ABSTRAK
Penelitian ini bertujuan untuk mengetahui sintesis, karakterisasi dan aktivitas antibakteri terhadap S.aureus dan E.coli. Kompleks disintesis dengan cara merefluks larutan CoCl2•6H2O dan hidantoin pada perbandingan mol 1:6 dalam pelarut metanol selama tiga jam. Kadar Co dalam kompleks ditentukan dengan SSA (Spektrofotometer Serapan Atom).
Hasil analisis thermal dengan Differential Thermal Analysis (DTA) menunjukkan bahwa satu mol kompleks mengandung empat molekul H2O. Daya hantar listrik larutan kompleks menunjukkan perbandingan muatan kation dan anion dalam kompleks 2:1. Formula kompleks yang diusulkan adalah {[Co(hidantoin)6]Cl2•4H2O}. Kompleks bersifat paramagnetik dengan momen magnet efektif (μeff) sebesar 4,22±0,02 BM. Spektra elektronik menunjukkan satu puncak serapan pada 521 nm dengan transisi elektronik 4T1g(F)→4T1g(P). Analisis spektroskopi IR menunjukkan pergeseran absorpsi gugus fungsi N-H yang mengindikasikan gugus fungsi tersebut terkoordinasi pada atom pusat kobalt. Kompleks {[Co(hidantoin)6]Cl2•4H2O} menunjukkan aktivitas antibakteri lebih besar daripada ion Co2+ dan hidantoin.
Kata kunci: antibakteri, kobalt(II), kompleks, hidantoin, sintesis.
ABSTRACT
The present study aimed is to synthesize, characterize Co2+-hydantoin based complex and investigate its antibacterial activity against S.aureus and E.coli. The complex was synthesized by refluxing the solution of CoCl2•6H2O and hydantoin in mole ratio of 1:6 in methanol for three hours. The cobalt-content of the complex was determined by atomic absorption spectrophotometer. Differential thermal analysis showed that one mole of complex containing four water molecules. Conductivity measurement indicated that the complex was in two to one of ratio cation to anion charge. Thus, the formula of the complex was proposed as {[Co(hydantoin)6]Cl2•4H2O}. The complex was paramagnetic with μeff 4,22±0,02 BM. UV-Vis spectra showed a peak at 521 nm assigning to electronic transition 4T1g (F) → 4T1g (P). IR spectroscopy analysis showed that a shifting of N-H group absorption, indicating this functional group was coordinated to center of cobalt atom. Complex of {[Co(hydantoin)6]Cl2•4H2O} has greater antibacterial activity than Co2+ and hydantoin. Keywords: antibacterial, cobalt(II), complex, hydantoin, synthesis