Functionally substituted organotin compounds I. Addition of thiols to alkenyltin compounds

3-(Trialkylstannyl)propyl aryl sulphides (R₃SnCH₂CH₂CH₂SR′; R = Me, Et, Bu; R′ = Ph, p-tolyl) were prepared by the addition of arenethiols to allyltrialkyltin compounds. Preferential cleavage of the allyl group by the reaction R₃SnCH₂CHCH₂+R′SH→R₃SnSR′+CH₃CHCH₂ occurred when R = R′ = Bu and R = R′ = Ph. Diallyltin dibromide and benzenethiol gave stannous bromide. Mössbauer parameters of the products are recorded.     

Photoelectron spectra of molecules : VI. Hyperconjugation versus pπdπ bonding in group IVb compounds

Helium(I) photoelectron spectra have been obtained for the compounds (CH₃)₃MPh and (CH₃)₃MCH₂Ph (M = Group IV metal). The results have been partitioned by first order perturbation theory into hyperconjugation, induction and in the phenyl derivatives p_πd_π bonding.     

The preparation and properties of some allyltin carboxylates:R3SnOOCR′ (R′ = CH3, CH2Cl), R2Sn(OOCR′)2 (R′ = CH2Cl,CHCl2) and [R2Sn(OOCR′)]2O (R′ = CH2Cl,CHCl2, CCl3)

Triallyl- and diallyltin carboxylates [(CH₂CHCH₂)₃SnOOCR′ with R′ = CH₃ and CH₂Cl, (CH₂CHCH₂)₂Sn(OOCR′)₂ with R′ = CH₂Cl and CHCl₂)] and tetraallyl-1,3-diacyloxydistannoxanes {[(CH₂CHCH₂)₂SnOOCR′]₂ with R′ = CH₂Cl,CHCl₂ and CCl₃}, have been prepared from the reaction of tetraallytin with carboxylic acids in methanol.     

A multinuclear NMR spectroscopy study of alkoxysilanes

¹⁷O, ²⁹Si, and ¹³C NMR spectra of more than 100 mono-, di-, tri- and tetra-alkoxysilanes R_4−nSi(OR′)_n; R = C_nH_2n+1, Ph, CH₂Cl, CH₂Br; R′ = C_nH_2n+1, CH₂Ph, CH₂CH₂Cl, CH₂CHCH₂, CH₂CCH, CH₂CF₃. (CH₂)₃Cl, (CH₂)₃CN have been studied.Linear relationships between the chemical shifts of ¹⁷O, ²⁹Si, ¹³C in alkoxysilanes and the inductive and steric constants of substituents R and R′ were observed. Different transmission of electronic effects along the SiO bond in various directions was revealed by means of ¹³C, ²⁹Si, ¹⁷O NMR spectroscopy and correlation analysis. The results are discussed in terms of (pd)_π-bonding between the oxygen and silicon atoms in compounds containing an SiO bond.     

Structure electronique de silacyclopentenes-2 et -3

Photoelectron spectroscopy is used to compare the electronic structures of 1,1′-dimethylsilacyclopent-3-ene, 1,1′-dimethylsilacyclopent-2-ene and several phenyl, vinyl and allyl derivatives. When a π orbital is on α position of the silicon atom, a hyperconjugation (α(SiC)π interaction) and a homoconjugation (p_πd_π interaction) are observed. The polarization induced by the P_πd_π interaction explains the differences of nucleophilic reactivity showed by the compounds studied. Also, the analysis of the shifts of first ionization potentials made it possible to propose a conformation for 1,1′-diallylsilacyclopent-3-ene.     

Infrared study of some specificities of the dπpπ interaction in organogermanium compounds

The analysis is presented for the frequencies of stretching modes ν(GeH) in the IR spectra of organogermanium compounds R₂XGeH, RX₂GeH, RXYGeH, X₂YGeH and XYGeH₂ (where R is a substituent which does not make a d_πp_π bond with germanium, and X and Y are groups capable of d_πp_π interaction with germanium). It is shown that ν(GeH) in these compounds is dependent on both the I effect of R, X and Y, and the d_πp_π interaction in GeX and GeY bonds. If only one substituent capable of d_πp_π interaction with germanium is present, the value of such an effect is determined by itsσo_Rconstant. However, when germanium is bound to several substituents capable of d_πp_π interaction its magnitude depends on the effective charge at germanium which is determined by the inductive and mesomeric effects of X and Y. The data obtained are compared to the dependences observed in the IR spectra of similar organosilicon compounds.     

