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Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,*,Fluorescence or Phosphorescence?,p,p,*transitions are most favorable for fluorescence.,e,is high(100 1000 times greater than n,p,*),k,F,is also high(absorption and spontaneous emission are related).,Fluorescence lifetime is short(10,-7,10,-9,s for,p,p,*vs.10,-5,10,-7,s for n,p,*).,Fluorescence or Phosphorescenc,1,Luminescence is rare in nonaromatic hydrocarbons.,Possible if highly conjugated due to,p,p,*transitions.,Seyhan Ege,Organic Chemistry,D.C.Heath and Company,Lexington,MA,1989.,Nonaromatic Unsaturated Hydrocarbons,Luminescence is rare in nonaro,2,Aromatic Hydrocarbons,Ingle and Crouch,Spectrochemical Analysis,Low lying,p,p,*singlet state,Fluorescent,Phosphorescence is weak because there are no n electrons,Aromatic HydrocarbonsIngle and,3,Heterocyclic Aromatics,Skoog,Hollar,Nieman,Principles of Instrumental Analysis,Saunders College Publishing,Philadelphia,2019.,Aromatics containing carbonyl or heteroatoms are more likely to phosphoresce,n,p,*promotes intersystem crossing.,Fluorescence is often weaker.,Heterocyclic AromaticsSkoog,H,4,Aromatic Substituents,Ingle and Crouch,Spectrochemical Analysis,Electron donating groups usually increase,f,F,.,Electron withdrawing groups usually decrease,f,F,.,Aromatic SubstituentsIngle and,5,Halogen Substituents,Ingle and Crouch,Spectrochemical Analysis,Internal Heavy Atom Effect,Promotes intersystem crossing.,f,F,decreases as MW increases.,f,P,increases as MW increases.,t,P,decreases as MW increases.,Halogen SubstituentsIngle and,6,Increased Conjugation,Ingle and Crouch,Spectrochemical Analysis,f,F,increases as conjugation increases.,f,P,decreases as conjugation increases.,Hypsochromic effect and bathochromic shift.,Increased ConjugationIngle and,7,Rigid Planar Structure,Skoog,Hollar,Nieman,Principles of Instrumental Analysis,Saunders College Publishing,Philadelphia,2019.,Ingle and Crouch,Spectrochemical Analysis,f,F,=1.0,f,F,=0.2,f,F,=0.8,not fluorescent,Rigid Planar StructureSkoog,H,8,Metals,Skoog,Hollar,Nieman,Principles of Instrumental Analysis,Saunders College Publishing,Philadelphia,2019.,Metals other than certain lanthanides and actinides(with f-f transitions)are usually not themselves fluorescent.,A number of organometallic complexes are fluorescent.,MetalsSkoog,Hollar,Nieman,P,9,Fluorescence and Phosphorescence,FluorescencePhosphorescence,Labels/Tags,172925,Dyes,1061256,Which effect is used more regularly?,SciFinder Scholar Citations,wikipedia.org,Fluorescence and Phosphorescen,10,Fluorescence or Phosphorescence Labels?Answer from a Commercial View,invitrogen/,Fluorescence or Phosphorescenc,11,Fluorescence or Phosphorescence Labels?Answer from a Commercial View,invitrogen/,Fluorescence or Phosphorescenc,12,Fluorescence or Phosphorescence?Commercially Available Phosphorescence Labels,Erythrosin derivative Eosin derivative,invitrogen/,Fluorescence or Phosphorescenc,13,Fluorescence or Phosphorescence?,Publications in,Analytical Chemistry,Fluorescence Phosphorescence,1380106,Phosphorescence is rarer than fluorescence=Higher selectivity.,Phosphorescence:Analysis of aromatic compounds in environmental samples.,Fluorescence or Phosphorescenc,14,Solvent Effects,Increased viscosity can increase luminescence intensity.,H-bonding and dipole interactions with the solvent contribute to the Stokes shift.,Ashutosh Sharma and Stephen Schulman,Fluorescence Spectroscopy,John Wiley&Sons,New York,2019.,Solvent EffectsIncreased visco,15,Solvent Polarity,Increasing solvent polarity usually causes a red-shift in fluorescence.,micro.magnet.fsu.edu/primer/techniques/fluorescence/fluorescenceintro.html,Solvent PolarityIncreasing sol,16,Solvent Polarity,Joseph Lakowicz,Principles of Fluorescence Spectroscopy,Kluwer Academic/Plenum Publishers,New York,2019.,Solvent PolarityJoseph Lakowic,17,Temperature,Joseph Lakowicz,Principles of Fluorescence Spectroscopy,Kluwer Academic/Plenum Publishers,New York,2019.,Increasing temperature increases k,s,TemperatureJoseph Lakowicz,Pr,18,Joseph Lakowicz,Principles of Fluorescence Spectroscopy,Kluwer Academic/Plenum Publishers,New York,2019.,Decreasing temperature can induce a blue-shift in fluorescence.,Joseph Lakowicz,Principles of,19,Epi-Fluorescence Microscopy,Light Source-Mercury or xenon lamp(external to reduce thermal effects),Dichroic mirror reflects one range of wavelengths and allows another range to pass.,Barrier filter eliminates all but fluorescent light.,micro.magnet.fsu.edu/primer/techniques/fluorescence/fluorosources.html,Epi-Fluorescence Microscopy Li,20,Fluorescence Microscopy,Need 3 filters:,Exciter Filters,Barrier Filters,Dichromatic Beamsplitters,microscope.fsu.edu/primer/techniques/fluorescence/filters.html,Fluorescence MicroscopyNeed 3,21,Are you getting the concept?,You plan to excite catecholamine with the 406 nm line from,a Hg lamp and measure fluorescence emitted at 470,15,nm.Choose the filter cube you
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