Ortho effects on the change in electronic absorption spectrum of pyridinium salts of saturated bromohydrocarbon.
The quaterisation process of 1,2-dibromoethane and pyridine is in situ traced by electronic absorption spectrum. Two absorption peaks, induced by mono- and bis-pyridinium salt of 1,2-dibromoethane, appear at 429 nm and 313 nm, respectively. To explain the phenomena, several kinds of alkyl bromides with special structures were selected and compared by experimental measurement and theoretical calculation. The results indicate that for mono-pyridinium salt of 1,2-dibromoethane, the electron donor property of ortho-bromine group increases the electron cloud density of the carbon atom associated with pyridinium cation, which induces red-shift of absorption wavelength.
Song
Jin-Ling
JL
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan South Road 27, Taiyuan 030001, China.
Gong
Li-Ming
LM
Feng
Shou-Ai
SA
Zhao
Jiang-Hong
JH
Zheng
Jian-Feng
JF
Zhu
Zhen-Ping
ZP
D000042:Absorption; D001965:Bromides / Q000737:chemistry; D004583:Electrons; D015946:Ethylene Dibromide / Q000737:chemistry*; D008956:Models, Chemical; D011726:Pyridinium Compounds / Q000737:chemistry*; D015203:Reproducibility of Results; D013057:Spectrum Analysis; D055672:Static Electricity; D013816:Thermodynamics
D001965:Bromides; D011726:Pyridinium Compounds; D015946:Ethylene Dibromide