Telomerisation par catalyse redox—XIII. Synthese d'alcools fluores a partir des telomeres des acetates de vinyle et d'allyle avec des telogenes fluores

Telomerizations by redox catalysis of vinyl and allyl acetates with carbon tetrachloride, 1,1,1 trichlorotrifluoroethane and CCl₃(CF₂CFCl)_nCl were studied. Chemical transformation of these telomers by various ways leads to corresponding alcohols: RCCl₂CH₂CH₂OH and RCCl₂CH₂CHClCH₂OH with R = Cl, CF₃, Cl(CFClCF₂)_n.     

Cleavage of benzyltrimethylstannanes by aqueous methanolic perchloric acid

The rates of cleavage of some XC₆H₄CH₂SnMe₃ bonds by aqueous-methanolic perchloric acid have been measured spectrophotometrically, and the rate of cleavage of the MeSn bonds of PhCH₂SnMe₃ and Me₄Sn by monitoring the methane evolution. The results indicate that for X = H, p-Me, o-Me, p-Bu^t, o-, m- and p-F and -Cl, and o-Br, the cleavage of the CH₂SnMe₃ bond involves attack of the acid at the benzylic atom, and is not much faster than that of the SnMe bonds, but that a mechanism involving ring-protonation is important for X = m-Me, and greatly predominant for X = m-OMe.     

Synthesis,molecular structures and PMR spectra of heteronuclear niobocene derivatives containing a niobium-tin bond

Treatment of niobocene carbonylhydride, Cp₂Nb(CO)H (I), with Ph_nSnCl_4?n and Et₂SnCl₂ in THF in the presence of Et₃N leads to the respective heteronuclear complexes Cp₂Nb(CO)SnR_nCl_3?n (R = Ph, n = 3 ÷ 1 (II–IV), R = Et, n = 2 (V)). Treatment of II with HCl in ether gives Cp₂Nb(CO)SnCl₃ (VI). Complex VI and its analog (MeC₅H₄)₂Nb(CO)SnCl₃ (VIII) were prepared by an alternative synthesis using direct reaction of I or (MeC₅H₄)₂Nb(CO)H with an equimolar quantity of SnCl₄ in THF in the presence of Et₃N. Complex VI is also generated by insertion of SnCl₂ into the NbCl bond in Cp₂Nb(CO)Cl (VII). X-Ray analysis of complexes II and VIII was performed: for II, space group P2₁/n, a = 10.1021(21), b = 17.4633(32), c= 14.2473(29) Å, β = 95.578(16)°, Z = 4; for VIII, space group. P2₁/n, a= 8.9369(15), b = 13.3589(12), c = 13.9292(20) Å, β = 99.490(14)°, Z = 4. The NbSn bond in VIII (2.764(9) Å) is shorter than that in II (2.825(2) Å). In both cases the NbSn bond is significantly shorter than the sum of Nb and Sn covalent radii (1.66 + 1.40 = 3.06 Å). It is probably partly multiple in character owing to an additional interaction of the lone electron pair of the Nb^III ion (d² configuration) with the antibonding Sn orbitals. The PMR spectra of II–VI exhibit two satellites of the singlet of C₅H₅ protons because of HSn¹¹⁷ and HSn¹¹⁹ spin-spin coupling (SSC). The SSC constant correlates with the number of electronegative chlorine atoms on the Sn atom.     

Über Antimon-haltige Heterocyclen—IV. Schwingungsspektren von phenylierten Oxadithia- und Trithiastibocanen, -bismocanen, -stannocanen und -plumbocanen

The i.r. and Raman spectra of the cyclic dithiolates Ph_nM(SCH₂CH₂)₂X (n = 1, M = Sb, Bi; n = 2, M = Sn, Pb; X = O, S) are reported (3200-100 cm⁻¹). The spectra are very similar for both X = O and X = S. The pentadeuterophenylated antimony analogues (Ph-d₅)Sb(SCH₂CH₂)₂X make it possible to separate signals originating from vibrations of the phenyl groups, of the aliphatic ring parts and of the coordination polyhedra around M, respectively.     

Electron diffraction investigation of the molecular structure of cyclopropyl silane

The molecular structure of cyclopropyl silane (CPS) has been determined by gas phase electron diffraction. Among other parameters the bond distances (r_a) are: C₁C₂ = 1.528(2) Å, C₂C₃ = 1.490(4) Å, SiC = 1.840(2) Å, CH = 1.095(3) Å. The angle between the ring plane and the bond SiC is 55.9(3)°. The introduction of a tilt of the silyl group is in agreement with the secondary effect of substituents. The role of the silicon 3d orbitals in the interpretation of the structural data of CPS is discussed. Our results support the interpretation of the SiC bond to silicon in terms of dπ conjugation. This causes an asymmetry in the structure of the ring. The (pd)_π bonding concept is considered to be the sum of three different contributions: ionic, steric and dπ conjugation.     

