Über die zinn-alkylierung sterisch gehinderter stanna-heterocyclen: synthese von tri-t-butylzinn-elementverbindungen

Lithium tri-t-butyltin chalcogenides t-Bu₃SnXLi (IIa, b) were synthesized by Sn-alkylation of the sterically hindered stanna heterocycles (t-Bu₂SnX)_n (Ia, b) with t-BuLi (a: X = O, n = 3; b: X = S, n = 2). In the presence of TMEDA the addition compound t-Bu₃SnSLi · TMEDA is formed. Hydrolysis of IIa, b yields the corresponding hydrochalcogenides t-Bu₃SnOH (IIIa) and t-Bu₃SnSH (IIIb), respectively. IIIB is the first tin hydrosulfide with a stable SnSH bond. On heating IIIa or b, condensation to the symmetrically substituted tin chalcogenides (t-Bu₃Sn)₂X takes place. Mixed-substituted tin chalcogenides, t-Bu₃SnXSnMe₃, were obtained by the transamination of IIIa, b with Me₃SnNMe₂ or by metathesis of IIa, b with Me₃SnCl. Acyl, ammonium, and hydrogen chlorides react with IIa, b to give t-Bu₃SnCl in good yields.     

Über polystannane: II. I(t-Bu2Sn)4I,ein 1,4-difunktionelles tetrastannan

The compound I(t-Bu₂Sn)₄I has been synthesized by controlled cleavage of the related cyclotetrastannane (t-Bu₂Sn)₄ with iodine in toluene. Both compounds have been investigated by mass, NMR and vibrational spectra. I(t-Bu₂Sn)₄I: δ(¹¹⁹Sn_terminal) 67.7, δ(Sn_central) 17.4 ppm; ¹J(SnSn) 2199 (terminal-central) and 1575 (central-central), ²J(SnSn) 20 (terminal-central), ³J (SnSn) 307 Hz (terminal-terminal); ν(SnSn) 119, ν(SnI) 167 cm^?1. (t-Bu₂Sn)₄: δ(Sn) 87.4 ppm; ν(SnSn) 125 cm^?1. The crystal structure of I(t-Bu₂Sn)₄I has been determined (R = 0.071): bond lengths SnSn 289.5(1) (terminal-central) and 292.4(1) (central-central), SnI 275.3(1) pm. The conformation of the chain ISn₄I is all trans.     

Bindungsabstände zwischen organylsubstituierten zinnatomen: II. Cyclo-tetrastannane

The crystal structures of octa-t-butyl-cyclo-tetrastannane (t-Bu₂Sn)₄ and octa-t-amyl-cyclo-tetrastannane (t-Am₂Sn)₄ have been determined by X-ray analysis. The four-membered tin ring of (t-Bu₂Sn)₄ is planar and the molecules are highly ordered in the crystal; the ring of (t-Am₂Sn)₄ is puckered.In both compounds the tintin bonds are longer than in other cyclostannanes which is probably caused by the size requirements of the organyl groups.     

Hydroxid-halogenid-verbindungen des di-t-butyl-substituierten zinns

The di-t-butyltin hydroxide halides t-Bu₂Sn(OH)X (X = F, Cl or Br) have been prepared starting from the dihalides t-Bu₂SnX₂ or the oxide (t-Bu₂SnO)₃. X-Ray analysis of the three compounds shows dimeric molecules: two 5-coordinated tin atoms and the oxygen atoms of the hydroxyl groups are linked to a four-membered ring. As confirmed by the IR spectra, the molecules in the crystal are held together by OH?X hydrogen bonds. These are strong in the hydroxide fluoride but are weak in the analogous chloride and bromide.     

Skew-trapezoidal bipyramidal diorganotin(IV) bischelates. Crystal structure of dimethylbis(2-pyridinethiolato-N-oxide)tin(IV)

Dimethylbis(2-pyridinethiolato-N-oxide)tin(IV), Me₂Sn(2-SPyO)₂, crystallizes in space group P2₁/c with a 9.877(3), b 11.980(4), c 13.577(3) Å, β 109.1(2)° and Z = 4. The structure was refined to R_F = 0.036 for 2263 Mo-K_α observed reflections. The coordination geometry at tin is a skew-trapezoidal bipyramid, with the oxygen [SnO 2.356(3), 2.410(4) Å] and sulfur [SnS 2.536(1), 2.566(1) Å] atoms of the chelating groups occupying the trapezoidal plane and the methyl groups [SnC 2.106(6), 2.128(7) Å] occupying the apical positions. The methyl-tin-methyl skeleton is bent [CSnC 138.9(2)°]. The SSnS angle is 77.8(1)°, but the OSnO angle is opened to 136.7(1)° to accommodate the intruding methyl groups. The carbontincarbon angles predicted from quadrupole splitting (^119mSn Mössbauer) and one-bond ¹¹⁹Sn¹³C coupling constant (solution ¹³C NMR) data agree closely with the experimental value.     

Über gemischte bindungen in der IV. hauptgruppe: III. Octaphenylpropan-analoga Ph3SnSiPh2SnPh3 und Ph3SnGePh2SnPh3, korrelation zwischen geminalen NMR-kopplungen 2J(SnMSn) und nicht-bindenden Sn⋯Sn-abständen

Reaction of Ph₃SnLi with Ph₂SiCl₂ or Ph₂GeCl₂ at −78°C in THF yields (Ph₃Sn)₂SiPh₂ (1) and (Ph₃Sn)₂GePh₂ (2). The crystal structure of 1 (R = 0.075) exhibits SnSi distances of 257.2(4) and 257.9(5) pm, an SnSiSn angle of 118.5(2)°, and a central C₃SnSiC₂SnC₃ molecular skeleton with symmetry close to C₂. The geminal NMR coupling ²J(¹¹⁹Sn ⋯ ¹¹⁹Sn) in 1, and in a tri-, tetra- and pentastannane series shows a linear correlation to their respective non-bonded d(Sn ⋯ Sn) distances (I(t-Bu₂Sn)₄I: 20 Hz/496 pm; 1: 724 Hz/443 pm).     

Structural chemistry of organotin carboxylates: I. The crystal structure of di-n-butylbis(thiophenoxyacetato)tin(IV): nBu2Sn(O2CCH2SC6H5)2

A crystal structure study of ⁿBu₂Sn(O₂CCH₂SC₆H₅)₂ reveals the compound to be monomeric with the tin atom situated on a crystallographic 2-fold axis in a skew-trapezoidal bipyramidal geometry. The basal plane is defined by two asymmetrically chelating carboxylate groups; SnO 2.134(4) and 2.559(5) Å and the ⁿBuSnⁿBu angle is 140.7(2)°. The sulphur atoms do not participate in any significant interactions to the tin atom. Crystals are monoclinic with space group C2 and unit cell dimensions a 18.668(6), b 15.761(6), c 5.106(5) Å, β 117.55(5)°; Z = 2. The structure was refined by a full-matrix least-squares procedure to final R = 0.034 and R_w = 0.033 for 1294 reflections with I ≥ 2.5σ(I).     

Dipole moments of compounds containing a cobalttin bond

The molecular electric dipole moments are reported for the series of tin-substituted tetracarbonyl cobalt compounds R_nY_m?nSn{Co(CO)₄}_4?m (m = 1–3; n ? m; R = alkyl, phenyl; Y = halogen). The effect of the substituents at the tin atom on the nature of the CoSn bond is established on calculating the (CO)₄CoSn group dipole moments. It is shown that the charge transfer in the CoSn bond is mainly determined by the inductive properties of the ligands attached to tin.     

Pulsed fourier transform NMR of substituted aryltrimethyltin derivatives : III. Proton data at 100 MHz and the derived Hammett σ-constant of the trimethyltin group

Proton NMR data at 100 MHz are reported for thirteen para- and meta-substituted phenyltrimethyltin compounds, XC₆H₄Sn(CH₃)₃, where X = para-N(CH₃)₂, para-OCH₃, para-OC₂H₅, para-CH₃, meta-CH₃, -H, para-F, meta-OCH₃, para-Cl, para-Br, meta-F, meta-Cl and para-Sn(CH₃)₃. Correlation coefficients with Hammett σ-constants of greater than 0.95 are obtained with the methyltin proton chemical shifts and coupling constants to carbon [¹J(¹³C¹H)] and tin [²J(SnC¹H)]. Solvent effects and other extraneous factors invalidate comparisons of ? values in terms of the relative attenuation of the transmission of substituent effects through homologous carbon, silicon, germanium and tin systems, but coupling constant data reflect a diminution of ca. one tenthfold per bond in the order ?[C(1)Sn] > ? [SnC] > ? [CH]. Satisfactory correlations (r > 0.95) are obtained in this series of closely-related compounds among the conventionally recorded two-bond, ²J(SnC¹H) and the constituent, one-bond ¹J (Sn¹³C) and J(¹³C¹H) coupling constants, but the correlation coefficient for the comparison between the two one-bond couplings, ¹J(Sn¹³C) and ¹J(¹³C¹H) is lower (r = 0.872). Changes in the couplings at the methyltin carbon bond tin-119 atoms are interpreted in terms of isovalent hybridization; a model based upon effective nuclear charges is tested with respect to both NMR coupling constants and ¹¹⁹Sn Mössbauer Isomer shifts at tin and is invalidated. Proton and carbon-13 NMR, chemical shift and coupling constant data are used to derive a Hammett σ-constant for the para-trimethyltin group of ?0.14, and the significance of this value is discussed.     

The crystal and molecular structure of BIS(1,3-diphenylpropane-1,3-dionato)-Di-n-butyltin(IV)

The crystal and molecular structure of bis(1,3-diphenylpropane-1,3-dianoto)di-n-butyltin(IV) has been determined from three-dimensional X-ray data by the heavy-atom method. The space group is P2₁/n. Unit cell constants are a 1117.56(30), b 857.87(16), c 1758.36(51) pm, and β 99.398(20)°. The observed density of the yellow crystals (m.p. 92–94°C) is 1.38 g ml⁻³ and requires two molecules per unit cell. The molecule has a center of symmetry. Refinement converged to give final discrepancy indices, R = 0.0481, R_w = 0.0607; and goodness-of-fit (GOF) was 3.216 for 1688 observed reflections. The molecular skeleton about tin is a slightly distorted octahedron with bond distances: SnC, 212 pm; and SnO, 219 and 220 pm. The O(1)SnO(2) bond angle is 83.8°, and CSnO bond angles are very nearly 90°. The structural parameters are compared with those of other organotin complexes of similar stoichometry.     

Group IB Organometallic chemistry : XV. Arylcopper compounds ArnCun as intermediates in organometallic synthesis. One-step synthesis of triorganotin halides of the type Ar3SnX and Ar3-nRnSnX

A new method for the one-step preparation of triorganotin halides is described. Triphenyltin halides are synthesized via the reaction of pure phenylcopper with SnX₄ or with Ph₂SnX₂. Me₂NCH₂, Me₂N and OMe-substituted phenylcopper react with Me₂(or Ph₂)SnBr₂ to give novel (substituted-phenyl)-diorganotin bromides in high yields. The selective arylation of tin halides by organocopper compounds is based upon the low reactivity of RCu towards the SnX bond in triorganotin halides. The selectivity of the arylation by the corresponding phenyllithium derivatives is connected with intra- or inter-molecular SnN (or O) coordination and/or of steric factors exerted by substituents ortho to the SnC(phenyl) bond.     

Cyclische diazastannylene : XIV. Das tetramere eines 1-oxa-2-sila-3-aza-4λ2-stannetidins mit S4-symmetrie

1,3-Di-t-butyl-2,2-dimethyl-1,3,2,4λ²-diazasilastannetidine (II) reacts with 3,4,5-trimethoxybenzaldehyde to yield 3,4,5-trimethoxybenzaldehyde-t-butylimine (IV) and the title compound 2,2-dimethyl-3-t-butyl-1,2,3,4λ²-oxasilazastannetidine (III). III combines four different Main Group elements in one ring and is tetrameric in solvents as well as in the tetragonal crystalline state. An X-ray structure determination (R-value: 0.037) reveals the tetramer to have crystallographic S₄-symmetry, and that the molecules of III interact via oxygen-tin bonds, which are perpendicular to the plane of the ring. The oxygen atoms thus adopt trigonal-planar coordination, while the tin atoms have grigonal-pyramidal environments. The tin atoms are substituted by three different ligands: one nitrogen and two chemically non-equivalent oxygen atoms (SnN: 209.5(9), SnO: 218.8(6), SnO′: 213.7(6) pm). Each tin atom thus represents a center of chirality, which due to symmetry must be divided into two R- and two S-enantiomers. As a consequence the whole tetrameric molecule belongs to the optically inactive “meso”-form.     

The trans-strengthening of the SnO bond in six-coordinated complexes of tin(IV): Crystal and molecular structures of SnI4·2DPSO and C2H5SnI·2DPSO

An X-ray study of SnI₄·2diphenylsulphoxide and EtSnI₃·2diphenylsulphoxide indicates octahedral geometry for all the tin atoms in both complexes, the two DPSO ligands being cis to each other and in the second complex the ethyl group being trans to one of the DPSO ligands. In the second complex, under the influence of the ethyl group lengthening of the cis SnI bonds by 0.06 Å and shortening of the trans SnO bond by 0.06 Å occur. The mutual dependence of the SnO and OS bond distances is noted.     

Cyclische diazastannylene: XXII. Zur umsetzung eines bis(amino)stannylens mit organylphosphanen, -methylen-phosphoranen, -phosphaniminen, -oxiden und -sulfiden

1,3-Di-t-butyl-2,2-dimethyl-1,3,2,4λ²-diazasilastannetidin (I) was allowed to react with the phosphanes PEt₃ and PPh₃ as well as with Me₃PCH₂, Ph₃PCH₂, Ph₃PNH, Me₃PO and Et₃PS. While the phosphor ylides and the phosphane oxide interact with I to yield crystalline acid-base adducts, no stable adducts can be isolated with the phosphanes and the phosphane sulfide. The adduct of Ph₃PCH₂ and I crystallizes with one benzene molecule per formula unit in the monoclinic space group P2₁/c (a 1188.2(8), b 1438.4(2), c 2169.4(5) pm, β 106.5(4)°). I and Ph₃PCH₂ are linked together by a SnC bond of 240.3(10) pm. The electron transfer from the ylide-carbon to the tin atom can be evaluated from the PC bond length of 174.3(11) pm. The phosphaneimine reacts with I by displacement of the tin atom in I by hydrogen atoms yielding N, N ′-di-t-butyl-Si, Si-dimethylsilazanean and Sn(NPPh₃)₄, and oxidation at the tin atom. 3 molecules of benzene are crystallizing together with one formula unit of Sn(NPPh₃)₄ (monoclinic; C2/c; a 2470.0(4), b 1643.6(6), c 2382.7(4) pm, β 128.1(3)°). The tin atom is the centre of a tetrahedron of nitrogen atoms, the mean SnN-bond length (197.5 pm) being the shortest so far reported.     

The crystal structure of triphenyltin isothiocyanate

The crystal structure of Ph₃SnNCS has been determined by single crystal X-ray diffraction. The crystals are monoclinic, P2₁, a = 19.02(3), b = 11.67(2), c = 15.49(2)Å;, β = 95.64(10)°, Z = 8. The molecules are arranged in infinite zig-zag S…SnNCS…Sn&.sbnd; chains similar to those in Me₃SnNCS, but with slightly longer SnN, shorter SnS bonds, and almost planar SnC₃ units. Principal mean bond lengths and angles are: SnN, 2.22(5); NC, 1.17(8); CS, 1.58(7); SSn, 2.92(1); SnC, 2.09(3); CC, 1.38(2)Å; SnNCm 161(4); CSSn, 97(3); SSnN, 175(3) and CSnC, 119.8(1.5)°.     

Synthese und spektroskopische Untersuchungen von Di-t-Butylzinn(IV)-dicarboxylaten

Synthesis and Spectroscopic Studies of Di-t-butyltin(IV) dicarboxylates Five Di-t-butyltin(IV) dicarboxylates t-Bu₂Sn(O₂CR)₂ (R ? CH₃, C(CH₃)₃, C₆H₅, C₆H₄NH₂-2, C₅H₄N-2) have been synthesized by reaction of Di-t-butyltinoxide (t-Bu₂SnO)₃ with corresponding ligands and studied by ¹H-, ¹³C-, ¹¹⁹Sn n.m.r. and infrared spectroscopy. The compounds are monomeric in CD₂Cl₂- or CDCl₃-solution and have pentacoordinated tin atoms with exception of the picolinate. The coordination takes place through the carboxylic oxygen atoms. In the Di-t-butyltin(IV)di-2-picolinate the tin atom is hexacoordinated by intramolecular tin-nitrogen-interaction.     

