Abstract
Regioselective synthesis using protecting-strategy yields azulene-cellulose conjugates 6-(azulene-2-carboxylate)-2,3-di-O-methyl cellulose AzC-1, 6-(4-azulene-1-yl-benzoate)-2,3-di-O-methyl cellulose AzC-2, and 6-(azulene-1-carboxylate)-2,3-di-O-methyl cellulose AzC-3. The spectral and electrochemical proper properties were investigated and compared with the azulene alkylesters Ib, 2b, and 3b. ...
Abstract
Regioselective synthesis using protecting-strategy yields azulene-cellulose conjugates 6-(azulene-2-carboxylate)-2,3-di-O-methyl cellulose AzC-1, 6-(4-azulene-1-yl-benzoate)-2,3-di-O-methyl cellulose AzC-2, and 6-(azulene-1-carboxylate)-2,3-di-O-methyl cellulose AzC-3. The spectral and electrochemical proper properties were investigated and compared with the azulene alkylesters Ib, 2b, and 3b. The relative fluorescence quantum yield of methyl 2-azulenecarboxylate Ib exceeds that 5% azulene cellulose AzC-1 by an order of magnitude. Cellulose derivative AzC-3 exhibits weak dual emission around 400 nm and 520 nm at room temperature. The circular dichroism (CD) of AzC-1, AzC-2, and AzC-3 are reported. intensity and feature of the CD signals depend on the degree of substitution (DS) as shown by AzC-1. The CD-split signals at 280 nm (3A(1) transition of azulene) are likely to result from interacting azulene groups. A regular (helical) structure of the cellulose backbone is postulated, leading to the (M)-configuration of the spatial Unlike esters 2b and 3b azulene appended celluloses AzC-1 and AzC-2 electropolymerize under potentiodynamic conditions. Chemically modified electrodes are formed. Dotation sates were characterized by UV-Vis-NIR-spectroelectrochemistry. Azulene appended celluloses are suitable for making conducting electrodes with tine materials.
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