- Synthesis and reactivity of heterodinuclear Fe-Ni complexes with a bridging alkoxysilyl ligand. Crystal structure of [(OC)3Fe{μ-Si(OMe)2(OMe)}(μ-dppm)NiMe]
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The new heterobimetallic complex [(OC)3Fe- {μ-Si(OMe)2(OMe)}(μ-dppm)NiCl] (1) was obtained in 95% yield by reaction of [NiCl2(PPh3)2] in THF with K[Fe{Si(OMe)3}(CO)3(dppm-P)] at -78°C. The analogous bromo and iodo complexes were also obtained; the latter is, however, less stable and could not be isolated pure. They display the first examples of a bridging alkoxysilyl ligand between Fe and Ni, and the μ2-η2-SiO bridge is also present in the methyl complex [(OC)3Fe{μ-Si(OMe)2(OMe)}(μ-dppm)NiMe] (4) and its phenyl analogue 5. The presence of the Fe-Si-O→Ni four-membered rings was confirmed by a crystal structure determination of 4. Treatment of 1 with excess (allyl)MgCl led to the expected bimetallic allyl complex [(OC)3{(MeO)3Si}Fe(μ-dppm)Ni(η3- C3H5)] (6). The rapid η3-allyl → η1-allyl → η3-allyl rearrangement is potentially assisted through stabilization of the coordinatively unsaturated Ni center by a SiO→Ni interaction. The bimetallic benzyl derivative 7 was also isolated. Purging a THF or benzene solution of 4 at room temperature with CO yielded after a few seconds the acyl complex [(OC)3Fe{μ-Si(OMe)2(OMe)}(μ-dppm)-NiC(O)Me] (8), which readily decarbonylates. Its reaction with norbornadiene leads to the insertion product, which is thought to exist as an isomeric mixture with terminal or chelating acyl group (11 ? 11′). When complex 4 was reacted with tBuNC, rapid insertion occurred and further coordination of a terminal tBuNC ligand to Ni led to the iminoacyl complex [(OC)3{(MeO)3Si}Fe(μ-dppm)Ni{C(NtBu)Me} (CNtBu)] (12). Complex 1 proved to be a more efficient catalyst (TON = 4100) for the dehydrogenative coupling of Ph3SnH than its mononuclear counterpart [NiCl2(PPh3)2] (TON = 1050). The maximum turnover frequency (TOF) was ca. 9800 h-1.
- Braunstein, Pierre,Clerc, Guislaine,Morise, Xavier
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- Synthesis of organotin derivatives of optically active eleven-membered macrodiolides
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The synthesis and the results obtained in the hydrostannation of eight new TADDOL diacrylates and methacrylates are reported. The addition of triorganotin hydrides, R3SnH, 12-14 (R = nBu, neophyl, Ph, respectively) to diesters 6-11 containing different combinations of substituents at the C-2 carbon of the dioxolane ring, led to macrocyclization products in all cases. The cyclohydrostannation of diacrylate 10 proceeded with complete diastereoselectivity. The cyclohydrostannation of diesters 33 and 34 with hydrides 12 and 14 in all cases only afforded one stannylated macrocycle.
- Scoccia, Jimena,Gerbino, Darío César,Podestá, Julio César
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- Electrochemical Formation of Dimeric Organostannyl Compounds
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Organosilyl stannanes were formed by electroreduction of the corresponding organostannyl chlorides or distannanes with silyl chlorides.The Sn-C bond formation was also confirmed in the reduction of a mixture of stannyl and alkyl chlorides.
- Ishiwata, Toyoaki,Nonaka, Tsutomu,Umezawa, Masanobu
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- Formation and Decay of Radical Anions of Aromatic Compounds Produced by Photoinduced Electron Transfer from the Triphenylstannyl Anion
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Upon steady-light illumination of aromatic compounds (A) in the presence of the triphenylstannyl anion (Ph3Sn-, M+) in tetrahydrofuran, radical anions of the aromatic compounds (A-.(M+)) were produced via electron transfer from Ph3Sn-, M+ to the excited aromatic compounds.After the light was cut off, the radical anions of perylene and tetracene persisted for a long time; for anthracene and pyrene, radical anions formed transiently and decayed rapidly.The decay rates depended on the reduction potentials of A.The decay processes were attributed to back electron transfer from A-.(M+) to the distannane (Ph3SnSnPh3) which is produced by the coupling of Ph3Sn., since the rate constants calculated on the basis of the above reactions were in good agreement with the observed rate constants.Slow decay of A-.(M+) could be realized when the reduction potentials of A are less negative than that of the distannane.
- Aruga, Tamotsu,Ito, Osamu,Matsuda, Minoru
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- Reactivity of heterobimetallic alkoxysilyl and siloxy complexes in the catalytic dehydrogenative coupling of tin hydrides
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Heterobimetallic complexes [(OC)3(R3Si)Fe(μ-dppm)Pd(η3-allyl)] 1 (R = OMe, Me, OSiMe3, OSi(H)Me2) and [(OC)3Fe{μ-Si(OR)2(OR)}(μ-dppm)PdCl] 6 (R = Me, SiMe3) are effective catalyst in the dehydrogenative coupling of triorganotin hydrides HSnR′3 (R′ = Ph, nBu). Although the elementary transformations during catalysis appear to take place at palladium, the function of the iron fragment is to provide the palladium center with the appropriate coordination environment through metal-metal bonding and the Si-containing ligand. Indeed, complexes 1 and 6 revealed a higher catalytic activity than mononuclear Pd catalysts. Modifications of the substituents at silicon resulted in considerable variations of the TON (turnover number) and TOF (turnover frequency) values as well as in the lifetime of the catalysts. In the case of siloxy derivatives, TON and TOF values higher than in the case of the alkoxysilyl analogs have been obtained whereas the lifetime of the catalyst is much longer for the latter. Possible mechanisms which rationalize the role of the silicon ligand are discussed. Solvent effects have also been observed. One of the key features of these systems is the retention of the bimetallic nature of the catalyst. TON and TOF higher than 2 × 105 and 3 × 107 h-1, respectively, have been obtained in the case of HSnnBu3. The catalytic activity of 1 toward the dehydropolymerization of tin dihydrides has been tested.
- Braunstein, Pierre,Morise, Xavier
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- Europium complexes with 1,2-bis(arylimino)acenaphthenes: A search for redox isomers
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Reduction of 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (dpp-bian, 1) with metallic europium in 1,2-dimethoxyethane (dme) under anaerobic conditions gave a europium(II) complex with the acenaphthene-1,2-diimine dianion, (dpp-bian)Eu(dme)2 (4), in high yield. Oxidation of complex 4 with triphenyltin chloride or 1,2-dibromostilbene afforded the corresponding halogen derivatives [(dpp-bian)Eu(μ-Cl)(dme)]2 (5) and [(dpp-bian)Eu(μ-Br)(dme)]2 (6). The molecular structures of complexes 4-6 were determined by X-ray diffraction. The magnetic moments of complexes 5 and 6 remain constant over a temperature range from 25 to 295 K; they are indicative of the presence of the europium(II) ion and the dpp-bian radical anion in both the complexes.
- Fedushkin,Skatova,Yambulatov,Cherkasov,Demeshko
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- Direct Observation of Stannyl Radicals by Laser-Photolysis of Carbon-Tin and Tin-Tin Bonds
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Photochemical primary processes of carbon-tin and tin-tin bonds were studied at room temperature.The stannyl radicals generated were observed directly by laser-photolysis.
