Papers by Offiong Offiong
![Research paper thumbnail of <b>Synthesis, crystal structure and magnetic properties of [Cu(mal)(abpt)(H<sub>2</sub>O)].3/2H<sub>2</sub>O and [Cu<sub>2</sub>(sq)(abpt) <sub>2</sub>].2H<sub>2</sub>O (mal = malonate, sq = squarate, abpt =4-amino-3,5-di-2-pyridyl-4H-1,2,4 triazole)</b>](https://attachments.academia-assets.com/121615471/thumbnails/1.jpg)
Bulletin of The Chemical Society of Ethiopia, Feb 3, 2011
Two new mixed-ligand complexes of formula [Cu(mal)(abpt)(H2O)].3/2H2O (1) and [Cu2(sq)(abpt)2].2H... more Two new mixed-ligand complexes of formula [Cu(mal)(abpt)(H2O)].3/2H2O (1) and [Cu2(sq)(abpt)2].2H2O (2) [mal = malonate, abpt = 4-amino-3,5-di-2-pyridyl-4H-1,2,4 triazole and sq = squarate], have been prepared and characterized by X-ray crystal structure determination and magnetic studies. Complex 1 crystallizes in the monoclinic system, space group C2/c, with a = 14.0086(2) Å, b = 10.0980(2) Å, c = 25.630(4) Å; β = 97.5900(10) o , and Z = 8. Complex 2 crystallizes in the triclinic system, space group P-1 with a = 7.5696(15) Å, b = 8.4697(17) Å, c = 11.049(2) Å; β = 93.00(3) o , α = 96.98(3), γ = 90.111( ) and Z = 1. Complex 1 consist of a neutral mononuclear [Cu(mal)(abpt)(H2O)] unit and water molecule of crystallization in a distorted square pyramidal coordination sphere, while complex 2 is viewed as being made up of [Cu(sq)(abpt)2] units with the squarato ligand bridging the two copper(II) cations. Variable temperature magnetic behaviour of the complexes reveals the existence of weak antiferromagnetic interaction for complex 1 and weak ferromagnetic intrachain interaction for complex 2.
CCDC 1009079: Experimental Crystal Structure Determination
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Eighty eight (88) water samples were collected from twenty two (22) locations across four periods... more Eighty eight (88) water samples were collected from twenty two (22) locations across four periods to highlight the micro-climatic conditions between January to September 2005 in three Formations intrusive, Asu River group and Eze-Aku. In this study, the relationship between various elements has been studied using correlation analysis, cluster analysis and factor analysis. The data also show that the aquifer in the study area are vulnerable to faecal coliform due to water from runoff that infiltrate into the aquifer from the vodose zone during precipitation in the area. This is evidence that the vulnerability of the study area is control by infiltration and runoff.
European Journal of Chemistry, 2019
A new copper(I) pyrazine-bridged coordination polymer [Cu2(pyz)3(NO3)2]·2DMF] (pyz = pyrazine) (1... more A new copper(I) pyrazine-bridged coordination polymer [Cu2(pyz)3(NO3)2]·2DMF] (pyz = pyrazine) (1) has been synthesized and characterized by FT-IR, TG/DTG, DSC and single crystal X-ray diffraction techniques. The X-ray crystallographic result reveals a two-dimensional network structure containing hexagonal pores. Thermal analysis of compound 1 reveals it is stable to 380 °C, and gas sorption studies showed that it adsorbs 1.04 wt% hydrogen at 1 atm and 77 K. Compound 1 crystallizes in a triclinic system, space group P-1 (no. 2), a = 7.9550(2) Å, b = 7.9810(2) Å, c = 11.0660(3) Å, α = 76.328(1)°, β = 71.115(1)°, γ = 84.577(1)°, V = 645.79(3) Å3, Z = 2, T = 150(2) K, μ(MoKα) = 1.709 mm-1, Dcalc = 1.639 g/cm3, 11111 reflections measured (7° ≤ 2Θ ≤ 54.96°), 2951 unique (Rint = 0.0539) which were used in all calculations. The final R1 was 0.0346 (>2σ(I)) and wR2 was 0.0727 (all data).
