Synthesis of pyrazoline derivatives from 2-acetylfuran along with its activity and selectivity assay as copper(II) ion fluorescent chemosensor

Ilham Dwi Rusydi, Prof. Dra. Tutik Dwi Wahyuningsih, M.Si., Ph.D.; Prof. Indriana Kartini, S.Si., M.Si., Ph.D.

2023 | Skripsi | KIMIA

Telah dilakukan sintesis turunan pirazolina beserta uji aktivitasnya sebagai kemosensor fluorosens untuk ion Cu2+. Penelitian ini terdiri dari beberapa tahapan yaitu sintesis turunan kalkon berbasis furan, siklisasi kalkon untuk menghasilkan  pirazolina dan evaluasi selektivitas dan aktivitas pirazolina sebagai kemosensor fluorosens terhadap ion Cu2+.

Sintesis kalkon dilakukan melalui kondensasi Claisen-Schmidt antara 2-asetilfuran dan 3,4,5-trimetoksibenzaldehida menggunakan katalis kalium hidroksida (KOH) dengan metode pengadukan pada suhu kamar. Sintesis pirazolina dilakukan dengan mereaksikan kalkon dan fenilhidrazin dengan basa KOH menggunakan metode sonikasi. Semua hasil sintesis dikarakterisasi menggunakan spektrometer FT-IR dan GC-MS. Uji aktivitas dan selektivitas dilakukan melalui tahapan skrining kation, penentuan LOD, LOQ dan quatum yield serta uji interfensi.

Sintesis kalkon menghasilkan padatan kekuningan dengan rendemen 71,1%, sedangkan pirazolina dihasilkan dengan rendemen sebesar 54,7?rupa padatan kemerahan dengan titik lebur 120 ?.  Pirazolina menunjukkan peningkatan fluoresensi yang unik ketika membentuk kompleks dengan ion Cu2+. Senyawa ini memberikan sistem deteksi turn-on untuk logam Cu2+ dengan nilai LOD dan LOQ sebesar 0,03 µM dan 0,1 µM. Meskipun demikian, nilai kuantum yield-nya relatif rendah yaitu 0,26 dan terdapat interferensi yang signifikan, sehingga senyawa pirazolina ini selektivitasnya terbatas terhadap ion logam Cu2+.

The synthesis of pyrazoline derivative was carried out, and its activity was assessed as a chemofluorosensor for detecting Cu2+ ions. This study involved several stages, i.e., synthesis of furan-based chalcone, the cyclization of chalcone to produce pyrazoline, and the evaluation of selectivity and activity of the pyrazoline compound towards Cu2+ ion as fluorescent chemosensor.  

Chalcone synthesis was carried out through Claisen-Schmidt condensation between 2-acetylfuran and 3,4,5-trimethoxybenzaldehyde with potassium hydroxide (KOH) as a catalyst with a stirring method at room temperature.  The pyrazoline was synthesized using the obtained chalcone and phenylhydrazine with KOH as the catalyst using a sonication method. The products were characterized by utilizing FT-IR and GC-MS. The activity and selectivity assay were conducted involving the screening cation, determination of LOD and LOQ, the quantum yield, and the interferences.

The synthesized chalcone produced a yellowish solid in 71.1% yields, and the pyrazoline was yielded in 54.7% as a reddish solid with a melting point of 120 ?. The pyrazoline demonstrated a unique fluorescence enhancement when complexed with Cu2+ ions. It exhibited a turn-on detection system for Cu2+ metal with LOD and LOQ values of 0.03 µM and 0.1 µM, respectively. However, the quantum yield value was relatively low at 0.26, and some interferences were observed, indicating limited selectivity for Cu2+ metal ions.

Kata Kunci : 2-acetylfuran, chemosensor, fluorescence, pyrazoline, sonication