1064-10-4Relevant articles and documents
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]
Braunstein, Pierre,Clerc, Guislaine,Morise, Xavier
, p. 5036 - 5043 (2001)
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.
Electrochemical Formation of Dimeric Organostannyl Compounds
Ishiwata, Toyoaki,Nonaka, Tsutomu,Umezawa, Masanobu
, p. 1631 - 1634 (1994)
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.
Reactivity of heterobimetallic alkoxysilyl and siloxy complexes in the catalytic dehydrogenative coupling of tin hydrides
Braunstein, Pierre,Morise, Xavier
, p. 540 - 550 (1998)
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.
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Stern,Becker
, p. 4052 (1962)
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Europium complexes with 1,2-bis(arylimino)acenaphthenes: A search for redox isomers
Fedushkin,Skatova,Yambulatov,Cherkasov,Demeshko
, p. 38 - 43 (2015)
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.
Lorenz, D. H.,Becker, E. I.
, p. 1707 - 1708 (1963)
Direct Observation of Stannyl Radicals by Laser-Photolysis of Carbon-Tin and Tin-Tin Bonds
Mochida, Kunio,Wakasa, Masanobu,Sakaguchi, Yoshio,Hayashi, Hisaharu
, p. 1793 - 1796 (1986)
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.
Reversible switching of coordination mode of ansa bis(Amidinate) ligand in ytterbium complexes driven by oxidation state of the metal atom
Tolpygin, Aleksei O.,Cherkasov, Anton V.,Fukin, Georgii K.,Trifonov, Alexander A.
, p. 1537 - 1543 (2014)
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.
A highly efficient reduction of group 14 heteroatom-chlorine single bonds by using samarium diiodide-mediated reaction systems
Kamiya, Ikuyo,Iida, Koichiro,Harato, Nami,Li, Zhi-Fang,Tomisaka, Yuri,Ogawa, Akiya
, p. 437 - 440 (2006)
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.
Syntheses and structures of 3-stannylcholest-5-ene species
Buchanan, Heather J.,Cox, Philip J.,Doidge-Harrison, Solange M. S. V.,Howie, R. Alan,Jaspars, Marcel,Wardell, James L.
, p. 3657 - 3664 (1997)
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°].
Synthesis, structure and bonding of a digold complex with bridging triphenylstannyl ligands
Adams, Richard D.,Wong, Yuen Onn,Zhang, Qiang
, p. 40 - 44 (2015)
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.
THE REACTIONS OF DIBORANE WITH ARYL-ORGANOTIN COMPOUNDS
Pickles, G. M.,Spencer, T.,Thorpe, F. G.,Chopa, A. B.,Podesta, J. C.
, p. 7 - 16 (1984)
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.
Samarium and ytterbium complexes based on sterically hindered 1,2-bis(imino)acenaphthene*
Baranov, E. V.,Fedushkin, I. L.,Lukina, D. A.,Moskalev, M. V.,Skatova, A. A.,Sokolov, V. G.
, p. 2119 - 2129 (2022/01/22)
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.
To Rearrange or not to Rearrange: Reactivity of NHCs towards Chloro- and Hydrostannanes R2SnCl2(R = Me, Ph) and Ph3SnH
Schneider, Heidi,Krahfu?, Mirjam J.,Radius, Udo
, p. 1282 - 1286 (2016/11/23)
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.
