Synthesis of a Valen Schiff-base bismuth(III) complex and its thermokinetic studies on the growth metabolism of S. pombe

A Valen Schiff-base ligand [1,5-bis(2-hydroxy-3-methoxybenzylidene)thiocarbonohydrazide] and its bismuth(III) complex were synthesized. The compositions and structures of two compounds were characterized by elemental analysis, spectrometry ( 1 HNMR, MS, FT-IR, and UV-visible), chemical analysis, molar conductivity, and TG–DTA analysis. The results showed that the molecular formula of Schiff base and its bismuth(III) complex was C 17 H 18 O 4 N 4 S (abbreviated as H 2 L, L = C 17 H 16 O 4 N 4 S) and [Bi(C 17 H 16 O 4 N 4 S)Cl·H 2 O] (abbreviated as [Bi(L)Cl·H 2 O]), respectively. Furthermore, the thermokinetic properties of the action of Schiff base and its bismuth(III) complex on the growth metabolism of S. pombe were studied by bio-microcalorimetry at 305.15 K. The growth rate constant ( k ), maximum heat power, generation time, inhibition ratio ( I ) and half inhibition concentration (IC 50 ), and their quantitative relationship with the concentration were calculated, respectively. Experimental results indicated that both Schiff base and its bismuth(III) complex could inhibit the growth of S. pombe , but the inhibitory effect of Schiff base was stronger than that of the complex. The half inhibition concentrations of Schiff base and its bismuth(III) complex were found to be 4.17 × 10 −3 mol L −1 and 6.13 × 10 −3 mol L −1 , respectively.