Journal of Structural Chemistry, 2012
Two new malonato-bridged copper(II) complexes of the composition [Cu 2 (mal) ) (mal = malonate, a... more Two new malonato-bridged copper(II) complexes of the composition [Cu 2 (mal) ) (mal = malonate, atz = 4-amino-1,2,4-triazole, datz = 3,5-diamino-1,2,4-triazole) are prepared and characterized by X-ray crystal structure determination and magnetic studies. The environment of each copper atom in 1 and 2 has distorted square pyramidal and octahedral geometries. The intrachain copper-copper separation is 6.305 Å and 3.640 Å across the carboxylates and trizolates bridges respectively for complexes 1 and 2. The magnetic properties of 1 and 2 are investigated in the temperature range 2-300 K. The overall antiferromagnetic behavior is observed in both cases. K e y w o r d s: malonate, 1,2,4-triazole, carboxylate, crystal structures, magnetic properties.
Evaluation of water quality pollution indices for heavy metal contamination monitoring. A study case from Akpabuyo-Odukpani area, Lower Cross River Basin (southeastern Nigeria)
GeoJournal, 2002
Información del artículo Evaluation of water quality pollution indices for heavy metal contaminat... more Información del artículo Evaluation of water quality pollution indices for heavy metal contamination monitoring. A study case from Akpabuyo-Odukpani area, Lower Cross River Basin (southeastern Nigeria).
Crystal Structure Theory and Applications, 2014
A novel dinuclear complex [Co 2 (atr) 3 (mal) 2 (H 2 O) 2 ]•4H 2 O(1) (atr = 4-amino-1,2,4-triazo... more A novel dinuclear complex [Co 2 (atr) 3 (mal) 2 (H 2 O) 2 ]•4H 2 O(1) (atr = 4-amino-1,2,4-triazole and mal = malonic acid) containing mixed N-and O-donor atoms has been prepared and structurally characterized. The structure is made up of the symmetrically 1, 2, 4-triazole bridged [Co 2 (atr) 3 (mal) 2 (H 2 O) 2 ] moiety and four lattice water molecules. The single crystal X-ray analysis reveals that the complex has a distorted octahedral structure. Magnetic susceptibility measurements reveals that antiferromagnetic interactions exists between the high spin Co(II) ions within the dinuclear unit.
International Journal of Inorganic Chemistry, 2013
Two new complexes of nickel (II) with 4-amino-3, 5-bis(pyridyl)-1, 2, 4-triazole (abpt) and iron ... more Two new complexes of nickel (II) with 4-amino-3, 5-bis(pyridyl)-1, 2, 4-triazole (abpt) and iron (II) with 2-(3-phenyl-1H-pyrazole-5-yl) pyridine (phpzpy) have been synthesized and characterized by elemental analysis and IR spectroscopy. The crystal structures of the complexes have been determined by single crystal X-ray diffraction techniques. In the nickel and iron complexes, the ligands are coordinated through nitrogen atoms in bidentate manner. The ligands and their respective complexes have been tested for their antifungal activity against Aspergillus niger, Aspergillus flavus, and Candida albicans. From the study, the complexes showed enhanced activities against the tested organisms compared to the ligands.
![Research paper thumbnail of 3.3.2. Synthesis, crystal structure and biological activity of 1-(phthalazin-1(2H)-one)[(Pyridin-2-yl)ethylidene]hydrazone and its cobalt (III) complex](https://attachments.academia-assets.com/83418120/thumbnails/1.jpg)
A new mononuclear complex of cobalt (III) (2) with 1-(phthalazin-1(2H)-one)[(Pyridin-2-yl) ethyli... more A new mononuclear complex of cobalt (III) (2) with 1-(phthalazin-1(2H)-one)[(Pyridin-2-yl) ethylidene] hydrazone ligand ( 1 ) has been synthesized and characterized by elemental analysis, IR and mass spectroscopic techniques. The crystal structures of the free ligand (1) and its complex ( 2 ) have been determined by single crystal X-ray diffraction technique. In complex 2 the hydrazone ligand chelates to the cobalt (III) ion through nitrogen atoms in a tridentate manner, giving an octahedral geometry where the cobalt (II) was oxidized to cobalt (III). The antifungal activity of ligand 1 and its complex 2 was studied against Aspergillus niger , Aspergillus flavus and Candida albicans . The results revealed modest activity of complex 2 against the tested organism with inhibition zones of 14, 15 and 14 mm, compared to the free ligand 1 with the inhibition zones of 12, 11 and 12 mm for A. niger, A. flavus, C. albicans respectively.