- Mochida, Kunio,Wakasa, Masanobu,Sakaguchi, Yoshio,Hayashi, Hisaharu
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- Reaction of a 2,4,6-triphenylphosphinine ferrate anion with electrophiles: A new route to phosphacyclohexadienyl complexes
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A novel, versatile route to phosphorus- and carbon-substituted η5-phosphacyclohexadienyl complexes was developed. Reaction of the anionic 2,4,6-triphenylphosphinine iron complex [K([18]crown-6)(thf)2][Cp?Fe(PC5Ph3H2)] (1) with selected main group element electrophiles afforded the new complexes [Cp?Fe(2-endo-H-PC5Ph3H2)] (endo-3), [Cp?Fe(2-exo-H-PC5Ph3H2)] (exo-3), [Cp?Fe(1-Me-PC5Ph3H2)] (4), [Cp?Fe(1-Me3Si-PC5Ph3H2)] (5), [Cp?Fe(1-PPh2-PC5Ph3H2)] (6) and [Cp?Fe(2-BCat-PC5Ph3H2)] (7, BCat = 2-benzo[d][1,3,2]dioxaborol-2-yl). Initial attack of the electrophile at phosphorus was observed, leading to a P-substitued phosphinine ligand. A subsequent rearragement occured in some cases, resulting in C-substituted phosphinine complexes endo-3, exo-3 and 7. The new complexes were characterized by 1H, 31P{1H}, and 13C{1H} NMR spectroscopy, UV-vis spectroscopy and elemental analysis; their molecular structures were determined by X-ray crystallography.
- Hoidn, Christian M.,Wolf, Robert
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- Reversible switching of coordination mode of ansa bis(Amidinate) ligand in ytterbium complexes driven by oxidation state of the metal atom
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Reaction of bisamidine C6H4-1,2-{NC(t-Bu)NH(2,6- Me2C6H3)}2 (1) and [(Me 3Si)2N]2Yb(THF)2 (THF = tetrahydrofuran) (toluene; room temperature) in a 1:1 molar ratio afforded a bis(amidinate) YbII complex [C6H4-1,2-{NC(t-Bu) N(2,6-Me2C6H3)}2]Yb(THF) (2) in 65% yield. Complex 2 features unusual κ1amide, η6- arene coordination of both amidinate fragments to the ytterbium ion, resulting in the formation of a bent bis(arene) structure. Oxidation of 2 by Ph 3SnCl (1:1 molar ratio) or (PhCH2S)2 (1:0.5) leads to the YbIII species [C6H4-1,2-{NC(t-Bu) N(2,6-Me2C6H3)}2]YbCl(1,2- dimethoxyethane) (3) and {[C6H4-1,2-{NC(t-Bu)N(2,6-Me 2C6H3)}2]Yb(μ-SCH 2Ph)}2 (4), performing classic κ2N,N′-chelating coordination mode of ansa bis(amidinate) ligand. By the reduction of 3 with equimolar amount of sodium naphthalide [C10H8?-][Na+] in THF, complex 2 can be recovered and restored to a bent bis(arene) structure. Complex 3 was also synthesized by the salt metathesis reaction of equimolar amounts of YbCl3 and the dilithium derivative of 1 in THF.
- Tolpygin, Aleksei O.,Cherkasov, Anton V.,Fukin, Georgii K.,Trifonov, Alexander A.
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- Single Electron Delivery to Lewis Pairs: An Avenue to Anions by Small Molecule Activation
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Single electron transfer (SET) reactions are effected by the combination of a Lewis acid (e.g., E(C6F5)3 E = B or Al) with a small molecule substrate and decamethylferrocene (Cp?2Fe). Initially, the corresponding reactions of (PhS)2 and (PhTe)2 were shown to give the species [Cp?2Fe][PhSB(C6F5)3] 1 and [Cp?2Fe][(μ-PhS)(Al(C6F5)3)2] 2 and [Cp?2Fe][(μ-PhTe)(Al(C6F5)3)2] 3, respectively. Analogous reactions with di-tert-butyl peroxide yielded [Cp?2Fe][(μ-HO)(B(C6F5)3)2] 4 with isobutene while with benzoyl peroxide afforded [Cp?2Fe][PhC(O)OE(C6F5)3] (E = B 5, Al 6). Evidence for a radical pathway was provided by the reaction of Ph3SnH and p-quinone afforded [Cp?2Fe][HB(C6F5)3] 7 and [Cp?2Fe]2[(μ-O2C6H4)(E(C6F5)3)2] (E = B 8, Al 9). In addition, the reaction of TEMPO with Lewis acid and Cp?2Fe afforded [Cp?2Fe][(C5H6Me4NOE(C6F5)3] (E = B 10, Al 11). Finally, reactions with O2, Se, Te and S8 gave [Cp?2Fe]2[((C6F5)2Al(μ-O)Al(C6F5)3)2]2 12, [Cp?2Fe]2[((C6F5)2Al(μ-Se)Al(C6F5)3)2]2 13, [Cp?2Fe][(μ-Te)2(Al(C6F5)2)3] 14 and [Cp?2Fe]2[(μ-S7)B(C6F5)3)2] 15, respectively. The mechanisms of these SET reactions are discussed, and the ramifications are considered.
- Liu, Liu Leo,Cao, Levy L.,Shao, Yue,Stephan, Douglas W.
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- A highly efficient reduction of group 14 heteroatom-chlorine single bonds by using samarium diiodide-mediated reaction systems
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The reduction of group 14 heteroatom-chlorine single bonds by using samarium diiodide-mediated reduction systems in tetrahydrofuran has been investigated in detail. When the reduction of chlorostannanes and chlorogermanes are conducted by employing excess amounts of samarium diiodide (4 equiv.) at the THF refluxing temperature, the corresponding distannanes and digermanes are obtained in good yields, respectively. By the combination with magnesium metal or samarium metal, a novel samarium diiodide-catalyzed reduction of chlorostannanes and chlorogermanes takes place successfully. In contrast, the reduction of chlorosilanes with SmI2 in THF does not occur at all, because the silylative ring-opening of THF with silyl iodode (formed in situ from chlorosilanes and SmI2) proceeds in preference to the desired reduction of chlorosilanes.
- Kamiya, Ikuyo,Iida, Koichiro,Harato, Nami,Li, Zhi-Fang,Tomisaka, Yuri,Ogawa, Akiya
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- Syntheses and structures of 3-stannylcholest-5-ene species
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The compounds, 3α- and 3β-triphenylstannylcholest-5-ene, 1 and 2 respectively, have been prepared stereospecifically in reactions of Ph3SnLi with cholesteryl methane- or toluene-p-sulfonates, and of Ph3SnCl with the Grignard reagent from cholesteryl chloride, respectively. Complete 1H and 13C NMR spectral assignments for 1 have been obtained using HMBC and HMQC techniques: these have been used to aid the 13C NMR spectral assignments for 2 and 3α- and 3β-(InPh3-nSn)cholest-5-enes (n = 1-2) (9-12). Crystal structure determinations of 3α-(IPh2Sn)cholest-5-ene 9 and 3α-(I2PhSn)cholest-5-ene 10 indicate distorted tetrahedral geometries about the tin centres in both compounds. The Sn-I bond lengths are 2.731(5) A in 9 and between 2.6979(12) and 2.7173(12) A in 10. Despite the similarity in the values (ca. 60°) of the dihedral angles, Sn-C(3)-C(2)-C(1) [C(1) aliphatic carbon] and Sn-C(3)-C(4)-C(5) [C(5) olefinic carbon], the values of 3J[119Sn-13C(1)] are about twice the 3J[119Sn-13C(5)] values in each of 1, 9 and 10; in contrast, 3J[119Sn-13C(1)] and 3J[119Sn-13C(5)] values are essentially the same in each of 2, 11 and 12 [Sn-C(3)-C(2)-C(1) and Sn-C(3)-C(4)-C(5) ca. 180°].
- Buchanan, Heather J.,Cox, Philip J.,Doidge-Harrison, Solange M. S. V.,Howie, R. Alan,Jaspars, Marcel,Wardell, James L.
