Search results for "organometalli"

Synthesis, infrared and M�ssbauer characterization and X-ray crystal structure of 1,10-phenanthrolinium tetrachloromethoxy phenylantimonate(V)

1991

The compound has been characterized by X-ray crystal structure determination, Mossbauer and i.r. spectroscopy. It crystallizes in the monoclinic space groupP21/c (No. 14) witha=24.228(4),b=8.335(2),c=23.975(4) A,β=117.83(3)° andZ=8. Least-squares refinement on 3749 observed reflections gave finalR=0.034 (Rw=0.037). The compound is constituted by [(C6H5)SbCl4OMe]− anions andphenH+cations. The coordination polyhedron about Sb is an octahedron (Sb-Cl 2.416(3), Sb-O 1.962(7) and Sb-C 2.138(9) A). The whole structure is characterized by two short contacts (O(1)⋯N(2) 2.76(1) O(2)⋯N(4) 2.75(1) A) involving the methoxy oxygens of the two independent anionic units [(C6H5)SbCl4OMe]− and two nitrogens…

Langmuir–Blodgett films based on inorganic molecular complexes with magnetic or optical properties

2005

Langmuir and Langmuir–Blodgett (LB) films of a great variety of molecular metal complexes with interesting magnetic or optical properties have been prepared in the last few years. Some of the results obtained by our group and others are summarized in this article. (i) LB films of polyoxometalates (POM) were first prepared taking advantage of the adsorption properties of these cluster anions along a positively charged monolayer of an organic surfactant spread in water. A correct choice of the POM allowed the preparation of LB films with magnetic, electrochromic, or luminescent properties. Besides this semiamphiphilic method, two new methods to prepare LB films of POMs have been developed by …

Ligand design for multidimensional magnetic materials: a metallosupramolecular perspective.

2008

The aim and scope of this review is to show the general validity of the ‘complex-as-ligand’ approach for the rational design of metallosupramolecular assemblies of increasing structural and magnetic complexity. This is illustrated herein on the basis of our recent studies on oxamato complexes with transition metal ions looking for the limits of the research avenue opened by Kahn's pioneering research twenty years ago. The use as building blocks of mono-, di- and trinuclear metal complexes with a novel family of aromatic polyoxamato ligands allowed us to move further in the coordination chemistry-based approach to high-nuclearity coordination compounds and high-dimensionality coordination po…

Functional end groups for polymers prepared using ring-opening metathesis polymerization.

2011

The precise placement of functional groups on the chain-ends of macromolecules is a major focus of polymer research. Most common living polymerization techniques offer specific methods of end-functionalization governed by the active propagating species and the kinetics of the polymerization reaction. Ring-opening metathesis polymerization has established itself as one of the most functional-group-tolerant living polymerization techniques known, but this tolerance has limited the number of available functionalization reactions. Metathesis chemists have therefore been required to develop a variety of end-functionalizations, adapting each of them to the reactivity scheme of the particular cata…

Synthesis and Structures of Two Triorganotin(IV) Polymers R3Sn{O2CC6H4[N=C(H)}{C(CH3)CH(CH3)-3-OH]-p} n (R = Me and Ph) Containing a 4-[(2Z)-(3-Hydro…

2009

Two new polymeric triorganotin(IV) complexes R3Sn{O2CC6H4[N=C(H)}{C(CH3)CH(CH3)-3-OH]-p} n ([Me3Sn(LH)] n : 1) and ([Ph3Sn(LH)] n : 2) containing a 4-[(2Z)-(3-hydroxy-1-methyl-2-butenylidene)amino]benzoate (LH) framework were prepared. Both compounds have been characterized by 1H, 13C, 119Sn NMR, IR and 119Sn Mossbauer spectroscopic techniques in combination with elemental analyses. The crystal structures of complexes 1 and 2 reveal that they exist as polymeric zig-zag chains in which the LH-bridged Sn-atoms adopt a trans-R3SnO2 trigonal bipyramidal configuration with R groups in the equatorial positions and the axial sites occupied by an oxygen atom from the carboxylate ligand and the alco…

Structure of 5,17-dimethyl-11,23-dioctylcalix[4]arene

1991

The title compound C46O4H60 crystallizes in the triclinic space group, P¯1, witha=11.584(2),b=16.261(2),c=11.172(1) A,α=103.15(8),β=95.68(1),γ=96.85(1)°. The structure was solved by direct methods, and refined by weighted full-matrix least squares toR=0.097. This is the second calix[4]arene with two different alkyl substituents atpara positions of the phenolic rings. The macrocycle adopts the cone conformation. Interactions CH3-π are established between two calixarenes related by a center of symmetry. Comparisons are made between the conformation of this molecule and that of symmetrically substituted calix[4]arenes.

Kineticversus thermodynamic synthesis pathways of solid bimetallic coordination compounds ? Synthesis and crystal structure of some bimetallic compou…

1985

Mono and dinuclear copper(II) complexes of 2,4,6-tris(2-pyridyl)-1, 3,5-triazine and halide or pseudohalide ions: Synthesis and spectral studies

1986

By inhibiting the copper(II) assisted TPT (TPT = 2,4,6-tris(2-pyridyl)-1,3,5-triazine) hydrolysis, monomeric and dimeric copper(II) complexes having as general formulae Cu(TPT)X, · nH2O (X = Cl, Br, NCS, NCO or N3) and [Cu(TPT)X]2(PF6)2 · nH2O (X = Cl, Br, NCS or N3) have been synthesized and characterized by i.r., electronic and e.p.r. spectra, x-ray powder diffraction and analytical data. Spectroscopic results indicate five-coordinate geometry around the copper(II) ion, intermediate between trigonal-bipyramid and square-pyramid structures. The half-field absorption in the ΔMS = 2 region of powdered X-band e.p.r. spectra has been observed for the dimeric species.

A novel ?-N-cyanate-bridged nickel dinier exhibiting ferromagnetic coupling: Di-?-cyanate-bis(aqua-2,2?:6?,2?-terpyridine)dinickel(II) hexafluorophos…

1986

ChemInform Abstract: Stereoselective Synthesis of α-Arylalkylamines by Glycosylation-Induced Asymmetric Addition of Organometallic Compounds to Imine…

2009

Arylalkylamines are of interest as building blocks for the synthesis of biologically active compounds and as chiral ligands or chiral auxiliaries in stereoselective syntheses [1]. Their stereoselective synthesis has been achieved by enantioselective reduction of ketimines using chiral reagents [2], as for example Corey’s oxaborolidines [3], or proline-derived triacyloxyborohydrides [4]. Particularly efficient asymmetric syntheses of chiral arylalkylamines have been accomplished by Noyori et al. [5] through enantioselective catalysis of hydrogen transfer reactions using a chiral 1,2-diphenyl-ethylenediamine ruthenium catalyst. Enantioselective transferhydrogenationshave also been achieved us…