Metal Complexes of Diisopropylthiourea: Synthesis, Characterization and Antibacterial Studies

Co(II), Cu(II), Zn(II) and Fe(III) complexes of diisopropylthiourea have been synthesized and characterized by elemental analyses, molar conductivity, magnetic susceptibility, FTIR and electronic spectroscopy. The compounds are non-electrolytes in solution and spectroscopic data of the complexes are consistent with 4-coordinate geometry for the metal(II) complexes and six coordinate octahedral for Fe(III) complex. The complexes were screened for their antibacterial activities against six bacteria: Escherichia coli, Pseudomonas auriginosa, Klebsiella pneumoniae, Bacillus cereus, Staphylococcus aureus and Bacillus pumilus. The complexes showed varied antibacterial activities and their minimum inhibitory concentrations (MICs) were determined

Synthesis and Use of [Cd(Detu) 2

Substituted thiourea ligands are of interest because they possess various donor sites for metal ions and their application in separation of metal ions and as antimicrobial agents. The coordination of the sulfur donor atom led to interest in them as precursor for semiconductor nanoparticles. In this study, cadmium(II) complex of diethylthiourea was synthesized and characterized by elemental analysis, FTIR, and X-ray crystallography. Single crystal X-ray structure of the complex showed that the octahedral geometry around the Cd ion consists of two molecules of diethylthiourea acting as monodentate ligands and two chelating acetate ions. The thermal decomposition of the compound showed that it decomposed to give CdS. The compound was thermolysed in hexadecylamine (HDA) to prepare HDA-capped CdS nanoparticles. The absorption spectrum showed blue shifts in its absorption band edges which clearly indicated quantum confinement effect, and the emission spectrum showed characteristic band edge luminescence. The broad diffraction peaks of the XRD pattern showed the materials to be of the nanometric size

Synthesis, characterization and antibacterial screening of 2,4-diaminopyrimidine pyrimethamine and trimethoprim silver complexes

Air stable silver Ag(I) complexes of pyrimethamine and trimethoprim drugs have been synthesized and characterized by elemental analysis, Fourier transform infrared (FTIR) and ultraviolet visible (UV-Vis) spectroscopy, and conductivity measurement. The metal complexes formed a three and four coordinate geometry with the ligands acting as a monodentate molecule bonding to the silver ion in each case through the pyrimidine N (1) nitrogen. The complexes have non-electrolyte behaviour in dimethylformamide (DMF) solution with its low conductivity values. Silver complexes, their free ligands alongside the corresponding silver salts were screened against selected bacterial isolates. All the silver complexes showed enhanced antibacterial activities compared to their free ligands and potential antibacterial agents have been identified.Key words: Pyrimethamine, trimethoprim, silver complexes, antibacterial screening, minimum inhibitory concentration

Synthesis and Characterization of Hexadecylamine Capped ZnS, CdS, and HgS Nanoparticles Using Heteroleptic Single Molecular Precursors

Zn(II), Cd(II), and Hg(II) complexes of tetramethyl thiuram disulfides and 1-ethoxylcarbonyl-1-ethylenecarbonyl-2-dithiolate were synthesized and characterized by elemental analysis, FTIR, and 1H- and 13C-NMR spectroscopy. The complexes were thermolysed in hexadecylamine as single molecule precursors to prepare HDA capped ZnS, CdS, and HgS nanoparticles. The optical and structural properties of the nanoparticles are reported. ZnS nanoparticles existed in the hexagonal phase with particle sizes of 8–15 nm; the CdS nanoparticles in the cubic phase have particle sizes in the range 4–7 nm and the HgS nanoparticles indexed to face-centered cubic phase have an average particle size of 7–12 nm

Cu(II), and Zn(II) complexes of (4E)-4

4-dihydroxyphenyl)ethylidene]amino}ethyl)imino]pentan-2-one have been synthesized and characterized by elemental analyses, molar conductance, electronic and IR spectral studies, and XRD. FTIR confirmed the ligand coordinates the metal ion to form mononuclear complex via the oxygen and nitrogen atoms of the phenolic group and azomethine group, respectively. Tetrahedral geometry is proposed for Co(II) complex and square-planar geometry for Ni(II) and Cu(II) complexes. The antibacterial studies of the compounds were determined and they show that the metal complexes are more active than the free ligands. The antioxidant activity by DPPH and ABTS method was examined and it shows Cu(II); IC 50 = 2.31 ± 1.54 M for DPPH and Co(II); IC 50 = 1.83 ± 1.08 M for ABTS were the most active

ASSESSMENT OF PHYSIOLOGICAL AND ELECTROCHEMICAL EFFECTS OF A REPURPOSED ZINC DITHIOCARBAMATE COMPLEX ON ACINETOBACTER BAUMANNII BIOFILMS