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- Catalytic dehydrogenative coupling of stannanes by alkoxysilyl heterobimetallic complexes: Influence of the assembling ligand
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The heterobimetallic complexes [(OC)3(R′3Si)Fe(μ-P-Z)Pd(η 3-allyl)] (1, P-Z = Ph2PNHPPh2 (dppa); 2, P-Z = Ph2P(o-C5H4N) (Ph2Ppy); 3, P-Z = Ph2PCH2PPh2 (dppm); R′3 = (OMe)3, Me(OSiMe3)2) are very efficient catalysts for the dehydrogenative coupling of tin hydrides R3SnH (R = Ph, nBu). Besides establishing that siloxy complexes are more active catalysts than their alkoxysilyl counterparts, the present study shows that modifications in the nature of the assembling functional phosphine ligand P-Z result in variations of catalyst efficiency, expressed by the TON (overall turnover number) and TOF (maximum turnover frequency) values and lifetime. The Ph2Ppy-bridged complexes are the most efficient catalysts, and in the case of nBu3SnH, TON and TOF values higher than 1.2 × 106 and 2 × 108, respectively, have been observed. A marked difference in reactivity is also observed between the diphosphine ligands dppa and dppm, with the dppa-bridged complexes being more active than their dppm analogues. The new complex [(OC)3{(Me3SiO)2MeSi}Fe(μ-Ph 2Ppy)Pd(η3-allyl)] (2b) prepared in the course of this work has been structurally characterized by X-ray diffraction.
- Braunstein, Pierre,Durand, Jér?me,Morise, Xavier,Tiripicchio, Antonio,Ugozzoli, Franco
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- Synthesis, structure and bonding of a digold complex with bridging triphenylstannyl ligands
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The reaction of Au(PPh3)Ph with HSnPh3 yielded the new digold-ditin complex, [Au(PPh3)(μ-SnPh3)]2, 6 in 52% yield. Benzene was also formed. Sn2Ph6 is a major coproduct that was formed by the degradation of 6. Compound 6 was characterized structurally by a single-crystal X-ray diffraction analysis. The molecule contains two Au(PPh3) groups that are joined by a strong Au-Au bond (2.5590(5) ? in length) that is bridged by two SnPh3 groups. The metal-metal bonding was analyzed by DFT Mo calculations. The Au-Sn bonding is represented by the HOMO which is a four center: two electron bond.
- Adams, Richard D.,Wong, Yuen Onn,Zhang, Qiang
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- THE REACTIONS OF DIBORANE WITH ARYL-ORGANOTIN COMPOUNDS
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A number of tetraaryltin compounds, Ar4Sn (where Ar = phenyl, o- and p-tolyl, and p-chlorophenyl) and tryphenyltin compounds, PH3SnX (where X = Cl, H, OH, OCOCH3 and OCOCF3) have been treated with diborane in tetrahydrofuran.Transmetallation occurs in which one or more aryl groups are transferred to boron.The organoboron intermediates give phenols upon oxidation and boronic and borinic acids upon hydrolysis.Pyridine complexes of organoboranes have also been isolated.
- Pickles, G. M.,Spencer, T.,Thorpe, F. G.,Chopa, A. B.,Podesta, J. C.
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- The structures of ring-expanded NHC supported copper(
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Three ring-expanded N-heterocyclic carbene-supported copper(i) triphenylstannyls have been synthesised by the reaction of (RE-NHC)CuOtBu with triphenylstannane (RE-NHC = 6-Mes, 6-Dipp, 7-Dipp). The compounds were characterised by NMR spectroscopy and X-ray crystallography. Reaction of (6-Mes)CuSnPh3 with di-p-tolyl carbodiimide, phenyl isocyanate and phenylisothiocyanate gives access to a copper(i) benzamidinate, benzamide and benzothiamide respectively via phenyl transfer from the triphenylstannyl anion with concomitant formation of (Ph2Sn)n. Attempts to exploit this reactivity under a catalytic regime were hindered by rapid copper(i)-catalysed dismutation of Ph3SnH to Ph4Sn, various perphenylated tin oligomers, H2 and a metallic material thought to be Sn(0). Mechanistic insight was provided by reaction monitoring via NMR spectroscopy and mass spectrometry.
- Charman, Rex S. C.,Liptrot, David J.,Lowe, John P.,Mahon, Mary F.
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supporting information
p. 831 - 835
(2022/02/01)
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- Samarium and ytterbium complexes based on sterically hindered 1,2-bis(imino)acenaphthene*
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Reactions of the samarium complex [(ArBIG-bian)2?Sm2+] (1) (ArBIG-bian is the 1,2-bis-[(2,6-dibenzhydryl-4-methylphenyl)imino]acenaphthene dianion) with iodine (0.5 mol. equiv.) or triphenyltin chloride lead to the oxidation of the metal and afford the corresponding derivatives [(ArBIG-bian)2?Sm3+I(dme)] (2) and [(ArBIG-bian)2?Sm3+Cl(dme)] (3). Meanwhile, the reaction of the related ytterbium complex [(ArBIG-bian)2?Yb2+(dme)] (4) with iodine (2:1) or copper(I) chloride resulted in the oxidation of the dianionic ligand rather than the metal to form the compounds [(ArBIG-bian)?Yb2+I(dme)] (5) and [(ArBIG-bian)?Yb2+Cl]2 (6), respectively. The reaction of 2 with one molar equivalent of potassium pentamethylcyclopentadienide gave the adduct [(ArBIG-bian)2?Sm3+(I)Cp*][K(dme)4] (7). The reaction of samarium complex 1 with 2,2′-bipyridine (bipy) (1:2) is accompanied by the oxidation of SmII to SmIII to form the derivative [(ArBIG-bian)2?Sm3+(bipy)2] (8) containing the radical-anion and neutral bipy ligands. The coordination of a neutral bipyridine molecule to the metal atom in ytterbium iodine complex 5 leads to the metal—ligand electron transfer giving [(ArBIG-bian)2?Yb3+I(bipy)] (9). All the newly synthesized compounds 2, 3, and 5–9 were characterized by IR spectroscopy (complexes 5 and 6 were also characterized by EPR spectroscopy) and elemental analysis. The molecular structures of complexes 2, 3, and 5–9 were determined by X-ray diffraction.
- Baranov, E. V.,Fedushkin, I. L.,Lukina, D. A.,Moskalev, M. V.,Skatova, A. A.,Sokolov, V. G.
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p. 2119 - 2129
(2022/01/22)
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- Bis(pentafluorophenyl)phenothiazylborane-an intramolecular frustrated Lewis pair catalyst for stannane dehydrocoupling
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We synthesized a novel Lewis acidic aminoborane containing a phenothiazyl substituent and demonstrated its potential to catalytically promote the dehydrocoupling of tin hydrides. The observed reactivity would imply a homolytic frustrated Lewis pair type mechanism, however computational analysis suggests a heterolytic mechanism for this reaction. This result represents one of the first frustrated Lewis pair systems to dehydrocouple stannanes in a heterolytic fashion.
- Bentley, Jordan N.,Caputo, Christopher B.,Pradhan, Ekadashi,Zeng, Tao
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supporting information
p. 16054 - 16058
(2020/12/03)
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- To Rearrange or not to Rearrange: Reactivity of NHCs towards Chloro- and Hydrostannanes R2SnCl2(R = Me, Ph) and Ph3SnH
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The reaction of 1,3-diisopropylimidazolin-2-ylidene (iPr2Im) with diphenyldichlorostannane and dimethyldichlorostannane, respectively, leads to the formation of the adducts (iPr2Im)·SnPh2Cl2(1) and (iPr2Im)·SnMe2Cl2(2). These compounds are stable in solution to temperatures up to 80 °C for several days and rearrangement to backbone-tethered bis(imidazolium) salts or ring expansion reaction to six membered heterocyclic rings was not observed. The reaction of iPr2Im with triphenylstannane Ph3SnH leads to reductive dehydrocoupling of the stannane to yield distannane Sn2Ph6and iPr2ImH2. Thus, the reactivity of these tin compounds is completely different compared to those of the lighter congener silicon, for which rearrangement (chlorides) and NHC ring expansion (hydrides) was reported earlier.
