Fluorescent turn-on chemosensors for detection of aluminum ion and azide

Abstract

Two rhodamine derivatives, L1 and L2, bearing 2-methoxy-1-naphthaldehyde and 5-bromo-3-methoxy salicylaldehyde units were synthesized using microwave-assisted organic synthesis and used for reversible sequential fluorescence detection of aluminum ion (Al3+) and azide (N3−) in aqueous acetonitrile solution.

1 . A compound having the formula: 
       
         
           
           
               
               
           
         
       
     
     
         2 . A compound having the formula: 
       
         
           
           
               
               
           
         
       
     
     
         3 . A method for synthesizing the compound L 1  of  claim 1 , comprising
 mixing a compound having the formula   
       
         
           
           
               
               
           
         
         with 2-methoxy-1-naphthaldehyde and ethanol, 
         stirring a resulting mixture until homogenous, 
         and irradiating the resulting mixture in a microwave reactor. 
       
     
     
         4 . A method for synthesizing the compound L 2  of  claim 1 , comprising
 mixing a compound having the formula   
       
         
           
           
               
               
           
         
         with 5-bromo-3methoxy salicylaldehyde and ethanol, 
         stirring a resulting mixture until homogenous, 
         and irradiating the resulting mixture in a microwave reactor. 
       
     
     
         5 . A method for determining a presence of Al 3+  in a sample, comprising:
 contacting the sample with a colorless solution comprising a compound according to  claim 1  and observing whether the colorless solution turns pink in color, where a change in color of the solution to pink indicates the presence of Al 3+  in the sample. 
 
     
     
         6 . A method for determining a presence of N 3   −  in a sample, comprising:
 contacting the sample with a pink solution comprising a compound according to  claim 2  and observing whether the pink solution turns colorless, where a change in color of the solution from pink to colorless indicates the presence of N 3   −  in the sample. 
 
     
     
         7 . A method according to  claim 5  wherein the colorless solution shows no absorption above 450 nm in UV-vis absorption spectra, and wherein an absorption peak above 525 nm indicates the presence of Al 3+  in the sample. 
     
     
         8 . A method according to  claim 6  wherein the pink solution shows an absorption peak above 525 nm in UV-vis absorption spectra, and wherein no absorption above 450 nm indicates the presence of N 3   −  in the sample.