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Computational Study of the Interactions between Antimalarial Chemotherapies with Folate Pathway Receptors and Telomerase Reverse Transcriptase

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Computational Chemistry 2021年第3期9卷 197-214页

作者： Djogang Lucie Karelle Forlemu Neville Emadak Alphonse Njabon Njankwa Eric Issofa Patouossa nenwa justin Physical and Theoretical Chemistry Laboratory Faculty of Science University of Yaounde I Yaounde Cameroon Applied Inorganic Chemistry Laboratory Faculty of Science University of Yaounde I Yaounde Cameroon School of Science & Technology (Chemistry) Georgia Gwinnett College Lawrenceville USA

Malaria is a life-threatening disease responsible for half a million death annually, and with nearly half of the world’s population at risk. The rapid drop in observed cases of malaria in the last two decades has been due to a combination of preventive and therapeutic remedies. However, the absence of a vaccine, new antimalarial chemotherapies and increased parasitic resistance have led to a plateau of infections and renewed research interest in target human and Plasmodium (the malaria parasite) receptors and new drugs. In this study, the impact of mutation on the affinity on antimalarial drugs with the bifunctional enzyme complex, dihydrofolate reductase (DHFR) is explored. In addition, homology modeling is used to build the three-dimensional models of the enzymes Plasmodium telomerase reverse-transcriptase (pf-TERT) and Plasmodium dihydropteroate synthetase (pf-DHPS) to determine their affinity with antimalarial drugs. The interaction energies and stable complexes formed between these enzymes and antimalarial drugs (chloroquine, artemisinin, primaquine, pyrimethamine, sulfadoxine and pentamidine) were modelled using AutoDock vina. Our data indicate that pf-TERT and pf-DHPS form stable complexes with the antimalarial ligands with affinity ranging from 𕒸.0 to 𕒺.9 kcal/mol. The affinity with crystal structures of DHFR receptors was higher ranging from 𕒺.0 to 󔼒.0 kcal/mol. The affinity to DHFR also decreases with the mutation a confirmation of the source of resistance. The highest affinity interaction for all the receptors modeled is observed with Artemisinin a benchma

关键词： Malaria Binding Energy Dihydrofolate Reductase Dihydropteroate

Synthesis and Crystal Structure of the First Example of a Tris-Chelated Co(II) Complex Based on Oxamide Dioxime Ligand

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Crystal Structure Theory and Applications 2015年第2期4卷 9-15页

作者： Gouet Bebga Emmanuel N. Nfor Yves A. Mbiangué Patrick L. Djonwouo justin nenwa Department of Chemistry Higher Teachers Training College University of Yaounde 1 Yaounde Cameroon Department of Chemistry University of Buea Buea Cameroon Department of Chemistry Higher Teachers Training College University of Maroua Maroua Cameroon Department of Inorganic Chemistry Coordination Chemistry Laboratory University of Yaounde 1 Yaounde Cameroon

A new cobalt(II) complex, [Co(H2 oxado)3 ]C2 O4 H2 oxado·2H2 O (H2 oxado = oxamide dioxime), has been synthesized in aqueous solution and characterized by elemental analysis and single crystal X-ray structure determination. The complex crystallizes in the triclinic space group P-1, with the parameters a = 9.46(4), b = 11.84(5), c = 12. 81(5)?Å, α = 104.94(6), β = 99.29(5), γ = 106.73(5), V = 1284(9) Å3, Z = 2. The central cobalt(II) cation is pseudo-octahedrally coordinated by six imino N atoms of the neutral oxamide dioxime ligand. In the solid state, each of the following bricks, namely the cationic complexes, the oxalate dianions as well as the oxamide dioxime crystallization molecules, pile up parallel to the a axis. The bulk structure is consolidated by an extended three-dimensional network of hydrogen bridgings—that link the ionic partners, oxamide dioxime and water molecules to one another—and by coulombic interactions.

关键词： Crystal Structure Cobalt(II) Complex Oxamide Dioxime Oxalate Hydrogen Bridging

A Chiral Three Dimensional Potassium(I)/Strontium(II)/Chromium(III) Oxalato-Bridged Coordination Polymer: Synthesis, Characterization and Thermal Analysis

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Crystal Structure Theory and Applications 2014年第4期3卷 67-75页

作者： justin nenwa Issoufou Kaboré Yves A. Mbiangué Patrick L. Djonwouo Peter T. Ndifon Department of Inorganic Chemistry University of Yaounde 1 Yaounde Cameroon Chemistry Department Higher Teachers’ Training College University of Maroua Maroua Cameroon

A new compound of general formula {[(H2O)2K(μ-H2O)Sr]@[Cr(C2O4)3]}n (1) has been synthesized in water and characterized by elemental and thermal analyses, EDX, IR and UV-Vis spectroscopies and by single crystal X-ray structure determination. Compound 1 crystallizes in the chiral space group Fdd2 of orthorhombic system with a = 14.110 (4) ?, b = 36.074 (11)?, c =11.034 (3)? and Z = 16. Compound 1 is a coordination polymer in which the three-dimensional lattice framework is realized by the interconnectivity between K+ cations, Sr2+ cations, aqua ligands and [Cr(C2O4)3]3– complex anions. The asymmetric unit of 1 consists of one cationic motif formally written [(H2O)2K(μ-H2O)Sr]3+ and one anionic entity, [Cr(C2O4)3]3–. The K+ and Sr2+ ions in the cationic motif are both eight-coordinate while the Cr3+ ions in the anionic complex are six-coordinate in a distorted octahedral geometry. Coulombic interactions between the ionic motifs and the three-dimensional H-bonding involving aqua ligands help to consolidate the bulk structure. Thermogra-vimetric analysis (TGA) shows that compound 1 is stable to heat up to ca. 80℃.

