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May 24, 2023
Abstract
Metathesis reactions designed to produce nominally the pseudo-ternary A Tl[N(CN) 2 ] 2 compounds ( A = Li, Na, K, Rb or Cs) either yielded solid solutions or separated pseudo-binary dicyanamides next to the new compounds LiTl[N(CN) 2 ] 2 and Tl 0.89(1) Cs 0.11(1) [N(CN) 2 ]. Tetragonal LiTl[N(CN) 2 ] 2 ( a = 724.96(2), c = 1411.77(6) pm, Z = 4) is crystallizing isotypically with LiK[N(CN) 2 ] 2 in the space group I 4/ mcm , while orthorhombic Tl 0.89(1) Cs 0.11(1) [N(CN) 2 ] ( a = 858.19(4), b = 654.22(2), c = 738.94(4) pm, Z = 4) adopts the α -K[N(CN) 2 ]-type structure in the space group Pbcm , which Tl[N(CN) 2 ] itself also assumes, with the unique cationic position shared by Tl + and Cs + in an approximate 9:1 molar ratio. The Raman spectra of the new compounds are presented and compared to those of Tl[N(CN) 2 ], LiK[N(CN) 2 ] 2 and LiRb[N(CN) 2 ] 2 .
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May 23, 2023
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Diphenyl(pentachlorophenyl)phosphanegold(I) chloride was synthesized and characterized via NMR spectroscopy, elemental analysis and X-ray diffraction.
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May 22, 2023
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(Pyrrolidinyldimethylsilyl)tetramethylcyclopentadienide complexes of lithium, sodium and potassium were synthesized and characterized, including crystal structure determinations. The lithium cyclopentadienide compound was used as a Cp transfer reagent to prepare the corresponding ferrocene, stannocene and plumbocene.
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May 22, 2023
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The gallide SrMg 2 Ga 2 was obtained by direct reaction of the elements in a sealed tantalum ampoule. Single crystals were grown by slowly cooling the sample within a muffle furnace. The SrMg 2 Ga 2 structure was refined from single crystal X-ray diffractometer data: I 4/ mmm , a = 450.52(7), c = 1169.39(18) pm, w R 2 = 0.0349, 164 F 2 values, 11 variables. The magnesium and gallium atoms build up a three-dimensional [Mg 2 Ga 2 ] network which is composed of layers of edge-sharing MgGa 4 tetrahedra with 280 pm Mg–Ga. Adjacent layers are condensed by Ga–Ga bonding (253 pm). The strontium atoms fill large Ga 8 Mg 8 cages. Electronic structure calculations within Density Functional Theory (DFT) show charge transfers from Sr and Mg to Ga with ionocovalent behavior. The electronic density of states is dominated by Ga states and reveals metallic behavior. The chemical bonding is strong with dominant Mg–Ga and Ga–Ga mixing.
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May 18, 2023
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Two metal coordination polymers [Ni(oba)(Py 2 TTz) 1.5 (H 2 O)]·2H 2 O·DMF ( 1 ) and [Co(oba)(Py 2 TTz)(H 2 O) 4 ]·2H 2 O ( 2 ) have been synthesized under solvothermal conditions [H 2 oba = 4,4′-oxybis(benzoic acid) and Py 2 TTz = 2,5-di(pyridine-4-yl)thiazolo[5,4- d ]thiazole]. Crystals of compound 1 belong to the orthorhombic system, space group Ibam , with a = 38.928(8), b = 7.7113(14), c = 28.508(6) Å, V = 8558(3) Å 3 , Z = 8. Compound 2 crystallizes in the monoclinic crystal system, space group C 2/ c , with a = 33.816(3), b = 6.2697(6), c = 13.5821(13) Å, β = 96.393(3)°, V = 2861.7(5) Å 3 , Z = 4. The oba 2− dianions link two Ni atoms through unidentate carboxylate moieties in a μ 1 − η 1 : η 0 coordination mode. Compound 1 features a three-dimensional (3D) framework structure with Py 2 TTz and oba 2− ligands. In compound 2 , the central cobalt ion is in an octahedral geometry, which is defined by four oxygen atoms from four different coordinated water molecules and two nitrogen atoms from two different Py 2 TTz ligands. It is noteworthy that the dicarboxylate ligands oba 2− with four oxygen atoms do not directly coordinate with the cobalt ion, and only act as a counter-anion. The luminescence properties of 1 and 2 were also investigated.
