591-51-5Relevant articles and documents
Lithium Hexaphenylrhodate(III) and-Iridate(III): Structure in the Solid State and in Solution
Iwasaki, Takanori,Hirooka, Yuko,Takaya, Hikaru,Honma, Tetsuo,Nozaki, Kyoko
, p. 2489 - 2495 (2021)
Anionic homoleptic organo-Transition metal complexes can be prepared from organolithium reagents and transition metal salts and are key reactive intermediates in C-C bond formation. However, the interaction between the anionic component and cationic counterparts of multianionic homoleptic organo-Transition metal complexes in solution remains unclear, unlike well-studied monoanionic complexes such as organocuprates. Here we have prepared and structurally characterized lithium hexaphenylrhodate(III) and-iridate(III) complexes, [Li(12-crown-4)2][MPh6{Li(thf)}2] (M = Rh and Ir), as the first examples of hexaaryl complexes of d6 metals. In the crystals, two Li cations contact the trianionic MPh6 moiety, while the other exists as a solvent-separated ion pair. In THF, hexaphenylrhodate decomposed within 1 h. In contrast, the Ir analog was stable. 7Li NMR and X-ray absorption fine structure analysis revealed the solution-phase structure of hexaphenyliridate, which maintained a partially contacted ion pair structure even in THF, a coordinating solvent.
CETONES PYRIDINIQUES. VIII. METALLATION REGIOSELECTIVE DE LA s-COLLIDINE: EFFETS DE METAUX ET DE SOLVANTS
Compagnon, P.-L.,Kimny, Tan
, p. 297 - 308 (1980)
The regioselective metalation of s-collidine yielding two anions, trapped by PhCN, was found to be essentially determined by the solvent and the size of the cation: twelve solvents and three cations (Li+, Na+, K+) were examined.The effect of various bases (alkali metals, phenyllithium, amides, "complex bases", amines) and of some metallic cations (Li+, Ag+, Pd2+) was studied.The solvent basicity was not responsible for the regioselectivity.
The Anionic Pathway in the Nickel-Catalysed Cross-Coupling of Aryl Ethers
Borys, Andryj M.,Hevia, Eva
supporting information, p. 24659 - 24667 (2021/10/20)
The Ni-catalysed cross-coupling of aryl ethers is a powerful method to forge new C?C and C?heteroatom bonds. However, the inert C(sp2)?O bond means that a canonical mechanism that relies on the oxidative addition of the aryl ether to a Ni0 centre is thermodynamically and kinetically unfavourable, which suggests that alternative mechanisms may be involved. Here, we provide spectroscopic and structural insights into the anionic pathway, which relies on the formation of electron-rich hetero-bimetallic nickelates by adding organometallic nucleophiles to a Ni0 centre. Assessing the rich co-complexation chemistry between Ni(COD)2 and PhLi has led to the structures and solution-state chemistry of a diverse family of catalytically competent lithium nickelates being unveiled. In addition, we demonstrate dramatic solvent and donor effects, which suggest that the cooperative activation of the aryl ether substrate by Ni0-ate complexes plays a key role in the catalytic cycle.
