Crystal Structure Investigations of Amide Sulfate Tetrahydrates with Divalent Cations

Single crystals of three amide sulfate tetrahydrate compounds, Ca(NH2SO3)2 ⋅ 4H2O, Mn(NH2SO3)2 ⋅ 4H2O and Ni(NH2SO3)2 ⋅ 4H2O, were synthesized by controlled evaporation of aqueous Solutions. The crystal structures were investigated using single-crystal X-ray diffraction methods. Ca(NH2SO3)2 ⋅ 4H2O: space group C2/c, Z = 4, a = 11.616(3) Å, b = 7.761(2) Å, c = 11.638(3) Å, β = 98.93(1)°, V = 1036.47 Å3, R1 = 0.026; Mn(NH2SO3)2 ⋅ 4H2O: space group P21/c, Z = 2, a = 6.143(2) Å, b = 5.324(2) Å, c = 15.441(5) Å, β = 91.72(1)°, V= 504.78 Å3, R1 = 0.024; Ni(NH2SO3)2 ⋅ 4H2O: space group P1̅, Z= 1, a = 6.331(8) Å, b = 6.731(9) Å, c = 6.784(8) Å, α = 88.93(9)°, β = 67.87(5)°, γ = 67.76(6)°, V = 245.27 Å3, R1 = 0.030. In Ca(NH2SO3)2 ⋅ 4H2O antiprismatic CaO8 polyhedra share four oxygen atoms with NH2SO3 tetrahedra forming sheets parallel (001). In Mn(NH2SO3)2 ⋅ 4H2O and Ni(NH2SO3)2 ⋅ 4H2O, MnO6 octahedra and NiN2O4 octahedra, respectively, are linked by common corners with two NH2SO3 tetrahedra forming isolated groups. These units are interconnected by hydrogen bonds only to form three-dimensional framework structures. The amide sulfate group has a distorted tetrahedral configuration with mean S−O and S−N bond lengths of 1.449 and 1.654 Å, respectively. The average cat-ion-oxygen distances are 2.456 Å (Ca−O), 2.173 Å (Mn-O), and 2.049 Å (Ni−O), both Ni−N bond lengths are 2.153 Å. Three different types of hydrogen bonds are observed in the title compounds, namely O−H⋅⋅⋅O bonds ranging from 2.680 to 2.968 A, N−H⋅⋅⋅O bonds between 2.966 and 3.339 Å, and one O−H⋅⋅⋅N bond with 2.905 Å. Generally, observed interatomic bond lengths and angles comply well with crystal Chemical expectations

Crystal Structure Investigations of Amide Sulfate Tetrahydrates with Divalent Cations

Single crystals of three amide sulfate tetrahydrate compounds, Ca(NH2SO3)2 ⋅ 4H2O, Mn(NH2SO3)2 ⋅ 4H2O and Ni(NH2SO3)2 ⋅ 4H2O, were synthesized by controlled evaporation of aqueous Solutions. The crystal structures were investigated using single-crystal X-ray diffraction methods. Ca(NH2SO3)2 ⋅ 4H2O: space group C2/c, Z = 4, a = 11.616(3) Å, b = 7.761(2) Å, c = 11.638(3) Å, β = 98.93(1)°, V = 1036.47 Å3, R1 = 0.026; Mn(NH2SO3)2 ⋅ 4H2O: space group P21/c, Z = 2, a = 6.143(2) Å, b = 5.324(2) Å, c = 15.441(5) Å, β = 91.72(1)°, V= 504.78 Å3, R1 = 0.024; Ni(NH2SO3)2 ⋅ 4H2O: space group P1̅, Z= 1, a = 6.331(8) Å, b = 6.731(9) Å, c = 6.784(8) Å, α = 88.93(9)°, β = 67.87(5)°, γ = 67.76(6)°, V = 245.27 Å3, R1 = 0.030. In Ca(NH2SO3)2 ⋅ 4H2O antiprismatic CaO8 polyhedra share four oxygen atoms with NH2SO3 tetrahedra forming sheets parallel (001). In Mn(NH2SO3)2 ⋅ 4H2O and Ni(NH2SO3)2 ⋅ 4H2O, MnO6 octahedra and NiN2O4 octahedra, respectively, are linked by common corners with two NH2SO3 tetrahedra forming isolated groups. These units are interconnected by hydrogen bonds only to form three-dimensional framework structures. The amide sulfate group has a distorted tetrahedral configuration with mean S−O and S−N bond lengths of 1.449 and 1.654 Å, respectively. The average cat-ion-oxygen distances are 2.456 Å (Ca−O), 2.173 Å (Mn-O), and 2.049 Å (Ni−O), both Ni−N bond lengths are 2.153 Å. Three different types of hydrogen bonds are observed in the title compounds, namely O−H⋅⋅⋅O bonds ranging from 2.680 to 2.968 A, N−H⋅⋅⋅O bonds between 2.966 and 3.339 Å, and one O−H⋅⋅⋅N bond with 2.905 Å. Generally, observed interatomic bond lengths and angles comply well with crystal Chemical expectations