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Abstract
Using high-pressure/high-temperature synthesis methods, it was possible to increase the number of known borates with a crystal structure derived from gadolinite. Syntheses of Tb 2 Co(B 2 O 5 ) 2 (8 GPa, 1000 °C) and Tb 2 Cu(B 2 O 5 ) 2 (11 GPa, 650 °C) were carried out in a Walker-type multianvil device. The crystal structures were determined by single-crystal X-ray diffraction methods and Rietveld refinements of the powder patterns. The new compounds were further characterized by their infrared spectra. The lanthanoid cobalt and copper borates Tb 2 Co(B 2 O 5 ) 2 and Tb 2 Cu(B 2 O 5 ) 2 crystallize in the monoclinic space group P 2 1 / c (no. 14) with the unit cell parameters a = 4.5630(1), b = 7.2991(2), c = 9.4161(2) Å, and β = 91.14(1)° for the cobalt and a = 4.5757(1), b = 7.3078(2), c = 9.3771(3) Å, β = 90.73(1)° for the copper compound.
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May 12, 2023
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A new series of derivatives (compounds 8 – 20 ) of the breast antihormonal drug letrozole tagged with additional aryl groups were synthesized starting from the letrozole analog 7 via Suzuki cross-coupling reaction. Treatment of the ketone 9 with various aldehydes in base afforded the chalcone analogs 21 – 27 . The structural assignments were done by IR, 1 H, 13 C and 2D NMR spectra. Compounds 13 , 21 – 23 , 25 and 26 have been selected for their anticancer activity against MCF-7 and WRL-68 cell lines. Compounds 13 and 22 were found to be the most potent anticancer agents with IC 50 values of 34.75 and 58.79 (μg mL −1 ) (SI = 3.3 and 2.6, respectively). Molecular docking study of compounds 13 and 22 revealed hydrogen bond with the amino acids Arg115, Met374 and Met364 residues of the receptor 3EQM, respectively. Therefore, compounds 13 and 22 can be considered as promising anticancer agents due to their potent cytotoxic activity.
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May 12, 2023
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The autoreduction of ammonium pertechnetate in solutions of trifluoromethanesulfonic acid (triflic acid, TfOH) and trifluoromethanesulfonic anhydride (triflic anhydride, TfOTf) results, in the presence of sodium ions, in the formation of the complex Na 2 [(Tc V O)(OTf) 5 ] · 2(TfOH). Its structure has been determined by single-crystal X-ray diffraction.
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May 5, 2023
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The dimetallacyclic complex H 2 C(Me 2 SiC≡CAuPMe 2 ) 2 CH 2 has been synthesized, in which the two gold centers are bridged by the diphosphine dmpme (= bis(dimethylphosphino)methane) and a diethynyl ligand providing “full support” for the possible transannular Au–Au contact ( 3 ). This compound and its “semi-” and “unsupported” analogues ( 2 , 1 ) have been characterized by NMR spectroscopy and elemental analysis. The monomeric nature of complex 3 in solution has been established using diffusion coefficients measured by DOSY-NMR spectroscopy and comparing the data with those of complexes 1 and 2 as references.
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April 14, 2023
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The intriguing experimental results regarding the synthesis and structure types adopted by binary InPd 3 have been fundamentally addressed using first-principles density functional theory calculations. Longer annealing time at higher temperature leads to stronger and more optimized heteroatomic In–Pd contacts that result in the extended ordering between them and leading to the ZrAl 3 structure type. This is followed by another ordered derivative of the TiAl 3 -type and the metastable disordered AuCu-type when the annealing time and temperature were reduced. The thermodynamic stability order of these three polymorphs of InPd 3 , i.e. ZrAl 3 -type > TiAl 3 -type > AuCu-type is understood from the correlation between formation enthalpies, Madelung energies, and electronic structure and chemical bonding analysis.
