Isatin phenylhydrazones: anion enhanced photochromic behaviour

Abstract

The photochemical properties of two basic easily synthesized isatin N(2)-phenylhydrazones were investigated. Contrary to the corresponding isatin N(2)-diphenylhydrazones, only Z-isomers were isolated from the reaction mixtures during the synthesis due to their stabilization by intramolecular hydrogen bonding. Although the presence of the C=N double bond creates conditions for the formation of a simple on-off photoswitch, the low photochemical quantum yield and particularly the low switching amplitude in absorbance hamper their photochromic applications. However, the addition of strongly basic anions to phenylhydrazone solutions leads to isatin NH group deprotonation and creates a new diazene T-type Vis-Vis photochromic system with sufficiently separated absorption maxima. Interestingly, although the thermally stable A-form is also photostable in ambient light, its irradiation with a stronger LED source leads to thermally unstable B-form formation which rapidly isomerizes back to the corresponding A-form. The process is reversible and switching cycles can be repeated in both directions. The important advantages of this two-component organic chromophore-inorganic anion photochromic system are its easy synthesis, easy handling due to its insensitivity to room light, easy further structural modification and reversibility. The corresponding photochemical quantum yield, however, remains relatively low (Φ ∼ 0.001). The theoretically calculated properties are in agreement with the obtained experimental results and support the proposed reaction mechanism.

Isatin-1,8-Naphthalimide Hydrazones: A Study of Their Sensor and ON/OFF Functionality

“…It also appeared in the ultraviolet-visible (UV-Vis) spectra (Table 1). Compared to the isatin N 2 -diaryl hydrazones or arylhydrazones these compounds have a long absorbent band, which is batochromically shifted at least about 30 nm [1,2]. The maximum band position is at 460 nm and depends a little on solvent polarity.…”

“…The photochromic molecules ability “to function” as molecular switches and to communicate with other chromophores create conditions for on Boolean’s logic working photonic gates formation. In our previous works the isatin N 2 -diarylhydrazone [1] or arylhydrazones [2,3] and their deprotonated forms were examined with the aim to use them as organic material for electronics or anion sensors. The UV-Vis spectra of these compounds are similar.…”

Spectral and Conductive Properties of Film Heterostructures Based on Fullerene-Containing Material and 4-Methylphenylhydrazone N-Isoamylisatine

“…The FCM obtained by the low-temperature cracking method [9] was used as an acceptor. The synthesis of the organic precursor was carried out according to the technique presented in previously published works [10,11].…”

Вольт-Амперные Характеристики И Фотоэлектрический Эффект Гетероструктур Фуллерен С-=sub=-60-=/SUB=--4-метилфенилгидразон N-Изоамилизатина

“…Хорошо известные органические соединения на основе изатина и его производных до недавнего времени использовались в основном как лекарственные препараты (в качестве антиоксидантов, антимикробных и противораковых средств) [2][3][4]. Однако в последнее десятилетие производные изатина также привлекают все большее внимание исследователей как доступные фотохромные материалы, эффективно поглощающие и в ряде случаев испускающие электромагнитное излучение в видимом диапазоне [5][6][7]. Легкость химической модификации изатинового ядра позволяет осуществлять " тонкую настройку" желаемых свойств.…”

“…Синтез органического прекурсора осуществляли по следующей методике. N-изоамилизатин в количестве 2.03 g (0.01 mol) (синтезирован по методике, описанной в [5]) растворяли в 50 ml метанола. Затем к раствору добавляли 1.35 g (0.011 mol) 4-метилфенилгидразина.…”