Search results for "dron"
showing 10 items of 4363 documents
Organotin(IV) azido and mixed azidothiocyanato complex anions; A Mössbauer and vibrational spectroscopic study
1975
Abstract Tetraphenylarsonium and tetramethylammonium salts of the complex anions Ph 3 Sn(N 3 ) − 2 , Ph 3 Sn(N 3 )(NCS) − , Me 2 Sn(N 3 ) 2− 4 and Ph 2 Sn(N 3 ) 2 (NCS) 2− 2 have been synthesized, and the solid state configuration of the complex anions has been studied by Mossbauer and vibrational spectroscopies. Trigonal bipyramidal structures are advanced for the Ph 3 Sn IV derivatives, with equatorial SnC 3 and apical pseudohalide ligands, while the R 2 Sn IV compounds are assumed to be trans -octahedral species. The NCS − ligands are observed to be N-bonded to Sn IV . Conductance and PMR (for the Me 2 Sn IV compound) data suggest the presence of the complex anions also in solution phase…
Potentiometric study of the formation of hydroxo complexes of [Cu(terpy)]2+. Synthesis and crystal structure of [Cu(terpy) (H2O)](CF3SO3)2
1992
Two complexes of formula [Cu(terpy)(H2O)](CF3SO3)2 (1) and [Cu(terpy)(OH)]BPh4 (2) (terpy=2,2′∶6′,2″-terpyridine and BPh4=tetraphenylborate anion) have been synthesized and characterized by spectroscopic techniques. The x-ray crystal structure of (1) has been determined by x-ray diffraction. The structure is made up of [Cu(terpy)(H2O)]2+ mononuclear cations plus semi-coordinated CF3SO3 − anions. The coordination geometry around the copper atom is approximately elongated tetragonal octahedral. The oxygen atom of water and the three nitrogen atoms of terpy occupy the equatorial sites whereas the apical ones are filled by trifluoromethanesulphonate oxygen atoms. The formation of hydroxo comple…
Synthesis, crystal structure, thermal and magnetic properties of [Mn(H2O)6][Cu(pdta).2H2O (pdta= 1,3-propylenediamine-N,N,N',N'-tetraacetate
2000
[EN] On mixing concentrated aqueous solutions of pdta, Cu(II) and Mn(II) in the ratio 1:1:1 at pH 4.5, single crystals of the complex [Mn(H2O)6][Cu(pdta)]·2H2O (1) (pdta=1,3-propylenediamine-N,N,N'N'-tetraacetate) were obtained. X-ray structural analysis revealed that in the anion [Cu(pdta)]2- the coordination polyhedron around the Cu(II) ion can be described as a tetragonaly distorted CuN2O4 octahedron, whereas the cation [Mn(H2O)6]2+ can be described as a very regular MnO6 octahedron. Thermogravimetric analysis shows that at 110°C compound 1 loses its eight water molecules yielding the anhydrous compound [MnCu(pdta)] (2). Variable-temperature magnetic susceptibility measurements indicate …
Preparation and Characterisation of Alendronate-Loaded Chitosan Microparticles Obtained Through the Spray Drying Technique
2009
Microparticles of chitosan (CHT) containing alendronate sodium (AL) were prepared in four drug:polymer ratios (1:1, 1:2, 1:4, 1:6) using the spray drying technique. The efficiency of the method was evaluated by determining production yield (about 70 %) and microencapsulation efficiency, which was almost 100 % in the case of all four of the formulations studied. Particles had a mean size of between 3.6 and 4.6 microm, and a near-spherical shape. The formulations with the highest content of AL (drug:polymer ratio 1:1 and 1:2) showed an asymmetrical distribution of particles, which were larger in size, and had a higher proportion of irregular particles than the other formulations. FT-IR analys…
Polycatenane systems from Co(II) and trans-1,2-bis(4-pyridyl)ethene (bpe). Synthesis and structure of Co(bpe)2(NCS)2·CH3OH, [Co(bpe)2(H2O)2](ClO4)2·2…
2001
Three new compounds of formulae Co(bpe)2(NCS)2·CH3OH, 1, [Co(bpe)2(H2O)2](ClO4)2·2CH3OH, 2 and [Co(bpe)2(H2O)2(CH3OH)2](ClO4)2·bpe·H2O, 3, [bpe = trans-1,2-bis(4-pyridyl)ethene] have been synthesised and characterised by single crystal X-ray diffraction. The metal environment in 1–3 is distorted octahedral. Compound 1 is a polycatenane. Its structure consists of parallel layers containing Co2+ ions linked by bpe ligands, the Co···Co distance through the bpe bridge being 13.65(3) A. Each metal ion, in a layer, defines the edges of a rhombus. Two thiocyanate groups trans-coordinated to the metal atoms are perpendicular to the sheets. Each sheet has an infinite number of perpendicular sheets …
