Jaroslav Holeček

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.

Solution and cross-polarization/magic angle spinning NMR investigation of intramolecular coordination SnN in some organotin(IV) C,N-chelates

Abstract An intramolecular donor/acceptor SnN bonding connection in a set of triphenyl- and diphenyl-(halogeno)tin(IV) C,N-chelates, Ph2XSnL, where Ph=C6H5, X=Ph, Cl or Br and L1=2-(dimethylaminomethyl)phenyl-, C6H4(CH2NMe2)-2, and L2=2,6-bis[(dimethylaminomethyl)phenyl]-, C6H3(CH2NMe2)2-2,6, respectively, was studied by 119Sn, 15N, 13C and 1H NMR spectroscopy in solution of non-coordinating solvent (CDCl3) and by 119Sn cross-polarization/magic angle spinning NMR techniques in the solid-state. The existence of SnN coordination bonds was confirmed in studied compounds and their strengths were evaluated through the values of NMR spectra parameters of nuclei directly involved in SnN connection, namely by characteristic changes of chemical shifts δ(119Sn) and δ(15N) and values of J(119Sn, 13C) and J(119Sn, 15N) coupling constants. The set was extended by compound [2,6-C6H3(CH2NMe2)2]PhSnCl2 (5a), that is the decomposition product of compound [2,6-C6H3(CH2NMe2)2]Ph2SnCl (5). This 5a was characterized by NMR spectroscopy and its structure was estimated by X-ray diffraction techniques.

Organostannate derivatives of dicyclohexylammonium hydrogen 2,6-pyridinedicarboxylate: solution/solid-state 13C,119Sn NMR and in vitro antitumour activity of bis(dicyclohexylammonium) bis(2,6-pyridinedicarboxylato)dibutylstannate, and the crystal structure of its monohydrate

Bis(dicyclohexylammonium) bis(2,6-pyridine-dicarboxylato)dibutylstannate is assigned seven-fold coordination at tin on the basis of its ll9 Sn CP/MAS NMR chemical shift (δ=-424.9 ppm). The assignment has been corroborated by a crystal structure determination of its monohydrate, whose tin atom has the trans-C 2 SnNO 4 pentagonal bipyramidal [Sn-C=2.040(9), 2.067(8) A; C-Sn-C =168.9(5)°] geometry. One 2,6-pyridine-dicarboxylato group chelates to the tin atom (Sn-O=2.234(4), 2.260(4); Sn-N = 2.279(5) A) whereas the other binds through only one carboxyl -C0 2 end (Sn-O=2.416(5), 2.441(5)A). Hydrogen bonds link the cation and the stannate into a linear chain parallel to the b-axis. The lattice water molecule is hydrogen-bonded to the free carboxyl end. The anhydrous compound showed higher in vitro antitumor activity than those of carboplatin and cisplatin when screened against breast (MCF-7, EVSAT), colonic (WiDr), ovarian (IGROV) and renal (A498) carcinoma, and melanoma (M19 MEL) cell lines.

High-resolution solid-state 119Sn NMR spectroscopy of some organotin(IV) oxinates and thiooxinates

Abstract Solid-state 119 Sn CP/MAS NMR spectra have been recorded for eleven triorganotin(IV) oxinates and thiooxinates and diorganotin(IV) dioxinates and dithiooxinates. The spectra of tri- and diorganotin(IV) oxinates and dioxinates reveal only one centre-band, in accord with their crystal structure determined by X-ray diffraction, whereas those of some analogous thiooxinates show two centre-bands. The 119 Sn CP/MAS NMR spectra of the isotopomers, with 14 N and 15 N, of triphenyltin(IV) 5-methyl-8-chinolinolate show three centre-bands as does the 15 N CP/MAS NMR spectrum of the isotopomer containing 15 N. In the 119 Sn NMR spectra of triorganotin(IV) oxinates and thiooxinates, the centre- and side-bands which are attributable to the Zeeman effect and to the interaction with the 14 N quadrupole nucleus are split unsymmetrically into “doublets” with an approximate integration ratio 1 : 2. The spectrum of the isotopomer containing 15 N, shows splitting into a symmetrical 1 : 1 doublet attributable only to the Zeeman effect. “Triplet” splittings with a 1 : 4 : 4 integration ratio in the spectra of diorganotin(IV) dioxinates and dithiooxinates is probable because of interaction with two equivalent 14 N quadrupole nuclei. The triorganotin(IV) oxinates and thiooxinates and diorganotin(IV) dioxinates and dithiooxinates crystallize as molecular chelate complexes, which retain their structure in solutions in non-coordinating solvents.

13C and 119Sn NMR spectra of some tribenzyltin(IV) compounds

Abstract The 13 C and 119 Sn NMR spectra of some tribenzyltin(IV) compounds and their complexes in coordinating and non-coordinating solvents have been studied. The δ( 119 Sn) chemical shifts and coupling constants 1 J ( 119 Sn, 13 C) clearly depend on the coordination number of the central tin atom and the geometry of its coordination polyhedra. Approximate ranges of the characteristic values of both the NMR parameters were determined for various configurational types of tribenzyltin compound. The 13 C and 119 Sn NMR parameters found are indicative of a distinct interaction between the polarized σ(SnC) bond and adjacent π-electron system of the aromatic ring(s).

Multinuclear NMR study of some diorgano(chloro)tin(IV) oxinates and thiooxinates

The 119Sn, 15N, 13C and 1H NMR aswell as the solid state 119Sn CP-MAS NMR spectra have been used to study the structures of four diorgano(chloro)tin(IV) oxinates and thiooxinates, (C6H5)2Sn(Cl)(oxin) and R2Sn(Cl)(Txin), where R = benzyl, phenyl, or vinyl groups, oxin = 8-quinolinolate, txin = 8-quinolinethiolate, in deuteriochloroform solution and in the solid state. Both in a non-coordinating solvent (CDCl3) and in the solid state the compounds studied are formed by monomeric molecular chelate complexes with a distorted cis-trigonal bipyramidal arrangement of coordination polyhedra centred on a five-coordinated tin atom. The fine structure of the centre-bands in the 119Sn CP-MAS spectra can qualitatively be explained as result of the combined effect of residual dipolar coupling and scalar interaction of the 119Sn nucleus with two different quadrupolar nuclei (14N, I = 1; 35,37Cl, I = 32).

27Al, 15N, 13C and 1H NMR spectra and negative-ion electrospray mass spectra of the 2:1 aluminium(III) complexes of azo dyes derived from anthranilic acid

Abstract The 27 Al, 15 N, 13 C and 1 H NMR spectra in DMSO and mass spectra of 2:1 aluminium(III) complexes ( 1b – 4b ) derived from anthranilic acid azo coupling products with 4-tert.butylphenol ( 1a ), 2-naphthol ( 2a ) acetoacetanilide ( 3a ) 3-methyl-1-phenylpyrazol-5-one ( 4a ) were measured and analysed. It was found that the aluminium atom was six-coordinated, being bound to two oxygens and the nitrogen originating from anthranilic acid.