1064-10-4Relevant academic research and scientific papers
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.
Synthesis of organotin derivatives of optically active eleven-membered macrodiolides
Scoccia, Jimena,Gerbino, Darío César,Podestá, Julio César
, p. 352 - 360 (2016)
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.
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.
Formation and Decay of Radical Anions of Aromatic Compounds Produced by Photoinduced Electron Transfer from the Triphenylstannyl Anion
Aruga, Tamotsu,Ito, Osamu,Matsuda, Minoru
, p. 2950 - 2953 (1982)
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.
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.
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.
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.
Reaction of a 2,4,6-triphenylphosphinine ferrate anion with electrophiles: A new route to phosphacyclohexadienyl complexes
Hoidn, Christian M.,Wolf, Robert
, p. 8875 - 8884 (2016)
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.
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.
Single Electron Delivery to Lewis Pairs: An Avenue to Anions by Small Molecule Activation
Liu, Liu Leo,Cao, Levy L.,Shao, Yue,Stephan, Douglas W.
, p. 10062 - 10071 (2017)
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.