Acinetobacter baumannii is an infectious agent of global proportion and concern, partly due to its proficiency in development of antibiotic resistance phenotypes and biofilm formation. Dithiocarbamates (DTC) have been identified as possible alternatives to the current antimicrobials. We report here the evaluation of several DTC-metal complexes against A. baumannii planktonic cells and biofilms. Among the DTC-metal complexes and DTCs tested, ZnL1 (N-methyl-1-phenyldithiocarbamato-S,S′ Zn(II)), originally designed as an antitumor agent, is effective against biofilm forming A. baumannii. A MIC value of 12.5 µM, comparable to that of Gentamicin (5 µM) was measured for planktonic cells in tryptic soy broth. Spectroscopy, microscopy and biochemical analyses reveal cell membrane degradation and leakage after treatment with ZnL1. Bioelectrochemical analyses show that ZnL1 reduces biofilm formation and decreases extracellular respiration of pre-formed biofilms, as corroborated by microscopic analyses. Due to the affinity of Zn to cells and the metal chelating nature of L1 ligand, we hypothesize ZnL1 could alter metalloprotein functions in the membranes of A. baumannii cells, leading to altered redox balance. Results indicate that the DTC-Zn metal complex is an effective antimicrobial agent against early A. baumannii biofilms under laboratory conditions

Translation and psychometric assessment of the mastectomy module of the BREAST-Q questionnaire for use in Nigeria

Background: The majority of non-metastatic breast cancer patients in sub-Saharan Africa are recommended to have mastectomy. The impact of mastectomy on a predominantly young African patient population requires evaluation. The BREAST-Q is a validated patient-reported outcome measure of quality-of-life following breast surgery that has been translated into 30 languages-none in Africa. This study aimed to translate and assess the psychometric properties of the mastectomy module of the BREAST-Q for use in Nigeria. Methods: The BREAST-Q mastectomy module was translated from English to Yoruba and its psychometric properties assessed using best practice guidelines. Translation was performed in 4 steps: forward translation (x2), back translation, back translation review, and cognitive interviews with post-mastectomy patients. The translated BREAST-Q instrument was administered to post-mastectomy patients (n = 21) alongside the EORTC-QLQ BR23 to evaluate construct validity. Test-retest reliability was evaluated using intraclass correlation coefficients (ICC); surveys were re-administered 4 weeks apart. Results: The translation process identified English phrases not amenable to direct translation, including “emotionally healthy” and descriptions of pain (“nagging,” “throbbing,” “sharp”). Translations were amended to reflect local context and question intent. During cognitive interviews, patients provided suggestions to simplify complex phrases, e.g. “discomfort in your breast area.”. Internal consistency within scales was over 0.70 for psychosocial wellbeing (α = 0.84–0.87), sexual wellbeing (α = 0.98–0.99), physical wellbeing in chest (α = 0.84–0.86), and satisfaction with care (α = 0.89–0.93). ICC for test-retest reliability was moderate (0.46–0.63). Conclusions: The Yoruba version of the BREAST-Q mastectomy module presents a unique opportunity to adequately capture the experiences of Nigerian women post mastectomy. This instrument is being used in a pilot study of Nigerian patients to identify targets for intervention to improve the patient experience and compliance with breast cancer surgery

A High Molar Extinction Coefficient Bisterpyridyl Homoleptic Ru(II) Complex with trans-2-Methyl-2-butenoic Acid Functionality: Potential Dye for Dye-Sensitized Solar Cells

In our continued efforts in the synthesis of ruthenium(II) polypyridine complexes as potential dyes for use in varied applications, such as the dye-sensitized solar cells (DSSCs), this work particularly describes the synthesis, absorption spectrum, redox behavior and luminescence properties of a new homoleptic ruthenium(II) complex bearing a simple trans-2-methyl-2-butenoic acid functionality as the anchoring ligand on terpyridine moiety. The functionalized terpyridine ligand: 4′-(trans-2-methyl-2-butenoic acid)-terpyridyl (L1) was synthesized by aryl bromide substitution on terpyridine in a basic reaction condition under palladium carbide catalysis. In particular, the photophysical and redox properties of the complex formulated as: bis-4′-(trans-2-methyl-2-butenoic acid)-terpyridyl ruthenium(II) bis-hexafluorophosphate [Ru(L1)2(PF6)2] are significantly better compared to those of [Ru(tpy)2]2+ and compare well with those of the best emitters of Ru(II) polypyridine family containing tridentate ligands. Reasons for the improved photophysical and redox properties of the complex may be attributed partly to the presence of a substituted α,β-unsaturated carboxylic acid moiety leading to increase in the length of π-conjugation bond thereby enhancing the MLCT-MC (Metal-to-ligand-charge transfer-metal centred) energy gap, and to the reduced difference between the minima of the excited and ground states potential energy surfaces

Synthesis, Characterization and Thermal Studies of Zn(II), Cd(II) and Hg(II) Complexes of N-Methyl-N-Phenyldithiocarbamate: The Single Crystal Structure of [(C6H5)(CH3)NCS2]4Hg2

Zn(II), Cd(II) and Hg(II) complexes of N-methyl-N-phenyl dithiocarbamate have been synthesized and characterized by elemental analysis and spectral studies (IR, 1H and 13C-NMR). The single crystal X-ray structure of the mercury complex revealed that the complex contains a Hg centre with a distorted tetrahedral coordination sphere in which the dinuclear Hg complex resides on a crystallographic inversion centre and each Hg atom is coordinated to four S atoms from the dithiocarbamate moiety. One dithiocarbamate ligand acts as chelating ligand while the other acts as chelating bridging ligand between two Hg atoms, resulting in a dinuclear eight-member ring. The course of the thermal degradation of the complexes has been investigated using thermogravimetric and differential thermal analyses techniques. Thermogravimetric analysis of the complexes show a single weight loss to give MS (M = Zn, Cd, Hg) indicating that they might be useful as single source precursors for the synthesis of MS nanoparticles and thin films