4-(Dimethyl­amino)­pyridinium trans-diaqua­bis­[oxalato(2−)-κ2 O 1,O 2]chromate(III)

In the title salt, (C7H11N2)[Cr(C2O4)2(H2O)2], the asymmetric unit contains one half-cation and one half-anion. The Cr atom, the C and N atoms involved in C— N(exocyclic) bonding and the N and H atoms of N—H groups lie on twofold rotation axis. The CrIII atom of the complex anion is six-coordinated in a distorted (4 + 2) octa­hedral geometry with four equatorial O atoms of two nearly coplanar oxalate and two quasi-axial aqua O atoms. In the crystal, the protonated N atoms of the pyridine rings are hydrogen bonded to the carbonyl O atoms of the anions, forming chains along [010]. These chains are connected by lateral O—H⋯O hydrogen bonds, stabilizing the structure

Geological context of the Boumnyebel talcschists (Cameroun): Inferences on the Pan-African Belt of Central Africa Le contexte géologique des talcschistes de Boumnyebel (Cameroun) : implications pour la chaîne panafricaine d'Afrique centrale

International audienceThe talcschists of the Boumnyebel area (southern Cameroon) form ≤ 30 m thick discontinuous layers within a Pan-African nappe unit (Yaoundé group), which includes, at the base, muscovite + biotite ± garnet micaschists associated with amphibolites and pyroxenites, and, at the top, muscovite + biotite + garnet + kyanite micaschists locally associated with marble and amphibolites. The metamorphic peak (not, vert, similar650 °C/9.5 kbar; ca. 620 Ma) postdates nappe emplacement. Isograds are in normal position, micaschists passing downwards to migmatites in the northwestern part of the area studied. The rock types in the lower part of this nappe suggest active margin environments with detrital input from a nearby continental crust (arc or back-arc context)

Assessing the impact of neurosurgery and neuroanatomy simulation using 3D non-cadaveric models amongst selected African medical students

BackgroundLaboratory dissections are essential to acquire practical skills to perform neurosurgical procedures. Despite being traditionally done on cadavers, they are often unavailable and suffer from cultural barriers in the African context. Non-cadaveric UpSurgeOn neurosurgery models have been developed to bridge this barrier, providing an almost similar experience with the human body. This study aimed to assess the impact of the UpSurgeOn hands-on-touch non-cadaver model training amongst selected Cameroon medical students.MethodsAn anonymous 35-item questionnaire was distributed online using Google drive systems to medical students who attended UpSurgeOn's hands-on-touch non-cadaver model training course. These questions aimed to capture data on previous experience with neuroanatomy and neurosurgery practicals and the perception, attitudes, and impact of the UpSurgeOn neurosurgery tool.ResultsEighty-six students completed the survey. The mean age was 21.2 ± 1.868 years, 61.6% were males with 62.8% of respondents being medical students in preclinical years. Before the training, 29.4% had a fair knowledge of neuroanatomy. Textbooks and Youtube videos were the main sources of neuroanatomy and neurosurgery knowledge for more than half of the respondents. Up to 91.5% had no prior exposure to a neuroanatomy/neurosurgery cadaver laboratory dissection, and 22.6% and 17.6% had witnessed and performed at least one craniotomy before, respectively. There were 11.1%, 15.5%, and 31.3% of our respondents who had used a surgical microscope, a neurosurgical instrument, and the UpSurgeOn Neurosurgery tool before, respectively. The majority perceived the UpSurgeOn tool easy to use and felt they needed to learn just a few things before getting going with the box. Most thought of increasing the use of the UpSurgeOn Box and saw the need to be part of the training curriculum. Finally, the majority felt this tool helped to increase familiarity and acquire neurosurgical skills, and to develop the orientation skills needed during neurosurgical approaches.ConclusionUndergraduate exposure to traditional neurosurgery/neuroanatomy labs is limited in Cameroon. Neurosurgery/neuroanatomy practical skills are gained essentially using non-practical means. Most students found the UpSurgeOn tool user-friendly, saw the need to incorporate it as part of their training, and perceived it to be essential in getting acquainted with neurosurgical skills

New hybrid metal-organic materials polyfunctional containing N-donor ligands\ud

During this work, we have synthesised and completely characterised four new ligands, twenty two novel coordination complexes and thirteen new hybrid Metal-\ud Organic Framework (supramolecular and coordination polymers) silver(I), Zinc(II) and copper(II)-containing with fascinating and intriguing structural architectures. To\ud achieve these results under mild conditions, we have chosen three secondary building units or building blocks (SBU): cationic unit by the trinuclear copper [Cu3(μ3-OH)(μ-\ud C3H3N2)3]2+, neutral complexes such as [M2(O2CC10H6CO2)].nH2O and [M3(C9H3O6)2]n.nH2O (where M = Cu(II), Zn(II), C9H3O6 3- = trianion of benzene tricarboxylic acid), O2CC10H6CO2 2- = dianionic naphthalene dicarboxylate) and finally the simple building unit, Zn(HCOO)2.2H2O. Their reactivity towards rigid or flexible "spacers" or "linker" such as 4,4 '-bipyridine (bpy), 1,2-bis(4-pyridyl)ethane has been investigated.\ud After the literature overview, we have focussed our attention to the polyfunctional reactivity of the copper trinuclear triangular [Cu3(μ3-OH)(μ-C3H3N2)3]2+ cores. The reaction in methanol of copper trinuclear core [Cu3(C3H3N2)3(OH)(C3H4N2)2R2] ( with R = HCOO- or H3CCOO-) with 4,4’-bipyridine, trans-(1,2-bis(pyridin-4-yl))ethene and bis(pyridin-4-yl))ethane had generated five novel hybrid Metal-Organic Framework (MOFs) well characterised by single-crystal Xray diffraction, elemental analysis, InfraRed spectroscopy and Thermogravimetry Analysis (TGA). Using the 4,4’-bipyridine, the two iso-strutural MOFs 2-1 and 2-6\ud having intriguing structures, are isolated and crystallised in space group Ibam with a = 35.201(6) Å, b = 13.843(2) Å, c = 23.590(6) Å, α = β= γ= 90°, Z = 4 for MOFs 2-1\ud and a = 36.098(3) Å, b = 12.766(10) Å, c = 24.031(2) Å, α = β= γ= 90°, Z = 4 for MOF 2-6 . Their structure determination reveals that they have 3D supramolecular network based on the stacking of the interpenetrating 2D honeycomb layers also resulting from the self-assembly of the 22-membered macrocycles or monomeric copper hexanuclear\ud cores. Replacing the 4,4’-bipyridine by the flexible and more longer connector trans-(1,2-bis(pyridin-4-yl))ethene in the slightly modify conditions had gave rise to the two\ud supramolecular isomers MOF 2-2 and 2-3 which crystallise respectively in triclinic space group P1 and monoclinic space group P21/n with a = 14.3105(5) Å, b = 15.3253(5) Å, c = 16.4073(6) Å, α = 99.7450(10)°, β = 108.313(2)°, γ = 98.198(2)°, Z = 1 (for MOF 2-2) and a = 24.9689(8) Å, b = 17.2737(5) Å, c = 29.6605(9) Å, α = γ = 90°, β = 92.623(2)°, Z = 8 (for MOF 2-3). The rhombic grid 2D-MOF 2-2 was\ud constructed with the self-organisation of the 26-membered macrocyles forming the monomeric unit through the strong intermolecular hydrogen bonds. This open network which exhibits various types of cavities is completely different to the polymeric 1D zigzag chain of the isomer MOF 2-3. When the 4,4’-bipyridine was replaced by the bis(pyridin-4-yl))ethane, flexible spacer with the same coordination sites , another 3D open framework, MOF 2-4 (triclinic space group P1, a = 12.5276(6) Å, b = 13.6797(6) Å, c = 15.5767(7) Å, α= 92.059(2)°, β= 103.1640(10)°, γ = 92.201(2)°,\ud Z = 2) was obtained. The polymeric crystal structure of this MOF or supramolecular coordination polymer was forming by the coordination of the branched bidimensional\ud monomeric structure through one bis(pyridin-4-yl))ethane and the intermolecular hydrogen bonds. In these five MOF structures, there are π-π interactions. These results\ud indicate that the nature of the co-ligand or connector plays the critical role in the construction of these novel hybrid coordination polymers or Metal-Organic Frameworks.\ud The second part of this report, described the synthesis of the new ligands and their reactivity towards metal ions of Group 11 and 12. In fact, these N-donors chelating and bridging ligands named (bis(indazol-1-yl)methane , Monoclinic with space group C2, a = 23.6048(7) Å, b = 4.10040(10) Å, c = 13.9516(4) Å, α = 90°, β = 117.8300(10)° , γ = 90° , Z = 4; bis(indazol-2-yl)methane, Monoclinic with space group P21, a = 4.5053(3) Å, b = 11.5398(8) Å, c = 11.9930(8) Å, α = 90°, β= 99.550(2)°, γ = 90°, Z = 2; 1-((indazol-2-yl)methyl)-indazole, Monoclinic with space group P21/c , a = 10.0876(5) Å, b = 8.1834(4) Å, c = 14.7602(7) Å, α = 90°, β = 98.168(2)°, γ = 90°, Z = 4), and bis(4,5,6,7-tetrahydroindazol-1-yl)methane, orthorhombic with a space group Pccn, a = 19.1237(15) Å, b = 8.4206(7) Å, c = 8.4529(7) Å, α = 90°, β = 90°, γ = 90°, Z = 4) have been synthesised using two methods: the reported well-known “Phase Transfer Catalyst (PTC)” and a new one here reported. The complementary confirmation of their structural characterisation was obtained from DFT calculations. By using these ligands, we have prepared and structurally characterised nine derivatives from their reaction with simple salts of d10 metals (silver(I), zinc(II), mercury(II) and Cadmium(II)). With the silver(I) salt, complex salts exhibiting the common tetracoordination on Ag(I), (3-10) [Ag(Bindm)2](NO3): monoclinic, space group P21/c, a = 11.3092(6) Å, b = 12.2646(6) Å, c = 20.1430(10) Å, α= 90°, β= 98.080(2)°, γ = 90°, Z = 4 and (3-20) [Ag(Bitim)2](NO3): triclinic, space group P1, a = 9.1219(9) Å, b = 14.2797(13) Å, c = 24.510(3) Å, α = 79.043(4)°, β= 79.298(3)°, γ = 77.068(3)°, Z = 4 containing two moieties Bindm or Bitim are reported. Also reported is a neutral\ud derivative containing two ligands Bindm, showing the interesting six-coordination on Cd(II) (3-17) [CdCl2(Bindm)2]: triclinic, space group P1, a = 7.9331(12) Å, b=\ud 7.9480(12) Å, c = 12.5068(18) Å, α = 83.519(7)°, β = 72.527(7)°, γ = 67.587(6)° and Z= 1. With the mercury and zinc salts, it was observed that only one ligand molecule is\ud chelating the metal centre which is then occupies the center of distorted tetrahedral. It is the case of the following five reported derivatives (3-21) [ZnCl2(Bitim)] (triclinic space group P1, a = 7.3686(18) Å, b = 9.388(2) Å, c = 12.975(3) Å, α = 80.438(6)°, β= 74.252(6)°, γ = 86.260(7)°, Z = 2); (3-6) [ZnBr2(Bindm)] (Orthorhombic, space group Pnma, a = 13.2080(11) Å, b = 14.2483(12) Å, c = 8.5448(7) Å, α= 90°, β= 90°, γ = 90°, Z = 4); (3-5) [ZnCl2(Bindm)](monoclinic, space group P21/m, a = 7.2900(11) Å, b\ud = 14.101(2) Å, c = 8.2929(13) Å, α= 90°, β= 112.802(4)°, γ = 90°, Z = 2); (3-11) [Hg(SCN)2(Bindm)](monoclinic, space group P21/n, a = 12.3387(5) Å, b = 8.1098(3) Å, c = 18.1621(7) Å, α = 90°, β = 96.9590(10)°, γ = 90°, Z = 4) and (3-13)\ud [HgCl2(Bindm)](triclinic, space group P1, a = 11.7136(5) Å, b = 12.5791(5) Å, c = 14.1761(6) Å, α = 72.102(2)°, β= 71.534(2)°, γ = 79.366(2)°, Z = 2).\ud Analogously to the work carried out in chapter 2, variety of diamine linkers (en, tn, pn, bipy, bipyetha, bipyethe) and/or monodentate N-donor ligand (pyrazole, imidazole and some of their derivatives) have been reacted at room temperature with a series of metal acceptors Zn(OOCH)2.2H2O, Zn(O2C-naph-CO2)2.3H2O or Zn(NDC)2.3H2O, Zn3(1,3,5-BTC)2.8H2O, CuNDC. 3H2O and Cu3(1,2,3-BTC)2.3H2O (where 1,3,5-BTC3- = 1,3,5-benzenetricarboxylate trianion, 1,2,3-BTC3- = 1,2,3-benzenetricarboxylate trianion and NDC2- = naphthalene dicarboxylate dianion) to obtain twenty nine new derivatives characterised by the elemental analysis,\ud spectroscopic and X-ray diffraction techniques for someone.\ud The reaction with zinc carboxylates have yielded the isolation of seventeen derivates among which five are completely structurally characterised: the complex derivative [Zn(imH)6](OOCH)2 (4-1), the coordination polymers 1D-MOFs (4-4){[Zn2(µ-OOCH)(OOCH)3(bipy)2(H2O)2].H2O}. and (4-7){[Zn2(OOCH)4(µ-bipyetha)].4H2O}. with a zig-zag array crystal structure; and finally, two inorganic supramolecular isomers, 1D-MOF [Zn2(OOCH)4(µ-bipyethe)]. (4-5)and 3D-MOF [Zn2(µ-OOCH)4(µ-bipyethe)(OH2)2]. (4-6). Their crystallographic parameters are the following: (4-1): Space group P21/a, a: 8.355 Å, b: 16.9590Å , c: 8.9400 Å, α: 90°, β: 91.68°, γ : 90 ° ; (4-4): Orthorhombic with space group Pbca, a = 6.7651(8) Å, b = 17.4876(19) Å, c = 23.180(3) Å, α = β = γ = 90°, Z = 8; (4-5): Monoclinic, P2/n, a = 8.8105(3) Å, b = 4.8235(2) Å, c = 16.4502(7) Å , α= 90°, β=\ud 102.9150(10)°, γ = 90° Z= 2; (4-6): Monoclinic, C2/c, a = 37.8876(14) Å, b = 7.6025(3) Å, c = 25.4422(9) Å, α= 90°, β= 90.489(2)°, γ = 90° , Z = 8 and (4-7): Monoclinic, C2/c , a = 18.0718(9) Å, b = 4.6178(3) Å, c = 17.3126(9) Å, α= 90°, β= 96.329(2)°, γ = 90°, Z = 4.\ud We have equally isolated variety of copper(II) derivatives from which three were structurally characterised: the complex salt derivative [Cu(tn)2(H2O)2](NDC).3H2O (4-\ud 26) which crystallises in system triclinic and Space group P1, a = 7.3274(2) Å, b = 9.9798(3) Å, c = 11.5687(3) Å, α= 100.6210(10)°, β = 95.1010(10)°, γ= 97.6160(10)°, Z = 1; and two Metal-Organic Frameworks 1D {[Cu(NDC)(tn)(H2O)(µ-H2O)].1/2H2O}8 (4-25) crystallising in Monoclinic system and\ud space group P21/c, a = 11.4293(4) Å, b = 10.4074(4) Å, c = 12.4403(5) Å, α= 90°, β= 117.2450(10)°, γ = 90°, Z = 2 and 2D {[Cu3(1,2,3-BTC)2(en)3(µ-H2O)(H2O)3].3H2O}.(4-29) with a space group P-1, a =12.157(2) Å, b=12.874(3) Å, c=14.054(3) Å, α= 75.08(3)°, β= 74.45(3)°, γ = 68.03(3)°.\ud Similarly to the previous derivatives reported in chapter 2, the connector trans-(1,2-bis(pyridin-4-yl))ethene (bipyethe) reacted with zinc formate (simple unit)\ud concomitantly gave rise to two supramolecular isomers. The MOFs (base either on zinc carboxylate or copper carboxylate derivatives) exhibit in the overall crystal structures\ud various types of open cavities or channels with someone occupy with solvent or water molecules.\ud The thermal analysis show that these MOFs could be considered as perspective materials for gas storage until to 180°C.\ud During the last part of this work, devoted to the synthesis of new coordination compounds based on phosphorous donor (mono- or di-) and N-donor ligands, we have reported the preparation of twenty one new compounds where eleven are structurally and completely characterised.\ud In more details, seven silver adducts (either monomeric or polymeric species) were structurally characterised from the interaction of silver(I)diethyldithiocarbamate (Ag(dtc)) with phosphorous donor (mono- or di-) ligands: monomeric species (5-7)[Ag(dtc)(PMePh2)2] (monoclinic with P21/c, a =10.2830(8)Å , b = 30.099(2)Å , c = 10.8760(8)Å, β =115.990(2)°, Z = 4), (5-13) [Ag(dtc)(dppet)] (monoclinic with\ud P21/n, a = 9.9615(9)Å , b =17.923(2)Å , c =16.932(2)Å, β = 95.235(2)°, Z = 4); dimeric species (5-1) [Ag(dtc)(PPh3)]2 ( triclinic, space group P1, a=10.410(1)Å, b = 10.641(1)Å, c = 10.867(1)Å, α = 92.523(3)°, β = 93.573(3)°, γ = 109.409(3)°, Z = 1 dimer ), (5-3) [Ag(dtc)(P-m-tolyl3)] (triclinic with space group P1, a = 10.373(1) Å, b = 11.441(1) Å, c = 12.275(2) Å, α = 71.407(2)° , β = 68.949(2)°, γ = 84.512(2)°, Z = 1 dimer ), (5-8) [Ag(dtc)(dppm)]2 (monoclinic with space group C21/c , a = 24.022(6)Å, b = 10.234(2)Å , c = 27.114(4)Å, β = 118.37(2)°, Z = 4 dimers), and polymeric\ud species or 1D polymer (5-6) [Ag(dtc)(PMePh2)]. (monoclinic with P21/n, a = 13.041(1)Å , b = 7.4238(6)Å , c = 19.892(2)Å, β = 93.237(2)°, Z = 4), (5-10) [Ag(dtc)(dppp)]. (monoclinic with P21/c, a = 14.880(2)Å , b = 12.035(2)Å , c = 18.025(2)Å, β = 101.09(1)°, Z = 4). Apart from derivative (5-1) where Silver (I) is pentacoordinated (P2AgS3), all the derivatives exhibit the tetracoordination (P2AgS2 or\ud PAgS3) on silver centre.\ud By reacting variety simple salts of Cu(I) with the 2,9-dimethyl-1,10- phenanthroline (dmp), eight new copper (I) derivatives have isolated among which, four were structurally characterized: (5-14) [Cu(dmp)(MeCN)]NO3 (monoclinic with P21/c, a = 10.8080(4)Å , b = 19.5740(8)Å , c = 7.8400(3)Å, β = 111.206(1)°), (5-15) [Cu(dmp)2]NO3 (monoclinic with C2/c, a = 17.648(4)Å , b =11.698(2)Å , c =\ud 12.466(3)Å, β = 113.61(3)°), (5-16) [Cu(dmp)2]ClO4 ( ), (5-17) [Cu(dmp)2]Cl (triclinic with space group P1, a = 12.799(3)Å , b = 13.598(3)Å , c = 18.688(4)Å, α = 70.011(3)° , β = 80.498(3)°, γ = 64.332(3)°).\u

