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Preparation of a Bis(cyclopentadienyl)acetylene-framed Heterobimetallic Complexes and its Reaction with Dicobalt Octacarbonyl
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Multiple arylations of aromatics via removable palladacycle scaffolds: polycyclic compounds and their way of formation
No full textMetal-template electrophilic substitution on phenols: Synthesis and crystal structure of bromomagnesium phenolate and its reactive complex with para-isopropylbenzaldehyde
No full textThe crystal structures of the bromomagnesium phenolate 5 and its complex 7 with para-isopropylbenzaldehyde are reported; for the first time it has been possible to demonstrate that the reactive complex 7, responsible for the complete ortho-regioselective control in the alkylation of phenoxymagnesium bromides with aldehydes, is not obtained by simple replacement of the ethereal ligand but by expansion of the metal coordination sphere from 4 (usual tetrahedral configuration) to 5. We infer from 1HNMR studies that the magnesium coordination of complex 7 in solution is analogous to that shown in the solid state, with a complexed ethereal molecule
Crystallization and structural characteristics of new borosilicates
No full textCrystals of stiilwellite-like lanthanum borosilicate were obtained from high-temperature solutions. Lithium and potassium di- and trimolybdates were used as fluxes for silicate systems. In the case of borosilicate crystals, the choice of fluxes was based on the potassium trimolybdate with an excess of potassium fluoride. The composition of grown crystals was studied by electron microprobe analysis, and structural characteristics were determined for the La3BSi2O10. It crystallizes in the orthorhombic system, space group Pbca, with cell dimensions a = 9,977(2), b = 7,269(2), c = 23.410(2) Angstrom, V = 1697.8(6) Angstrom (3), and final agreement factors R = 0.059, R-W = 0,089
Steric and electronic effects of N-coordinated NC- and NCS- on NiS2PN: synthesis, spectral and single crystal X-ray structural studies on N,N'-di-n-butyldithiocarbamate complexes of nickel(II) with phosphorus and nitrogen donor ligands
No full textPlanar nickel(II) complexes involving N,N'-dibutyldithiocarbamate, such as [Ni(bu(2)dtc)(PPh(3))(NC)] (1) and [Ni(bu(2)dtc)(PPh(3))(NCS)] (2) (where bu(2)dtc N,N'-dibutyldithiocarbamate anion) have been prepared, characterized by electronic, IR and NMR spectra and their structures determined by single crystal X-ray crystallography. Cyclic voltammetric characterizations of the complexes are also reported. IR spectra of the two complexes indicate the isobidentate coordination (nu(c-s) similar or equal to 1095 cm(-1) without splitting) of the dithiocarbamate moiety. The important stretching mode characteristic of the thioureide bond (nu(C-N)) occurs at higher wave numbers compared to that of the parent dithiocarbamate complex [Ni(bu(2)dtc) 2]. The electronic spectra of 1 and 2 show signature bands at 426 nm and 478 nm, respectively. NMR spectra show large (31)P chemical shifts in both compounds and the most important N(13)CS(2) chemical shift appears at 204.86 ppm and 203.23 ppm for 1 and 2, respectively. The CV studies clearly show the presence of reduced electron density on the nickel ions in mixed-ligand complexes 1 and 2 compared to the parent dithiocarbamate. Single crystal X-ray structure studies show that 2 crystallizes as a new triclinic polymorph, whose molecular structure closely resembles that of the previously reported monoclinic form. Both complexes contain a planar NiS(2)PN chromophore in keeping with the observed diamagnetism. In both complexes the Ni-S distances are significantly different. The thioureide C-N distances of the complexes are shorter than those observed in the parent [Ni(bu(2)dtc)(2)]. The two compounds allow comparison of the influence of NCS-in place of NC(-)
A new and efficient palladium-catalysed synthesis of 2,3,4,5-tetrahydro-1H-2,4-benzodiazepine-1,3-dione derivative
No full textPalladium catalyzed multicomponent reactions in ordered sequence: new syntheses of o,o’-dialkylsubstituted diarylacetylenes and diarylalkylidenehexahydromethanofluorenes
No full textSingle-crystal investigation of the compounds NdRu2Si2 and NdRh2(Si,Ge)2
No full textThe crystal structures for two compounds were determined from single-crystal X-rap diffraction: NdRu2Si2, 14/mmm space group, a=4.189(1), c=9.754(8) Angstrom, V=171.16 Angstrom(3), rho=7.811 g/cm(3), mu = 240.7 cm(-1), R = 0.0379 for 114 reflections and NdRh2(Si,Ge)(2), 14/mmm space group, a = 4.182(1), c=9.829(4) Angstrom, V = 171.90 Angstrom(3), rho = 8.708 g/cm(3), mu = 330.1 cm(-1), R = 0.0533 for 152 reflections. Both structures belong to the CeGa2Al2 type of structure
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