Tetraammonium Tetrametaphosphimate Tetrahydrate

The tetrametaphosphimate ring in the title compound, (NH4)4+(PO2NH)4-.4H2O exhibits a chair conformation. The tetrametaphosphimate rings are linked by N-HO bonds forming columns along [100]. These columns are interconnected by O-HO and N-HO hydrogen bonds through water molecules and ammonium ions. All H atoms are involved in hydrogen bonding

Thermal Activation of Copper Oxide Based upon the Copper Hydrotalcites of the Type CuxZn6-xCr2(OH)16(CO3).4H2O

A combination of DSC and high resolution DTG coupled to a gas evolution mass spectrometer has been used to study the thermal properties of a series of Cu/Zn hydrotalcites of formulae CuxZn6-xAl2(OH)16(CO3).4H2O where x varied from 6 to 0. The effect of increased Zn composition results in the increase of the endotherms and weight loss steps to higher temperatures. Evolved gas mass spectrometry shows that water is lost in a number of steps. The interlayer carbonate anion is lost simultaneously with hydroxyl units. The endotherms and differential weight loss steps were both cation and mole ratio dependent

Molecular Assembly in Synthesized Hydrotalcites of Formula CuxZn6-xA12(OH)16(CO3).4H2O-A Vibrational Spectroscopic Study

Infrared and Raman spectroscopy have been used to characterize synthetic hydrotalcites of formula CuxZn6-xAl2(OH)16(CO3).4H2O . The spectra have been used to assess the molecular assembly of the cations in the hydrotalcite structure. The spectra may be conveniently subdivided into spectral features based (a) upon the carbonate anion (b) the hydroxyl units (c) water units. The Raman spectra of the hydroxyl-stretching region enable bands to be assigned to the CuOH, ZnOH and AlOH units. It is proposed that in the hydrotalcites with minimal cationic replacement that the cations are arranged in a regular array. For the CuxZn6-xAl2(OH)16(CO3).4H2O hydrotalcites, spectroscopic evidence suggests that 'islands' of cations arte formed in the structure. In a similar fashion the bands assigned to the interlayer water suggest that the water molecules are also in a regular well-structured arrangement. Bands are assigned to the hydroxyl stretching vibrations of water. Three types of water are identified (a) water hydrogen bonded to the interlayer carbonate ion (b) water hydrogen bonded to the hydrotalcite hydroxyl surface and (c) interlamellar water. It is proposed that the water is highly structured in the hydrotalcite as it is hydrogen bonded to both the carbonate anion and the hydroxyl surface

Synthesis, characterization and antimicrobial activities of some 5-bromouracilmetal ion complexes

Six new complexes, [Mn(Br-U)2(H2O)2]×4H2O (1), [Cd(Br-U)2]×2H2O (2), [Cu(Br-U)2(H2O)2]×2H2O (3), [Co(Br-U)2(H2O)2]×4H2O (4), [Ni(Br-U)2(H2O)2]×4H2O (5) and [Ag(Br-U)(Br-U-H)]×2(H2O) (6)  were prepared by the reaction of 5-bromoouracil with MnCl2·4H2O, CdCl2·2.5H2O, CuSO4·5H2O, (CH3COO)2Co·4H2O, (CH3COO)2Ni·4H2O and AgNO3 respectively. The complexes were characterized by melting point, elemental microanalyses, IR and 1H NMR spectroscopy. The obtained data indicated that the ligand interacted with the metal ions in its mononegatively charged enol form in a bidentate fashion. Thermogravimetric analyses (TGA and DTG) were also carried out. The data obtained agreed well the proposed structures and showed that the complexes were finally decomposed to the corresponding metal or metal oxide. The ligand and its metal-ion complexes were tested for their antimicrobial activities against four bacterial strains (B. subtillis, S. aureus, E. coli and P. aeruginosa) by the agar-well diffusion technique using DMSO as a solvent. The obtained data showed that the complexes were more potent antimicrobial agents than the parent ligand.               KEY WORDS: 5-Bromoouracil–M2+ complexes, IR, Thermal analyses, 1H NMR, Antimicrobial activity Bull. Chem. Soc. Ethiop. 2019, 33(2), 255-268.DOI: https://dx.doi.org/10.4314/bcse.v33i2.