Diorganotin(IV) bis(O,O-alkylenedithiophosphates)

O,O-Alkylenedithiophosphates of diorganotin(IV) of the type R₂Sn[SP(S)O₂G]₂ (R = Me, Et, n-Bu, Ph; G = CH₂CMe₂CH₂, CMe₂CMe₂, CMe₂CH₂CHMe) have been synthesized by the reactions of diorganotin(IV) dichlorides with ammonium O,O-alkylenedithiophosphates or that of diorganotin(IV) oxides with O,O-alkylenedithiophosphoric acids in 1:2 molar ratio in benzene. These new complexes are white solids which are soluble in common organic solvents and are monomeric in refluxing benzene; and they have been characterized by elemental analysis and by different spectroscopic (IR, ¹H, ¹³C, ³¹P and ¹¹⁹Sn NMR) studies, on the basis of which a six coordinated octahedral structure has been suggested in solution.     

Neighbouring group participation in reactions between iodine and Ph3Sn(CH2)nS(O)mC6H4Me-p

Reaction of Ph₃Sn(CH₂)_nS(O)_mC₆H₄Me-p (n = 2, 3, or 4; m = 0, 1 or 2) with iodine in CCl₄ result in phenyltin bond cleavage. The relative reactivities indicate intramolecular nucleophilic catalysis by the sulphur-containing substituents.     

The crystal structure of triphenylallyltin

The crystal structure of (C₆H₅)₃SnCH₂CHCH₂ has been determined. The asymmetric unit consists of two molecules of triphenylallyltin having virtually the same conformation. Their geometrical parameters exclude p_π-d_π bonding between the metal and the allyl double bond, and seem to be in a better agreement with a σ-π conjugation effect.     

New di- and triorganotin(IV) complexes of tripodal Schiff base ligand containing three imidazole arms: Synthesis, structural characterization, anti-inflammatory activity and thermal studies

Some new tri- and diorganotin(IV) complexes of the general formula, R₃Sn(H₂L) and R′₂Sn(HL) [where R = Me, n-Pr, n-Bu and Ph; R′ = Me, n-Bu, Ph and n-Oct; H₃L = Schiff base (abbreviated as tren(4-Me-5-ImH)₃) derived from condensation of tris(2-aminoethyl)amine (tren) and 4-methyl-5-imidazolecarboxaldehyde (4-Me-5-ImH)] have been synthesized. The coordination behaviour of Schiff base towards organotin(IV) moieties is discussed on the basis of infrared and far-infrared, ¹¹⁹Sn Mössbauer and multinuclear (¹H, ¹³C and ¹¹⁹Sn) magnetic resonance (NMR) spectroscopic studies. Thermal studies of all of the synthesized organotin(IV) complexes have been carried out using TG, DTG and DTA techniques. The residues thus obtained from pyrolysis of the studied complexes have been characterized by X-ray powder diffraction analysis and IR. The newly synthesized complexes have been tested for their anti-inflammatory activity and toxicity (LD₅₀).     

A “double-zeta” type wavefunction for an organometallic: Bis-(π-allyl)nickel

A wavefunction which is of double-zeta quality at the level of the valence orbitals [based on a (11, 7, 5/8, 4/4) gaussian basis set contracted to (4, 3, 2/3, 2/2)] is reported for thebis-(π-allyl)nickel molecule. Independant SCF calculations for two ionized states substantiate the conclusion reached previously for a number of organometallics with a minimal basis set that Koopmans' theorem is not valid for these molecules, namely that the highest occupied orbital from the ground state calculation for the neutral molecule is mostly a ligand π orbital whereas the lowest ionization potential corresponds to the removal of an electron from a molecular orbital which is mostly a metal 3d orbital. The nature of the bonding inbis-(π-allyl)nickel is discussed on the basis of the possible interactions between the metal orbitals and the π orbitals of the allyl group. The interaction between the filled nonbonding π orbital of the allyl group and the empty 3d _xz orbital of the Ni atom appears responsible for most of the bonding, together with some backbonding through an interaction between the 3d x ²?y ²and 3d xyorbitals and the σ and π orbitals of the ligands. The computed value for the rotation barrier about the C-C allyl bond, 90 kcal/mole, rules out this rotation as one of the possible mechanisms which account for the equivalence of the terminal hydrogens in the proton magnetic resonance spectra of π-allyl complexes.     

