СOMPLEXES OF Sn(IV) WITH ISONICOTINOYLHYDRAZONES OF AROMATIC ALDEHYDES. SYNTHESIS, CHARACTERIZATION, EFFECT ON THE GROWTH OF Mycobacterium Tuberculosis

Abstract

Сomplexes[SnCl4(R-Ib∙Н)], where R=H (1), 4-Br (2), 4-NO2(3), 2-OCH3(4), 4-OCH3(5), -ОC7H15(6),were synthesized by interaction of SnCl4 with isonicotinoylhydrazones of R-benzoic aldehydes (R-HIb) in acetonitrile and complex [SnCl3(2-OH-Inf∙Н)](9) – by interaction of SnCl4with 2-OH- naphthaldehydeisonicotinoylhydrazone (2-OH-H2Inf). In (1-6) bidentateO(C-O)–N(N=CH)-coordination of the enol form of the ligand is realized and the coordination node {SnCl4ON}– is formed, and in (9) the enol form remains, but the composition of the node changes – {SnCl3O2N}– due to O(C-O)–N(N=CH)–О(Ph-O)- tridentate coordination.The compounds were characterized by the methods of elemental analysis, mass spectrometry, conductometry, thermogravimetry. Their structure was established by comparing the mass- and IR spectra (1-6) and (9) with previously obtained and X-ray structurally characterized complexes [SnCl4(R-Ib∙Н)]∙CH3CN (R=4-N(CH3)2(7)) and [SnCl3(R-Ib∙Н)]∙2CH3CN (R=2-OH(8))with bi- (7) and tridentate coordination (8) of isonicotinoylhydrazones, respectively. It is shown that (1-6) and (9) are complex compounds of the zwitterionic type: the negative charge on the coordination nodes of tin(IV)is delocalized by the oxyazine fragment N=C–O, and the positive charge – by the protonation of the vacant pyridine nitrogen atomof hydrazide fragment. The influence of the composition of the coordination node of complexes (1-9), as well as the nature and position of the substituents (R) in their molecules on the activity against Mycobacteriumtuberculosis was determined. It was found that the effect of complexes with tridentate hydrazones (8) and (9) on the growth of pathogen is lower (MIC = 12.5 and 25 μM/ml, respectively) compared with bidentatehydrazones (MIC (1-7) = 0,8 – 6,25 μM/ml), among which [SnCl4(2-OCH3-Ib∙Н)] (4) stand out (MIC = 0.8 μM/ml).

Keywords

• станум тетрахлорид, SnCl4, ізонікотиноїлгідразони, комплекси Sn(IV), мінімальна інгібуюча концентрація, МІК, Mycobacterium tuberculosis