1066-45-1Relevant articles and documents
Alkyl- and acyl-substituted vinylstannanes: Synthesis and reactivity in electrophilic substitution reactions
Cochran, John C.,Prindle, Vicki,Young, Heather A.,Kumar, Mark H.,Tom, Samson,Petraco, Nicholas D. K.,Mohoro, Clare,Kelley, Brendan
, p. 885 - 902 (2002)
Six substituted vinylstannanes have been prepared. (E)- and (Z)-2-trimethylstannyl-2-butene, (1) and (2), respectively, 2-methyl-1-(trimethylstannyl) propene, (3), and 3-methyl-2-trimethylstannyl-2-butene, (4), were prepared by coupling the appropriate lithium or Grignard reagent with chlorotrimethylstannane. 3-Trimethylstannyl-3-butene-2-one, (5), and (Z)-3-trimethylstannyl-3-hexene-2-one, (6), were prepared by palladium(O) catalyzed hydrostannation of the appropriate ynone. This reaction was regiospecific such that the trimethylstannyl and carbonyl groups were bonded at the same vinyl carbon. The reaction was also stereospecific giving syn addition in each case. However, isomerization to a mixture of isomers was observed for the reaction of (5) with Me3SnD and complete isomerization of E-(6) to Z-(6). Each compound was characterized by 1H, 13C, and 119Sn NMR. The reactivity to protodestannylation was determined for each compound by spectrophotometric measurement of second order rate constants. The reactivity of the multimethyl-substituted vinylstannanes was consistent with the reactivity determined previously for monomethyl-substituted vinylstannanes. However, two methyl groups at the remote vinyl carbon exhibited a synergistic activating effect on the protodestannylation reactivity. The acyl group was found to be deactivating for protodestannylation. The stereochemistry of the reaction was round to take place with retention of configuration.
Synthesis and reactivity of germanium heterocycles containing germanium - tin bonds
Nosov,Lalov,Borovik,Lee,Egorov,Nefedov
, p. 2623 - 2626 (1996)
Previously unknown stannyl-substituted germanium heterocycles, 1,1-bis(trimethylstannyl)-2,3,4,5-tetraphenyl-1-germacyclopenta-2,4-diene and 1,1-bis(trimethylstannyl)-3,4-dimethyl-1-germacyclopent-3-ene were synthesized, and their photolysis and chemical
Reagents based on cyclopentadienyl derivatives of the group 14 elements for the synthesis of indium(I) derivatives. Crystal and molecular structure of in(C5H4SiMe3)
Beachley Jr.,Lees,Glassman,Churchill, Melvyn Rowen,Buttrey, Lisa A.
, p. 2488 - 2492 (1990)
Cyclopentadienyl trimethyl derivatives of the group 14 elements (C5H4MMe3, M = Si, Ge, Sn) have been investigated for their effects on indium(I) chemistry. The compounds In(C5H4SiMe3) and In(C5H4GeMe3) have been prepared from the corresponding lithium cyclopentadienyl reagent LiC5H4MMe3 and InCl. Characterization data have included partial elemental analyses (C, H), physical properties, IR and 1H NMR spectroscopic data, oxidation reactions with dilute aqueous HCl, and a single-crystal X-ray structural study in the case of In(C5H4SiMe3). When cyclopentadienyltrimethyltin, C5H5SnMe3, was combined with InCl in diethyl ether, In(C5H5) and Me3SnCl were formed in good yields. In(C5H4SiMe3) crystallizes in the centrosymmetric monoclinic space group P21/c (C2h5; No. 14) with a = 9.171 (5) ?, b = 9.910 (6) ?, c = 11.677 (7) ?, β = 97.30 (5)°, V = 1052.6 (11) ?3, and Z = 4. Diffraction data (Mo Kα radiation, 2θ = 4.5-50.0°) were collected on a Syntex P21 automated four-circle diffractometer, and the structure was solved and refined to RF = 5.0% and RwF = 4.0% for all 1851 independent reflections (RF = 3.1% and RwF = 3.5% for those 1336 data with |Fo| > 6σ|Fo|)). The solid-state structure consists of infinite zigzag chains of [In(C5H4SiMe3)]∞. Each indium atom interacts with two η5-C5H4SiMe3 ligands with a centroid?In?centroid angle of 131.78°, and each η5-C5H4SiMe3 ligand is linked to two indium atoms with In?centroid?In angles of 175.94°. There are no short interstrand In?In interactions, the shortest such distance being 5.428 ?. Thus, In(C5H4SiMe3) is the first cyclopentadienylindium(I) derivative with no apparent indium-indium interactions.
