Chemiluminescence spectrum

The bioluminescence spectrum of P. stipticus and the fluorescence and chemiluminescence spectra of PM are shown in Fig. 9.7. The fluorescence emission maximum of PM-2 (525 nm) is very close to the bioluminescence emission maximum (530 nm), but the chemiluminescence emission maximum in the presence of a cationic surfactant CTAB (480 nm) differs significantly. However, upon replacing the CTAB with the zwitter-ionic surfactant SB3-12 (3-dodecyldimethylammonio-propanesulfonate), the chemiluminescence spectrum splits into two peaks, 493 nm and 530 nm, of which the latter peak coincides with the emission maximum of the bioluminescence. When PM-1 is heated at 90°C for 3 hr in water containing 10% methanol, about 50% of PM-1 is converted to a new compound that can be isolated by HPLC the chemiluminescence spectrum of this compound in the presence of SB3-12 (curve 5, Fig. 9.7) is practically identical with the bioluminescence spectrum. 

Fig. 9.13 Absorption spectrum of one of the luciferin precursors of Mycena cit-ricolor in methanol (dash-dot line, A.max 369 nm). The absorption and fluorescence emission spectra of the decylamine-activation product of the same precursor in neutral aqueous solution (solid lines abs. Amax 372 nm and fl. Xmax 460 nm), and in ethanol (broken lines abs. Amax 375 nm and fl. Amax 522 nm). The chemiluminescence spectrum of the same activation product (dotted line, A.max 580 nm). The dotted line (7max 320 nm) is the absorption spectrum of M. citricolor natural luciferin reported by Kuwabara and Wassink (1966).

Gorsuch and Hercules 109> stated that certain discrepancies between the fluorescence spectrum of 3-amino-phthalate dianion and the chemiluminescence spectrum of luminol are partly due to reabsorption of the shorter-wavelength chemiluminescence light by the luminol monoanion. These authors confirmed the results of E. H. White and M. M. Bursey 114> concerning the very essential solvent effect on luminol chemiluminescence the relative intensity of the latter in anhydrous DMSO/t-BuOK/ oxygen was found to be about 30,000 times that in DMSO/28 mole % water/potassium hydroxide/oxygen. 

The chemiluminescence spectrum matches the fluorescence of both thianthrene and 2.5-diphenyl-1.3.4-oxadiazole (430 and 340 nm, respectively). 

A continuous flow system utilising the oxidation of formaldehyde and gallic acid with alkaline hydrogen peroxide to produce a chemiluminescence was studied by Slawinska and Slawinski [ 137]. While the major peak of the chemiluminescence spectrum occurred at 635 nm, the photomultiplier used summed all of the available light between 560 and 850 nm. The intensity of the chemiluminescence was linearly proportional to formaldehyde concentration from 10 7 to 10 2 M, producing a detection limit of 1 xg/l. This method should be sensitive enough for use in seawater. 

Figure 10 Chemiluminescence spectrum of S2 observed in the selective reaction of OCIO with H2S. Note that this is the same excited-state species observed by the FPD. (Reprinted with permission from Ref. 81. Copyright 1982 American Chemical Society.)...

The emitting species was found to be the singlet-excited state of 3-aminophthlate ion in both protic and aprotic solvents. This identification was made based on the equivalence of the chemiluminescence spectrum of luminol and the fluorescence spectrum of 3-AP ion . In different reaction media, slightly different maximum chemiluminescence wavelengths are observed (Table 2). The spectral shift observed when the system changes from aqueous media to DMSO or other aprotic solvents can be ascribed to a quinoidal form of 3-aminophthalate (26) formed in aprotic solvents (Scheme 15). ... 

A more detailed study of the electrochemiluminescence of 9,10-dimethyl-anthracene in dimethylformamide has been carried out by Parker and Short127 who measured the ratio of excimer/molecular fluorescence yields (y°/yp)p in the chemiluminescent spectrum, and (yp/yp)D in the delayed emission spectrum, at different temperatures. The general scheme... 

The chemiluminescence spectrum is therefore the fluorescence spectrum of the dye. Many different colours of cold light can be obtained in chemiluminescent systems according to the nature of fluorescing species. 

