Free electron transfer mirrors rotational conformers of substituted aromatics: Reaction of benzyltrimethylsilanes with n-butyl chloride parent radical cations
Φόρτωση...
Ημερομηνία
Συγγραφείς
Brede, O.
Hermann, R.
Naumov, S.
Zarkadis, A. K.
Perdikomatis, G. P.
Siskos, M. G.
Τίτλος Εφημερίδας
Περιοδικό ISSN
Τίτλος τόμου
Εκδότης
Royal Society of Chemistry
Περίληψη
Τύπος
Είδος δημοσίευσης σε συνέδριο
Είδος περιοδικού
peer reviewed
Είδος εκπαιδευτικού υλικού
Όνομα συνεδρίου
Όνομα περιοδικού
Physical Chemistry Chemical Physics
Όνομα βιβλίου
Σειρά βιβλίου
Έκδοση βιβλίου
Συμπληρωματικός/δευτερεύων τίτλος
Περιγραφή
The rotation motion of a larger substituent of an aromatic ring is accompanied by the electron density fluctuation of the highest occupied molecular orbitals. For benzyltrimethylsilanes p-R-3-C6H4-(sic)-CR1-R2(SiMe3) [R-3 = H,PhCO; R-1, R-2 = H,H; H,Me; Me,Me; H,Ph; Ph,Ph] the silyl containing substituent rotates on the axis between the aromatic moiety and the benzylic carbon as indicated in the formula. In the course of this rotation a diversity of various conformers is passed. For the sake of simplicity, we reduce this diversity to two (extreme) borderline structures, one with the substituent in plane with the aromatic ring (transient), and one where the substituent is twisted by 90degrees (stable structure). In the very rapid and non-hindered electron transfer from the conformer mixture to n-butyl chloride parent radical cations, the singlet ground state conformers are converted into two kinds of radical cations. The cations tending to the planar type are stable whereas those of the twisted type dissociate immediately into benzyl type radicals (p-R-3-C6H4-(CR1R2)-R-.) and trimethylsilyl cations. The above mentioned product pattern and quantum-chemical calculations on characteristic parameters of the ground state conformers and the product cations, show that the electron transfer occurs completely unhindered after diffusional encounter, i.e. after each approach of the reactants. Therefore the statistics of the rotation conformers mixture is reflected by the pattern and ratio of the product transients such as metastable radical cations and radicals derived from a dissociative radical cation. Up to now this is the only case where a diffusion-controlled electron transfer reaction proceeding in the nanosecond scale is influenced by intramolecular rotation motions within the electron donor.
Περιγραφή
Λέξεις-κλειδιά
density-functional thermochemistry, charge-transfer, exact-exchange, photochemistry, dependence, mechanism, cleavage, dynamics, phenols, silicon
Θεματική κατηγορία
Παραπομπή
Σύνδεσμος
<Go to ISI>://000221886100051
http://pubs.rsc.org/en/content/articlepdf/2004/cp/b402052a
http://pubs.rsc.org/en/content/articlepdf/2004/cp/b402052a
Γλώσσα
en
Εκδίδον τμήμα/τομέας
Όνομα επιβλέποντος
Εξεταστική επιτροπή
Γενική Περιγραφή / Σχόλια
Ίδρυμα και Σχολή/Τμήμα του υποβάλλοντος
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας