Organotin(IV) compounds of 2-thiopyridine. Crystal and molecular structure of dicyclohexyltin(IV) bis(2-pyridylthiolate)

Diorganotin(iv) 4,6-dimethyl-2-pyrimidyl selenolates: synthesis, structures and their utility as molecular precursors for the preparation of SnSe2 nano-sheets and thin films

Organotin complexes, [R₂Sn{SeC₄H(Me-4,6)₂N₂}₂] and [R₂SnCl{SeC₄H(Me-4,6)₂N₂}] (R = alkyl) were prepared and utilized as ssps for the preparation of SnSe₂ nanosheets and thin films. Tunability of band gaps has been demonstrated.

Diorganotin(iv) 2-pyridyl and 2-pyrimidyl thiolates: synthesis, structures and their utility as molecular precursors for the preparation of tin sulfide nanosheets

Organotin complexes, [R₂Sn(2-SC₅H₄N)₂] and [R₂SnCl{SC₄H(Me-4,6)₂N₂}] (R = Me, Et) were prepared, characterized and utilized as ssps for the preparation of SnS nanosheets. The direct/indirect band gaps of the latter were evaluated.

DFT Calculations of the Electric Field Gradient at the Tin Nucleus as a Support of Structural Interpretation by119Sn Mössbauer Spectroscopy

DFT calculations, using an all-electron basis set and with full geometry optimization, were performed on 34 Sn(II) and Sn(IV) compounds of known structure and (119)Sn Mössbauer parameters, to obtain the theoretical values of the electric field gradient components, V(xx), V(yy), and V(zz), at the tin nucleus. These were used to determine the quantity V = V(zz)[1+ 1/3((V(xx) - V(yy))/((V(zz))(2)](1/2), for each investigated compound, which is related to the quadrupole splitting (DeltaE) parameter according to DeltaE = 1/2eQV, where e is the electronic charge and Q is the quadrupole moment of the tin nucleus. The linear fitting of the correlation plot of the experimental DeltaE, versus the corresponding calculated V values, produced a slope that is equal to 0.93 +/- 0.03 and a correlation coefficient R = 0.982. The value of Q obtained, 15.2 +/- 4.4 fm(2), is in agreement with that previously experimentally determined or calculated by analogous procedures. The calculation method is able to establish the sign of the electric field gradient component V(zz), in agreement with the sign of DeltaE determined experimentally by Mössbauer-Zeeman spectroscopy. The calculated structural parameters are in good agreement with the corresponding experimental data, determined by X-ray crystallography in the solid state, with average structural deviations of about 3 % for bond lengths and angles in the tin environment. Calculated values of DeltaE were obtained from the calibration fitting constant and from the values of V. By comparing experimental and calculated DeltaE parameters, the structure assignment of configurational isomers was successful in two test cases, in agreement with the experimental X-ray crystallographic structures. These results indicate that the method can be used as a tool to support the routine structure interpretation of tin compounds by (119)Sn Mössbauer spectroscopy.

Syntheses, characterization, and X-ray crystal structures of diorganotin(IV) derivatives of 2-pyridinethiolato-N-oxide

The diorganotin(IV) dichloride reacts with sodium 2-pyridinethiolato-N-oxide in a 1:1 ratio to produce [Me2SnCl(2-SpyO)] (1), [Et2SnCl(2-SpyO)] (2), [Bu2SnCl(2-SpyO)] (3), [Ph2SnCl(2-SpyO)] (4), and [(PhCH2)2SnCl(2- SpyO)] (5). The new complexes have been characterized by elemental analysis and IR and NMR (1H, 119Sn, and 13C) spectroscopy. On the basis of 119Sn NMR data the effective coordination number in solution is five. The structures 1 and 4 have been confirmed by X-ray crystallography. Crystals of 1 are triclinic with space group P[Formula: see text] and those of 4 are monoclinic, P21/n. The tin environment is a distorted trigonal bipyramid with the Cl and oxygen atoms in apical positions. Both complexes exhibit strong π–π stacking interactions. Key words: diorganotin, π–π stacking interaction, 2-pyridinethiolato-N-oxide, crystal structure.

Pyridine-2-selenolate and -2-tellurolate as ligands: a multinuclear (77Se, 119Sn, 125Te) magnetic resonance study of some tin(IV) complexes, and X-ray structural analyses of Sn(SPh)2(2-Se-C5H4N-N,Se)2 and Sn(SPh)1.85(2-Se-C5H4N)2.15

Reactions between Sn(E′Ph)n (E′ = S or Se; n = 2 or 4) and the bis(pyridine) dichalcogenides 2,2′-(C5H4NE)2 (E = Se or Te), abbreviated py2E2, have been studied using multinuclear (77Se, 119Sn, 125Te) magnetic resonance. In this way the occurrence of the pyridine-2-chalcogenate complexes Sn(E′Ph)4−x(Epy)x (E′ = S or Se; E = Se, x = 1–4; E = Te, x = 1 or 2) has been demonstrated. The pattern of 119Sn NMR chemical shifts for Sn(E′Ph)4−x(Sepy)x (E′ = S or Se, x = 0–4) is consistent with bidentate bonding for the pySe− ligand when x = 1 and 2. The pyTe− ligand is probably bidentate also in all four complexes containing this ligand. As part of the NMR analysis, 77Se and (or) 125Te NMR data were obtained for py2Te2 and for the new mixed dichalcogenides PhE′ER (E′ = S, Se, or Te; E ≠ E′ = Se or Te; R = 2-py or Ph), which were produced in the systems Ph2E′2:R2E2. The complex Sn(SPh)2(Sepy)2 (1) was isolated pure and its structure determined by the single crystal X-diffraction technique. The compound crystallizes in the monoclinic space group P21/n, with unit cell dimensions a = 9.7929(9) Å, b = 22.340(2) Å, c = 11.368(1) Å, β = 108.803(7) °, V = 2354.3(4) Å3, dcalc = 1.837 g cm−3 and Z = 4. Refinement by full-matrix least squares on F2 gave agreement factors R1 = 0.0425 and wR2 = 0.0882 for 2823 independent reflections with F0 ≥ 4σ(F0) and 258 variables. The structure confirms that the PySe− ligand behaves in a chelating manner. The molecule Sn(SPh)2(2-Se-C5H4N-N,Se)2 has a distorted octahedral structure with the PhS− ligands in cis positions and the two Se donor atoms in trans positions. The Sn—Se, Sn—S, and Sn—N distances are 2.6291(8) and 2.6358(8) Å, 2.475(2) and 2.464(2) Å, and 2.325(5) and 2.333(5) Å. The bite angles N-Sn-Se of the chelating ligands are 65.9(1)° and 65.8(1)°. En route to 1, the yellow crystalline compound Sn(SPh)1 85(2-Se-C5H4N)2 15 (2) was isolated. This was shown by 119Sn NMR spectroscopy to contain both Sn(2-Se-C5H4N)2(SPh)2 and Sn(2-Se-C5H4N)3(SPh). The crystal and molecular structure of 2 was determined by single crystal X-ray diffraction techniques. Crystal data: monoclinic, space group P21/n, a = 9.795(2) Å, b = 22.355(4) Å, c = 11.362(2) Å, β = 108.87(3)°, V = 2354.2(8) Å3, dcalc = 1.837 g cm−3, dobs = 1.87(5) g cm−3Z = 4, R1 = 0.0306, wR2 = 0.0651 for 2756 data (F0 ≥ 4σ(F0)) and 258 parameters. Crystallographic evidence for the presence of co-crystallized Sn(2-Se-C5H4N)3(SPh) occurs only in a minor lengthening of one of the two Sn—S bonds, Sn—S(1) (compared with expectation for 1), and an excess of electron density at S(1) when the data are modelled as Sn(2-Se-C5H4N)2(SPh)2. These effects are attributed to a crystallographic disorder of SPh and η1-{2-Se-C5H4N} at the S(1)Ph site, involving isostructural Sn(η2-{2-Se-C5H4N})2({η1-{2-Se-C5H4N})(SPh) and Sn(η2-{2-Se-C5H4N})2(SPh)2. Key words: pyridine-2-selenolate, pyridine-2-tellurolate, tin complexes.