SINTESIS DAN UJI AKTIVITAS TURUNAN SENYAWA STIRENA DARI VANILIN SEBAGAI SENSOR KOLORIMETRI ANION; SYNTHESIS AND ACTIVITY TEST OF STYRENE DERIVATIVES FROM VANILLIN AS A COLORIMETRIC ANION SENSOR
Utami, Uyun Husna, Bambang Purwono
2015 | Disertasi | FMIPAStyrene derivatives and activity tested as a colorimetric anion sensor based on vanillin have been examined. The compound 1 (ferulic acid) and 2 (2-(4- hydroxy-3-methoxy-benzylidene)malononitrile) have been obtained by the Knoevenagel condensation reaction in 52.51 and 38.60% yield respectively. The compound 3 (3-(4-hydroxy-3-methoxy-phenyl)-2-(1H-tetrazole-5-yl)acrylonitrile) have been obtained by the Knoevenagel condensation and 1,3-dipolar cycloaddition reactions of vanillin in 25.77% yield. Anion sensing characteristic were determined using visual color change inspection and UV-vis spectroscopy. The activity test of anion sensing showed that in general compound 1, 2, and 3 resulted bathochromic shift allowing naked eyes color change on addition of CN-, AcO-, F-, and H2PO4 - in various solvent (DMSO, MeOH, EtOAc). In dipolar aprotic solvent (DMSO), high sensitivity and selectivity for CN- was observed over other anions (F-, Cl-, Br-, I-, AcO-, and H2PO4 -) with significant color and UV-vis spectral changes. This observation indicated that compound 2, compared to compound 1 and 3, showed more enhanced intramolecular charge transfer process due to the presense of dicyanovynil group. The compound 2 displayed an obvious color change from yellow to pink with bathochromic shift at 540 nm upon selectively detection for CN- through the deprotonation of the phenolic -OH. But the presence of 1H-tetrazole in compound 3 more enhanced acidity of -NH so that its sensitivity for CN- (4,8 × 10-5 M) was better than that of compound 2 (1,8 × 10-4 M), which displayed color change from colorless to yellow with bathochromic shift at 430 nm.
Kata Kunci : anion sensors; colorimetric; bathochromic shift; charge transfer