Investigation of the catalyst system tungsten hexachloride/tetramethyltin; reduction of tungsten hexachloride during the alkylation step
Thorn-Csanyi, E.,Kessler, M.
, p. 253 - 260 (1991)
The alkylation steps in the catalyst system tungsten hexachloride/tetramethyltin have been studied kinetically. FTIR examinations in combination with UV and GC results have shown that the alkylation of tungsten hexachloride is accompanied by a reduction of the tungsten component. Ether addition increases the amount of the tungsten chloride which is reduced.
Donor-Acceptor Complexes of Organometals and Iodine. Alkyl Ligands as Probes for Steric Effects in Charge Transfer
Fukuzumi, S.,Kochi, J. K.
, p. 608 - 616 (1980)
Charge-transfer (CT) absorptions are observed between iodine and a variety of homoleptic alkylmetals including dialkylmercury (R2Hg) and tetraalkylmetals (R4M) of the group 4A elements (where M = lead, tin, germanium, and silicon) in carbon tetrachloride solutions.These alkylmetal-iodine complexes are all classified as weak, the formation constants, K, being generally less than 5 M-1 for dialkylmercury and less than 3 M-1 for the methylethyllead compounds.The formation constants of tetraalkyltin, -germanium, and -silicon are too small to measure (K -1).The frequency of the charge-transfer bands (hνCT) varies lineary with the vertical ionization potential (ID) of the alkylmetal, determined independently from the photoelectron spectra.However, two separate correlations are required for these alkylmetals-one for the series of two-coordinate, linear dialkylmercury compound and another for the series of four-coordinate, tetrahedral tetraalkylmetals corresponding to a sterically open and a quasi-spherical configuration of electron donors, respectively.Steric effects in these alkylmetal-iodine complexes may be evaluated in two ways.By the direct method, the role of steric effects in determining the charge transfer transition energy is associated with the Coulombic term (e2/rDA) in the first-order treatment of weak complexes according to the Mulliken theory.The mean separation rDAin the CT complexes of R2Hg and R4M, calculated from the measured values of βCT, ID, and the vertical electron affinity of iodine, shows two paralell trends, both increasing with decreasing values of the ionization potentials.This behavior is the same as that evaluated for the CT complexes of tetracyanoethylene (TCNE) with the same series of alkylmetals, in which K is larger and can be measured for as well as complexes.By the indirect method, steric effects are evaluated relative to a reference alkylmetal (Me2Hg for R2Hg and Me4Sn for R4M).The difference ΔE, taken as the relative change in steric effects, is shown to be essentially the same in TCNE and iodine complexes.The later bears on the general question as to whether small (intermediant) values of K (-1) or -ΔH (-1) can be used as adequate criteria for contact charge transfer.
Aryltrimethylstannane Cation Radical Fragmentation Selectivities That Depend on Codonor: Evidence for Reactions from Heterodimer Cation Radicals
Luo, Pu,Dinnocenzo, Joseph P.
, p. 11052 - 11055 (2017)
The aryl/methyl fragmentation selectivities for the photooxidations of phenyltrimethylstannane and (4-methylphenyl)trimethylstannane by 1,2,4,5-tetracyanobenzene in acetonitrile were found to depend on the codonor used to generate the stannane cation radi
Supramolecular host-guest coordination systems: [(G+)(Me3E)3MII(CN) 6]∞ as ion exchangers, where (G+=Me3E, Et4N or stp), (E=Sn or Pb) and (M=Fe or Ru)
Ibrahim, Amany M.A.
