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.
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.
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.