Syntheses and structures of lithiated sulfones Li[CR(R′)SO2Ph] - C versus O bound lithium. [{Li{CH(Me)SO2Ph}(thf)}∞] - The structure of a C-bound derivative

Sulfones RCH(R′)SO₂Ph were reacted with n-BuLi in thf/n-hexane (R/R′ = H/Me, Me/Et, H/CH₂Ph) and toluene/n-hexane (R/R′ = Me/Ph) yielding under deprotonation Li[CR(R′)SO₂Ph] which reacted with Me₃SiCl and n-Bu₃SnCl forming the requisite trimethylsilyl and tri(n-butyl)tin substituted derivatives . Performing the reactions of RCH(R′)SO₂Ph with n-BuLi in n-hexane (instead of thf/n-hexane) and toluene/n-hexane, respectively, resulted in the precipitation of the organo lithium compounds Li[CR(R′)SO₂Ph] (1-4) which were isolated as strongly moisture-sensitive yellow powders in essentially quantitative yields. Their identities were confirmed by ¹H and ¹³C NMR spectroscopic measurements in thf-d₈. Solutions of each 1, 3, and 4 in thf/n-hexane and thf/n-pentane afforded crystals of each [{Li{CH(Me)SO₂Ph}(thf)}_∞] (1a), [{Li{CH(CH₂Ph)SO₂Ph}(thf)}_∞] (3a), and [{Li{CMe(Ph)SO₂Ph}(thf)₂}₂] (4a), respectively, whose structures were determined by single-crystal X-ray crystallography. The compounds 1a and 3a crystallize in 1D polymeric ladder-like structures. The strands of 1a are built-up by eight-membered Li₂C₂S₂O₂ rings having direct Li-C bonding interactions (Li-C 2.215(5) Å). The donor set of Li is completed by three oxygen atoms, one from the thf ligand and two from SO₂ groups of neighboring Li{CH(Me)SO₂Ph}(thf) entities. The strands of 3a are built-up of alternating Li₂S₂O₄ eight- and Li₂O₂ four-membered rings. Each lithium atom is coordinated to three oxygen atoms, two from O₂S(Ph)CHCH₂Ph groups and one from thf oxygen atom. There is no Li-C bonding. Compound 4a crystallizes in dimers consisting of eight-membered Li₂S₂O₄ rings in which the two lithium atoms are bridged by two O₂S(Ph)CHMePh groups. The coordination sphere of lithium is completed by two oxygen atoms of the thf ligands.     

Étude lcao-mo-cndo/2 des liaisons po et no dans des composés X3PO ET X3NO

The authors have studied the electronic structure of X₃PO and X₃NO compounds (with X = F, Cl, CH₃), using the semi-empirical CNDO/2 method. All the calculations have been made with and without 3d functions on the phosphorus atom. The comparison between the calculated and experimental values, especially in the case of bond length, dipole moment, and orbital level order, shows the influence of the 3d orbitals in the PO bond, which contains a sigma donation P → O and a pπ(O)-dπ(P) back bonding. The NO bond has sigma character in trimethylamine oxide, but is partially a double bond in trifluoramine oxide.     

Ultraviolet photoelectron spectroscopic study of MS σ bonding energy and of spiroconjugation effects in group IVA thiospiranes

He(I) and He(II) ultraviolet photoelectron spectra of tetrathiometallaspiranes

(M = C, Si, Ge, Sn) yield data for quantitative characterization of several structural effects. Spiroconjugation of the lone pair orbitals of the sulfur atoms is indicated by the splitting patterns of the n_s ionization bands in the low IE region (8–9_eV); quantitative evaluation confirms that there is a marked decrease of the spiroconjugation effects with increasing size of M. Energy values are assigned by UP spectral analysis to MS σ bond orbitals which show a small variation with M between ca. 10 and 11 eV, consistent with the small electronegativity variation, and to CS bond orbitals in the spirane rings, fairly constant around 13.5 eV. Ionizations of the quasi-valence 4d orbitals in the Sn derivative are identified at 34.38 and 35.42 eV, and suggest, by comparison with other known Sn compounds, a considerably high overall electronegativity of the ligands in the present compound.     

Double bond migration in Sallyl systems catalysed by [RuClH(CO)(PPh3)3]

Reactions of Sallyl systems (allyl sulphides of RSallyl type, where R=Et, allyl, Ph, Me₃C, Ph₃C, as well as of allyl phenyl sulphoxide, allyl phenyl sulphone, 2,5-dihydro-1,1-dioxothiophene) with [RuClH(CO)(PPh₃)₃] and other ruthenium compounds have been investigated. Double-bond migration was observed in the case of allyl trityl sulphide, allyl t-butyl sulphide and both sulphones, that is, where co-ordinating properties of sulphur were not too strong. High-yielded syntheses of (E)- and (Z)-RSCHCHCH₃ (R=Me₃C, Z:E=96:4 and Ph₃C, Z:E=92:8), (E)PhS(O₂)CHCHCH₃ and 2,3-dihydro-1,1-dioxothiophene from respective allyl systems are described. The binuclear Ru complex, formed in the model reaction of allyl phenyl sulphide with [RuClH(CO)(PPh₃)₃] has been isolated and its structure has been resolved. The mechanism of the reaction between Sallyl systems and [RuClH(CO(PPh₃)₃] is proposed.