关键词： Tris(Oxalato)Chromate(III) Anion Heterometallic Complex Polymer Chiral Compound Crystal Structure Thermal Stability

Synthesis, Structural Characterization and DFT Studies of Silver(I) Complex Salt of Bis(4,5-dihydro-1<i>H</i>-benzo[g]indazole)

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Crystal Structure Theory and Applications 2017年第2期6卷 11-24页

作者： Tanyi Rogers Fomuta Golngar Djimassingar Jean Ngoune Nana Odette Ngnabeuye Jean Jacques Anguile justin nenwa Department of Chemistry University of Dschang Dschang Cameroon Department of Chemistry Mongo Polytechnique University Institute (IUPM) Mongo Chad Department of Chemistry University of Sciences & Techniques of Masuku Franceville Gabon Department of Inorganic Chemistry University of Yaounde 1 Yaounde Cameroon

A new silver complex salt [Ag(N2C11H10)2]NO3 (where N2C11H10 = 4,5-dihydro-1H-benzo[g]indazole), has been synthesized and characterized by elemental and thermal analyses, IR and 1HNMR spectroscopies, single crystal X-ray structure determination and DFT studies. Its molecular structure comprises of a silver center coordinated to two nitrogen atoms from two 4,5-dihydro-1H-benzo[g]indazole molecule giving rise to a cationic complex entity, [Ag(N2C11H10)2]+ with as counter ion. The bulk structure is consolidated by N–H…O, C–H…π, Ag…π and Ag…O intermolecular interactions, thus generating a pseudo-helical network. The optimized structure, frontier molecular orbitals (HOMO and LUMO) and global reactivity descriptors were investigated by performing DFT calculations.

关键词： Silver Complex Salt 4 5-dihydro-1H-benzo[g]indazole Hydrogen Bonds Thermogravimetric Analysis 1HNMR X-Ray DFT Studies

Synthesis, Characterization and X-Ray Structure of a Ba(II)/Ag(I)/Cr(III)-Oxalate Salt with Water-Filled Nanochannels

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American Journal of Analytical Chemistry 2016年第1期7卷 99-106页

作者： Clémence Eboga Tanke Bridget N. Ndosiri Yves A. Mbiangué Gouet Bebga justin nenwa Inorganic Chemistry Department Faculty of Science University of Yaounde 1 Yaounde Cameroon Chemistry Department Higher Teacher Training College University of Maroua Maroua Cameroon Chemistry Department Higher Teacher Training College University of Yaounde 1 Yaounde Cameroon

A novel mixed barium(II)/silver(I)/chromium(III) oxalate salt, Ba0.5Ag2[Cr(C2O4)3]·5H2O (1), with open architecture has been synthesized in water and characterized by elemental analysis, vibrational and electronic spectra, and single crystal X-ray structure determination. Compound 1 crystallizes in a monoclinic space group C2/c, with unit cell parameters a = 18.179(3), b = 14.743(2), c = 12.278(2)Å, β = 113.821(3), V = 3010.34(90) Å3, Z = 8. The structure is characterized by a network of anionic [Cr(C2O4)3]3- units connected through the O atoms of the oxalates to Ba2+ and Ag+ sites, forming a three-dimensional coordination polymer with one-dimensional isolated nanochannels parallel to the c axis, and encapsulating hydrogen-bonded guest water molecules. The bulk structure is consolidated by O–H···O bridgings within the nanochannels and by coulombic interactions.

关键词： Crystal Structure Chromium(III) Complex Nanochannels Coordination Polymer Guest-Water Molecules

Ni(II) N-(2-Pyridylmethyl)-L-Alanine) Complex: Structural Diversity and Photoluminiscent Studies

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Crystal Structure Theory and Applications 2020年第4期9卷 63-72页

作者： Bridget N. Ndosiri Emmanuel N. Nfor Jérôme Marrot Aminou Mohamadou justin nenwa Department of Inorganic Chemistry Faculty of Science University of Yaoundé I Yaoundé Cameroon Department of Chemistry Faculty of Science University of Buea Buea Cameroon Université de Versailles Saint-Quentin-en-Yvelines Institut Lavoisier UMR 8180 Versailles France Université de Reims Champagne-Ardenne Institut de Chimie Moléculaire de Reims (ICMR) CNRS UMR 7312 UFR des Sciences

A novel chiral Nickel (II) complex of N-(2-pyridylmethyl)-L-alanine (Hpyala) 1 has been prepared and structurally characterized by elemental analysis, FT-IR, UV-visible, TGA and single crystal X-ray diffraction techniques. Complex 1 crystallizes in an orthorhombic P212121 space group. The nickel (II) centre in the complex adopts a distorted octahedral geometry. This compound has been seen to exhibit structural diversity resulting from the number of lattice water molecules. The photoluminescent properties of this compound which have also been investigated, indicates the potential application in luminescence.

