title: Photophysics of 2-(4'-N,N-dimethylaminophenyl)imidazo[4,5-b]pyridine in micelles: selective dual fluorescence in sodium dodecylsulphate and Triton X-100.
abstract: The photophysical behavior of 2-(4'-N,N-dimethylaminophenyl)imidazo[4,5-b]pyridine (DMAPIP-b) has been studied in nonionic triton X-100 (TX-100), cationic cetyltrimethylammonium bromide (CTAB) and anionic sodium dodecylsulfate (SDS) micelles using steady state and time resolved fluorescence techniques. The molecule emits both normal and TICT fluorescence in SDS and TX-100 but emits only normal fluorescence in CTAB. This difference in behavior of the fluorophore is due to varying extent of hydrogen bonding experience by it in different micelles. Of the three possible monocations, only two kinds of monocations, MC1 (formed by protonation of pyridine ring nitrogen) and MC2 (formed by the protonation of imidazole nitrogen) are present in all the micelles (Scheme 1). DFT calculations performed on the monocations reveal that MC1 and MC2 are more stable than MC3, the monocation formed by the protonation of dimethylamino nitrogen.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, India.
authors.forename: Nihar
authors.initials: N
authors.lastname: Dash
authors.forename: G
authors.initials: G
authors.lastname: Krishnamoorthy
mesh_terms: D000042:Absorption; D001665:Binding Sites; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D004579:Electron Transport; D005456:Fluorescent Dyes / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000737:chemistry*; D008823:Micelles; D017830:Octoxynol / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013997:Time Factors
chemical_list: C549150:2-(4'-N,N-dimethylaminophenyl)imidazo(4,5-b)pyridine; D002593:Cetrimonium Compounds; D005456:Fluorescent Dyes; D007093:Imidazoles; D008823:Micelles; D011725:Pyridines; D012967:Sodium Dodecyl Sulfate; D017830:Octoxynol; D000077286:Cetrimonium
references.citation: Chem Rev. 2003 Oct;103(10):3899-4032
references.pmid: 14531716
references.citation: Phys Rev B Condens Matter. 1988 Jan 15;37(2):785-789
references.pmid: 9944570
references.citation: Biochim Biophys Acta. 2002 Jun 13;1563(1-2):35-44
references.pmid: 12007623
references.citation: J Phys Chem B. 2008 Jun 19;112(24):7211-9
references.pmid: 18503274
references.citation: J Phys Chem B. 2008 Mar 13;112(10):2868-73
references.pmid: 18278903
references.citation: J Colloid Interface Sci. 2008 Sep 1;325(1):236-42
references.pmid: 18538335
references.citation: J Phys Chem B. 2007 Nov 15;111(45):12985-92
references.pmid: 17958349
references.citation: Colloids Surf B Biointerfaces. 2008 Oct 1;66(1):103-9
references.pmid: 18621510
references.citation: J Colloid Interface Sci. 1999 May 1;213(1):53-61
references.pmid: 10191006
references.citation: J Phys Chem B. 2008 Mar 27;112(12):3684-92
references.pmid: 18307338
references.citation: J Org Chem. 1999 Sep 3;64(18):6566-6574
references.pmid: 11674658
references.citation: J Phys Chem B. 2008 Jun 19;112(24):7338-44
references.pmid: 18503268