- Schneider, Heidi,Krahfu?, Mirjam J.,Radius, Udo
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p. 1282 - 1286
(2016/11/23)
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- Chemistry of homoleptic phenylethynyl complexes of lanthanides
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Methods to prepare homoleptic phenylethynyl complexes of lanthanides, the products properties and possible applications in organoelement synthesis of polyfunctional compounds are discussed.
- Zhiltsov,Druzhkova,Pimanova,Makarov
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p. 1910 - 1919
(2015/10/12)
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- A convenient route to distannanes, oligostannanes, and polystannanes
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The quantitative conversion of the tertiary stannane (ν;-Bu) 3SnH (2) into (ν-Bu)6Sn2 (4) was achieved by heating the neat hydride material under low pressure or under closed inert atmosphere conditions. A 31% conversion of Ph3SnH (3)to Ph6Sn 2 (5) was also observed under low pressure; however, under closed inert atmosphere conditions afforded Ph4Sn (6) as the major product. A mixed distannane, (ν-Bu)3SnSnPh3 (7), can also be prepared in good yield utilizing an equal molar ratio of 2 and 3 and the same reaction conditions used to prepare 4. This solvent-free, catalyst-free route to distannanes was extended to a secondary stannane, (ν-Bu)2SnH 2 (8), which yielded evidence (NMR) for hydride terminated distannane H(ν-Bu)2SnSn(ν-Bu)2H(9), the polystannane [(ν-Bu)2Sn] ' (10), and various cyclic stannanes [(ν- Bu)2Sn]ν=5,6=5,6 (11, 12). Further evidence for 10 was afforded by gel permeation chromatography (GPC) where a broad, moderate molecular weight, but highly dispersed polymer, was obtained (Mw = 1.8 × 104 Da, polydispersity index (PDI) = 6.9) and a characteristic UV-vis absorbance (1max)of ν370 nm observed.
- Khan, Aman,Gossage, Robert A.,Foucher, Daniel A.
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p. 1046 - 1052
(2011/02/16)
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- Synthesis and reactivity of new κ2-[P,N]Pt(II) complexes of diisopropylphosphino-substituted 2-dimethylaminoindene
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Treatment of 1-PiPr2-2-NMe2-indene (la[H]) with either czs/trans-(SMe2)2PtCl2 or PtCl2 provided (κ22-P,N-2-NMe2-3-P iPr2-indene)PtCl2 (2) in 84% and 55% yield, respectively, while the reaction of 1a[H] with (η4-COD)PtClMe afforded (κ2-P,N-2-NMe2-3-PiPr 2-indene)PtClMe (3) in 91% yield. Whereas in the formation of 2 and 3 the ligand precursor 1a[H] undergoes a rearrangement to give a coordinated 2-NMe2-3-PiPr2-indene (1b[H]) ligand, 1a[H] reacted cleanly with 0.5 equiv of [(μ-SMe2)PtMe2] 2 to give (κ2-P,N-1a[H])PtMe2 (4a) in 97% yield. The isomerization of 4a to (κ2-P,N-1b[H])PtMe 2 (4b) in a THF/iPrOH mixture is rapid and allowed for the isolation of 4b in 99% yield. Heating of 4a in CH2Cl2 resulted in the quantitative formation of 3, while the thermolysis of 4a in toluene in the presence of SMe2 afforded 5, the apparent product of intramolecular C-H activation of an NMe group. The reactivity of 4a with a variety of other two-electron donors, as well as E-H-containing substrates (E = main group fragment), is reported. Although NMR spectroscopic evidence indicated the formation of an intermediate of the type (κ2-P,N-1[H]) Pt(SnPh3)(Me), as well as Ph6Sn2, in the reaction of 4a with 10 equiv of Ph3SnH, negligible conversion of Ph3SnH to Ph6Sn2 was obtained when employing 1 mol % 4a as a catalyst. Single-crystal X-ray diffraction data for 2 and 5 are reported.
- Wile, Bradley M.,McDonald, Robert,Ferguson, Michael J.,Stradiotto, Mark
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p. 1959 - 1965
(2008/10/09)
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- Synthesis, structure, and α-elimination chemistry of hafnocene triarylstannyl complexes
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New hafnocene triarylstannyl complexes were prepared and were shown to undergo clean thermal decompositions via α-aryl-elimination to produce the corresponding stannylene and a hafnocene aryl complex. The rate of the decomposition is highly dependent on the nature of the ancillary ligand, with the stabilities of the CpCp*Hf(SnPh3)X compounds following the order X = NMe2 > Np (α-agostic) > OMe > Cl > Me. Mechanistic information suggests that α-aryl-elimination may be viewed as a concerted process involving nucleophilic attack of the migrating aryl group onto the electrophilic metal center.
- Neale, Nathan R.,Tilley, T. Don
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p. 14745 - 14755
(2007/10/03)
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- Dehydrogenative stannane coupling by platinum complexes
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The complexes Pt(acac)2, (PhMe2P) 2PtMe2, (dppe)PtMe2 (dppe=bis(diphenylphosphino)ethane) , and the (P∩N)PtMe2 complexes [(κ2-P,N)-Ph 2PCH2CH2CH2NMe2]PtMe 2 and [(κ2-P,N)-Ph2PCH2CH 2NMe2]PtMe2 catalyse the formation of distannanes by dehydrogenative coupling of triphenyltin hydride or tri-n-butyltin hydride. While Pt(acac)2 appears to react by a radical mechanism, the bis(stannyl) complexes (PhMe2P) 2Pt(SnR3)2 and (dppe)Pt(SnR3) 2 were observed in the reaction of (PhMe2P) 2PtMe2 and (dppe)PtMe2. At longer reaction periods the complexes (PhMe2P)2Pt(H)SnBu3 and (PhMe2P)2Pt(Ph)SnHPh2, respectively, were formed. There is evidence that the distannanes are formed by a similar mechanism when (P∩N)PtMe2 is employed as the catalyst instead of (R3P)2PtMe2. However, the presence of the P,N-chelating ligand results in the stabilisation of the intermediate (P∩N)Pt(Me)SnR3 and in the formation of redistribution products.
- Thompson, Susan M.,Schubert, Ulrich
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p. 329 - 338
(2008/10/08)
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- Ti-Sn, Zr-Sn, and Hf-Sn heterodimetallic complexes: Stabilizing unsupported group 4-group 14 metal-metal bonds
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Reaction of the tripodal amido complexes [MeSi{SiMe2N(4-CH3C6H4)}3 ZrCl] and [MeSi{SiMe2N(4-CH3C6H4)}3 HfCl] with LiSnPh3 in toluene yielded the Zr-Sn and Hf-Sn complexes [MeSi{SiMe2N(4-CH3C6H4)}3 ZrSnPh3] (1) and [MeSi{SiMe2N(4-CH3C6H4)}3 -HfSnPh3] (2), while attempts to synthesize the corresponding Ti-Sn complex resulted in the oxidative coupling of the stannate to give Ph3Sn-SnPh3 and unidentified titanium species. More stable group 4-group 14 complexes were obtained by reaction of the triamido stannate complex [MeSi{SiMe2N(4-CH3C6H4)}3 SnLi(OEt2)] with the metallocene dichlorides [Cp2MCl2] of all three titanium group metals, giving [MeSi{SiMe2N(4-CH3C6H4)}3 SnM(η5-C5H5)2(Cl)] (M = Ti, 3; Zr, 4; Hf, 5). X-ray diffraction studies of 4 and 5 established Zr-Sn and Hf-Sn bond lengths of 3.02313(17) and 2.9956(3) A?, respectively.
