Tetrakis(methylthio)ethylene

Synthesis of some transition metal complexes of novel 1-methylpyrazole-3-aldehyde-4-(2-pyridyl) thiosemicarbazone: Spectroscopic and in vitro biological activity studies

“…This also confirms the IR and spectral data which assumed that the C=S on coordination gains C-S character. Similar structural features are known for other metal complexes of such ligands that have the same coordination sites [70,73]. The other bond lengths and angles also suffer some changes, but not significantly.…”

“…Gram-positive bacteria possess a thick cell wall containing many layers of peptidoglycan and teichoic acids, but in contrast, Gram negative bacteria have a relatively thin cell wall consisting of a few layers of peptidoglycan surrounded by a second lipid membrane containing lipopolysaccharides and lipoproteins. These differences in cell wall structure can produce differences in antibacterial susceptibility and some antibiotics can kill only Gram-positive bacteria and is ineffective against Gram-negative pathogens [66,67]. It is worth noting that the comparison of antimicrobial activity of the compounds against the selected types of bacteria (Figure 1 (Table 4).…”

“…The coordination results in the changes of bond lengths and angles of the thiosemicarbazone moiety, as expected, thus when the bond lengths in the coordinated thiosemicarbazone ligand are compared with those in the free thiosemicarbazone ligand, it is seen that coordination elongates the thiosemicarbazone moiety's C-S bond from 1.664 Å to 1.709-1.787 Å and contracts adjacent N-C(S) bond from 1.420 Å to 1.325-1.347 Å in which is consistent with the C-S acquiring a partial single bond and N-C(S) a partial double bond character. These changes in bond lengths are attributable to stabilization of the iminothiolate form of the thiosemicarbazone ligand upon complexation via loss of the hydrazinic proton [70]. This means that, C-S distances which are in the range of single bond character being some of the largest found for M(II) complexes (typical bond lengths being C(sp 2 )-S 1.706 Å in (MeS)2C=C(SMe)2 and C=S 1.630 Å in naphthylphenylthioketone) [71,72].…”

Characterization and biological activity studies on some transition metal complexes of thiosemicarbazide derived from 2-picolinic acid hydrazide

“…The coordination results in the changes of bond lengths and angles of the thiosemicarbazone moiety, as expected, thus when the bond lengths in the coordinated thiosemicarbazone ligand are compared with those in the free thiosemicarbazone ligand, it is seen that coordination elongates the thiosemicarbazone moiety's C-S bond from 1.660 Å to 1.729-1.811 Å and contracts adjacent N-C(S) bond from 1.426 Å to 1.313-1.361 Å in , which is consistent with the C-S acquiring a partial single bond and N-C(S) a partial double bond character. These changes in bond lengths are attributable to stabilization of the iminothiolate form of the thiosemicarbazone ligand upon complexation via loss of the hydrazinic proton [72]. This means that, C-S distances which are in the range of single bond character being some of the largest found for M(II) complexes (typical bond lengths being C(sp 2 )-S 1.706 Å in (MeS)2C=C(SMe)2 and C=S 1.630 Å in naphthylphenyl thioketone) [73,74].…”

Nickel(II) complexes of novel thiosemicarbazone compounds: Synthesis, characterization, molecular modeling and in vitro antimicrobial activity

“…Gram-positive bacteria possess a thick cell wall containing many layers of peptidoglycan and teichoic acids, but in contrast, Gram negative bacteria have a relatively thin cell wall consisting of a few layers of peptidoglycan surrounded by a second lipid membrane containing lipopolysaccharides and lipoproteins. These differences in cell wall structure can produce differences in antibacterial susceptibility and some antibiotics can kill only Gram-positive bacteria and is ineffective against Gram-negative pathogens [64,65]. It is worth noting that the comparison of antibacterial activity of the compounds against the selected types of bacteria (Figure 1) indicates that TPHP  MTPHP  PTPHP.…”