Peter A. Ajibade

Synthesis of zinc-carboxylate metal-organic frameworks for the removal of emerging drug contaminant (amodiaquine) from aqueous solution

We herein report the removal of amodiaquine, an emerging drug contaminant from aqueous solution using [Zn2(fum)2(bpy)] and [Zn4O(bdc)3] (fum=fumaric acid; bpy=4,4-bipyridine; bdc=benzene-1,4-dicarboxylate) metal-organic frameworks (MOFs) as adsorbents. The adsorbents were characterized by elemental analysis, Fourier transform infrared (FT-IR) spectroscopy, and powder X-ray diffraction (PXRD). Adsorption process for both adsorbents were found to follow the pseudo-first-order kinetics, and the adsorption equilibrium data fitted best into the Freundlich isotherm with the R2 values of 0.973 and 0.993 obtained for [Zn2(fum)2(bpy)] and [Zn4O(bdc)3] respectively. The maximum adsorption capacities foramodiaquine in this study were found to be 0.478 and 47.62mg/g on the [Zn2(fum)2(bpy)] and [Zn4O(bdc)3] MOFs respectively, and were obtained at pH of 4.3 for both adsorbents. FT-IR spectroscopy analysis of the MOFs after the adsorption process showed the presence of the drug. The results of the study showed that the prepared MOFs could be used for the removal of amodiaquine from wastewater.

Tris(dithiocarbamato)iron(III) complexes as precursors for iron sulfide nanocrystals and iron sulfide-hydroxyethyl cellulose composites

ABSTRACT Iron(III) complexes of dimethyldithiocarbamate and imidazolyl dithiocarbamate were synthesized and characterized by elemental analyses, FTIR, UV–VIS and the ligands by NMR spectroscopy. The complexes were thermolysed as single molecule precursors at 180°C to prepare octadecylamine (ODA) capped iron sulfide nanocrystals and iron sulfide-hydroxyethyl cellulose (HEC) composites. UV–VIS, PL, FTIR, P-XRD, HRTEM, FESEM and EDS were used to characterize the iron sulfide nanocrystals and corresponding HEC nanocomposites. XRD confirmed iron sulfide nanocrystal (NP1) from dimethyldithiocarbamate to be hexagonal pyrrhotite-5H, Fe9S10 crystalline phase while iron sulfide nanocrystals (NP2) from imidazolyl dithiocarbamate is in pyrrhotite, Fe11S12 crystalline phase. TEM images show that the iron sulfide nanocrystals have particle sizes in the range 24–32u2009nm for NP1 and 18–25u2009nm for NP2 iron sulfide nanocrystals. The optical band gaps of the iron sulfide nanocrystals obtained from Tauc plots are 3.83 and 4.16u2009eV for NP1 and NP2, respectively. IR spectra, FESEM surface morphology and EDS spectra of iron sulfide/HEC composites confirmed dispersion of the iron sulfide nanocrystals within the hydroxyethyl cellulose (HEC) matrix. GRAPHICAL ABSTRACT

A Simple Route to Ruthenium Sulfide Nanoparticles via Thermal Decomposition of Precursor Complexes

The research work presented here investigate the use of homonuclear tris-dithiocarbamato ruthenium(III) complexes as single-source molecular precursors to ruthenium sulfide nanoparticles. The dithiocarbamate ligands with their respective precursor complexes were characterized by UV-Vis, FTIR, 1H- and 13C-NMR, and in addition TGA was used for precursors. The absorption spectra confirmed the geometry of tris-chelate ruthenium complexes [Ru(S2CNR2)3] to be octahedral and were very stable both in solution and in the solid state. The optical and structural properties of the ruthenium sulfide nanoparticles were examined using FTIR, XRD, EDS, SEM, TEM, UV-Vis and photoluminescence (PL). FTIR studies revealed that Ru2S3 nanoparticles are capped through the interaction of the –NH2 group of hexadecylamine (HDA) adsorbed on the surfaces of nanoparticles with the prominent band observed around 3330 cm-1 due to v(N-H). The XRD confirmed the successful formation of ruthenium sulfide nanoparticles with a cubic crystal structure within the nano-scale range. The optical band gap(Eg) determined from Tauc plot was found in the range (3.44 to 4.18 eV) values.

Synthesis, characterization and anticancer studies of bis-(N-methyl-1-phenyldithiocarbamato) Cu(II), Zn(II) and Pt(II) complexes. Single crystal X-ray structure of the copper complex

Abstract Cu(II), Pt(II), and Zn(II) complexes of N-methyl-1-phenyldithiocarbamate were synthesized and characterized by FTIR, NMR, UV-visible spectroscopy and elemental analysis. The complexes were formulated as [Cu(L)2], [Zn(L)2] and [Pt(L)2] (where Lu2009=u2009N-methyl-1-phenyldithiocarbamate) in which two molecules of the ligands coordinate to the metal ions in a bidentate chelating fashion. This is confirmed by elemental analysis and the presence of strong single bands at 952, 951, and 955u2009cm−1 for Cu(II), Pt(II), and Zn(II) complexes, respectively, in the FTIR spectra. The electronic spectra of Pt(II) and Cu(II) complexes are consistent with four-coordinate square planar geometry. Single crystal X-ray of [Cu(N-mpDTC)2] confirmed square planar structural arrangement (CuS4) in which the ligands are asymmetrically bonded to the Cu(II) ion building a centrosymmetric monomer entity. The S-Cu-S bite angle is 77.95° (3) whereas the intramolecular N–C bond length is 1.318 Å and trans S11-Cu-S1u2009=u2009S21-Cu-S2 is 180°, which are consistent with reported copper thiolates in square planar environment. In vitro antiproliferative activity of the complexes against three human cancer cell lines showed that the zinc complex has better activity compared to Cu and Pt complexes, with IC50 values of 14.28, 22.74 and 20.10u2009μM against TK10, UACC62, and MC7 cell lines, respectively. Graphical Abstract

The Anticancer Activities of Some Nitrogen Donor Ligands Containing bis-Pyrazole, Bipyridine, and Phenanthroline Moiety Using Docking Methods

The anticancer study of nitrogen-chelating ligands can be of tremendous help in choosing ligands for the anticancer metal complexes design especially with ruthenium(II). The inhibitory anticancer activities of some nitrogen-chelating ligands containing bis-pyrazole, bipyridine, and phenanthroline were studied using experimental screening against cancer cell and theoretical docking methods. In vitro anticancer activities showed compound 11 as the most promising inhibitor, and the computational docking further indicates its strong inhibitory activities towards some cancer-related receptors. Among the twenty-one modelled ligands, pyrazole-based compounds 7, 11, and 15 are the most promising inhibitors against the selected receptors followed by 18 and 21 which are derivatives of pyridine and phenanthroline, respectively. The presence of the carboxylic unit in the top five ligands that displayed stronger inhibitory activities against the selected receptors is an indication that the formation of noncovalent interactions such as hydrogen bonding and a strong electron-withdrawing group in these compounds are very important for their receptor interactions. The thermodynamic properties, the polarizabilities, and the LUMO energy of the compounds are in the same patterns as the observed inhibitory activities.