CCDC 802201: Experimental Crystal Structure Determination
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Revista CENIC Ciencias …, 2002
A novel Mn(II) complex with thiosemicarbazone derived from 2-acetylpyridine and N(4)-ethylthiosem... more A novel Mn(II) complex with thiosemicarbazone derived from 2-acetylpyridine and N(4)-ethylthiosemicarbazide has been prepared. The single-crystal X-ray analysis of the Mn (II) complex showed a distorted octahedral MnN 4 S 2 environment with the ligand chelating via the nitrogen and sulfur donor atoms in a tridentate manner. The triclinic form of the ligand which has crystallized in a monoclinic system in other works is also described. The basicity of nitrogen atoms of the ligand was tested with its reaction with HNO 3 and the structure of the salt obtained is reported. The result shows that the lone pair of the pyridine nitrogen is more available due to the delocalization of other nitrogen lone pair of electron.
Synthesis, Characterization, and Theoretical Study of Sulfur-Containing Donor− Acceptor DCNQI Derivatives with Photoinduced Intramolecular Electron Transfer
J. Org. …, 1996
Because you do not have JavaScript enabled, the Quick Search functionality is not displayed here.... more Because you do not have JavaScript enabled, the Quick Search functionality is not displayed here. Please enable JavaScript or use the Advanced Search Page. ... In papers with more than one author, the asterisk indicates the name of the author to whom inquiries about the ...
Open Journal of Physical Chemistry
The inhibition performance of 1-hydralazinophthalazine (HPZ) (1), and syn-thesized1-(2-[(5-methyl... more The inhibition performance of 1-hydralazinophthalazine (HPZ) (1), and syn-thesized1-(2-[(5-methylfuran-2-yl)methylene)] hydrazono) phthalazine (MFHPZ) (2), 1-(phthalazin-1(2H)-one) [(pyridin-2-yl) ethylidene] hydrazone (ACPHPZ) (3) and (2-acetylthiophene hydrazono) phthalazine (ACTHPZ) (4) has been investigated for mild steel in 1 M HCl. Compound 4 shows maximum inhibition efficiency of 93% at 5.0 × 10 −3 M concentration. The evaluation of thermodynamics and activation parameters indicated spontaneous adsorption of the inhibitor molecules which takes place through chemisorption. The adsorption of 3 and 2 follows Langmuir adsorption isotherm and Temkin adsorption isotherm for 4 and 1. The inhibitor efficiency was of the order 4 > 3 > 1 > 2. Impedance study for the representative inhibitor compounds 4 and 3 showed that decrease in charge transfer resistance is responsible for effective protection of mild steel surface by the tested inhibitor.
Journal of Advances and Scholarly Researches in Allied Education
The Recent research deals with the analysis of fresh water quality of Indra Gandhi Nahar in Surew... more The Recent research deals with the analysis of fresh water quality of Indra Gandhi Nahar in Surewala Hanumangarh District with regards to physical-chemical factors like water Thermogenesity of water , Hydrogen ion concentration, Electrical conductivity(EC), Turbidity, Dissolved oxygen (DO), Total alkalinity (TA), Total Hardness, Total Dissolved Solid, Chloride and phosphate (PO43-). The physico chemical characteristic of Indra Gandhi Nahar in Surewala villege is found to be highly fluctuated with seasonal variations during the present investigation. Higher level of DO analysed during winter season and that represent reciprocity against Thermogenesity of water, TDS, EC which have higher level in summer. The researches explain that the quality of water is higher than fresh water limits and highly polluted.
