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Cobalt and nickel complexes of versatile imidazole- and pyrrole-2-carbaldehyde thiosemicarbazones. Synthesis, characterisation and antimicrobial activity
No full textNi(II), Co(II) and Co(III) complexes of imidazole- and pyrrole-2-carbaldehyde thiosemicarbazone ligands (H2L1 and H2L2, respectively)
have been prepared. The X-ray crystal structures of [Co(L1)(HL1)], [Ni(H2L1)2]Cl2 _ 3.5H2O and [Ni(HL2)2] have been solved. The
Co(III) ion assumes a slightly distorted octahedral coordination geometry, involving both N2S binding domain of diand monoanionic
ligand molecules. Whereas in [Ni(HL2)2] the metal ion is tetracoordinated in a square planar geometry by two pyrrole-2-carbaldehyde
thiosemicarbazone molecules acting as NS-donor, the spatial array of non deprotonated H2L1 ligand molecules in [Ni(H2L1)2]Cl2 _
3.5H2O is equivalent to that found for [Co(L1)(HL1)]. The in vitro antimicrobial properties of the ligands and their complexes were tested
against representative bacterial and fungal strains in broth culture. The compounds H2L2 and [Co(L2)(HL2)(H2L2)] _ 1.5H2O exhibit a
moderate inhibitory effect on the microbial proliferation and only against some Gram positive bacteria
Synthesis, characterization and biological activity of Ni, Cu and Zn complexes of isatin hydrazones
No full textNickel, copper, and zinc complexes of isatin (H2L1) and N-methylisatin 3-picolinoyl hydrazone (HL2), were synthesized and
characterized by means of spectroscopic techniques. H2L1 and a nickel complex [Ni(L2)2] 2C6H14 were also characterized by X-ray
diffractometry. Biological studies, carried out in vitro on human leukemic cell lines TOM 1 and NB4, have shown that both ligands
and some copper and nickel complexes are active in inhibiting cell proliferation. Compounds H2L1, Cu(HL1)2 2H2O,
Zn(HL1)2 2H2O inhibit DNA synthesis and act constantly with time between 0 and 72 h. The cell cycle analysis has highlighted a
reduction in the number of cells in phase S of about 40%. The same compounds present only a precocious action on cell line NB4
and therefore their activity is cell target specific
Isatin 3-semicarbazone and 1-methyl-isatin 3-semicarbazone
No full textThe two title semicarbazones, namely 2,3-dihydro-1H-indole-
2,3-dione 3-semicarbazone, C9H8N4O2, (I), and 1-methyl-2,3-
dihydro-1H-indole-2,3-dione 3-semicarbazone, C10H10N4O2,
(II), show the same con®guration, viz. Z around the imine
C N bond and E around the C(O)ÐNH2 bond, stabilized by
two intramolecular hydrogen bonds. The presence of a methyl
group on the isatin N atom determines the difference in the
packing; in (I), the molecules are linked into chains which lie
in the crystallographic (102) plane and run perpendicular to
the b axis, while in (II), the molecules are arranged to form
helices running parallel to a crystallographic screw axis in the
a direction
Copper complexes of imidazole-2-, pyrrole-2-and indol-3-carbaldehyde thiosemicarbazones: Inhibitory activity against fungi and bacteria
No full textCopper complexes of thiosemicarbazones of imidazole-2-carbaldehyde, pyrrole-2-carbaldehyde and indole-3-carbaldehyde were synthesised and characterised. The antimicrobial properties of the free ligands and their complexes were evaluated against yeasts, moulds and bacteria (Gram-positive and Gram-negative). Some copper chelates exhibited a moderate inhibitory activity, better than that of the corresponding free ligands. In particular, the pyrrole derivative [Cu(HL2)2] proved to be a wide spectrum agent, showing an interesting inhibition of the growth of all Gram-positive bacteria and fungi tested at concentrations of 12–50 microg/mL. In contrast, a selective effect was observed for imidazole and indole chelates against fungi and Gram-positive bacteria, respectively
Antibacterial and antifungal activity of metal(II) complexes of acylhydrazones of 3-isatin and 3-(N-methyl)isatin
No full textComplexes of 2-acetyl-c-butyrolactone and 2-furancarbaldehyde thiosemicarbazones: Antibacterial and antifungal activity