- Lutz, Matthias,Findeis, Bernd,Haukka, Matti,Pakkanen, Tapani A.,Gade, Lutz H.
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p. 2505 - 2509
(2008/10/08)
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- Cyclohexasilanes with exocyclic organogermanium, -tin or -lead groups
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A new class of mono- (2-4) and bis(undecamethylcyclohexasilanyl) (5-9) substituted germanium, tin and lead compounds is described. These molecules are accessible by treatment of undecamethylcyclohexasilanyl potassium (1) with chlorogermanes, -stannanes or plumbanes. Attempts to generate bis(cyclohexasilanyl)methanes, -plumbanes or tris(cyclohexasilanyl)methylstannane starting from dihalomethanes, -plumbanes or methyltrichlorostannane and 1 result only in transmetallation reactions. The molecular structures of a mono- (3) and a dicyclohexasilanyl stannane derivative 5 were determined by single-crystal X-ray crystallography.
- Englich,Hengge,Hermann,Marschner,Ruhlandt-Senge,Uhlig
-
-
- Novel heteroleptic stannylenes with intramolecular O,C,O-donor stabilization
-
The heteroleptic organotin(II) halides {2,6-[P(O)(OEt)2]2-4-tert-Bu-C6H2}SnX (1, X = Cl; 2, X = Br) have been prepared starting from {2,6-[P(O)(OEt)2]2-4-tert-Bu-C6H2}Li and SnX2 and have been used as precursors for the preparation of the heteroleptic stannylenes {2,6-[P(O)(OEt)2]2-4-tert-Bu-C6H2}SnX (4, X = SPh; 5, X = CH(SiMe3)2; 6, X = SiPh3; 7, X = SnPh3; 7a, X = SnMe3), the tetravalent monorganotin derivatives {{2,6-[P(O)(OEt)2]2-4-tert-Bu- C6H2}SnCl(μ-S)}2 (8) and {2,6-[P(O)(OEt)2]2-4-tert-Bu-C6 H2}SnBr3 (9), the diorganotin cation {2,6-[P(O)(OEt)2]2-4-tert-Bu-C6 H2}(Ph3C)(Cl)Sn+PF6- (10), and the metal-stannylene complexes {2,6-[P(O)(OEt)2]2-4- tert-Bu-C6H2}(Cl)Sn[M(CO)n] (11, M = W, n = 5; 12, M = Cr, n = 5; 13, M = Fe, n = 4). Multinuclear (1H, 13C, 31P, 119Sn) NMR of all compounds, 119Sn Mossbauer spectra of 1 and 10, and single-crystal X-ray structure analyses of 6, 8, and 12 are reported. The derivatives 6, 7, and 7a are rare examples of compounds containing Sn-(II)-Si(IV) and Sn(II)-Sn(IV) bonds, respectively.
- Mehring, Michael
-
p. 4613 - 4623
(2008/10/08)
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- Photochemical synthesis of new (η6-arene)Cr-hydrido stannyl and (η6-arene)Cr-bis-stannyl complexes. Ligand effects on the Sn-H interaction in the hydrido stannyl compounds
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Hydrido stannyl compounds containing the η2-H-SnPh3 ligand and bis-stannyl compounds containing two SnPh3 ligands have been obtained from the photolysis of (η6-arene)Cr(CO)3 and HSnPh3. New complexes with different arenes (mesitylene, trifluorotoluene and 1,4-dimethoxybenzene) have been obtained and characterized by X-ray diffraction: (η6-C6H4(OCH3) 2)Cr(CO)2(HSnPh3) (3a), (η6-C6H4(OCH3) 2)Cr(CO)2(SnPh3)2 (3b). Structural data for 3a: monoclinic; space group P21/c (No. 14); a=17.445(3), b=9.820(3) and c=16.302(5) A; Z=4; V=2539.2(12) A3; 3b: monoclinic; space group P21/n (No. 14); a=13.904(3), b=20.567(5) and c=13.911(3) A; Z=4; V=3994(2) A3. 1H-NMR as well as X-ray provided evidence for the existence of three-center two-electron bonds in the hydrido stannyl complexes. The effects of different ligands on bonding and spectroscopic parameters were studied. Arene exchange reactions of the bis-stannyl complexes, as well as reactions of some of these compounds with P(C2H5)3 and CO, were also investigated.
- Khaleel, Abbas,Klabunde, Kenneth J.,Johnson, Alison
-
-
- Metal π complexes of benzene derivatives. 53 [1] tin in the periphery of bis(arene)metal complexes of vanadium and chromium
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By means of metal-atom ligand-vapor cocondensation as well as via wet chemical methods (lithiation and follow-up reaction) the first organostannyl substituted bis(arene)metal complexes (R3Sn-η6-C6H5)2M have been prepared: 15 (R = Me, M = V), 16 (R = Ph, M = V), 13 (R = Me, M = V), 17 (R = Ph, M = Cr). Despite the bulkiness of the Ph3Sn groups the geometry of the central sandwich unit in 17 deviates only marginally from that of the parent complex (C6H6)2Cr (2). The triclinic unit cell of 17 (space group: P1; a = 9.414(4), b = 9.877(5), c = 11.012(13) A; α = 83.51(7), β = 87.95(7), γ = 72.67(4)°) contains one independent molecule. Perturbation of the electronic structure of the bis(arene)metal unit by organostannyl groups appears to be minute because EPR spectra of the M(d5) species fail to reveal deviations from axial symmetry. The potentials for reversible oxidation of the Me3Sn-substituted complexes 13 and 15 differ insignificantly (anodic shifts ≤ 20 mV) from those of the parent species 1 and 2; reductions are irreversible in both cases. More sizeable anodic shifts are observed for the Ph3Sn-derivatives 16 and 17; here as well, only the redox pairs 0/+ are reversible. The resistance of the neutral complexes to protic media contrasts to ready hydrodestannylation of the complex cations. By way of metal exchange, employing n-butyl lithium, 13 affords (Li-η6-C6H5)2Cr strictly 1,1′-disubstituted and devoid of auxiliary base.
- Elschenbroich, Christoph,Schmidt, Eckhardt,Metz, Bernhard,Massa, Werner,Wocadlo, Sigrid,Burghaus, Olaf
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p. 875 - 886
(2008/10/08)
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- Synthesis and reactivity of stannyloligosilanes, I. Stannyloligosilane chains containing SiMe2 moieties
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Stannyloligosilanes 1 and 2 with terminal organotin groups are available by reacting alkali metal tri-or diorganostannides with α,ω-dichloro-or difluorosilanes, or by treatment of organochlorostannanes with α,ω-difluorosilanes in the presence of magnesium. Attempts to functionalize the triorganotin derivatives 2 by halogenation reagents did not result in the halogen compounds 5; instead cleavage of silicon-tin bonds is observed. In contrast, reactions of the hydridotin derivatives 1 with CHX3 (X = Cl, Br) lead to the quantitative formation of the bis(chloro-or bromostannyl)oligosilanes 5. All compounds were characterized by NMR, IR, MS and elemental analysis. In addition, the triorganotin compound 2i and the hydridotin species 1b have been characterized by X-ray crystallography.