Phenylchromium(III) Chemistry Revisited 100 Years after Franz Hein (Part II): From LinCrPh3+ n(thf)x(n = 1, 2, 3) to Dimeric Triphenylchromate(II) Complexes
Fischer, Reinald,G?rls, Helmar,Suxdorf, Regina,Westerhausen, Matthias
, p. 3892 - 3905 (2020/11/13)
Polyphenylchromium(III) organometallics with various phenylation degrees and stabilized by diverse Lewis bases with various donor strengths and denticity were investigated in order to better understand the formation of (η6-arene)chromium complexes according to the procedure of Franz Hein (1892-1976) [ Organometallics 2019, 38, 498-511, DOI: 10.1021/acs.organomet.8b00811]. Part II focuses on hexa-, penta-, and tetraphenylchromates(III). Chromium(III) compounds with a lower phenylation degree will be discussed in a future part III. The numbering scheme of the complexes relates to the number of Cr-bound phenyl substituents. Hexaphenylchromate(III): The reaction of Ph3Cr(thf)3·0.25dx (3) (dx = 1,4-dioxane) with an ethereal solution of phenyllithium yields yellow-orange [Li3CrPh6(thf)2.3(OEt2)0.7] (6-thf-OEt2) which slowly degrades in contact with the reaction solution leading to emerald-green crystals of [{(Et2O)Li}2Ph3Cr(μ-O)]2 (3-Li2O). Pentaphenylchromate(III): Compound 6-thf-OEt2 reacts with 1 equiv of HCl-OEt2 solution to turquoise [{(thf)2Li}{(Et2O)Li}CrPh5] (5-thf-OEt2) that reacts with THF to the green contact ion pair [{(thf)2Li}2CrPh5] (5-thf) and with 12-crown-4 (12C4) to the light green solvent-separated ion pair [(12C4)Li(thf)]2 [CrPh5] (5-thf-12C4). Refluxing of 5-thf-OEt2 in diethyl ether leads to ether degradation and formation of 3-Li2O, whereas 5-thf-12C4 liberates biphenyl under similar reaction conditions. Tetraphenylchromate(III): The reaction of 3 with 1 equiv of phenyllithium in THF leads to a green reaction mixture. At -50 °C, red [(thf)4Li] [cis-(thf)2CrPh4]·2THF (4-thf) crystallizes which reversibly transforms into a green oil above -50 °C. Upon acidolysis of 5-thf-OEt2 with 1 equiv of HCl-OEt2 at -20 °C, the intermediately formed red complex is reduced to the dinuclear chromate(II) [{(thf)Li}CrPh3]2 (3-CrII-thf) (Cr-Cr 187.66(8) pm). Recrystallization of this product from THF yields solvent-separated [(thf)4Li]2 [(CrPh3)2] (3-CrII-thf4) with a Cr-Cr quadruple bond (Cr-Cr 183.7(2) pm) without contacts between the lithium ions and Cr-bound phenyl groups. Complex 3-CrII-thf reacts at room temperature in diethyl ether to the sandwich complexes bis(biphenyl)chromium(0) [(η6-Ph2)2Cr0] (π-4) and benzene-biphenylchromium(0) [(η6-C6H6)(η6-Ph2)Cr0] (π-3). Compounds in bold letters are authenticated by X-ray structure determinations.
Generation of Phosphonium Sites on Sulfated Zirconium Oxide: Relationship to Br?nsted Acid Strength of Surface -OH Sites
Rodriguez, Jessica,Culver, Damien B.,Conley, Matthew P.
supporting information, p. 1484 - 1488 (2019/01/25)
The reaction of (tBu)2ArP (1a-h), where the para position of the Ar group contains electron-donating or electron-withdrawing groups, with sulfated zirconium oxide partially dehydroxylated at 300 °C (SZO300) forms [(tBu)2ArPH][SZO300] (2a-h). The equilibrium binding constants of 1a-h to SZO300 are related to the pKa of [(tBu)2ArPH]; R3P that form less acidic phosphoniums (high pKa values) bind stronger to SZO300 than R3P that form more acidic phosphoniums (low pKa values). These studies show that Br?nsted acid sites on the surface of SZO300 are not superacidic.
Dichotomy within 1,4-addition of organolithium and Grignard reagents to α,β-unsaturated Fischer alkoxycarbenes: A new synthesis of Fischer carbenes
Tobrman, Tomá?,Polák, Peter,?ubiňák, Marek,Dvo?áková, Hana,Dvo?ák, Dalimil
, p. 2175 - 2181 (2019/03/05)
The reaction of organolithium and Grignard reagents with pentacarbonyl[(ethoxy)(2-phenylethenyl)carbene]chromium(0) gave, after the quenching of the initially formed product of the 1,4-addition, different products depending on the organometallic and quenching reagents used. The addition of organolithiums, followed by a work-up with acid (AcOH or HCl), afforded the corresponding carbene complexes. In contrast, quenching the reaction mixture with ethanol led to the stereoselective formation of (Z)-enol ethers. The usage of Grignard reagents led to the formation of the carbene complexes regardless of which quenching reagent was used.
