1+) reported earlier providing a significant indication of the flexibility and selectivity afforded by atomic metal reagent ions.
