Photoinduced alkaline pH-jump on the nanosecond time scale

被引:20
作者
Abbruzzetti, S
Carcelli, M
Pelagatti, P
Rogolino, D
Viappiani, C
机构
[1] Univ Parma, Dipartimento Fis, I-43100 Parma, Italy
[2] Ist Nazl Fis Mat, I-43100 Parma, Italy
[3] Univ Parma, Dipartimento Chim Gen & Inorgan, I-43100 Parma, Italy
关键词
D O I
10.1016/S0009-2614(01)00807-7
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The triphenylmethane leucohydroxide salt 4-(dimethylamino)-4 '-(trimethylammonium) triphenylmethanol iodide has been used as a photoactivatable caged hydroxide to rapidly increase the pH of a neutral aqueous solution on the nanosecond time scale. Photoexcitation of the compound with a nanosecond ultraviolet laser pulse results in the formation of a colored carbocation with a rate greater than 10(8) s(-1); recombination occurs with a multiexponential kinetics. The dissociation is completely reversible on time scales of 10(2) s and offers a large time window after the pH-jump, in which the proton transfer reactions can be studied. The effectiveness of the photodissociation process to increase the pH of the solution has been demonstrated by means of the pH indicator bromoxylenol blue. (C) 2001 Elsevier Science B.V. All rights reserved.
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页码:387 / 394
页数:8
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