- Uhlig, Frank,Kayser, Christian,Klassen, Ralph,Hermann, Uwe,Brecker, Lothar,Schürmann, Markus,Ruhland-Senge, Karin,Englich, Ulrich
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p. 278 - 287
(2007/10/03)
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- Organostannanes Derived from (-)-Menthol: Controlling Stereochemistry during the Preparation of (1R,2S,5R)-Menthyldiphenyltin Hydride and Bis((1R,2S,5R)-menthyl)phenyltin Hydride
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Reaction of (1R,2S,5R)-menthylmagnesium chloride (MenMgCl) with triphenyltin chloride in THF proceeds with epimerization of the C-1 carbon of the menthyl group and results in a mixture of (1R,2S,5R)-menthyltriphenyltin (1) and (1S,2S,5R)-menthyltriphenyltin (2). Addition of Lewis bases such as triphenylphosphine to the THF solution of triphenyltin chloride prior to addition of the Grignard reagent suppresses epimerization and enables isolation of pure 1. An epimerization mechanism involving one-electron-transfer reactions is postulated. Compound 1 is the precursor for reactions that lead to the formation of a series of compounds, namely, (1S,2S,5R)-menthyldiphenyltin iodide (4), (1S,2S,5R)-menthyldiphenyltin fluoride (5), (1S,2S,5R)-menthyldiphenyltin hydride (6), (1S,2S,5R)-menthylphenyltin dibromide (7), and (1S,2S,5R)-menthylphenyltin dichloride (8). The synthesis of the dimenthyl derivatives bis((1S,2S,5R)-menthyl)diphenyltin (9), bis((1S,2S,5R)-menthyl)-phenyltin iodide (10), bis((1S,2S,5R)-menthyl)phenyltin hydride (11), and bis((1S,2S,5R)-menthyl)tin di(chloroacetate) (12) is described. Crystal structure determinations of 7,8, and 12 confirm the absolute configuration of the menthyl groups.
- Dakternieks, Dainis,Dunn, Kerri,Henry, David J.,Schiesser, Carl H.,Tiekink, Edward R. T.
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p. 3342 - 3347
(2008/10/08)
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- Photochemical 1,3-stannyl rearrangement of allylic stannanes
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The photochemical 1,3-stannyl rearrangement of allylic stannanes has been investigated. The photorearrangement of (E)-cinnamyl(triphenyl)stannane is not observed in benzene under anaerobic conditions, while the photoinduced 1,3-stannyl migration takes place in the same solvent under aerobic conditions, or in the presence of organic halides or a radical-trapping agent to give a photoequllibrium mixture of the cinnamylstannane and its branched regioisomer, 1-phenylprop-2-enyl(triphenyl)stannane, with the latter predominating. Cinnamyl(trialkyl)stannanes and their homologues also afford the corresponding branched allylstannanes under similar photochemical conditions. These 1,3-stannyl migrations proceed intramolecularly via cinnamyl π-π* excitation in competition with homolytic (cinnamyl)C-Sn bond fission. In contrast, the 1,3-stannyl migration of crotyl- and prenyl-(tributyl)-stannanes is not efficient, but their triphenyl or dibutylphenyl derivatives undergo the 1,3-rearrangement via excitation of the phenyl group(s) on the tin atom to give a regioisomeric mixture of the starting linear tin compounds and the branched ones with the former predominating.
- Takuwa, Akio,Kanaue, Takashi,Yamashita, Koichi,Nishigaichi, Yutaka
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p. 1309 - 1314
(2007/10/03)
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- Synthesis, characterization and biological activity of (Z)-1-[2]-1-cyclopentanol and their arylhalostannyl derivatives
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The synthesis and characterization by elemental analysis, IR and 1H NMR of (Z)-1 - 1-cyclopentanol,CH2(CH2)3C(OH)CHCHSnPh 3 (1) and (Z)-1 - 1-cyclopentanol, CH2(CH2)3C(OH)CHCHSn(p-toly)3 (2) are described, together with their halodemetallation by I2, Br2 and ICl to yield derivatives of the types CH2(CH2)3C(OH)CHCHSnAr3-nX n (Ar = phenyl or p-tolyl ; n = 1, 2 ; X = I, Br, Cl). The solid-state structures of two compounds have been determined by X-ray diffraction analysis. In the crystal of CH2(CH2)3C(OH)CHCHSnph3 (1) the Sn atom has a distorted tetrahedral geometry but intramolecular contact with the hydroxyl O atom has not been found. A trigonal bipyramidal geometry is found in CH2(CH2)3CC(OH)CHCH SnphBr2(11), in which OSn - interaction is noted [2.446(8) A] The biological activity of the title complexes is also investigated.
- Dai, Hui Cong,Ying, Qihua,Wang, Xiao Hong,Yue, Su Mei,Pan, Hua De,Chen, Xi
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p. 2503 - 2509
(2008/10/09)
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- Oxidation of Magnesium with Triphenylchlorostannane and Hexaphenyldistannane
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The equilibrium constants, enthalpies, and entropies of adsorption of triphenylchlorostannane on the magnesium surface were determined. A scheme is proposed of bis(triphenylstannyl)magnesium formation by oxidation of magnesium with hexaphenyldistannane.
- Maslennikov,Piskunov,Bochkarev,Spirina
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p. 907 - 909
(2007/10/03)
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- Organotin compounds containing a bulky (Me3Si)3C or related ligand. Crystal structures of {(Me3Si)3CMe(O2NO)Sn}2O, (PhMe2Si)3CSnMeCl2 and (PhMe2Si)3CSnCl3
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Some compounds having very bulky ligands, mainly (Me3Si)3C (denoted by Tsi) or (PhMe2Si)3C (denoted by Tpsi), attached to functional tin centres have been studied. Treatment of TsiSnR2Cl, R=Me or Ph, with one equivalent of ICl gave the corresponding chloride TsiSnRCl2, and use of an excess of ICl gave TsiSnCl3 in both cases. Reaction of either chloride with one equivalent of Br2 gave the dibromide TsiSnRBr2; when an excess of Br2 was used TsiSnMe2Cl still gave the dibromide but TsiSiPh2Cl gave the tribromide TsiSnBr3. Reaction of TsiSnMe2Br with AgSCN or Ag2O gave TsiSnMe2NCS and (TsiSnMe2)2O, respectively, but when the crude product from the reaction of TsiSnMeBr2 with AgNO3 was recrystallized from MeOH the nitrato-oxide {TsiMe(O2NO)Sn}2O was obtained. In a seemingly previously unreported type of reaction, the alkoxide TsiSnMe2OEt reacted with ICl, Br2, or I2 to give TsiSnMe2X, X=Cl, Br, or I, respectively, and Bu3SnOEt likewise reacted with ICl to give Bu3SnCl. The chlorides TsiSnMe2Cl and TsiSnMeCl2 gave the hydrides TsiSnMe2H and TsiSnMeH2 on treatment with LiAlH4, but in the case of TpsiSnMe2Cl the Tpsi-Sn bond was cleaved to give TpsiH. The compound (Me3Si)2C(SnMe2Ph)(SiMe2Cl) reacted with a 1 M proportion of AgBF4 in CH2Cl2 with cleavage of the Sn-Ph bond to give the difluoride (Me3Si)2C(SnMe2F)(SiMe2F). The crystal structures of the monomeric compounds {TsiMe(O2NO)Sn}2O, TpsiSnMeCl2 and TpsiSnCl3 are reported; {TsiMe(O2NO)Sn}2O provides the first example of unidentate bonding of an NO3 group to four-coordinate tin.
- Al-Juaid, Salih S.,Al-Rawi, Mustafa,Eaborn, Colin,Hitchcock, Peter B.,Smith, J. David
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p. 215 - 226
(2007/10/03)
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- Novel redox properties of HB(3-Butpz)3- as shown by its reaction with InIII and SnIV
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The novel redox properties of HB(3-Butpz)3- are demonstrated by the isolation and structural characterisation of [In2I3{η3-HB(3-Butpz) 2(5-Butpz)}-(η1-5-ButpzH)] 1, a novel In-In bonded species, and Sn2(Ph)6 2, on reaction with InIII and SnIV, respectively.
