{"5767125e082a2e256cf94d3f9c3c7f17huebleriac":{"DOI":"","ISBN":"","ISSN":"0300-9580","URL":"","abstract":"UV-VIS Absorption spectroscopy of the unusually stable and structurally characterized radical cations 1,4-diethyl-1,4-dihydropyrazinium (1.bul.+), 1,4-diethyl-1,4-dihydroquinoxalinium monomer (2.bul.+) and p-p dimer [(2.bul.+)2], 1,4,6,7-tetramethyl-1,4-dihydroquinoxalinium (3.bul.+) and 5,10-diethyl-5,10-dihydrophenazinium (4.bul.+) reveals low-energy p$\\rightarrow$p* transitions with different intensities and partial vibrational structuring.  The spectra of the radical cations and of the corresponding dications (12+-42+) have been analyzed with the help of INDO/S calcns.; the resulting assignments could also be rationalized using HMO theory.  Both higher sym. systems 1.bul.+ and 4.bul.+ exhibit vibrationally split long-wavelength bands.  The addnl. long-wavelength absorption of the p-p dimer (1.bul.+)22 (KD ca. 4 $\\times$ 103) is assigned to a charge transfer transition, similar to that of methylviologen radical dimer. [on SciFinder(R)]","annote":"","author":[{"family":"Hilgers","given":"Frank"},{"family":"Kaim","given":"Wolfgang"},{"family":"Schulz","given":"Andreas"},{"family":"Zalis","given":"Stanislav."}],"citation-label":"Hilgers.1994","collection-editor":[],"collection-title":"","container-author":[],"container-title":"Journal of the Chemical Society, Perkin Transactions 2: Physical Organic Chemistry","documents":[],"edition":"","editor":[],"event-date":{"date-parts":[["1994"]],"literal":"1994"},"event-place":"","id":"5767125e082a2e256cf94d3f9c3c7f17huebleriac","interhash":"c3770b0d4c17884f0f9441d6617c2013","intrahash":"5767125e082a2e256cf94d3f9c3c7f17","issue":"1","issued":{"date-parts":[["1994"]],"literal":"1994"},"keyword":"UV absorption cation cation;transition cation;vibrational dialkyldihydrodiazinium dimerization electronic pi radical stable structure","misc":{"issn":"0300-9580"},"note":"","number":"1","number-of-pages":"3","page":"135--138","page-first":"135","publisher":"","publisher-place":"","status":"","title":"Electronic absorption spectroscopy of some exceptionally stable 1,4-dialkyl-1,4-dihydro-1,4-diazinium radical cations: Assignment of transitions, vibrational structure and effects of p-p dimerization","type":"article-journal","username":"huebleriac","version":"","volume":""},"5767125e082a2e256cf94d3f9c3c7f17b_schwederski":{"DOI":"","ISBN":"","ISSN":"0300-9580","URL":"","abstract":"UV-VIS Absorption spectroscopy of the unusually stable and structurally characterized radical cations 1,4-diethyl-1,4-dihydropyrazinium (1.bul.+), 1,4-diethyl-1,4-dihydroquinoxalinium monomer (2.bul.+) and p-p dimer [(2.bul.+)2], 1,4,6,7-tetramethyl-1,4-dihydroquinoxalinium (3.bul.+) and 5,10-diethyl-5,10-dihydrophenazinium (4.bul.+) reveals low-energy p$\\rightarrow$p* transitions with different intensities and partial vibrational structuring.  The spectra of the radical cations and of the corresponding dications (12+-42+) have been analyzed with the help of INDO/S calcns.; the resulting assignments could also be rationalized using HMO theory.  Both higher sym. systems 1.bul.+ and 4.bul.+ exhibit vibrationally split long-wavelength bands.  The addnl. long-wavelength absorption of the p-p dimer (1.bul.+)22 (KD ca. 4 $\\times$ 103) is assigned to a charge transfer transition, similar to that of methylviologen radical dimer. [on SciFinder(R)]","annote":"","author":[{"family":"Hilgers","given":"Frank"},{"family":"Kaim","given":"Wolfgang"},{"family":"Schulz","given":"Andreas"},{"family":"Zalis","given":"Stanislav."}],"citation-label":"Hilgers.1994","collection-editor":[],"collection-title":"","container-author":[],"container-title":"Journal of the Chemical Society, Perkin Transactions 2: Physical Organic Chemistry","documents":[],"edition":"","editor":[],"event-date":{"date-parts":[["1994"]],"literal":"1994"},"event-place":"","id":"5767125e082a2e256cf94d3f9c3c7f17b_schwederski","interhash":"c3770b0d4c17884f0f9441d6617c2013","intrahash":"5767125e082a2e256cf94d3f9c3c7f17","issue":"1","issued":{"date-parts":[["1994"]],"literal":"1994"},"keyword":"UV absorption cation cation;transition cation;vibrational dialkyldihydrodiazinium dimerization electronic pi radical stable structure","misc":{"issn":"0300-9580"},"note":"","number":"1","number-of-pages":"3","page":"135--138","page-first":"135","publisher":"","publisher-place":"","status":"","title":"Electronic absorption spectroscopy of some exceptionally stable 1,4-dialkyl-1,4-dihydro-1,4-diazinium radical cations: Assignment of transitions, vibrational structure and effects of p-p dimerization","type":"article-journal","username":"b_schwederski","version":"","volume":""}}