The crystal and molecular structure of tris[(triphenylstannyl)methyl]methane

The title compound, C₅₈H₅₂Sn₃, belongs to the triclinic space group P$\text{1}$, with a 10.165, b 13.365, c 18.670 Å, α 96.28, β 93.88, γ 103.15°, V = 2443.8 ų, f_w = 1105.1, Z = 2, D_calc 1.501 g cm^?3, m.p. 206.5–208°C, λ(Mo-K_$\text{α}$) 0.71069 Å. The structure was refined on 2684 nonzero reflections to an R factor of 0.044. The crystal contains molecules in which the (SnCH₂)₃CH core possesses an approximate C₃ symmetry. The three SnC(H₂) bonds are gauche to the C(4)-H bond. Repulsive interactions involving the bulky Ph₃Sn substituents lead to large SnC(H₂)C(H) angles (av. 117.3°), whereas the C(H₂)C(H)C(H₂) angles at the tertiary carbon average 111.3°. Little distortion of the Ph₃Sn groups themselves is present, since the PhSnPh angles (av. 109.8°) are almost equal to the C(H₂)SnPh angles (av. 109.9°). The molecule as a whole has no symmetry because the aromatic rings in the three Ph₃Sn groups have different orientations. The phenyl groups create a pocket in the middle of the molecule which encloses and shields the tertiary hydrogen atom. The resulting inaccessibility of this hydrogen accounts in part for the low reactivity of the title compound in redox reactions.     

Synthese und strukturuntersuchungen von zwei stannylwolframpentacarbonylen R2Sn-W(CO)5 (R = (o-dimethylaminomethyl)phenyl bzw. (o-diphenylphosphinomethyl)phenyl)

The compounds [o-C₆-H₄CH₂E]₂Sn-W(CO)₅, (E = NMe₂ (1) or PPh₂ (2)) have been prepared by reaction of o-LiC₆H₄CH₂E with pentacarbonyltungsten tin(II) chloride (CO)₅WSnCl₂. The complexes were characterized by ¹³C, ³¹P, and ¹¹⁹Sn NMR spectroscopy and by X-ray diffraction analyses. 1 crystallizes monoclinically in the space group C/c (no. 15) with a 1310.2(4), b 1552.1(4), c 1202.9(4) pm, β 90.11(4)°, and Z = 4. 2 crystallizes monoclinically in the space goup P2₁/n (no. 14) with a 2108.1(4), b 1707.7(4), c 1283.7(3) pm, β 97.47(2)° and Z = 4. The structures were refined to final R values of 0.029 and 0.039, respectively.The SnW bond distances of 274.9 and 276.2 pm are very similar in both complexes. The Sn atoms are penta-coordinated by 2C, 2N and W in 1 and by 2C, 2P and W in 2. The penta-coordination comprises one SnW and two SnC single bonds, and either a SnN (in 1) or a SnP bond (in 2) of bond order 0.45. In the stannyl group of 1 the SnN bond distances both are identical by symmetry (256.4 pm), whereas the two SnP bond lengths of 2 differ to some extent (283.1 and 301.2 pm).     

Synthetic and structural studies on some 1,3-diselena- and 1,3-dithia-[3]ferrocenophanes of germanium and tin. crystal and molecular structure of 1,3-diselena-2,2- dichlorogermyl-[3]ferrocenophane

A series of [3]ferrocenophanes of general formula Fe(C₅H₄X)₂YCl₂ and the spiro compounds [Fe(C₅H₄X)₂]₂Ge (X = S, Se; Y = Ge, Sn) have been prepared by the reaction of ferrocene 1,1′-dithiol and ferrocene 1,1′-diselenol with tetrahalides of germanium and tin. Spectroscopic properties of the compounds are reported. In solution, the compounds are fluxional by a bridge reversal process. The crystal structure of 1,3-diselena-2,2-dichlorogermyl-[3]ferrocenophane at 163 K. has been determined by X-ray diffraction methods. At that temperature, crystals have space group P2₁/n with a 6.222(3), b 16.156(13), c 12.968(4) Å, β 97.53(1)° and Z = 4. Least-squares refinement gave R = 0.033 for 2834 unique significant reflections whose intensities were measured by counter diffractometry. The two SeGe bond lengths are 2.323 and 2.325(1) Å, with GeCl 2.148 and 2.161(1) Å. The SeGeSe bond angle is 118.2(1)°, ClGeCl 104.7(1)°, and SeGeCl angles range from 106.2 to 109.8(1)°. The SeC bond lengths are 1.901 and 1.904(5) Å, with CSeGe angles of 95.8 and 96.5(2)°. The cyclopentadienyl rings are in an eclipsed conformation with a mean twist angle of 2.7°, and are inclined to one another at 6.1°. The Se atoms are displaced from the ring planes by 0.17 and 0.20 Å yielding a non-bonded intramolecular Se…Se contact of 3.99 Å.