PUMA publications for /tag/dimerizationWed Jun 15 11:26:56 CEST 2022Journal of the Chemical Society, Perkin Transactions 2: Physical Organic Chemistry1135--138Electronic 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 \textgreek{p}-\textgreek{p} dimerization1994UV absorption cation cation;transition cation;vibrational dialkyldihydrodiazinium dimerization electronic pi radical stable structure 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 \textgreek{p}-\textgreek{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 \textgreek{p}$\rightarrow$\textgreek{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 \textgreek{p}-\textgreek{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)]Mon Jul 15 13:41:23 CEST 2019Journal of the Chemical Society, Perkin Transactions 2: Physical Organic Chemistry1135--138Electronic 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 \textgreek{p}-\textgreek{p} dimerization1994UV absorption cation cation;transition cation;vibrational dialkyldihydrodiazinium dimerization electronic pi radical stable structure 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 \textgreek{p}-\textgreek{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 \textgreek{p}$\rightarrow$\textgreek{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 \textgreek{p}-\textgreek{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)]dimerizationCommunity for tag(s) dimerization