Karel Handlíř

13C and 119Sn NMR spectra of Di-n-butyltin(IV) compounds

Abstract The 13C and 119Sn NMR spectra of a set of di-n-butyltin(IV) compounds and their complexes in coordinating and non-coordinating solvents have been studied. The results have shown that it is possible to describe semiquantitatively the shape of coordination polyhedra of these compounds from analysis of their δ(119Sn) and 1J(119Sn-13C) parameters. The values of δ(119Sn) define the regions with different coordination numbers of the central tin atom, so that four-coordinate compounds have δ(119Sn) ranging from about + 200 to −60 ppm, five-coordinate compounds, −90 to −190 ppm, and six-coordinate compounds, −210 to −400 ppm. The values of 1J(119Sn-13C) were used for the calculation of the CSnC angle in the coordination polyhedron of individual compounds.

13C and 119Sn NMR Study of some four- and five-coordinate triphenyltin(IV) compounds

Abstract The 13C and 119Sn NMR spectra of four- and five-coordinate triphenyltin(IV) compounds have been examined. The chemical shifts δ(119Sn) and the coupling constants 1J(119Sn-13C) depend markedly on the coordination number of the tin atom and on the geometry of the coordination sphere. The chemical shifts and the coupling constants 1J(119Sn-13C) for four-coordinate compounds are in the range −40 to −120 ppm and 550–660 Hz, respectively. The δ(119Sn) values for five-coordinate compounds (trigonal bipyramid arrangement) are in the range −180 to −260 ppm. The 1J(119Sn-13C) values for the compounds with three phenyl groups in the equatorial plane and the other ligands in axial positions (trans) are in the range 750–850 Hz. The chelate compound with two phenyl groups in the equatorial plane and the third in the axial position and the two donor atoms of chelating ligand in equatorial and axial positions, respectively, have the coupling constants in the range 600–660 Hz. The NMR spectra are discussed in terms of a three-centre molecular orbital model.

The 13C and 119Sn NMR spectra of some four- and five-coordinate tri-n-butyltin(IV) compounds

The 13C and 119Sn NMR spectra of a set of tri-n-butyltin(IV) compounds and their complexes in coordinating and non-coordinating solvents have been studied. The chemical shifts δ(119Sn) and δ(13C) and the coupling constants 1J(119Sn13C) depend significantly on the coordination number of the tin atom and on the geometry of its coordination sphere. Approximate ranges of these characteristic NMR parameters for various types and configurations of tri-n-butyltin(IV) compounds have been defined. The data for these compounds are discussed in comparison with those for triphenyltin(IV) compounds.

13C, 15N and 119Sn NMR spectral evidence for tin five-coordination in triorganotin(IV) oxinates

The 13C and 119Sn NMR spectra of tri(1-butyl)tin(IV) and triphenyltin(IV) oxinates and 1-naphthoxides in neat liquid and deuteriochloroform, pentadeuteriopyridine and hexamethylphosphortriamide solutions, and the 15N NMR spectra of both the oxinates and 8-methoxyquinoline in deuteriochloroform have been recorded. From the comparison of chemical shifts δ(13C), δ(15N) and δ(119Sn) and coupling constants nJ(119Sn13C) of the compounds it is concluded that the triorganotin(IV) oxinates, both as the neat liquid and in solution, form complexes containing five-coordinate tin atoms. In the neat liquid and in deuteriochloroform (a non-coordinating solvent) oxinates form chelate complexes with a cis-trigonal bipyramid arrangement. In coordinating solvents (pentadeuteriopyridine, hexamethylphosphortriamide) these are equilibria involving the formation of small amounts of oxinate complexes with one solvent molecule. These complexes have trans-trigonal bipyramid geometry with butyl or phenyl groups in equatorial plane and the monodentate oxinate group and a solvent molecule in axial positions.

Sorption of Acetic and Propionic Acids and Propanal on a Molybdenum-Vanadium Oxide Catalyst

It has been found by gas chromatography that the equilibrium adsorption of propanal, propionic and acetic acids on molybdenum-vanadium oxide catalyst can be described by the Langmuir adsorption isotherm. The existence of carboxylates on the catalyst surface has been proved by IR spectroscopy.