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| DC Field | Value | Language |
|---|---|---|
| dc.contributor.author | Tasis, D. A. | en |
| dc.contributor.author | Siskos, M. G. | en |
| dc.contributor.author | Zarkadis, A. K. | en |
| dc.contributor.author | Steenken, S. | en |
| dc.contributor.author | Pistolis, G. | en |
| dc.date.accessioned | 2015-11-24T16:41:25Z | - |
| dc.date.available | 2015-11-24T16:41:25Z | - |
| dc.identifier.issn | 0022-3263 | - |
| dc.identifier.uri | https://olympias.lib.uoi.gr/jspui/handle/123456789/8416 | - |
| dc.rights | Default Licence | - |
| dc.subject | laser flash-photolysis | en |
| dc.subject | nucleophile-assisted cleavage | en |
| dc.subject | silicon bond-cleavage | en |
| dc.subject | radical cations | en |
| dc.subject | methyl-methacrylate | en |
| dc.subject | aqueous-solution | en |
| dc.subject | carbon-carbon | en |
| dc.subject | aromatic-amines | en |
| dc.subject | photochemistry | en |
| dc.subject | fragmentation | en |
| dc.title | Mechanism of the photodissociation of 4-diphenyl( trimethylsilyl)methyl-N,N-dimethylaniline | en |
| heal.type | journalArticle | - |
| heal.type.en | Journal article | en |
| heal.type.el | Άρθρο Περιοδικού | el |
| heal.identifier.primary | Doi 10.1021/Jo000023w | - |
| heal.identifier.secondary | <Go to ISI>://000088261900006 | - |
| heal.identifier.secondary | http://pubs.acs.org/doi/pdfplus/10.1021/jo000023w | - |
| heal.language | en | - |
| heal.access | campus | - |
| heal.recordProvider | Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας | el |
| heal.publicationDate | 2000 | - |
| heal.abstract | On irradiation in hexane (248- and 308-nm laser light) 4-diphenyl(trimethylsilyl)methyl-N,N-dimethylaniline, undergoes photodissociation of the C-Si bond giving 4-N,N-dimethylamino-triphenylmethyl radical, 3(.) (lambda(max) at 343 and 403 nm), in very high quantum yield (Phi = 0.92). The intervention of the triplet state of 2 (lambda(max) at 515 nm) is clearly demonstrated through quenching experiments with 2,3-dimethylbuta-1,3-diene, styrene, and methyl methacrylate using nanosecond laser flash photolysis (LFP). The formation of 3(.) is further demonstrated using EPR spectroscopy. The detection of the S-1 state of 2 was achieved using 266-nm picosecond LFP, and its lifetime was found to be 1400 ps. in agreement with the fluorescence lifetime (tau(f) = 1500 ps, Phi(f) = 0.085). The S-1 state is converted almost exclusively to the T-1 state (Phi T = 0.92). In polar solvents such as MeCN, 2 undergoes (1) photoionization to its radical cation 2(.+), and (2) photodissociation of the C-Si bond, giving radical 3(.) as before in hexane. The formation of 2(.+) occurs through a two-photon process. Radical cation 2(.+) does not fragment further, as would be expected, to 3(.) via a nucleophile(MeCN)assisted C-Si bond cleavage but regenerates the parent compound 2. Obviously, the bulkiness of the triphenylmethyl group prevents interaction of 2(.+) with the solvent (MeCN) and transfer to it of the electrofugal group Me3Si+. The above results of the laser flash photolysis are supported by pulse radiolysis, fluorescence measurements, and product analysis. | en |
| heal.publisher | American Chemical Society | en |
| heal.journalName | Journal of Organic Chemistry | en |
| heal.journalType | peer reviewed | - |
| heal.fullTextAvailability | TRUE | - |
| Appears in Collections: | Άρθρα σε επιστημονικά περιοδικά ( Ανοικτά). ΧΗΜ | |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| Tasis-2000-Mechanism of the pho.pdf | 238.86 kB | Adobe PDF | View/Open Request a copy |
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