Transcriptional profiling of midguts prepared from Trypanosoma/T. congolense-positive Glossina palpalis palpalis collected from two distinct Cameroonian foci : coordinated signatures of the Midguts' remodeling as T.congolense-supportive niches

Our previous transcriptomic analysis of Glossina palpalis gambiensis experimentally infected or not with Trypanosoma brucei gambiense aimed to detect differentially expressed genes (DEGs) associated with infection. Specifically, we selected candidate genes governing tsetse fly vector competence that could be used in the context of an anti-vector strategy, to control human and/or animal trypanosomiasis. The present study aimed to verify whether gene expression in field tsetse flies (G. p. palpalis) is modified in response to natural infection by trypanosomes (T. congolense), as reported when insectary-raised flies (G. p. gambiensis) are experimentally infected with T. b. gambiense. This was achieved using the RNA-seq approach, which identified 524 DEGs in infected vs. non-infected tsetse flies, including 285 downregulated genes and 239 upregulated genes (identified using DESeq2). Several of these genes were highly differentially expressed, with log2 fold change values in the vicinity of either +40 or -40. Downregulated genes were primarily involved in transcription/translation processes, whereas encoded upregulated genes governed amino acid and nucleotide biosynthesis pathways. The BioCyc metabolic pathways associated with infection also revealed that downregulated genes were mainly involved in fly immunity processes. Importantly, our study demonstrates that data on the molecular cross-talk between the host and the parasite (as well as the always present fly microbiome) recorded from an experimental biological model has a counterpart in field flies, which in turn validates the use of experimental host/parasite couples