![Research paper thumbnail of Solvent-Mediated Synthesis of M(II)-Coordination Polymer Part 1: Crystal Structure of Poly(1,2-di(4-pyridyl)ethylene-k2N,N')-bis(1,4-benzenediacetato-k4O,O′,O′′,O′′')zinc(II)], C22H18ZnN2O4](https://attachments.academia-assets.com/68635552/thumbnails/1.jpg)
Molbank
An interaction of water-methanol solution of sodium1,4-benzenediacetate (bda) and 4,4-bipyridylet... more An interaction of water-methanol solution of sodium1,4-benzenediacetate (bda) and 4,4-bipyridylethelene (bpee) with aqueous solution of Zn(NO 3) 2 •6H 2 O at room temperature yielded colourless crystals of 1 after three weeks in a sealed glass tube. The compound with composition C 22 H 18 ZnN 2 O 4 crystallizes in monoclinic space group P2 1 /c, with the following cell dimensions: a = 10.4566(2), b = 13.3085(2), c = 13.7189(2) Å, β = 101.491(1) •. In the structure of 1, two Zn(II) neighbours are connected by two bda ligands adopting chelating and bidentate-bridging coordination modes to form a dimeric unit (Zn 2 O 8 N 4) with the Zn-Zn distance of 4.0432(6) Å. The carboxyl-bridged dimeric units are extended along the [001] direction by bpee co-ligands and further linked by bda ligand to form a three-dimensional network structure. The IR shows the characteristic bands of the carboxylates at 1611/1507 cm −1 and 1424/1373 cm −1 , respectively, for asymmetric and symmetric stretching −CO 2 − vibrations. The separation ∆[ν asym (CO 2 −) − ν sym (CO 2 −)] values of 187 and 134 cm −1 are indicative of chelating and bidentate bridging coordination modes of the carboxylate to the metal centre.
Di-�-acetato-bis[(2-acetylpyridine thiosemicarbazonato)zinc(II)]
Acta Crystallogr C Cryst Str, 2006
Synthesis and biological activity of platinum group metal complexes of o-vanillin thiosemicarbazones
Il Farmaco, 1996
o-Vanillin-(4-methylthiosemicarbazone), o-Vanillin-(4-phenylthiosemicarbazone) and some of their ... more o-Vanillin-(4-methylthiosemicarbazone), o-Vanillin-(4-phenylthiosemicarbazone) and some of their metal complexes of the platinum group have been synthesized, characterized by chemical and spectral methods and studied for their antibacterial, antifungal and amoebicidal activity in vitro. The platinum group metal chelates exibited significant activity against a wide spectrum of microorganisms at different concentrations. The Pt(II) and Ru(III) chelates derived from o-vanillin-(4-phenylthiosemicarbazone) seem to be the most efficient inhibitors. Evaluation of the antimalarial activity of the compounds in mice infected with Plasmodium berghei indicated that cures were attainable at dose levels of 40-160 mg/kg but with toxic death prevalence at higher dose levels.
Pollution Indices of Trace Metals in Urban Dumpsite Soils within Akwa Ibom State, Nigeria
International Research Journal of Pure and Applied Chemistry, 2015
Journal- Chemical Society of Pakistan
Kinetics of reduction of iron (III) kojic acid complex by ascorbic acid has been carried out usin... more Kinetics of reduction of iron (III) kojic acid complex by ascorbic acid has been carried out using photodiode array spectrophotometer over the ranges: 4.0 ≤ pH ≤ 5.5 and 5.0 ≤ T ≤ 25.0 0 C at ionic strength 0.2 M under pseudo-first order conditions by stopped-flow technique. Rate of the reaction was found to be pH dependent. The redox reaction followed the saturation kinetics. The rate law is deduced as follows:
Synthesis and spectral studies of platinum metal complexes of benzoin thiosemicarbazone
Spectrochimica Acta Part A: Molecular Spectroscopy, 1994
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Papers by Offiong Offiong