Structure and photochromic properties of single crystals of spiropyran salts

Molecular and crystalline structure has been studied for the single crystals of neutral spiropyran (SP) 1,3,3,6′-tetramethyl-spiro[indoline-2,2′-[2H]pyrano[3,2-b]pyridine] (Ia) and its salts, 1,3,3,5′,6′-pentamethyl-spiro[indoline-2,2′-[2H]pyrano[3,2-b]pyridinium] iodide (I) and 5′-hydroxymethyl-1,3...

Full description

Saved in:
Bibliographic Details
Published in:Journal of molecular structure 2005-08, Vol.750 (1-3), p.158-165
Main Authors: Aldoshin, S.M., Nikonova, L.A., Smirnov, V.A., Shilov, G.V., Nagaeva, N.K.
Format: Article
Language:English
Subjects:
Magnetic materials
Photochromism
Solid phase transformations
Spirooxazines
Spiropyrans
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Molecular and crystalline structure has been studied for the single crystals of neutral spiropyran (SP) 1,3,3,6′-tetramethyl-spiro[indoline-2,2′-[2H]pyrano[3,2-b]pyridine] (Ia) and its salts, 1,3,3,5′,6′-pentamethyl-spiro[indoline-2,2′-[2H]pyrano[3,2-b]pyridinium] iodide (I) and 5′-hydroxymethyl-1,3,3,7′,8′-pentamethyl-spiro[indoline-2,2′-[2H]pyrano[3,4-b]pyridinium] iodide (II). The crystalline structure of salts I and II differs from that of the neutral SP being formed by the cationic layers separated by I− ions, thus providing a sufficient volume for spiropyran phototransformations. Photochromism of I and II single crystals has been first studied. The quantum yield of the open form formation is about 0.1, and of bleaching 0.04. Ten-fold reversible photocycling reduces absorption of the colored form by 10–15%. Photochromic properties have been correlated with the single crystals structure.
ISSN:0022-2860
1872-8014
DOI:10.1016/j.molstruc.2005.04.030