Figure 28.15 a, Chemiluminescence spectrum obtained from electrolysis of a DMF solution containing 1 mM fluoranthene and 1 mAf 10-MP. Alternating steps at-1.75 V and +0.88 V vs. SCE were used, b, Chemiluminescence spectrum under the same conditions, but with 1 mM anthracene added. Inset shows anthracene fluorescence spectrum for a 10-5 M DMF solution. Reabsorption reduces the 0,0 intensity in b. [From Ref. 99, adapted with permission.]... 

Visible chemiluminescence has been observed [338] from the BaO product of the reaction Ba + 03 at pressures less than 1 m Torr. The chemiluminescent spectrum is complex and the identity of the BaO excited state is not certain. The possible states are BaO (A 2 or a 3II). Arguments have been presented [330] which suggest that BaO (a 3ri) is the favoured reaction product, but that mixing of the states or collisional relaxation [340] would cause population of the A state. No detailed analysis of the vibration—rotation state populations of BaO has been possible. 

The most prominent feature in the chemiluminescent spectrum from the reaction M + S2C12 is emission from S2(J33S ), although emission is also observed from several electronic states of MCI and possibly... 

Molecular beam experiments perhaps remain most restricted in their ability (or inability) to yield the distributions of product molecules among the various available internal energy states. Where electronically excited species are produced, the low pressure will ensure that no relaxation will occur before emission and the chemiluminescent spectrum then directly reflects the vibrational-rotational distribution produced chemically within the emitting state. Several chemiluminescent reactions have now been studied in beams, but it is not easy to estimate the ratio of the cross sections for production of excited- and ground-state product. Furthermore, collisions leading to these... 

The chemiluminescence spectrum obtained from the reaction of ozone with methyl mercaptan at a pressure of 0.2 torr is shown in Figure 5. Reaction of hydrogen sulfide with dimethylsulfide with ozone give identical spectra consisting of a broad structureless band centered at approximately 370 nm (uncorrected for spectral sensitivity of the detection system). We have recently shown that this emission is identical to the fluorescence spectrum of sulfur dioxide (16). Since ozone oxidizes hydrogen sulfide to sulfur dioxide and water in the gas phase 17, 18), this result is not surprising. 

Figure 14. Chemiluminescence spectra of CaBr following different excitations of the Ca- HBr complex, as indicated by arrows connecting the excitation region on the action spectrum (displayed vertically at the left of the figure) to the corresponding chemiluminescence spectrum (shown horizontally). From top to bottom Pb, Pa the ratios, from simulations, are (A/B)p = 2 and (A/B)p = 1.1, respectively. Next come Db and Da whose ratios are 11 and 5, respectively. Adapted from Ref. [245].

Emission of phosphorescence by 1,2-dioxetanes and a-peroxylactones has also been observed, but is quite rare. Thus, in degassed acetonitrile the 430 nm emission exhibited by the tetramethyl-l,2-dioxetane (7) has been assigned to acetone phosphorescence. Similarly, this acetone phosphorescence has been detected for the dimethyl-a-peroxylactone. ° For the acetyl derivative (19), both the n,TT fluorescence and phosphorescence of 2,3-butanedione have been reported. Thus, if the photoexcited luminescence spectrum of the carbonyl product is known or can be readily measured, the chemiluminescence spectrum can be used as corroborative structure confirmation of the 1,2-dioxetane or a-peroxylactone. 

Figure3. Chemiluminescence spectrum of H202-0CI singlet oxygen reaction. (Reproduced from Ref. 15. Copyright 1981, American Chemical Society.)...

Fig. 1. Chemiluminescence spectrum taken during the reaction of 0.1 mL acetone with a solid mixture of 20 mg Curox and 17 mg Eu(N03)3 at 90 °C.

On treatment with potassium t-butoxide instead of sodium t-butoxide in THF, dioxetane 2 decomposed more rapidly (kCTICL - 0.11 s 1) to emit a flash of light with AmaxCTICL = 539 nm. The chemiluminescence spectrum is illustrated in Fig. 3 together with chemiluminescence spectra for TBAF system and for the other alkaline metal t-butoxide (vide infra). 0 decreased to 4.5 x 10 though it was yet effective 10 times more than that in the TBAF system. Finally, we carried out the decomposition of 2 with lithium t-butoxide in THF. Lithium ion in general coordinates strongly to oxidoaryl anion in an organic solvent because of the smallest ion radius, thus, we did... 

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