- Frazer, Andrew,Hodge, Paul,Piggott, Brian
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p. 1727 - 1728
(2007/10/03)
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- Kinetics, mechanism and thermodynamics of iron carbon bond dissociation in organoiron porphyrin complexes
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Thermolysis of Fe(P)R (P = octaethylporphyrinato dianion, R = C6H5, CH3, C2H5, CH2C(CH3)3; P = tetraphenylporphyrinato dianion, R = C6H5; P = tet
- Riordan, Charles G.,Halpern, Jack
-
-
- Reactivity of Heterobimetallic Alkoxysilyl and Siloxyl Complexes in the Dehydrogenative Coupling of Stannanes
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Heterobimetallic iron-palladium alkoxysilyl- and siloxyl-complexes catalyse the dehydrogenative tin-tin coupling reaction; high turnover numbers are obtained, whereas modifications of the silicon-containing ligand strongly influence the efficiency of the catalyst.
- Braunstein, Pierre,Morise, Xavier,Blin, Joel
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p. 1455 - 1456
(2007/10/02)
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- Wurtz-type reductive coupling reaction of allyl bromides and haloorganotins in cosolvent/H2O(NH4Cl)/Zn media as a route to allylstannanes and hexaaryldistannanes
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Twenty-one allylstannanes have been prepared via a simple Wurtz-type coupling reaction of allyl bromides and R3SnX compounds (R = Me, Et, Pr, Bu, Ph; X = Cl, I, OH), Bu2SnCl2, and (Bu2SnCl)2O in cosolvent/H2O (NH4Cl saturated) media under the mediation of zinc powder. Also R3SnSnR3 compounds (R = Ph, p- and m-Tol) have been prepared via coupling of triaryltin chlorides. The stereochemical course of the reaction between R3SnCl and (C4H7)Br (C4H7 = α-methylallyl, trans- and cis-crotyl) has been extensively studied. Two distinct reactions are involved in the overall process: (i) the coupling reaction, which gives rise stereoselectively to the sole R3SnCH(CH3)CH=CH2 (α-isomer), and (ii) the subsequent isomerization of the α-isomer furnishing mixtures of (α, trans, cis)-isomers. The occurrence of reaction ii depends upon the nature either of the R group or the employed cosolvent. In cyclohexane, the α-isomer is exclusively obtained with R = Bu, while with R = Me, Et, and Pr it is found as a major component in the ternary isomeric mixture. In tetrahydrofuran, 2-propanol, acetonitrile, and pyridine, the isomerization occurs to an extent which depends on the polarity and the coordinating ability of the cosolvent itself. The observed stereoselection has been hypothesized to occur through one-electron transfer from the zinc metal to the (C4H7)Br to form stereoselectively an adsorbed CH2=CHCH(CH3)Br?-Zn?+ radical ion which is trapped by the R3SnCl reactant to form the α-isomer. Similarly, ditin compounds are thought to be formed by interaction of R3SnCl?-Zn?+ radical ions with R3SnCl molecules.
- Von Gyldenfeldt, Friederike,Marton, Daniele,Tagliavini, Giuseppe
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p. 906 - 913
(2008/10/08)
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- 2,2-Functionally disubstituted organotin compounds: synthesis and reactivity
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A series of 2,2-difunctional organotin compounds of the general type Me3SnCH2CHXY (X, Y=P(O)R2 or C(O)R; R=Oi-Pr, OEt or Ph) has been synthesized by stannylmethylation of the appropriate 2,2-difunctional methanides Na with iodomethyl trimethylstannane.Derivaties with phenyl groups on tin cannot be made by this method.The reactions of the title compounds at the tin atom and at the acidic CH group of the bridging carbon atom and modifications of the functional P(O)R2 and C(O)R groups are described. Key words: Tin; Phosphoryl
- Richter, F.,Weichmann, H.
-
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- Preparation and transmetallation of a triphenylstannyl β-D-glucopyranoside: A highly stereoselective route to β-D-C-glycosides via glycosyl dianions
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The triphenylstannyl β-D-glucopyranoside 4 was synthesized in one step from the 1,2-anhydro-α-D-glucopyranose 3 with (triphenylstannyl)lithium. Transmetallation of 4 with excess BuLi, followed by quenching the dianion 7 with CD3OD gave (IS)-1,5-anhydro-3,4,6-tri-o-benzyl-[1-2H]-D-glucitol (8) in 81% yield. Trapping of 7 with benzaldehyde, isobutyraldehyde, or acroleine gave the expected β-D-configurated products 11, 12, and 13 in good yields. Preparation of C-acyl glycosides from acid chlorides, such as acetyl or benzoyl chloride was not practicable, but addition of benzonitrile to 7 yielded 84% of the benzoylated product 14. Treatment of 7 with MeI led to 15 (30%) along with 40% of 18, C-alkylation being accompanied by halogen-metal exchange. Prior addition of lithium 2-thienylcyanocuprate increased the yield of 15 to 50% and using dimethyl sulfate instead of MeI led to 77% of 15. No α-D-anomers could be detected, except with allyl bromide as the electrophile, which yielded in a 1:1 mixture of the anomers 16 and 17.
- Frey,Hoffmann,Wittmann,Kessler,Uhlmann,Vasella
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p. 2060 - 2069
(2007/10/02)
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- Synthesis, characterization, and reaction chemistry of [2-(2-pyridyl)ethyl]-, [2-(4-pyridyl)ethyl]-, and [2-(2-Oxo-N-pyrrolidinyl)ethyl]triphenyltin(IV)
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The compounds Ph3SnR [R = (CH2)2C5H5N-2 (1), (CH2)2C5H5N-4 (2), and (CH2)2C3H6C(O)N-2 (3)] have been synthesized by hydrostannylation of 2- or 4-vinylpyridine and N-vinylpyrrolidin-2-one, respectively, with Ph3SnH. Reaction of 1-3 with 1 equiv of X2 (X = Br, I) gives Ph2RSnX, which have been used to synthesize representative compounds of general formula Ph2RSn(L), L = S2CNR′2 (R′ = Me, Et) or O2CR′ (R′ = Me, Ph). The structures of the compounds are discussed on the basis of their 1H, 13C, 119Sn NMR and 119Sn M?ssbauer data The structure of Ph2Sn[(CH2)2C5H 5N-2](S2CNMe2) has been determined by X-ray crystallography: C22H24N2S2Sn, fw 499.28, a = 9.611 (4) ?, b = 10.255 (3) ?, c = 12.896 (9) ?, α = 75.35 (4)°, β = 70.97 (4)°, γ = 68.09 (3)°, V = 1102.2 ?3, Z = 2, space group P1, ρcalc = 1.50 g cm-3, μ(Mo Kα) = 12.42 cm-1, λ(Mo Kα) = 0.710 69 ?, F(000) = 504, R = 0.0492, Rw = 0.0542 for 2133 unique data. The tin is in a five-coordinate, trigonal bipyramidal trans-NSSnPh2R environment, with nitrogen and sulfur in the axial positions. The 2-ethylpyridyl ligand chelates the metal, while the dithiocarbamate is monodentate.
- Mahon, Mary F.,Molloy, Kieran C.,Waterfield, Philip C.
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p. 769 - 774
(2008/10/08)
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- Organotin compounds and anti-tumor compositions containing them
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The invention relates to anti-tumor compositions containing as an active ingredient one or more compounds of the formulae: in particular compounds having the formulae (1), (2) and (3) and to anti-tumor compositions containing a compound having the formula (6) and to novel compounds, in particular of the formulae (2), (3) and 40 (6).
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-
-
- Tricoordinate Tin Cations in Solutions under Ambient Conditions
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The tricoordinate form of organotin (R3Sn+) has been prepared under ambient conditions in a variety of nonnucleophilic solvents.
- Lambert, Joseph B.,Kuhlmann, Barbara
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p. 931 - 932
(2007/10/02)
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- Synthesis and structure of organotin complexes of ytterbium
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Reactions of Ph3SnCl, PhSnCl3 and Ph3SnSnPh3 with ytterbium in THF lead to the formation of the complex (Ph3Sn)2Yb(THF)4 (1) in high yields.According to X-ray data, tin atoms in complex 1 are covalently bonded with the ytterbium atom.Ionic organotin compl
- Bochkarev, Leonid N.,Grachev, Oleg V.,Ziltsov, Sergey F.,Zakharov, Lev N.,Struchkov, Yury T.