Synthesis, characterization and molecular structure of a zinc(II) formate-2,2′-bipyridine mono-dimensional coordination polymer. Comparison with other 2,2-bipyridine coordination compounds

Hydrated zinc(II) formate reacts with 2,2′-bipyridine (2,2′-bpy) to form a novel zig-zag mono-dimensional coordination polymer (1D CP) [{Zn(μ-OCHO)(OCHO)(2,2′-bpy)(HO)}·HO], 1, which was structurally characterized by a single-crystal X-ray diffraction study. Title compound crystallizes in the orthorhombic system, Pbca space group, [a = 6.7651(8), b = 17.4876(19), c = 23.180(3)]. Each zinc ion displays a distorted octahedral geometry due to the coordination of a monotopic formate, one molecule of water and the two nitrogen atoms of 2,2′-bpy, while the octahedral scheme is completed by the coordination of a ditopic formate connecting two zinc ions according to a syn-anti configuration, thus generating the polymeric structure. Moreover, a crystallization water molecule acts as a supramolecular bridge connecting formate ions belonging to neighboring, symmetry equivalent, 1D CPs through quite strong H-bonds, thus leading to an overall waved 2D open framework. Thermal analyses show significant weight losses corresponding to the elimination of water molecules followed by the decomposition of both formate groups and 2,2′-bipyridine.Financial support from the University of Camerino, the Junta de Andalucía (Grant 2009/FQM-4826) and CSIC (Grant PIF/2008-017-1) is gratefully acknowledged

A supramolecular copper(II) compound with double bridging water ligands: synthesis, crystal structure, spectroscopy, thermal analysis, and magnetism

A complex of composition {[{Cu(NDC)(OH2)(tn)(mu-OH2)}(2)]center dot 2H(2)O}(a) (1) and a mononuclear complex salt [Cu(OH2)(2)(tn)(2)](NDC)center dot 3H(2)O (2), where NDC = 2,6-naphthalenedicarboxylate dianion and tn = 1,3-diaminopropane, were simultaneously crystallized from an aqueous solution of the copper(II) naphthalenedicarboxylate-1,3-diaminopropane-methanol system. The crystal and molecular structures of both complexes were determined by single-crystal X-ray diffraction. Compound (1) consists of a supramolecular coordination complex in which the monomeric unit is assembled from a homodinuclear Cu(II) bridged by two water ligands. The Cu(II) centers exhibit distorted octahedral coordination; the equatorial plane is provided by one chelating tn ligand, one NDC2- ligand, one mu-H2O while the axial positions are occupied by H2O and mu-H2O. Strong intra- and/or intermolecular hydrogen bonds, also involving the crystallization water molecules, together with pi-pi stacking interactions, are involved in building up the supramolecule. The solid structure of compound (2) includes three water molecules of crystallization, the counter ion NDC2-, and a Cu(II) cationic complex in which the metal is six-coordinated in an axially elongated octahedron defined by two chelating tn ligands in the equatorial plane and two water ligands in the axial positions. Thermal analyses of (1) show two significant weight losses corresponding to water molecules (lattice and coordinated), followed by the decomposition of the network