关键词： Nickel (II) Complex Chiral Photoluminescent X-Ray Diffraction

Synthesis, Rietveld Refinement and DFT Studies of Bis(4,5-dihydro-1<i>H</i>-benzo[g]indazole)silver(I) Hexafluorophosphate Complex Salt

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Open Journal of Inorganic Chemistry 2017年第4期7卷 102-115页

作者： Tanyi Rogers Fomuta Jean Ngoune Golngar Djimassingar Tayo Alain Djampouo Junior Ma Ntep Tobie Matemb Jean Jacques Anguile justin nenwa Department of Chemistry University of Dschang Dschang Cameroon Department of Chemistry Mongo Polytechnique University Institute (IUPM) Mongo Tchad Department of Chemistry University of Sciences & Techniques of Masuku Franceville Gabon Department of Inorganic Chemistry University of Yaounde 1 Yaounde Cameroon

The new salt bis(4,5-dihydro-1H-benzo[g]indazole)silver(I) hexafluorophosphate, [Ag(N2H10C11)2]PF6, has been synthesized in methanol at ambient temperature and characterized by elemental and thermal analyses, FTIR and 1HNMR spectroscopies, Rietveld refinement from powder diffraction data and DFT studies. The salt crystallizes in the triclinic space group P-1 with the parameters: a = 7.776 ?, b = 8.676 ?, c = 9.226 ?, α = 69.27° β = 89.86°, γ = 74.50°, V = 558.02 ?3, Z = 1. In the structure, the silver center is coordinated to two nitrogen atoms from two 4,5-dihydro-1H-benzo[g]indazole ligands, forming a centrosymmetric complex cation, [Ag(N2H10C11)2]+, with a linear coordination geometry around the silver center. The hexafluorophosphate ion, , acts as counter anion. The crystal packing is governed by N-H···F and C-H···F hydrogen bonds that interconnect the ionic constituents and Ag···F and Ag···π interactions help for the stabilization of the packing. The optimized structure was obtained at B3LYP/LanL2DZ level in the gas phase. The stability and reactivity of the structure were studied using respectively HOMO-LUMO gap and electronic global quantities (ionization potential (I) and electron affinity (A)) as descriptors.

关键词： Silver Complex Salt 4 5-dihydro-1H-benzo[g]indazole 1HNMR Powder Diffraction Rietveld Refinement DFT

Anionic Nanochanneled Silver-Deficient Oxalatochromate(III) Complex with Hydroxonium as Counter Ion: Synthesis, Characterization and Crystal Structure

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Open Journal of Inorganic Chemistry 2017年第3期7卷 75-87页

作者： Clémence T. Eboga Gouet Bebga Yves A. Mbiangué Emmanuel N. Nfor Patrick L. Djonwouo Michel M. Bélombé justin nenwa Inorganic Chemistry Department University of Yaounde Yaounde Cameroon Chemistry Department Higher Teacher Training College University of Yaounde 1 Yaounde Cameroon Chemistry Department Higher Teacher Training College University of Maroua Maroua Cameroon Department of Chemistry University of Buea Buea Cameroon

Reaction of Ba0.50[Ag2Cr(C2O4)3]·5H2O with Ag2SO4 in an aqueous solution of sulfuric acid (pH ≈ 3) yielded the silver(I)/chromium(III) oxalate salt H0.50[Ag2.50Cr(C2O4)3]·5H2O (1). Compound 1 can be best described as an anionic silver-deficient oxalatochromate(III) complex [Ag2.50Cr(C2O4)3]0.5- with nanochannels containing hydrogen-bonded water molecules and protons. Thermal analyses show significant weight losses corresponding to the elimination of water molecules of crystallization followed by the decomposition of the network.

关键词： Silver-Deficient Oxalatochromate(III) Water-Filled Nanochannels Protons Thermal Analysis Crystal Structure

A Novel Mixed Ligand Dinuclear Complex of Cobalt (II): Synthesis, Characterization and Magnetic Studies

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Crystal Structure Theory and Applications 2014年第1期3卷 22-29页

作者： Emmanuel N. Nfor Luke L. Keenan justin nenwa Peter T. Ndifon Romanus N. Njong Christelle N. T. Dzesse Offiong E. Offiong Department of Chemistry University of Bath Bath UK Department of Chemistry University of Buea Buea Cameroon Department of Inorganic Chemistry Coordination Chemistry Laboratory University of Yaounde I Yaoundé Cameroon Department of Pure and Applied Chemistry University of Calabar Calabar Nigeria

A novel dinuclear complex [Co2(atr)3(mal)2(H2O)2]·4H2O(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 [Co2(atr)3(mal)2(H2O)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.

关键词： Dinuclear Complex Cobalt (II) Complex Magnetic Properties Mixed Triazole-Malonate