Experimental evidence for the role of the πCO∗ orbital in electron transfer to gas phase acetic acid CH3CO2H: Effects of molecular orientation

2009 ◽  
Vol 130 (15) ◽  
pp. 151102 ◽  
Author(s):  
Philip R. Brooks
Chemistry ◽  
2021 ◽  
Vol 3 (4) ◽  
pp. 1286-1301
Author(s):  
Amedeo Capobianco ◽  
Alessandro Landi ◽  
Andrea Peluso

The mechanism of aromatic nitration is critically reviewed with particular emphasis on the paradox of the high positional selectivity of substitution in spite of low substrate selectivity. Early quantum chemical computations in the gas phase have suggested that the retention of positional selectivity at encounter-limited rates could be ascribed to the formation of a radical pair via an electron transfer step occurring before the formation of the Wheland intermediate, but calculations which account for the effects of solvent polarization and the presence of counterion do not support that point of view. Here we report a brief survey of the available experimental and theoretical data, adding a few more computations for better clarifying the role of electron transfer for regioselectivity.


1991 ◽  
Vol 10 (4) ◽  
pp. 1089-1094 ◽  
Author(s):  
Steven L. VanOrden ◽  
R. Marshall. Pope ◽  
Steven W. Buckner
Keyword(s):  

2008 ◽  
Vol 130 (44) ◽  
pp. 14584-14596 ◽  
Author(s):  
František Tureček ◽  
Jace W. Jones ◽  
Tyrell Towle ◽  
Subhasis Panja ◽  
Steen Brøndsted Nielsen ◽  
...  

1996 ◽  
Vol 49 (2) ◽  
pp. 403 ◽  
Author(s):  
PD Burrow ◽  
GA Gallup ◽  
II Fabrikant ◽  
KD Jordan

The dissociative attachment (DA) process appears in a surprisingly diverse number of research disciplines. Although gas phase studies have been carried out for approximately 30 years, there are no calculations of the cross sections for this process in molecules larger than diatomics. In this presentation, we review briefly the role of DA in several contexts generally unfamiliar to workers in atomic and molecular physics, and touch on some of the theoretical difficulties. We continue with a discussion of our work, both experimental and theoretical, on compounds containing a single halogen atom and conclude with results showing how the DA process can be used to study intramolecular electron transfer.


Planta Medica ◽  
2009 ◽  
Vol 75 (09) ◽  
Author(s):  
FM de-Faria ◽  
A Luiz-Ferreira ◽  
ACA Almeida ◽  
V Barbastefano ◽  
MA Silva ◽  
...  

2019 ◽  
Author(s):  
Chris Robert Harrison Brown

Attention has long been characterised within prominent models as reflecting a competition between goal-driven and stimulus-driven processes. It remains unclear, however, how involuntary attentional capture by affective stimuli, such as threat-laden content, fits into such models. While such effects were traditionally held to reflect stimulus-driven processes, recent research has increasingly implicated a critical role of goal-driven processes. Here we test an alternative goal-driven account of involuntary attentional capture by threat, using an experimental manipulation of goal-driven attention. To this end we combined the classic ‘contingent capture’ and ‘emotion-induced blink’ (EIB) paradigms in an RSVP task with both positive or threatening target search goals. Across six experiments, positive and threat distractors were presented in peripheral, parafoveal, and central locations. Across all distractor locations, we found that involuntary attentional capture by irrelevant threatening distractors could be induced via the adoption of a search goal for a threatening category; adopting a goal for a positive category conversely led to capture only by positive stimuli. Our findings provide direct experimental evidence for a causal role of voluntary goals in involuntary capture by irrelevant threat stimuli, and hence demonstrate the plausibility of a top-down account of this phenomenon. We discuss the implications of these findings in relation to current cognitive models of attention and clinical disorders.


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