No full textCobalt, nickel, copper and zinc coordination compounds of two thiosemicarbazones with general composition ML2 (L: monodeprotonated ligand corresponding to 2-acetyl-c-butyrolactone thiosemicarbazone, HL1, and 2-furancarbaldehyde thiosemicarbazone, HL2) and also complexes with general composition MCl2(HL2) were synthesized (except [NiCl2(HL2)] and [Co(L2)2]). The interaction of CuCl2 with HL2 gave [CuCl(HL2)], a copper(I) complex. The ligands and metal complexes were characterized by IR, 1H and 13C NMR spectroscopy, and magnetic susceptibility measurements. The crystal structure of [Ni(L2)2]⋅2dmso was determined and a trans-square planar coordination of the two κ2-N,S chelate rings forming polymeric strips through H-bonds with dmso was observed. Actually, in all the reported complexes both ligands behaved as κ2-N,S chelates, except in the case of [Co(L1)2] in which HL1 is tridentate κ3-N,S,O. The antimicrobial properties of all compounds were studied using a wide spectrum of bacterial and fungal strains. The copper complexes of HL2 were the most active against all strains, including dermatophytes and phytopathogenic fungi. Most of the studied compounds, especially [Cu(L1)2], presented good activity against Haemophilus influenzae, a very harmful bacterium to humans
Antimicrobial and mutagenic properties of organotin(IV) complexes with isatin and N-alkylisatin bisthiocarbonohydrazones
No full textA new series of ligands is synthesised starting from thiocarbonohydrazide and isatin (H2itc) or N-alkylisatin (methyl, H2mtc;
butyl, H2btc; pentyl, H2ptc); the X-ray structure of H2mtc is discussed. The bis imine ligands are reacted with diorganotin(IV) compounds,
obtaining monometallic complexes. In order to establish unequivocally their coordination geometry, the X-ray structures of
(C2H5)2Sn(Hmtc)Cl Æ THF (THF, tetrahydrofuran) and (C6H5)Sn(Hptc)Cl2 are determined. In (C2H5)2Sn(Hmtc)Cl Æ THF, the ligand
results monodeprotonated and, essentially, monodentate through the sulphur atom, while in (C6H5)Sn(Hptc)Cl2 the ligand is
still monodeprotonated but SNO tridentate. The organotin(IV) complexes of isatin and N-methylisatin exhibit good antibacterial
activity, better than that of the corresponding N-butyl and N-pentylisatin derivatives. Gram positive bacteria are the most sensitive
microorganisms. No growth inhibition of fungi is detected up to the concentration of 100 lg/ml. H2mtc shows mutagenic activity
with and without metabolic activation, whereas no mutagenicity is found for its organotin complexes and for the other compounds
Corrigendum to “Macroalgae to nanoparticles: Study of Ulva lactuca L. role in biosynthesis of gold and silver nanoparticles and of their cytotoxicity on colon cancer cell lines” [Mater. Sci. Eng. C 97 (2019) 498–509](S0928493118326729)(10.1016/j.msec.2018.12.066)
No full textThe authors regret having to add the ‘e’ letter to Franca Bigi. The authors would like to apologise for any inconvenience caused
Efficient extraction of carrageenans from Chondrus crispus for the green synthesis of gold nanoparticles and formulation of printable hydrogels
Get PDFThe integral utilization of sustainable resources with versatile, efficient and cleaner processes is encouraged. Hydrothermal treatment with subcritical water is a chemical free, tunable and rapid technology providing enhanced yield compared to conventional extraction and was explored for the benign by design extraction and depolymerization of carrageenan from Chondrus crispus. Up to 90% of the seaweed was solubilized operating under nonisothermal regime during heating up to 200 °C and 75.5% crude carrageenan yield was attained at 140 °C. Crude carrageenan could not be precipitated by ethanol from the extracts produced at 180 °C and higher temperatures, but ultrafiltration (100 kDa) of the extract obtained at 160 °C provided comparable recovery yields and similar rheological features to those of the ethanol precipitated product. Operation at 140 °C was preferred based on the higher recovery yield of the biopolymer and the whole extract was suitable for the green synthesis of polycrystalline decahedral quasi-spherical gold nanoparticles with a mean size distribution of 8.4 nm and Z potential value of −40.2 mV. Alternatively, the crude carrageen fraction was used for the formulation of printable biopolymer based gels with suitable mechanical properties, including a relevant gel strength enhancement (about 10-fold) when compared with conventional procedures
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