Ultra-low temperature structure determination of a Mn12 single-molecule magnet and the interplay between lattice solvent and structural disorder

We have determined the ultra-low temperature crystal structure of the archetypal single-molecule magnet (SMM) [Mn12O12(O2CMe)16(H2O)4]·4H2O·2MeCO2H (1) at 2 K, by using a combination of single-crystal X-ray and single-crystal neutron diffraction. This is the first structural study of any SMM in the same temperature regime where slow magnetic relaxation occurs. We reveal an additional hydrogen bonding interaction between the {Mn12} cluster and its solvent of crystallisation, which shows how the lattice solvent transmits disorder to the acetate ligands in the {Mn12} complex. Unusual quantum properties observed in 1 have long been attributed to disorder. Hence, we studied the desolvation products of 1, in order to understand precisely the influence of lattice solvent on the structure of the cluster. We present two new axially symmetric structures corresponding to different levels of desolvation of 1, [Mn12O12(O2CMe)16(H2O)4]·4H2O (2) and [Mn12O12(O2CMe)16(H2O)4] (3). In 2, removal of acetic acid of crystallisation largely resolves positional disorder in the affected acetate ligands, whereas removal of lattice water molecules further resolves the acetate ligand disorder in 3. Due to the absence of acetic acid of crystallisation, both 2 and 3 have true, unbroken S4 symmetry, showing for the first time that it is possible to prepare fully axial Mn12–acetate analogues from 1, via single-crystal to single-crystal transformations

Novel Polypyridyl Ruthenium(II) Complexes Containing Oxalamidines as Ligands.

The complexes [Ru(bpy)2(H2TPOA)](PF6)2 ⋅ 4H2O, (1); [Ru(Me-bpy)2(H2TPOA)](PF6)2 ⋅ 2H2O, (2); [Ru(bpy)2(H2TTOA)](PF6)2 ⋅ 2H2O, (3); [Ru(Me-bpy)2(H2TTOA)](PF6)2 ⋅ 2H2O, (4) and {[Ru(bpy)2]2(TPOA)}(PF6)2 ⋅ 2H2O, (5) (where bpy is 2,2´bipyridine; Me-bpy is 4,4´- dimethyl-2,2´-bipyridine; H2TPOA is N, N´, N´´, N´´´- tetraphenyloxalamidine; H2TTOA is N, N´, N´´, N´´´- tetratolyloxalamidine) have been synthesized and characterized by 1H-NMR, FAB-MS, infrared spectroscopy and elemental analysis. The X-ray investigation shows the coordination of the still protonated oxalamidine moiety via the 1,2−diimine unit. The dimeric compound (5) could be separated in its diastereoisomers (5´) and (5´´) by repeated recrystallisation. The diastereomeric forms exhibit different 1H-NMR spectra and slightly shifted electronic spectra. Compared with the model compound [Ru(bpy)3]2+, the absorption maxima of (1)–(5) are shifted to lower energies. The mononuclear complexes show Ru(III/II)- couples at about 0.9 V vs SCE, while for the dinuclear complex two well defined metal based redox couples are observed at 0.45 and 0.65 V indicating substantial interaction between the two metal centres

Cycloauration of pyridyl sulphonamides

The pyridyl-2-alkylsulfonamides C₅H₄N(CH₂)nNHSO₂R (n = 1,2; R = Me, Ph or p-C₆H₄Me) and 8-(p-tosylamino)quinoline undergo facile cycloauration reactions with H[AuCl₄] in water, giving metallacyclic complexes coordinated through the pyridyl (or quinolyl) nitrogen atom and the deprotonated nitrogen of the sulfonamide group. The complexes have been fully characterised by NMR spectroscopy, ESI mass spectrometry and elemental analysis. The X-ray crystal structures of two derivatives reveal the presence of non-planar sulfonamide nitrogen atoms. The complexes show low activity against P388 murine leukaemia cells, possibly as a result of their ease of reduction with mild reducing agents

PXRD and PDF analysis of multifunctional lanthanide nitrilotris-methylphosphonate-based proton conductors

Metal phosphonates are multifunctional solids which possess tunable properties, such as H-bond networks, while exhibiting high chemical and thermal stability. Depending on the protonation of the ligand, different crystalline phases can be obtained. Here, we report three different families of proton conductors based on lanthanide nitrilotrismethylphosphonates. Compounds having cationic layers compensate by chloride or sulfate anions were isolated: [Ln(H4NMP)(H2O)2]Cl·2H2O and Ln(H5NMP)]·SO4·4H2O [H6NMP = nitrilotris(methylphosphonic acid)]. The crystal structure of Gd-(H5NMP)]·SO4·4H2O was solved ab initio from synchrotron powder diffraction data (λ=0.4124 Å, beamline BL04-MSPD ALBA) and refined by the Rietveld method. Chloride containing phases show two irreversible solid state transformations take place: (1) a crystalline-to-crystalline phase transition, {Ln-H4NMP → [Ln2(H3NMP)2(H2O)4]·4.5H2O for Ln= La, Pr}, and (2) crystalline-to-amorphous phase transition, {LnH4NMP → [Ln(H3NMP)]·1.5H2O for Ln= Gd - Ho}, both implies the loss of HCl and structural rearrangements of the frameworks. Variations in average and local structure have been monitored by high resolution powder diffraction and PDF analysis, upon exposure the samples at high relative humidity and temperature (95% RH and 80 ºC), in order to understand their behavior as proton conductors.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech