Synthesis and spectral, antibacterial, molecular studies of biologically active organosilicon(IV) complexes

Abstract

A series of new organosilicon(IV) complexes have general formulae R 3 SiL and RSiLOEt with Schiff bases (R = Me and Ph). The Schiff bases (LH) have been derived from the condensation of (2-hydroxyphenyl)(pyrrolidin-1-yl)methanone with semicarbazide, thiosemicarbazide, and phenylthiosemicarbazide, respectively. The compounds have been characterized by the elemental analysis, molar conductance, and spectral (UV, IR, 1 H, 13 C, and 29 Si NMR) studies. These studies showed that the ligands coordinate with the silicon atom in a tridentate manner through phenolic oxygen, azomethine nitrogen and thiolic sulfur. Further applying experimental spectroscopic techniques, theoretical data calculated using density functional theory by B3LYP/6.31+g(d,p) has also been used for structural determination. The resulting complexes have been proposed to have trigonal bipyramidal and distorted octahedral geometries. Few representative Schiff base and their silicon complexes have been screened for their in vitro antibacterial activity against Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration (MIC) of selected compounds was determined. The screening results show that organosilicon(IV) complexes have better antibacterial activity than the free ligands.

The challenge of separating and determining biologically active electrostatically stabilized silanates using the high‐performance liquid chromatography technique

“…The linearity for the analyzed derivatives ranged from 1.09 to 52.64 µg/L. The lowest LOD of 0.05 µg/L was determined for (9) and the highest one of 0.16 µg/L for (2). The LOQ ranged from 0.17 µg/L for (9) to 0.53 µg/L for (2).…”

“…Many of the known organosilicon compounds are biologically active and are used in medicine [1][2][3]. The first drugs based on silicon compounds were discovered at the beginning of the 19th century and they show antineoplastic properties [4].…”

Synthesis, spectroscopy, and density functional theory of organotin and organosilicon complexes of bioactive ligands containing nitrogen, sulfur donor atoms as antimicrobial agents: in vitro and in silico studies

“…24 The absorption bands associated with -SH around 2600-2550 cm −1 have not been detected in metal complexes, implying that sulphur is covalently bound to the metal atoms. 25 The emergence of new bands at 430 ± 10, 575 ± 05, 526 ± 6 and 440 ± 4 cm −1 may be assigned 26,27 to vSn ← N, vSn-S, vSi ← N and vSi-S), respectively. This confirmed the coordination of the metal ions through the azomethine-N, and thiolic-S atoms.…”

“…These bands are attributed to the asymmetric and symmetric modes of Si-CH 3 /Si-C 6 H 5 groups, respectively. 27…”

Spectral, DFT and Antibacterial Studies of Tin(ii) Complexes of Schiff Bases Derived From Aromatic Aldehyde and Amino Acids

“…The products were re-crystallized from the same solvent and dried in vacuum. Antibacterial Activity: Agar-well diffusion method The antibacterial activity was determined by agar well diffusion method 24 . Pure cultures of the microorganism were dissolved in peptone-water and uniformly seeded on nutrient agar Petri plates having the composition (Peptone 5g, Beaf extract 5g, NaCl 5g, Agar-Agar 20g, and distilled water 1000 ml).…”