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p. 299 - 311
(2007/10/02)
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- Synthesis and structure of bimetallic allyl, alkoxysilyl complexes [Fe{Si(OMe)3}(CO)3(μ-dppm)M(η3-2-RC 3H4)] (M = Pd, Pt; R = H, Me) and of [Fe{μ-Si(OMe)2(OMe)}(CO)3(μdppm)Pd(SnPh 3)], a Sn-Pd-Fe-Si chain complex with a μ2-η2-SiO bridge
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The bimetallic allyl, alkoxysilyl complexes [Fe{Si(OMe)3}(CO)3(μ-dppm)M(η3-2-RC 3H4)] (M = Pd, R = Me, 2a; M = Pd, R = H, 2b; M = Pt, R = H, 3) have been prepared from the iron metalate [Fe{Si(OMe)3}-(CO)3(η1-dppm)]-, in which the dppm ligand helps in assembling and stabilizing the dinuclear unit. The crystal structure of 2a was determined by X-ray diffraction (Fe-Pd = 269.94 (7) pm). Reaction of 2a with HSnPh3 afforded [Fe{μ-Si(OMe)2(OMe)}(CO)3(μ-dppm)Pd(SnPh 3)] (4a), the first Sn-Pd-Fe-Si chain complex, in which the presence of an unusual μ2-η2-SiO bridge between the Fe and Pd atoms was established by X-ray diffraction (Fe-Pd = 266.55 (5), Sn-Pd = 259.50 (4), Pd-O(4) = 216.5 (2) pm). The lability of the O→Pd bond accounts for the dynamic behavior of the alkoxysilyl ligand, evidenced by variable-temperature 1H NMR spectroscopy, which renders the methoxy protons equivalent above 313 K (ΔG? ≈ 65 ± 2 kJ/mol).
- Braunstein, Pierre,Knorr, Michael,Piana, Hermann,Schubert, Ulrich
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p. 828 - 831
(2008/10/08)
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- Intramolecular O→Sn coordination in (Z)-17-[2-(triphenylstannyl)vinyl]-4-estren-17-ol: Evidence by X-ray diffraction analysis and iodo demetalation
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The synthesis and properties of (Z)-17-[2-(triphenylstannyl)vinyl]-4-estren-17-ol (1) are described. Compound 1 crystallizes in the orthorhombic space group P212121 (Z = 4) with a = 8.007 (2) ?, b = 15.152 (1) ?, and c = 26.807 (2) ?. The X-ray diffraction analysis of this compound shows the presence of an intramolecular coordination to the tin atom giving rise to a five-membered ring in which the metal exhibits a distorted-trigonal-bipyramidal geometry; as a consequence, a phenyl group, probably the apical one, is cleaved more easily by iodine than the vinyl substituent.
- Pan, Huade,Willem, Rudolph,Meunier-Piret, Jacqueline,Gielen, Marcel
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p. 2199 - 2201
(2008/10/08)
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- Organotin Biocides. XIII. C-Triorganostannylimidazoles, -benzoxazoles and -benzothiazoles
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The synthesis, spectroscopic characterisation, and reactivity of a series of triorganotin imidazoles, benzothiazoles and benzoxazoles R3Sn(Het) (R=Me, Bu, Ph) are described.The structure of 2-(triphenylstannyl)benzothiazole has been determined by crystallographic methods.Space group: Triclinic, P1; a 9.501(1), b 10.172(2), c 13.231(2) Angstroem, β 70.46(1), γ 69.71(1) deg, U 1082.8 Angstroem3, F(000)=484, μ(Mo-Kα) 11.74 cm-1, R=0.0719 for 2264 reflections with I>3?I.The geometry at the tin is tetrahedral.Bond angles at tin are used to discuss the reactivity and Moessbauer spectra of these species.
- Molloy, Kieran C.,Waterfield, Philip C.,Mahon, Mary F.
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- Metal to ligand charge-transfer photochemistry of metal-metal bonded complexes. 5. ESR spectra of stable rhenium-α-diimine and spin-trapped manganese-α-diimine radicals
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Irradiation (λ ≥ 320 nm) of (CO)5MM′(CO)3L and Ph3SnM′(CO)3L (M, M′ = Mn, Re; L = α-diimine = 2,2′-bipyridine, 1,10-phenanthroline, pyridine-2-carbaldehyde imine, and 1,4-diaza-1,3-butadiene) leads to homolysis of the metal-metal bond yielding fairly stable solvated radicals SM′(CO)3L?. These paramagnetic species have been studied by ESR spectroscopy in solution directly or by using nitroso-2,2-dimethylpropane as a spin-trapping reagent. The ESR spectra show extensive hyperfine splittings of the unpaired electron with the nuclei 14N, 1H, and 55Mn or 185,187Re. From the observed and computer-simulated coupling constants important information could be derived about the electronic structure of the singly occupied molecular orbital (SOMO). After in situ addition of P(OPh)3, P(OMe)3, or pyridine (= L′) to Re(CO)3(t-Bu-DAB)?, the new paramagnetic adducts axial-(L′)Re(CO)3(t-Bu-DAB)? could be identified.
- Andréa, Ronald R.,De Lange, Wim G. J.,Van Der Graaf, Tim,Rijkhoff, Marcel,Stufkens, Derk J.,Oskam, Ad
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p. 1100 - 1106
(2008/10/08)
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- UEBER 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-ABSTAENDEN
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Reaction of Ph3SnLi with Ph2SiCl2 or Ph2GeCl2 at -78 deg 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) deg, and a central C3Sn-SiC2-SnC3 molecular skeleton with symmetry close to C2.The geminal NMR coupling 2J(119 Sn...119 Sn) 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).
- Adams, Stefan,Draeger, Martin
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- Stereochemistries and mechanisms of reactions of electrophiles with organotin compounds
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The effect of solvent and electrophile on halodemetalation reactions of carbon-tin bonds has been investigated. Both stereochemical results and 119Sn NMR have been used as mechanistic probes. The effect of solvent is extreme; reactions performed in polar solvents such as acetonitrile and dimethylformamide yield cleavage products with predominantly inversion of configuration, whereas nonpolar solvents yield products with predominantly retention. Polar-aprotic solvents appear to be highly efficient in promoting inversion stereochemistry. Polar-protic solvents are not as efficient. This is explained in terms of some very specific solvation phenomena. Also, 119Sn NMR studies of several trialkyltin halides in various solvents show that these specific solvation phenomena can be qualitatively assessed. The nature of the electrophile also plays an important role in eventual stereochemistry; Br2, I2, ICl, and IBr are compared and discussed.
- Fukuto, Jon M.,Newman, David A.,Jensen, Frederick R.
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p. 415 - 420
(2008/10/08)
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- Reduction of bis(triorganotin) oxides by metals: An easy route to hexaorganoditins
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Bis(triorganotin) oxides have been reduced in high yield to hexaorganoditins by titanium, magnesium, potassium, and sodium.
- Jousseaume, Bernard,Chanson, Evelyne,Pereyre, Michel
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p. 1271 - 1272
(2008/10/08)
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- LASER-PHOTOLYSIS STUDY OF ARYL-SUBSTITUTED SILYL AND STANNYL ANIONS
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Photochemical primary processes of aryl-substituted silyl and stannyl anions were studied at room temperature.The silyl and stannyl radicals generated were observed directly by laser-photolysis.
- Mochida, Kunio,Wakasa, Masanobu,Sakaguchi, Yoshio,Hayashi, Hisaharu
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p. 773 - 776
(2007/10/02)
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