Charge-transfer interaction in triplet quenching of naphthalenes in solution

Ander, S.; Blume, H.; Heinrich, G.; Schulte‐Frohlinde, D.

doi:10.1039/c19680000745

Cited by 7 publications

(6 citation statements)

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“…We have reported the structures of the products of irradiation of naphthalene and indene with acrylonitrile, in alcohol solution. 2 [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] The products of the naphthalene reaction are 1:1 adducts and include the cyclobutanes 1 and 2 (ratio 13:1) together with the substituted 1 2 3 and 4 naphthalenes, 3 and 4. The ratio cyclobutanes: substituted naphthalenes is variable and depends on the alcohol used as solvent.…”

Section: Resultsmentioning

confidence: 99%

Medium effects and quantum yields in the photoaddition of naphthalene and acrylonitrile. Chemical evidence on an exciplex structure

Bowman¹,

Chamberlain²,

Huang³

et al. 1974

J. Am. Chem. Soc.

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The photoaddition of naphthalene and acrylonitrile at 313 nm and in hydroxy lie solvents to afford e«ífo-7-cyano-2,3-benzobicyclo[4.2.0]octa-2,4-diene (1), the mfo-8-isomer, and 1-and 2-naphthylpropionitrile (3 and 4) is investigated. The reactive state is naphthalene Si which is determined by kinetically relating quantum yields and fluorescence quenching dependences on acrylonitrile concentration. The fluorescence quenching is proposed to occur by charge-transfer exciplex formation. Good Stern-Volmer plots are obtained for quenching in acetonitrile and rert-butyl alcohol, and the rate constant for the latter is 14 X 107 M~1 sec-1. Fluorescence of indene and anthracene is also quenched, the rate for indene being diffusion controlled. The dilution plot of reciprocal quantum yield against reciprocal acrylonitrile concentration is linear if 2,3-dimethylbuta-l,3-diene is added to prevent triplet-sensitized decomposition of 1. It is proposed that the exciplex responsible for fluorescence quenching has a polar structure, and the substituted products 3 and 4 arise from protonation of the exciplex. The evidence is that (i) the fraction of substitution increases with medium polarity and (ii) reaction in deuteroxylated solvents gives 3 and 4 labeled in the methyl groups. It is believed that indene reacts similarly and some results for the latter are presented. The exciplex structure is discussed. A correlation exists between the energetics of electron transfer and exciplex behavior for some reactions of naphthalene and benzene derivatives and acrylonitrile. This correlation may be of useful predictive value. have been published.3•5-8(1) For preliminary reports of this work see (a) R. M. Bowman and

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Section: Resultsmentioning

confidence: 99%

Medium effects and quantum yields in the photoaddition of naphthalene and acrylonitrile. Chemical evidence on an exciplex structure

Bowman¹,

Chamberlain²,

Huang³

et al. 1974

J. Am. Chem. Soc.

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“…However, a slightly different scheme for diffusion-controlled reactions has been presented by North.9 It is, as written for fluo-Figure 1. Fluorescence quenching of acridine: (1) triethylamine (IP = 7.50eVlla), (2) trimethylamine (IP = 7.82eVlla), (3) dimethylamine (IP = 8.24 eV),lla (4) benzylamine (IP = 8.64 eVlla), (5) n-butylamine (IP = 8.71 eVUa), ( 6) isopropylamine (IP = 8.72 eVlla), ( 7) methylamine (IP = 8.97 eVlla), ( 8) ammonia (IP = 10.19 eVUa). The least-squares procedure gives the empirical equation, In [kflqfkdmkf)] = 14.9 -2.03IP, with kduf(water) = 7.38 X 1091. mol-1 sec-*, with a correlation coefficient of 0.966. where is the rate constant for the diffusion of As and Q to form the proximity pair (As| Q), fc_q is the rate constant for diffusion of the proximity pair out of the solvent cavity, and kT is the rate constant for the quenching reaction.…”

Section: Sirmentioning

confidence: 99%

New synthesis of aldehydes via vinylsilanes

Stork¹,

Colvin²

1971

J. Am. Chem. Soc.

139

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“…The existence of A~X+ exciplexes is well documented when X is diethylaniline or triethylamine27 and the A+X_ type has been found when X is carbon tetrachloride.28 Simi- lar dependence of the quenching mechanism on the electronic nature of the quencher has been found with naphthalene, 1-methoxynaphthalene, and 1-cyanonaphthalene. 29 In this work, substituents were placed only at the 9 or 9 and 10 positions of A since these have been shown to be the most reactive thermally,30 electrochemically,31 and photochemically. 32 As can be seen from the data in Table II, kq decreases steadily as the Ri and R2 groups on A become more electropositive.…”

Section: Discussionmentioning

confidence: 99%