, p. 2711 - 2721 (1999)
A number of 3D-coordination polymers, constructed via [dM(CN)6] building blocks and (Me3E) connecting units, have been prepared and characterized by X-ray powder diffraction and different spectroscopic methods. 1-Methyl-4-(4′-R-styryl) or (2′-R-styryl) pyridinium cations (stp) have been successfully encapsulated within the expandable wide channels of the 3D-coordination polymers by tribochemical or ion exchange reactions producing novel molecular composites. Apart from 6, [(4′-OCH3-stp)(Me3Sn)3Fe II(CN)6-MeOH]∞ which exhibits thermochromic behaviour, the molecular composites [(stp)x(Me3E)3FeIII 1-xFeIIx(CN)6]∞, 1-12 are mixed valence materials exhibiting localized interaction between the mixed valence iron. The results indicated an ion charge transfer interaction between the guest stp-cations and the host matrix. The molecular composites [(stp)(Me3E)3 MII(CN)6]∞, 13-18 are due to the facile readiness of the coordination polymers [(Me3E)4M(CN)6]∞ and [(Et4N)(Me3Sn)3Fe(CN6)] ∞ to ion exchange. Elsevier Science Ltd.
Simple procedure for conversion of a trialkyltin fluoride into the corresponding chloride or bromide
Mitchell, Terence N.,Kwetkat, Klaus,Godry, Bernd
, p. 1633 - 1634 (1991)
Trialkyltin fluorides are converted into the chlorides or bromides on treatment with an excess of the corresponding sodium halide in tetrahydrofuran.
Electon-Transfer, Halogen-Metal Exchange and Direct Processes in Formal Nucleophilic Substitutions on Alkyl Halides by Trimethyltinsodium
Smith, Gary F.,Kuivila, Henry G.,Simon, Reyna,Sultan, Leslie
, p. 833 - 839 (1981)
Formal nucleophilic substitutions have been studied by simple trapping techniques designed to separate and estimate contributions of reactions proceeding by way of free radicals, by way of anions, and by way of geminate or synchronous processes.Reactions of trimethyltinsodium with organic halides in tetrahydrofuran at 0 deg C were examined, using dicyclohexylphosphine for trapping free radicals and tert-butylamine for free anionoids.Among 22 halides included in this study nine have been shown to involve two or all three of the mechanistic pathways.Primary chlorides reacted predominantly by a direct mechanism (SN2, geminate reaction of intermediates, or multicenter process).Branching, as in isobutyl and neopentyl, led to contributions from electron-transfer (free radical) and halogen-metal exchange (anionoid) mechanisms.Secondary bromides reacted predominantly by the ET process (major) and HME (minor) while the relative contributions from these were reversed in importance with the iodides.Triethylcarbinyl chloride reacted exclusively by elimination while the bromide reacted by ET alone or in competition with elimination. 1- and 2-bromoadamantanes reacted by ET, and 1-chloroadamantane showed no reaction after 10 days at -4 deg C.
Redox properties of dihalogermylenes, dihalostannylenes and their complexes with Lewis bases
Lee, V.Ya.,Basova, A.A.,Matchkarovskaya, I.A.,Faustov, V.I.,Egorov, M.P.,et al.
, p. 27 - 34 (1995)
Reduction and oxidation potentials of Gel2, GeBr2 * B (B = dioxane, PPh3), GeCl2 * B (B = dioxane, PPh3, AsPh3, Py, dip), SnCl2 * dioxane, SnX2 (X = F, Cl Br, I) were measured in MeCN at 20 deg C.The data obtained indicate that in many cases the EX2 and EX2 * B (E = Ge, Sn) can act not only as a good reducing agents, but also as strong oxidants.Examples of redox reactions in which EX2 and EX2 * B react as oxidizing agents were found.The variation of the redox potentials of the dihalogermylenes and dihalostannylenes with complexation and with the nature of the halogen substituent and the Lewis base is discussed.In some cases (GeI2, GeX2 * B; X = Cl, Br, B = dioxane, PPh3), the reduction or oxidation was found to be quasi-reversible, indicating the presence of relatively stable ion radicals.AM1 calculations on GeCl2 * dioxane and GeCl2 * PH3 complexes show that the complexation destabilizes both the highest occupied and the lowest unoccupied MOs of the carbene analogues.The complexation reduces the IP and lowers the oxidation potential; its intluence on the electron affinity is not straightforward.Calculations of the ion radicals of GeCl2 and GeCl2 * B (B = dioxane, PH3 ) show that in the ground state an unpaired electron occupies ?-MO in the cation and ?-MO in anion radicals.Keywords: Germanium; Tin; Germylenes; Stannylene; Electrochemistry; AM1 calculations