Synthetic, structural and reaction chemistry of N-heterocyclic germylene and stannylene compounds featuring: N -boryl substituents
Kristinsdóttir, Lilja,Oldroyd, Nicola L.,Grabiner, Rachel,Knights, Alastair W.,Heilmann, Andreas,Protchenko, Andrey V.,Niu, Haoyu,Kolychev, Eugene L.,Campos, Jesús,Hicks, Jamie,Christensen, Kirsten E.,Aldridge, Simon
supporting information, p. 11951 - 11960 (2019/08/14)
This study details the syntheses of N-heterocyclic germylenes and stannylenes featuring diazaborolyl groups, {(HCDippN)2B} (Dipp = 2,6-iPr2C6H3), as both of the N-bound substituents, with a view to generating electron rich and sterically protected metal centres. The energies of their key frontier orbitals-the group 14-centred lone pair and orthogonal pπ-orbital (typically the HOMO-2 and LUMO) have been probed by DFT calculations and compared with a related acyclic analogue, revealing (in the case of the stannylenes) a correlation with the measured 119Sn chemical shifts. The reactivity of the germylene systems towards oxygen atom transfer agents has been examined, with 2:1 reaction stoichiometries being observed for both Me3NO and pyridine N-oxide, leading to the formation of products thought to be derived from the activation of C-H bonds by a transient first-formed germanone.
Systematic synthesis and crystal structures of tetraaryltellurium compounds Ar4TeIV
Kobayashi, Sho,Sugamata, Koh,Minoura, Mao
supporting information, p. 661 - 663 (2019/04/05)
Hypervalent tetraaryltellurium(IV) compounds of the type Ar4TeIV(1: Ar = C6H5; 2: Ar = p-H3CC6H4; 3: Ar = p-t-BuC6H4; 4: Ar = p-F3CC6H4) were prepared via a convenient one-pot reaction between the isolated corresponding ArLi reagent and TeCl4. X-ray crystallographic analyses of 14 revealed distorted pseudo-trigonal-bipyramidal (TBP) structures for Ar4Te and the TBP character was analyzed by the dihedral angle method.
Preparation method of phenyl lithium
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Paragraph 0031-0034; 0037; 0038; 0040; 0041; 0043; 0044, (2018/04/03)
The invention discloses a preparation method of phenyl lithium. The method comprises the following steps of (1) under the protection of inert gas, feeding natrium-lithium alloy and n-butyl ether intoa system; performing stirring to obtain a natrium-lithium alloy dispersion solution; (2) under the condition of 10 to 30 DEG C, dripping bromobenzene into the obtained natrium-lithium alloy dispersionsolution obtained in the step (1) under the stirring condition; controlling the system temperature to be 10 to 30 DEG C; after the dripping is completed, performing heat insulation reaction; performing treatment to obtain a phenyl lithium solution. The n-butyl ether is used for replacing the conventional diethyl ether or diethyl ether-phenyl mixed solution; the reaction temperature is strictly controlled, so that the reaction is successfully triggered; the product purity is high; the industrial scaled production of the phenyl lithium is realized.
A Zinc Catalyzed C(sp3)?C(sp2) Suzuki–Miyaura Cross-Coupling Reaction Mediated by Aryl-Zincates
Procter, Richard J.,Dunsford, Jay J.,Rushworth, Philip J.,Hulcoop, David G.,Layfield, Richard A.,Ingleson, Michael J.
supporting information, p. 15889 - 15893 (2017/10/24)
The Suzuki–Miyaura (SM) reaction is one of the most important methods for C?C bond formation in chemical synthesis. In this communication, we show for the first time that the low toxicity, inexpensive element zinc is able to catalyze SM reactions. The cross-coupling of benzyl bromides with aryl borates is catalyzed by ZnBr2, in a process that is free from added ligand, and is compatible with a range of functionalized benzyl bromides and arylboronic acid pinacol esters. Initial mechanistic investigations indicate that the selective in situ formation of triaryl zincates is crucial to promote selective cross-coupling reactivity, which is facilitated by employing an arylborate of optimal nucleophilicity.