Isolation of Two Different Ni2Zn Complexes with an Unprecedented Cocrystal Formed by One of Them and a “Coordination Positional Isomer” of the Other
2013
A new homometallic trinuclear Ni(II) complex [(NiL)2Ni(NCS)2] (1) and three heterometallic trinuclear Ni(II)-Zn(II)-Ni(II) complexes [(NiL)2Zn(NCS)2] (2), [(NiL)2Zn(NCS)2(CH3OH)2]·2CH3OH (3) and {[(NiL)2Zn(NCS)2(CH3OH)2]} {[(NiL)2Zn(NCS)2]} (4) have been synthesized by using the "complex as ligand" approach with the "metalloligand" [NiL] (H2L = N,N'-bis(salicylidene)-1,3-propanediamine) and thiocyanate in different ratios. All the complexes have been structurally and magnetically characterized. In the isomorphous complexes 1 and 2, the two terminal square planar Ni atoms and the central octahedral nickel atom (in 1) or zinc atom (in 2) are arranged in a bent structure where two cis κN-SCN(-…
Study of the mutual influence of ligands in cobalt(II) complexes containing thiocyanate and imidazole derivatives
1997
Abstract The cobalt(II) complexes of formula [Co(NCS)2L2] and [Co(NCS)2L′4] (L = imidazole (iz) derivatives, I-Meiz (1), Z-Meiz (2), 2-Etiz (3), 2-Isopropiz (4), 2-Pheniz (5), 1,2-Me2iz (6), Biz (7), 2-Mebiz (8), 2-Etbiz (9); L′ = iz (10), 1-Meiz (11)) have been synthesized and characterized by spectroscopic methods and magnetic measurements. The crystal and molecular structures of complexes 6 and 11 have been determined by X-ray diffraction methods. Complex 6 crystallizes inthe orthorhombic space group Pnma with cell constants a=9.209 (3), b = 12.462 (5), c = 14.851(3) A ; V = 1704.3(9) A 3 , D ( calc ., Z = 4) = 1.43 g cm −3 , M r =367.35, F(000)=640 , λ( Mo K α)=0.71079 A , μ=11.2 cm−1 a…
Ferromagnetic Coupling Through the End-to-End Thiocyanate Bridge in Cobalt(II) and Nickel(II) Chains
2015
The preparation, spectroscopic characterization, and X-ray crystal structure of two novel one-dimensional compounds of formula [MII(tppz)(NCS)(μ-1,3-NCS)]n [tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine and M = Co(1) and Ni (2)] are reported. 1 and 2 are isomorphous compounds, and they crystallize in the P21/n space group. Their structures are made up of zigzag chains of cobalt(II) (1) and nickel(II) ions (2) bridged by single end-to-end thiocyanate groups with a tridentate tppz molecule and a terminally bound thiocyanate-N ligand achieving distorted MN5S octahedral surroundings around each metal center. The main source of the distortion of the ideal octahedron is due to the geometrical constr…
Synthesis, crystal structure and magnetic properties of the dinuclear manganese(II) complexes [Mn2(bpym)3(NCX)4] (bpym = 2,2′-bipyrimidine; X = S, Se)
1997
Abstract The dinuclear manganese(II) compounds of formula [Mn2(bpym)3(NCX)4], where bpym = 2,2′-bipyrimidine and X = S(1) and Se(2), have been prepared and their crystal structures determined by X-ray diffraction methods. 1 and 2 are isostructural. They crystallize in the triclinic P 1 space group with Z = 1, γ ( Mo K α ) = 0.71073 A , T = 295 K and a = 9.141(2), b = 9.248(2), c = 11.733(2) A , α = 74.88(2), β = 80.29(2), γ = 61.03(2)°, V = 836.7(3) A 3 , D c = 1.621 g cm −3 , M r = 316.7, F(000) = 412, and μ( Mo K α) = 10.54 cm −1 for 1 and a = 9.244(2), b = 9.278(2) A , c = 11.887(2) A , α = 75.19(2), β = 80.83(2), γ = 61.54(2)°, V = 865.7(3) A 3 , D c = 1.926 g cm −3 , M r = 1004.3, F(00…
Atypical titration curves for GaAl12Keggin-ions explained by a joint experimental and simulation approach
2018
Although they have been widely used as models for oxide surfaces, the deprotonation behaviors of the Keggin-ions (MeAl127+) and typical oxide surfaces are very different. On Keggin-ions, the deprotonation occurs over a very narrow pH range at odds with the broad charging curve of larger oxide surfaces. Depending on the Me concentration, the deprotonation curve levels off sooner (high Me concentration) or later (for low Me concentration). The leveling off shows the onset of aggregation before which the Keggin-ions are present as individual units. We show that the atypical titration data previously observed for some GaAl12 solutions in comparison to the originally reported data can be explain…