Justin Nenwa

Université de Yaoundé I

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Michel M. Bélombé

Université de Yaoundé I

Boniface P. T. Fokwa

University of California, Riverside

Bridget N. Ndosiri

Université de Yaoundé I

Gouet Bebga

Université de Yaoundé I

Michel Foulon

Université de Lille

Ledoux S. Pouamo

Université de Yaoundé I

Jean Ngouné

Université de Dschang

Frédéric Capet

École Nationale Supérieure de Chimie de Lille

Emmanuel N. Nfor

Management Sciences for Health

Patrick L. Djonwouo

Université de Yaoundé I

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Université de Yaoundé I

Centre National de la Recherche Scientifique

University of Buea

Université de Lille

Leipzig University

University of California, Riverside

RWTH Aachen University

Institute of Inorganic Chemistry of the Slovak Academy of Sciences

Unité de catalyse et de chimie du solide de Lille

Université de Dschang

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Synthesis, crystal structure and thermal stability of the novel coordination polymer of general formula: {[(H₂O)Ba(μ-H₂O)Ba(OH₂)₄]@[(C₂O₄)₂Al(μ-OH)₂Al(C₂O₄)₂].H₂O}n^§

Michel M. Bélombé Justin Nenwa N.A.S.N. Tchuisse Franziska Emmerling S. Obbade

Thermal Stability

Coordination polymer

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CCDC 2025577: Experimental Crystal Structure Determination

The Cambridge Structural Database (2020)

Coustel M. N. Choubeu Bridget N. Ndosiri Hervé Vezin Claire Minaud James B. Orton

10.5517/ccdc.csd.cc25zs65

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Crystal structure of catena- bis[aqua-μ-(2S,3S)-tartratocobalt(II)]trihydrate,[Co(H2O)(C4H4O6)]2·3H2O, a new polymorph

Zeitschrift für Kristallographie - New Crystal Structures (2009)

Michel M. Bélombé Justin Nenwa Boniface P. T. Fokwa Richard Dronskowski

Article Crystal structure of catena- bis[aqua-μ-(2S,3S)-tartratocobalt(II)]trihydrate,[Co(H2O)(C4H4O6)]2·3H2O, a new polymorph was published on April 1, 2009 in the journal Zeitschrift für Kristallographie - New Crystal Structures (volume 224, issue 1-4).

Crystal (programming language)

10.1524/ncrs.2009.224.14.251

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CCDC 959915: Experimental Crystal Structure Determination

The Cambridge Structural Database (2013)

Justin Nenwa Patrick L. Djonwouo Michel M. Bélombé Emmanuel N. Nfor Franziska Emmerling

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.

10.5517/cc116w04

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Bis[tris(oxamide dioxime-κ²N,N′)cobalt(III)] oxalate bis(sulfate) dodecahydrate

Acta Crystallographica Section E Structure Reports Online (2007)

Michel M. Bélombé Justin Nenwa Gouet Bebga Boniface P. T. Fokwa Richard Dronskowski

In the title compound, [Co(C2H6N4O2)3]2(C2O4)(SO4)212H2O, the Co3+ ion adopts a distorted octahedral coordination involving six imino N atoms of three bidentate oxamide dioxime ligands. The oxalate ion is centrosymmetric. The bulk structure is consolidated by a network of O—H⋯O and N—H⋯O hydrogen bonds, interconnecting the building blocks in such a manner that the framework delineates infinite channels parallel to [100]. The 12 water molecules are lodged inside the channels, six of them being O—H⋯O and N—H⋯O bonded to the ionic species, whilst the other six, located along the central axis of the channel, form infinite cyclohexameric water tapes. Two of the water molecules are disordered over two sites, in 0.786 (7):0.214 (7) and 0.637 (8):0.363 (8) ratios.

Oxamide

10.1107/s1600536807031169

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Unusual aquation of Ba²⁺ions in the solid state: synthesis and X-ray structural and spectroscopic characterization of the novel polymeric complex salt of empirical formula {Ba₆(H₂O)₁₇[Cr(ox)₃]₄}·7H₂O (ox = oxalate dianion)

Dalton Transactions (2003)

Michel M. Bélombé Justin Nenwa Yves-A. Mbiangué Germain Evina Nnanga Israël M. Mbomekallé

Reaction of BaII and CrIII,VI compounds with oxalates in water affords a salt of empirical formula {Ba6(H2O)17[Cr(ox)3]4}·7H2O (1), consistent with the expected 3BaII/2CrIII ratio; the triclinic structure is held together by unusual water and oxalate bridges, and compound 1 proved to be suitable for the synthesis of new salts with chiral cations and anions.

Triclinic crystal system

Aquation

10.1039/b302489j

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catena-Poly[[[(oxamide dioxime-κ²N,N′)copper(II)]-μ-L-tartrato-κ⁴O¹,O²:O³,O⁴] tetrahydrate]: a chiral nanochannel framework hosting solvent water molecules

Acta Crystallographica Section C Crystal Structure Communications (2012)

Michel M. Bélombé Justin Nenwa Jean S. T. Wankap Kouamo Siméon Ponou Andreas Fischer

The crystal structure of the title compound, {[Cu(C(4)H(4)O(6))(C(2)H(6)N(4)O(2))]·4H(2)O}(n), contains the central Cu(II) cation in a distorted octahedral coordination, symmetrically chelated by the two imine N atoms of a neutral oxamide dioxime (H(2)oxado) ligand [Cu-N = 1.9829 (16) Å] and unsymmetrically bis-chelated by two halves of the L-(+)-tartrate(2-) (tart) ligands, each half being linked to the Cu(II) cation via the deprotonated carboxylate group and protonated hydroxy group [Cu-O = 1.9356 (14) and 2.4674 (13) Å, respectively]. The extended asymmetric unit is defined by twofold axes, one passing through the Cu(II) cation and the centre of the oxamide dioxime (H(2)oxado) ligand and the another two (symmetry related) bisecting the central C-C bonds of the tartrate ions. The structure is chiral, consisting of enantiomeric linear-chain polymers oriented along [001], with virtual monomeric {Cu(tart(0.5))(2)(H(2)oxado)} repeat units and with the chains interleaved face-to-face into `twin pillars'. Nanochannels exist, running parallel to the c axis and bisecting a and b, which host `double strings' of solvent water molecules. Extensive hydrogen bonding (O-H···O and N-H···O) between the chains and solvent water molecules, together with extended π-σ interactions, consolidate the bulk crystal structure.

Oxamide

Carboxylate

Tartrate

10.1107/s0108270112016435

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{[Na1(μ-H₂O)Na2]₂[(C₂O₄)₂Cr(μ-OH)₂Cr(C₂O₄)₂]·H₂O}_n, a novel hydrated form

Acta Crystallographica Section E Structure Reports Online (2010)

Michel M. Bélombé Justin Nenwa Jean Ngouné Eleuterio Álvarez Agustı́n Galindo

The unit cell of the title compound, poly[[μ-aqua-μ-hydroxido-di-μ-oxalato-chromium(III)disodium] monohydrate], {[CrNa(2)(C(2)O(4))(2)(OH)(H(2)O)]·H(2)O}(n), contains four [Na1(μ-H(2)O)Na2][(C(2)O(4))(2)Cr(μ-OH)·H(2)O] formula units, each of which consists of two crystallographically independent Na(+) sites (bridged by one aqua ligand), one half of a centrosymmetric di-μ-hydroxido-bis-[cis-bis-(oxalato)chromate(III)] dimer, [(C(2)O(4))(2)Cr(μ-OH)(2)Cr(C(2)O(4))(2)](4-), and one uncoordin-ated water mol-ecule. The structure is best described as a coordination polymer in which the three-dimensional lattice framework is realized by the inter-connection of the metallic atoms via the O atoms of the aqua, hydroxide and oxalate ligands. One Na atom is hepta-coordinated by one water, one hydroxide and five oxalate O atoms, whilst the other is penta-coordinated by one water and four oxalate O atoms. The coordination around the Cr(3+) sites is pseudo-octa-hedral, involving four aqua and two hydroxide O atoms. Adjacent Na atoms are separated by 3.593 (2) Å, whereas the intra-dimer Cr⋯Cr spacing is 2.978 (1) Å. The crystal structure is consolidated by extended relatively weak O-H⋯O hydrogen bonding with O⋯O distances ranging from 2.808 (4) to 3.276 (5) Å.

10.1107/s1600536810023986

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Synthesis, crystal structure and thermal stability of the novel coordination polymer of general formula: {[(H₂O)Ba(μ-H₂O)Ba(OH₂)₄]@[(C₂O₄)₂Al(μ-OH)₂Al(C₂O₄)₂].H₂O}n^§

HAL (Le Centre pour la Communication Scientifique Directe) (2012)

Michel M. Bélombé Justin Nenwa N.A.S.N. Tchuisse Franziska Emmerling S. Obbade

Thermal Stability

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Tris(oxalato)chromate(III) hybrid salts templated by pyridinium and mixed pyridinium-ammonium cations: synthesis, structures and magnetism

Journal of Coordination Chemistry (2021)

Coustel M. N. Choubeu Bridget N. Ndosiri Hervé Vezin Claire Minaud James B. Orton

By modifying the stoichiometric ratio of starting materials, two tris(oxalato)chromate(III) salts, (C7H11N2)3[Cr(C2O4)3] (1) and (C5H8N3)2(NH4)[Cr(C2O4)3]·2H2O (2) {(C7H11N2)+ = 2-amino-4,6-dimethylpyridinium, (C5H8N3)+ = 2,6-diaminopyridinium}, were synthesized and characterized by elemental and thermal analyses, single-crystal X-ray diffraction, IR and UV − Vis spectroscopies, EPR and SQUID measurements. Salt 1 exhibits a 3-D supramolecular framework based on [Cr(C2O4)3]3- and 2-amino-4,6-dimethylpyridinim cations, (C7H11N2)+, via N–H···O hydrogen bonds. Interestingly, π–π stacking interactions between pyridine rings contribute to the stabilization of the crystal packing. In contrast to salt 1, no π–π stacking interactions are observed in the mixed-cation salt 2 and its crystal packing is consolidated by N–H···O and O − H···O hydrogen bonds. EPR spectra of 1 and 2 are consistent with the oxidation state +3 of the chromium center in an octahedral environment. Temperature-dependence of the magnetic susceptibility data investigated from 2 to 300 K revealed the existence of zero-field splitting effects (ZFS) for Cr(III) ions in both compounds.

Chromate conversion coating

Tungstate

10.1080/00958972.2021.1890048

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Citations (5)