Preparation of cellulose derivatives containing carbazole chromophore

Abstract

Cellulose derivatives containing long hydrocarbon side chains and the carbazole chromophore are prepared. N-4Ј-Bromobutylcarbazole is first synthesized from carbazole and 1,4-dibromobutane. Alkylated carbazole is then reacted with cellulose acetate in dimethyl sulfoxide solution to produce cellulose ethers containing the desired chromophore. Polymers containing a mixture of alkyl side chains are also prepared by the subsequent addition of 1-bromododecane to the reaction mixture. Characterization of the resulting cellulose derivatives by FTIR spectroscopy indicates that the deacetylation of cellulose acetate and the subsequent etherification are both complete. In addition, the incorporation of the carbazole chromophore is clearly shown by 1 H-and 13 C-NMR spectroscopy. Polymers of different carbazole content, ranging from 2.9 to 1.1 chromophores per anhydroglucose repeat unit, are obtained by varying the reaction conditions. Substitution is found to be controlled primarily by the quantity of alkylating agent introduced while variation of the reaction time has little effect. This method is used to prepare (dodecyl) y (N-4Ј-carbazolylbutyl) x cellulose, (decyl) y (N-4Ј-carbazolylbutyl) x cellulose, and (butyl) y (N-4Ј-carbazolylbutyl) x cellulose. Cellulose acetate can be replaced by (methyl)cellulose as the starting material to obtain analogous products.

CMR 2005: 9.05: Magnetic labeling and in vivo tracking of embryonic stem cells: efficacy, biological effects, high‐field detection limits and long‐term results

“…The resonance corresponding to C1 is situated at 103 ppm. Resonances characteristic of the carbazole moiety are clearly present between 105 and 145 ppm 21, 24. The chemical shifts at around 140.5, 126.4, 122.6, 120.9, 119.3 and 109.4 ppm correspond to C4′, C9′, C7′, C8′, C6′ and C5′, respectively.…”

“…Resonances corresponding to H1, H3 and H2 of propyl linked to the carbazole moiety should be situated near 4.5 ppm ( t , methylene H), 3.6 ppm ( t , methylene H) and 2.4 ppm ( m , methylene H). Resonances characteristic of the carbazole moiety in the 13 C NMR spectrum are present between 110 and 141 ppm 21, 24. The chemical shifts corresponding to C1, C3 and C2 of propyl linked to the carbazole moiety should be situated near 75.7, 41.3 and 32.6 ppm.…”

“…Peaks corresponding to the carbon atoms located in the cellulose backbone are weaker and more difficult to identify. C1, C2, C3, and C6 are assigned from literature values for cellulose alkyl ethers 21. The resonance corresponding to C1 is situated at 103 ppm.…”

“…Br‐Cz was prepared by modification of a previously reported method for N‐alkylation of carbazole 19, 21. Firstly, 1,3‐dibromopropane (30.2 g, 0.1495 mol) and KOH (8.37 g, 0.1495 mol) were added to 20 mL N , N ‐dimethylformamide (DMF) to obtain a mixture.…”

Preparation of the new derivatives of cellulose and oligomeric species of cellulose containing magneson II chromophore

“…With this procedure, new cellulosic derivatives containing various alkylated groups can be conveniently prepared 18–20. On the other hand, the obtained compounds, like some other natural and biocompatible compounds, have potential applications as the Langmuir–Blodgett films in the different fields and have been appreciated 21–27. The Langmuir–Blodgett films in comparison with the common films have some advantages such as high degree of molecular orientation, precise control of film thickness at the molecular level, control of layer architecture, high optical stability for optical processes, and building up noncentrosymmetric structures for second‐order nonlinear optics 28–30.…”